Hurricane Dean

[HAltschule]

The GFS model...which was dead on right earlier in the season this far out, now has progged what looks to be a major hurricane making landfall along the East Coast. This afternoon's run brings onshore over Charleston, SC.

While the proposed landfall location has changed drastically over the past couple of days, the intensity still looks very significant. The GFS has shown this for about 5 days straight now and 2 days ago had an "Andrew" looking storm striling the Miami/Homestead area. While it is very far out still out, I am making any bets just yet. BTW...the model also shows a 2nd tropical system fast on its heels a few days later.

But persistence of the model runs could make it very interesting in another 11-16 days from now :eek:

[rdale]

It also had a major east coast system about a week ago that never materialized, and developed a hurricane off of Florida that was supposed to happen this week...

[John Peters]

Latest run brings it up the eastern seaboard into Maine/Nova Scotia.

[rdale]

It could happen... tomorrow?

[Jim Bishop]

The GFS model...which was dead on right earlier in the season this far out

I recall it advertising a couple different times a hurricane over the Eastern Atlantic in the past few weeks that never materialized. When was it dead on right?

I will say this. The GFS has been REMARKABLY concistant for (I believe) five days now in advertising a tropical system to develop this weekend over the Eastern Atlantic. Furthermore it has had support from the Canadian for a couple days as well as the GFS Ensemble, and today NOGAPS and the UKMET are at least advertising lowered pressures. The Euro jumped on board too.

This will be a home run for the GFS if a tropical system does indeed develop this weekend.

[Bob Schafer]

It's interesting, yeah. Today's 18Z run places it E of FL/GA at 252 hours (070820/06Z), and then it skirts the E coast to become sub-trop.

MSLP only 999mb. How is GFS at trop storm pressures? Anyway, SST's are pushing 30C in that area now, so depending on shear we could well see something deeper than that.... if we get anything at all, LOL.

[HAltschule]

I recall it advertising a couple different times a hurricane over the Eastern Atlantic in the past few weeks that never materialized. When was it dead on right?

http://www.stormtrack.org/forum/showthread.php?t=12564

[Jim Leonard]

I think the system the models are keying on is the complex low and convection thats about to come off the African coast at the moment, we'll have to see if the is the real thing. The center is down at about 9N so it should come off the coast and develop further.

[Doug_Kiesling]

It could happen... tomorrow?

BAHAHAHAHA yeah, it could happen... Just like the major system that the GFDL had for a system that was suppose to hit Central America over a week ago.

I seem to recall the hype of May 2006 that last year was going to be the "SEASON OF DOOM BUT WATCH US TO STAY ALIVE..." and the "GLOBAL WARMING IS MAKING HURRICANES BIGGER...

Then what happened? Um, not much hit the United States and it was pretty much a normal hurricane season with some storms that hit the fish and shipping lanes.

Yes the latest computer models show something brewing but how many times has SPC Day 1 said something was brewing and then it turned out to be a bust? I'm not buying the models this year since they have been way off on a lot of the forecasts in general.

[Stuart Robinson]

For example.... look at the current CMC model run

Big Hurricane in the GOM within the next 5 days...

http://moe.met.fsu.edu/cgi-bin/cmctc2.cgi?time=2007081000&field=Sea+Level+Pressure&hour=Animation (http://moe.met.fsu.edu/cgi-bin/cmctc2.cgi?time=2007081000&field=Sea+Level+Pressure&hour=Animation)

[Jim Bishop]

BAHAHAHAHA yeah, it could happen... Just like the major system that the GFDL had for a system that was suppose to hit Central America over a week ago.

I seem to recall the hype of May 2006 that last year was going to be the "SEASON OF DOOM BUT WATCH US TO STAY ALIVE..." and the "GLOBAL WARMING IS MAKING HURRICANES BIGGER...

Then what happened? Um, not much hit the United States and it was pretty much a normal hurricane season with some storms that hit the fish and shipping lanes.

Yes the latest computer models show something brewing but how many times has SPC Day 1 said something was brewing and then it turned out to be a bust? I'm not buying the models this year since they have been way off on a lot of the forecasts in general.

Last year El Nino developed around this time, increasing the wind shear and effectively dampening the season. (I agree there was a lot of over hype coming off the 2005 season).

NOW La Nina is developing. Huge difference. Plus, the Indian monsoon season has been incredible, which is currently helping the African wave train.

As far as the computer models, having the American, European & Canadian global models concistently forecast tropical systems is, at the very least, these models tellings us the hurricane season about to get going in the next week or so.

This year is quite interesting because most people simply do not believe this hurricane season will amount to anything. Let's see what people think in about one month.

Cheers

[Jim Bishop]

http://www.stormtrack.org/forum/showthread.php?t=12564

I wasn't aware the GFS forecast that so far in advance, wow. Gives me more reason to believe it's Eastern Atlantic wave development coming up here in the next few days.

[HAltschule]

I wasn't aware the GFS forecast that so far in advance, wow. Gives me more reason to believe it's Eastern Atlantic wave development coming up here in the next few days.

Yes...the GFS Operational model located at this link goes out to 360 hours. http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/

Incidentally, this mornings 6z run still has a MAJOR hurricane approaching the bahamas and East Coast Florida..then taking a hook north and out to sea BEFORE making landfall. Of course lots will change...but it's still interesting to see the GFS consistency.

[Bob Schafer]

...this mornings 6z run still has a MAJOR hurricane approaching the bahamas and East Coast Florida

Howie, with all due respect, you keep saying "MAJOR" hurricane, but the (same) 6Z GFS run this morning progs a central pressure in the 980's at 288 hours:

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/06/images/gfs_ten_288l.gif

That, of course, would be unlikely to be a major 'cane. Do you have some other reason to believe cat3 or higher should be expected attm?

[cdcollura]

Good day all,

One MAJOR thing to consider with the models is the SCALE of an "expected" weather system.

Jet-Stream flow and troughs are very large (sometimes a trough is larger than half the USA). These are large scale patterns.

Smaller lows, such as MCV's and MCS type features are on the MEDIUM to small scale (mesoscale).

Things like dust devils, waterspouts, and tornadoes are of the microscale (smallest).

My point is that the smaller the scale, the more chaotic, complicated, and difficult to forecast / model it becomes.

Fortunately, tornadoes are produced by larger scale systems that they depend on (such as a trough), so forecasting them is "do-able" to some extent.

Hurricanes fall into the medium scale, and about 90% of the time, the models do not handle them well, with the GFS being the most successful, if you wish to call it "successful" for tropical systems.

Remember the storm Ernesto last year in 2006, how the models handle that one?

They (the models) had the storm OVER CUBA, and going from a 40 MPH storm to a 80-95 MPH hurricane hitting Florida. We (or most of us) know hurricanes do not strengthen over land, let alone mountains! Sure enough, with a hurricane warning, closures, and all the "hassles" uderway in FL, the storm came in as a 30 MPH depression.

Intensity / formation model forcasts for tropical systems are pretty much junk most of the time. Track forecasts, governed by steering flow (such as a trough on the east US coast causing a storm to recurve) are henerally MUCH more reliable.

[HAltschule]

Howie, with all due respect, you keep saying "MAJOR" hurricane, but the (same) 6Z GFS run this morning progs a central pressure in the 980's at 288 hours:

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/06/images/gfs_ten_288l.gif

That, of course, would be unlikely to be a major 'cane. Do you have some other reason to believe cat3 or higher should be expected attm?

Well, yes. Let me first clarify that if this does in indeed develop, this is my reasoning for a "Major" labelling. Now that we have a reoccurring system on numerous model runs, it has been my experience over the years that isobaric patterns and pressures on the GFS are almost always underdone and not idicative of the true strength of the system. All of the CAT 3+ storms that I have seen on the GFS have had similar presentations on the gridsand they have been Major Hurricanes. This is why I think it will be a major hurricane if it does indeed form.

[Jim Leonard]

One thing to remember that if you have a significant tropical showing up on most models in mid-August to mid-September and their holding on to it run to run through the ten day forecast time coming across from the eastern atlantic, also showing several isobars around it one could assume it will be a major hurricane. The models show little or no shear to deny major intensification. The sst's will be more than warm enough especially when any developed storm gets past 60W. Those two perameters should work together to make a storm in my opinion reach an intensity of 950Mb or lower if it comes to a position north of Puerto Rico like the gfs is indicating today.

[HAltschule]

One thing to remember that if you have a significant tropical showing up on most models in mid-August to mid-September and their holding on to it run to run through the ten day forecast time coming across from the eastern atlantic, also showing several isobars around it one could assume it will be a major hurricane. The models show little or no shear to deny major intensification. The sst's will be more than warm enough especially when any developed storm gets past 60W. Those two perameters should work together to make a storm in my opinion reach an intensity of 950Mb or lower if it comes to a position north of Puerto Rico like the gfs is indicating today.

Indeed. One thing very favorable are the very warm, so far undisturbed SST's.

[Doug_Kiesling]

Well if the model runs hold together after several days worth of runs, and something shows up on the sat that looks decent, then I might get excited and pay attention to them but right now, I'm really not trusting them 10 days out or even 5 days out.

Just look at the models from yesterday for todays setup in the upper midwest compaired to what is really happening right now. Even the Day1 has changed so much that I'm sitting at home thanking the lord that I did not get suckered into driving 300 miles to find out it moved another 250 miles west.

I just don't trust the models at all that far out and nobody can predict the future.

[HAltschule]

Hi Doug,

I do understand what you are saying and I also am somewhat skeptical on mid-range and long-range forecasts too. That said, the models have shown this monster for about 6 days now and that kind of consistency tends to make these events (or other synoptic scale events) more believable. Obviously if a storm occurred in another week, a 250 mile difference between the model forecast NOW and the verification position THEN doesn't mean diddly. The fact that it got it right within a 1000 square mile area would be impressive enough.

I don't think it's reasonable to compare the GFS model run's accuracy over a mid-range period to the SWOD1 being 250 miles off. Mesoscale processes affect the severe potential very differently than synoptic scale procceses do for the GFS runs.

[SteveCarter]

Normally I would just forget about any forecasts this far out, BUT like Jim L. said.....any time you get a solid system moving off the African coast in August/September, there COULD be something to look out for. The local weather forecast on T.V. tonight said to keep an eye on this system, or the one behind it. They said something about dry air being pulled into the first one, but still, it could be a major system. We'll see. Here in south Carolina, we desperately need the rain, and I'm desperately in need of "chasing" something! LOL

[Gene Moore]

Normally I would just forget about any forecasts this far out, BUT like Jim L. said.....any time you get a solid system moving off the African coast in August/September, there COULD be something to look out for.

I think this statement about the African coast is the key. Many of the phantom storms already forecast this season and one huge one last season came out of nothing real at the surface. At least this time there is a real storm now moving in the ITCZ east of Africa. I can only speculate it's this storm complex that the GFS is working its voodoo on. It makes more sense at this time to watch the actual cloud mass for development than get too wound up over the model. Perhaps one of the reasons it jumped on it so soon was the large size when it came off the coast, but this morning (afternoon there) it's not nearly so big.

The easterlies are strong this year but the ITCZ appears to be a bit further south than usual, thus leading the easterly waves into southern Mexico. There have been numerous convective outbursts that seem to die south of Cuba....in fact there is a very large one this mornig. Most of these don't make it into the Gulf of Mexico, the trajectory just seems wrong....any thoughts on that?

Gene

[Justin Bailey]

Its been so dry all summer up here in Tennessee, especially this month, that our forcasters in Nashville arealready talking about this system! we really could use the rain from the remnants of some sort of tropical system to help with the drought!


FORECAST DISCUSSIONNATIONAL WEATHER SERVICE NASHVILLE TN253 AM CDT SAT AUG 11 2007.DISCUSSION................BEYOND FRI...LOOKS LIKE THE SLGT CHC (http://www.srh.noaa.gov/fwd/glossary/def/chc.htm) OF RAIN WILL CONTINUE FOR SAT-MONAS LIGHT SELY (http://www.srh.noaa.gov/fwd/glossary/def/sely.htm)/SLY (http://www.srh.noaa.gov/fwd/glossary/def/sly.htm) FLOW CONTINUES. BEYOND MON...GFS (http://www.srh.noaa.gov/fwd/glossary/def/gfs.htm) BRINGS A SFC (http://www.srh.noaa.gov/fwd/glossary/def/sfc.htm)LOW OUT OF THE TROPICS AND TURNS IT NWD (http://www.srh.noaa.gov/fwd/glossary/def/nwd.htm). PREVIOUS RUN OF THE GFS (http://www.srh.noaa.gov/fwd/glossary/def/gfs.htm)BROUGHT IT THROUGH THE CARIBBEAN JUST SOUTH OF CUBA. CURRENT RUNBRINGS IT THROUGH THE SWRN ATLANTIC JUST NORTH AND EAST OF THE BAHAMAS.WELL SEE.

[HAltschule]

The local weather forecast on T.V. tonight said to keep an eye on this system, or the one behind it.


They must read Stormtrack ;)

[HAltschule]

A Sunday morning check of models shows the GFS bringing the system into Mexico in around 9 days, the Candian Model bringing it near St. Thomas and the northern V.I.'s in 120-144 hours. The GFDL has listed the system as invest 90i and has a CAT 3 hurricane knocking on the door of the northern and central Virgin Island in 126 hours. The HWRF is almost identical to the GFDL and also brings a CAT 3 hurricane to the same location in 126 hours.

I am very impressed with all of the model consistency this far out. All of this makes me 100% believe there will be a CAT 3 or higher hurricane in the Tropical Atlantic or Carribean in a few days. Next question is whether it hooks just to the north and heads toward FL or does it stay west (like the GFS says) and hit Houston, TX?

[Jim Leonard]

My thinking this morning that this system will probably be a compact "Charley" type hurricane size wise, as it approaches the Lesser Antilles later this coming week. It appears now there will be a solid zonal ridge across the atlantic this coming week or so, remember "Emily" 2005. The gfs track across the Caribbean into the southern GOM looks reasonable. If the storm were to reach the western Caribbean the warm ridge over the U.S. should keep it on a westerly heading.

[richhorodner]

30 years ago 84 hrs. was about as far as one could have any confidence in a GFS/Aviation (or any other model or prog) forecast of a general area or position of a tropical system. Today, it is about the same: Maybe 90 hrs. now, for a general area. And general area can even be just "what ocean, gulf or sea" the system will be in.

These mid range progs (3-15 days) should only be used as one source of
GUIDANCE in making a hurricane forecast; and that is limited to 3-5 days at best.

If one thinks the GFS plots of 4-16 days have any validity, a hurricane watch should now be issued from Brownsville, TX, to Augusta, Maine in the USA; and probably Nova Scotia and Vero Cruz, Mexico as well. The long range has gone frow a system hitting S. Florida, to NC, to New England, back to Florida, then to Mexico south of Texas, to Houston, and now back to NC and the mid Atlantic States. I need to board up my summer home on Martha's Vineyard, secure my yacht on S. Padre Island, and tie down my quadruple-wide trailer on Key Largo. Busy, busy, busy.

[Stuart Robinson]

I am sure that by now you will all know that Tropical Storm DEAN has formed...

[mcrowther]

We now have Dean- Position and track are now shifted south- this really puts Puerto Rico under the gun- the 06Z HWRF has the storm as a 920!!! mb monster just south of the island
:eek:

[John Peters]

We now have Dean- Position and track are now shifted south- this really puts Puerto Rico under the gun- the 06Z HWRF has the storm as a 920!!! mb monster just south of the island
:eek:

where are you viewing the most recent HWRF run?


Looks like today's GFS run still wants to bring the storm north toward the Carolinas..

[Terry Tyler]

i know it...

sure hope it goes into the gulf of mexico...

aint never seen a hurricane...and i got a freind down in columbia mississippi...she got tore up when katrina hit, and already said if a cane is coming i can go down there and use the house as a place to start from instead of coming all the way from mantachie...

[rdale]

So of the four hurricanes that the GFS developed in the last 5 days, one TD has developed... Not bad!

[MClarkson]

I like the lastest HWRF run... sub 900mb by day 5. Obviously thats not likely to happen, but I said the same thing when the GFDL progged wilma to sub 900 last year as well when it was still a baby. The lastest GFDL is a bit more modest at ~975 for Dean. Regardless, what the storm does intensity wise 1000 miles from the US isnt particularly relevant to our chasing prospects, as long as it stays alive. I'll keep my fingers crossed for a track closer to me, if it nears the US at all.

[John Peters]

gfs, hwrf, and gfdl now seem to agree on the westerly path into the Caribbean and across Jamaica. If I'm not mistaken, isn't the Caribbean less climatologically favorable at this point in the season as apposed to later on? Ocean temps appear to be in the 83-85 degree range... i find it highly unlikely that we will have a sub-900mb monster on our hands until the storm nears at least the western Caribbean and/or gulf (where temps are in the 85-87 degree range).

[MClarkson]

the GFS has been developing pretty solid poleward outflow, and I would like to see the SSTs up higher but solid outflow can make up for that. A track further north runs into slightly higher SSTs(according to unisys analysis) and maybe better outflow, which probably accounts for the more northerly HWRF being stronger than the GFDL.

[HAltschule]

"Dean" is the tropical system that the GFS had pegged as a major hurricane in the 12-14 day range...before it even existed as a blob moving off the African coast. THAT is impressive. As I mentioned previously, when the GFS has such strong signals and such a strong appearance in the model, there is a very good bet there will be something forming. Good job by the GFS and to those forecasters who nailed it early on!! And for the non-believers who dismiss everything tropical on the GFS as a bias, I don't know what to say except "told ya so". ;)

[Justin E. Reed]

I judt got back into JAX from vacation to see familty in TN. Hmm, I predict a landfall between Louisiana and NC, wide swath, but Im seriously thinkin this could be the start of the season. Most of us agreed this would be a late-bloomer season. I hope it rides the FL east coast, get me outta here again! J/K, but I hope it hits the CTRL GULF COAST. As bad as that sounds, it'd be about the ONLY way to get some rain into TN,AL,GA,MS and several other states. Its horribly bad there, lets hope and pray, yet, I see a major landfall.

[John Peters]

New runs for GFDL, HWRF, and GFS in. Looks like GFS and HWRF pretty much agree on something between an "Allen" and "Gilbert" type path that takes the storm across Jamaica at 918 mb (HWRF) and just north of the tip of the Yucatan into the gulf (possibly briefly onshore). GFDL has resolved an even more southerly path and continues to project more conservative strength estimates. GFS develops very nice outflow in the western Caribbean near the Yucatan, which would suggest further strengthening as the storm leaves Jamaica (corresponds to higher SSTs inthe western Caribbean).

As stated above, higher SSTs in the northern Caribbean probably explain the strength disagreement between GFDL and HWRF. Even with the northern track, i wouldn't expect a 918 mb cat 4 or 5 by Jamaica (GFS strengthens outflow and pressure gradient after Jamaica), though i could easily see a strong Cat 4/5 come ashore on the northern Yucatan.

This is my first season attempting to make use of computer models, so feel free to make any comments and/or correct any wrongful assumptions i have made.


Addition:
As of 11:00 AM AST pressure is down to 997 mb, sustained winds are up to 60 mph, and CDO is looking much more organized than earlier. We could very well be dealing with hurricane dean by the end of the day.

[rdale]

"Dean" is the tropical system that the GFS had pegged as a major hurricane in the 12-14 day range...before it even existed as a blob moving off the African coast. THAT is impressive.

It will be impressive if it happens - don't think you can verify a forecast before the event ;>

[cedwards]

Im seriously thinking this could be the start of the season. Most of us agreed this would be a late-bloomer season.

I don't think this is the start, OR a "late-bloomer season". We already have the "D" storm and possibly the "E" storm today, and it is only Mid-August. The peek of the season is a month away. typically, you will just be starting off now with the "A" storm.

I do think that Dean could pose a significant threat to the US, It is too early to tell where. The best of all possibilities (For the US) appears to be that it goes over Hispaniola and Cuba, weakens then hits Florida before it has time to re-strengthen. If it misses the islands, it could pose a significant threat to the Gulf coast.

[Jeff Piotrowski]

I would like to point out that if Dean reaches the Western Caribbean at 120 hrs based on HWRF and other models.
http://moe.met.fsu.edu/cgi-bin/hwrftc2.cgi?time=2007081506-dean04l&field=Sea+Level+Pressure&hour=Animation (http://moe.met.fsu.edu/cgi-bin/hwrftc2.cgi?time=2007081506-dean04l&field=Sea+Level+Pressure&hour=Animation)
This area has some of the deepest 26C water over 100-150 meters in that region.
]http://www.aoml.noaa.gov/phod/dataphod1/work/HHP/NEW/2007226d26.png (http://www.aoml.noaa.gov/phod/dataphod1/work/HHP/NEW/2007226d26.png)
This depth of the warm water can supper charge the hurricane as it moves into that region. The area from Jamaica, Grand Cayman, and Cancun will likely have to deal with a major hurricane next week.

[richhorodner]

I would like to point out that if Dean reaches the Western Caribbean at 120 hrs: This area has some of the deepest 26C water over 100-150 meters in that region.]
This depth of the warm water can supper (super?) charge the hurricane as it moves into that region.

Basically this is always the case in the Western Caribbean July-Sept. Climatology.

An added note on trajectory, which may or may not apply this time: large tropical circulations, especially in the intensifying mode, "tend" to move 5-10 degrees to the right of the percieved steering flow.

[mcrowther]

The chances of a U.S. landfall have lessened considerably- the strong ridge in the States combined with the ridge over the Atlantic should keep Dean on a WNW track quite close to Gilbert's path back in 1988. So if you want to chase this one, I suggest looking into tickets to the Yucutan...Jim L?:)

[Gregg Gallina]

On a side note...
Very interesting set up for potential volcanic eruption as well here with Dean. Soufriere Hills volcano, located on the Southern end of Montserrat is extremely unstable at the moment. Hvy rainfall events have lead to prior dome collapses in the past and with the forecast track, currently south of Mont. but already busted a bit north...who knows...this is about as good as you get to predicting a volcanic eruption ;) though I would never wish to do that forecast

Additionally, Volcano vs. TC Volcano wins, as proof, Mt. Pinatubo blew apart all circulation to TC Yunya in 1991. Though the scale of that eruption would dwarf anything by SH.

[John Massura]

Interesting, it's been awhile since I've heard mention of Soufriere Hills. Hi Gregg! :)

[John Peters]

On a side note...
Very interesting set up for potential volcanic eruption as well here with Dean. Soufriere Hills volcano, located on the Southern end of Montserrat is extremely unstable at the moment. Hvy rainfall events have lead to prior dome collapses in the past and with the forecast track, currently south of Mont. but already busted a bit north...who knows...this is about as good as you get to predicting a volcanic eruption ;) though I would never wish to do that forecast

Additionally, Volcano vs. TC Volcano wins, as proof, Mt. Pinatubo blew apart all circulation to TC Yunya in 1991. Though the scale of that eruption would dwarf anything by SH.

I think pinatubo ejected something like 6-8 cubic km of ash during it's 1991 eruption (compared to 1 cubic km in st. helens' 1980 eruption). It was the second largest volcanic eruption of the 20th century (1912 Novarupta eruption in Alaska was #1). Soufriere hills probably only belches out a few hundred thousand cubic meters when it goes off (most of which is probably in the form of pyroclastic flows).

I find it an amazing coincidence that pinatubo entered it's climactic phase while a typhone was making landfall.

Also, the ash column produced by pinatubo's eruption reached heights of 34km (over 110,000 feet!). Obviously that is much higher than any convection produced by tropical cyclones (or any weather phenomena for that matter)

Edit: HWRF and GFDL have backed down significantly on their strength estimates (mentioned in recent nhc forecast discussion). Any ideas on why this may be?

[MClarkson]

well the 18z GFDL doesnt appear much different than the previous model concensus, gradually taking the storm to ~950mb, probably a cat 3. It seems to be a bit too weak in the short term.


the 18z HWRF... I dont know why it possibly flip flopped like that and now refuses to develop the storm at all. The poleward outflow on day 4+ will be gone, but overall shear isnt bad. Considering on IR that the storm looks pretty decent, and might allready be a hurricane, I would toss this run. The 00z run is almost available... see if that changes.


EDIT: well the 00z hurricane runs are in and... there is no significant change from the 18z. The GFDL still keeps the storm a little weaker at first and then ~955mb for a yucatan landfall. HWRF still dissipates the system in the central carib. The GFDL seems to be resolving a front of sorts to the southwest of the storm which could be throwing off its internal dynamics and intensity for day ~2. Then again it might be on to something. We will see. The HWRF... just looks wrong. SHIPS model hasnt changed much either and still progs a very powerful storm.

[Stuart Robinson]

Dean was upgraded to a CAT1 hurricane in the 500 AM EDT update

The first Hurricane of the 2007 season.

[Justin Turcotte]

The TPC will be sending out the Gulfstream-IV this afternoon for a synoptic surveillance mission. This data will at the least improve initial 00z model conditions and perhaps give us a better idea where Howard Dean is gonna scream next.

Houston NWS isn't totally sold on a Gilbert type track just yet...

LONG RANGE PROGS STILL TRYING TO RESOLVE THE PATH OF DEAN BUT THERE ARE HINTS THAT A TUTT LOW WILL BE MOVING UNDER THE HIGH (SLIGHTLY NORTH/AHEAD OF DEAN) ACROSS THE GULF ON/ABOUT THIS SAME TIME. A BEAR WATCH REMAINS IN PLACE.

[John Peters]

Latest GFDL has progged a more "Allen" type track (north of yucatan) and is a little more aggressive in terms of strength projections. As of the 11:00 AM advisory, winds are up to 90 mph and pressure is down to 979 mb (yet HWRF still has the storm remaining below the hurricane threshold throughout the caribbean.

Satellite images show the storm steadily becoming more organized.

[Charles Kuster]

Dean continues to strengthen and outflow is looking more and more healthy in all quadrants.

Track is still uncertain, but the deep-layer ridge should steer Dean on a mostly westward track into the western Carribean. After that, I think Dean will take a more WNW track as it reaches the edge of the ridge. As of now, I think it will make a brief landfall in the northern Yucatan and then move towards the Texas coast. It is still too far out to be sure, but I like the guidance offered by the GFDL and the NOGAPS right now. :)

[MClarkson]

yes, the 06z GFDL has a very interesting track. 12z GFS still has the yucatan track. Recon is about to make its first pass, 100 miles out or so.

12z cane models are in... HWRF is back! <900mb and into the southern gulf. GFDL is further into the gulf and <920mb

[John Peters]

Reconnaissance aircraft confirmed 970 mb central pressure and 90 mph sustained winds (will probably increase soon in response to pressure drop). This thing is deepening fairly quickly.

Edit: I just nearly lost it after looking at the latest HWRF, which brings it ashore on the northern yucatan with at 887 mb!


GFDL puts it dead center of the gulf as a 913 mb cat 5 with winds of 159 kts, poised to make landfall somewhere in the western Gulf coast!

[aaron.burkham]

887 mb, whoa, thats pretty low.

[John Peters]

887 mb, whoa, thats pretty low.

Yeah, if (unlikely) dean did indeed achieve an 887 mb central pressure, it would become the second most intense tropical cyclone ever in the atlantic basin. IMO HWRF tends to underestimate central pressure though (model only corresponds 145 sustained winds). I think GFDL's 915-920ish, if not higher would be a more realistic outlook (considering climatology among other factors).


Edit: Winds now to 100 mph (cat 2) as of 5PM AST advisory. Pressure was fluctuating between 974 and 979 mb based on reconnaissance observations.

[aaron.burkham]

Im starting to see the track go slightly more to the north, im thinking it might only brush the Yucatan and weaken slightly before entering the gulf and then rapidly strengthen before landfall and quite possibly slow down,
thats my educated guess.

[John Peters]

One thing these models may not take into account is eyewall replacement cycles (correct me if i'm wrong). Dean's central circulation currently seems compact - when an eye develops it will probably be small with a tightly wound eyewall. It seems that storms that initially develop this very compact circulation quickly undergo an eyewall replacement cycle and develop a larger eye (Examples: Katrina, Wilma, Ivan).

[Brandon Clement]

The upper level low is going to make the decision for Dean. It crosses over Florida then heads across the Gulf before moving in by Houston, Texas. While that is going on Dean will be in the Carribean. 12z Monday seems to be the big point that will determine Dean's final landfall. The GFDL was showing a strong turn north at 12z the past few runs but has since come back towards the other models. I actually think the GFS has handled this thing incredibly and my money is still on the GFS despite that it is not one of the better tropical models. IMO Dean will not be able to maintain a forward speed over 25 all the way through the Yucatan. The Upper level low should have plenty of time to move on shore allowing High pressure from the West to push back in. I would expect Dean to cross the Yucatan then move just a little north of West before catching the SW portion of the High pressure and making a turn almost due West into Mexico.

I love chasing Hurricanes but there is no way I can root for a storm to hit anywhere near La. I hope this thing stays away from the populated cities, La and the oil rigs. The last thing the people along the Gulf Coast, our economy or gas prices need is a major Hurricane in the northern Gulf because all are too vulnerable right now.

The storm looked like it ingested some dry air earlier today and even though maximum winds and the core of the storm has continued to hold its own today I don't see it exploding into a major Hurricane just yet. Once the convection to the South of Dean gets wrapped or Dean finds a good inflow tail from the SE we will see it hover around cat 2 status. Once it moves off a little farther to the West and gets in the extremely warm Carribean waters and gets a larger core by wrapping the convection south of the main circulation Dean is going to go crazy. I think the HWRF and GFL are over doing the strength just a bit (especially the HWRF) but I do think this will be a major hurricane. Unless Dean can maintain speed and the upper level low can either slow down or deepen then I highly doubt we will see a US landfall, much less a direct hit to the Northern Gulf Coast. I wouldn't rule out a cat 5 or a US landfall but I do highly doubt it. IMO, the GFS had this thing pegged a couple days ago outside of a couple throw away runs.

My best guess (and it is exactly that) is about 100 miles south of Matamores, Mx as a Category 3.

[John Peters]

The upper level low is going to make the decision for Dean. It crosses over Florida then heads across the Gulf before moving in by Houston, Texas. While that is going on Dean will be in the Carribean. 12z Monday seems to be the big point that will determine Dean's final landfall. The GFDL was showing a strong turn north at 12z the past few runs but has since come back towards the other models. I actually think the GFS has handled this thing incredibly and my money is still on the GFS despite that it is not one of the better tropical models. IMO Dean will not be able to maintain a forward speed over 25 all the way through the Yucatan. The Upper level low should have plenty of time to move on shore allowing High pressure from the West to push back in. I would expect Dean to cross the Yucatan then move just a little north of West before catching the SW portion of the High pressure and making a turn almost due West into Mexico.

I love chasing Hurricanes but there is no way I can root for a storm to hit anywhere near La. I hope this thing stays away from the populated cities, La and the oil rigs. The last thing the people along the Gulf Coast, our economy or gas prices need is a major Hurricane in the northern Gulf because all are too vulnerable right now.

The storm looked like it ingested some dry air earlier today and even though maximum winds and the core of the storm has continued to hold its own today I don't see it exploding into a major Hurricane just yet. Once the convection to the South of Dean gets wrapped or Dean finds a good inflow tail from the SE we will see it hover around cat 2 status. Once it moves off a little farther to the West and gets in the extremely warm Carribean waters and gets a larger core by wrapping the convection south of the main circulation Dean is going to go crazy. I think the HWRF and GFL are over doing the strength just a bit (especially the HWRF) but I do think this will be a major hurricane. Unless Dean can maintain speed and the upper level low can either slow down or deepen then I highly doubt we will see a US landfall, much less a direct hit to the Northern Gulf Coast. I wouldn't rule out a cat 5 or a US landfall but I do highly doubt it. IMO, the GFS had this thing pegged a couple days ago outside of a couple throw away runs.

My best guess (and it is exactly that) is about 100 miles south of Matamores, Mx as a Category 3.

great post Brandon, i agree with your analysis :)

Recent runs seem to be favoring the full-blown Yucatan landfall rather than the "Allen" brush-by. I also think HWRF and GFDL are overestimating landfall intensity, though I wouldn't rule out a cat 4 landfall just yet. Dean will have a good deal of higher SSTs and likely decent outflow between Jamaica and the Yucatan.

As for the US/Gulf, we will almost certainly dodge the bullet if the storm makes a more southerly landfall and has more distance to dissipate over land. The further north this thing goes, the stronger it is going to be as it emerges into the warm Gulf waters - the less of a turn to the N it is going to need to make a US landfall.

My *rough* estimates would be: 110mph as it enters the Caribbean, 115-125 mph across Jamaica, and then 135-155 onto the Yucatan.

[Brandon Clement]

great post Brandon, i agree with your analysis :)

Recent runs seem to be favoring the full-blown Yucatan landfall rather than the "Allen" brush-by. I also think HWRF and GFDL are overestimating landfall intensity, though I wouldn't rule out a cat 4 landfall just yet. Dean will have a good deal of higher SSTs and likely decent outflow between Jamaica and the Yucatan.

As for the US/Gulf, we will almost certainly dodge the bullet if the storm makes a more southerly landfall and has more distance to dissipate over land. The further north this thing goes, the stronger it is going to be as it emerges into the warm Gulf waters - the less of a turn to the N it is going to need to make a US landfall.

My *rough* estimates would be: 110mph as it enters the Caribbean, 115-125 mph across Jamaica, and then 135-155 onto the Yucatan.

I am not ruling out a cat 4 landfall by any means. I actually think a strong 4 is a good chance when it hits the Yucatan. I also think it could easily get back to a 4 in the Gulf but I said 3 just because most major hurricanes weaken some just before landfall. I'm not sure this holds up as well along the Mexico coast as well as it does along the La/Ms coast and the forward motion of Dean wont give much time to weaken before landfall.

Again, this is a long way out and usually the safest place you could be 5+ days out is where the GFS is predicting landfall but I am really confident in the GFS being pretty close for Dean.

[Blake Michaleski]

I was wondering how much tropical chatter would have to take place to get Brandon talking...:D

As Brandon mentioned, I love chasing 'canes we sure don't need one on the upper gulf coast... Mobile is still recovering as is the MS Coast. There are places in teh FL panhandle that are still recovering from Ivan.

With the oil refinery fire in Pascagoula today and fear over this storm, we're already going to see prices rise some tomorrow. Then if Dean decided to take a more northerly track we'll be hurting bad with teh gas prices.

[Jeff Snyder]

I am not ruling out a cat 4 landfall by any means. I actually think a strong 4 is a good chance when it hits the Yucatan. I also think it could easily get back to a 4 in the Gulf but I said 3 just because most major hurricanes weaken some just before landfall. I'm not sure this holds up as well along the Mexico coast as well as it does along the La/Ms coast and the forward motion of Dean wont give much time to weaken before landfall.

Again, this is a long way out and usually the safest place you could be 5+ days out is where the GFS is predicting landfall but I am really confident in the GFS being pretty close for Dean.

I seem to remember a lot more hurricanes that are severely interrupted (inner core disrputions) as they cross the Yucatan and are unable to regain their strength than otherwise. There are many cases of storms crossing smaller land masses (e.g. Cuba) and reintensifying quickly thereafter (e.g. Dennis in 2005), but I can't think of too many major hurricanes that spent >6 hrs of land crossing the Yucatan that were then able to reach their previous intensity (or within 20 kts of that intensity). Just my limited experience, though!

[Blake Michaleski]

Like Isadore?;)

[Brandon Clement]

I seem to remember a lot more hurricanes that are severely interrupted (inner core disrputions) as they cross the Yucatan and are unable to regain their strength than otherwise. There are many cases of storms crossing smaller land masses (e.g. Cuba) and reintensifying quickly thereafter (e.g. Dennis in 2005), but I can't think of too many major hurricanes that spent >6 hrs of land crossing the Yucatan that were then able to reach their previous intensity (or within 20 kts of that intensity). Just my limited experience, though!

I agree for the most part but not many hurricanes have hit the Yucatan as a category 4 storm moving 20mph and then moving into the Gulf with ideal conditions for a tropical system. Opal hit the Yucatan (didn't graze it) as a tropical depression, moved slowly over land and was a Category 4 hurricane before it made it half way across the Gulf. Granted, Opal was moving much slower but it was also MUCH, MUCH weaker when moving on to land.


Hey Blakeypoo:eek:

[Blake Michaleski]

Hey now!!! None of that...;)

The worst part of this so far is all the people in Mobile, asking me what I think. I typically dont begin watching these things untill they get in the Carribbean. So maybe tomorrow I'll form an opinion.

[Brandon Clement]

I also forgot to mention that the SW Gulf of Mexico is the deepest area in the Gulf:
http://www.gulfbase.org/facts.php


And the warmest:
http://polar.ncep.noaa.gov/sst/ophi/color_sst_NW_ophi0.png

[Brandon Clement]

Looking at the latest water vapor and IR on Goes Floater 1 it appears that Dean has either pushed the really dry air off or the dry air retreated to the north. My theory is that the night time temperatures and the dewpoints yeild better moisture. Anyway, looking at the Satellite you can see storms blowing up then Dean is pulling them up and around the center from the SE quadrant instead of from the SW. On IR you can see a warm dot in the center indicating an eye is reforming. The outflow to the south is much better the past few frames since the afternoon convection a few hundred miles to the SE of Dean has died down. I'm thinking that Dean is going to get a good bit stronger overnight.

We shall see and I will shut up for the night.

[MClarkson]

it would be difficult for a storm to landfall in the yucatan and then recover to cat 4 strength for a second landfall along mainland mexico or southern texas. Of course that depends on exactly how solid(if any) the yucatan landfall is... scraping the northern yucatan or splitting the uprights between cuba and cancun are still easily possible this far out, and would leave a much greater threat to the western GOM, while a further south track could mean no significant second landfall.


00z models: GFS continues with its mid yucatan landfall, I dont think its changed by more than 20 miles in the last day. HWRF and GFDL are in surprisingly good agreement with eachother, both ending up in almost the exact same spot and intensity by day 5, scraping the northern yucatan as a <920mb monster.

on to the less reliable models...
00z NOGAPS and GEM are a bit south, UKMET close to the GFDL-HWRF. I wish the euro runs werent so old.

[Gene Moore]

Reference tonights NAM run. Look at the forecast of another cutoff low aloft breaking away form the base of the trof....getting caught up in the easterly flow and moving across the Gulf of Mexico. Texas has seen a number of these this season. Question is, will this one clear out it time or will it be a spoiler?

[Rob Lightbown]

I found it interesting that most the GFS Ensemble members show a further north track than the operational GFS model. Perhaps, the GFDL, UKMET and HWRF models are onto something.

GFS Ensemble tracks: http://www.crownweather.com/ensemble.png

[John Peters]

Morning visible showing CDO Expanding on the western side of the storm, and it appears that eyewall convection is wrapping around to the east. As soon as the eyewall becomes "complete" i'd expect more rapid intensification.

[Paul Redmond]

I looked at the latest models at the weather underground. The BAMM, GFS and NOGAP computor models show dean moving over yucatan as a catagory 4 and then reentering the gulf and quickly becoming a cat 5. These runs show DEAN heading for the south texas coast or into old mexico. The GFDL and UKMET models show DEAN missing yucatan and heading for Houstun northwards. It looks like the worst case scenarios outlined in the UKMET and GFDL models are less likely. Still could dean make a sharp turn to the north once it is in the gulf? Timing seems to have been stretched out as well with a projected landfall thursday.

My next dumb question will be if it makes landfall south of Houston, as a cat 5 and heads towards San Antonio, how strong will it be over SA? Its kinda like one of those plan a trip north or buy plywood and stay questions.

[Warren Faidley]

Your biggest problem in SA would likely be tornadoes (and flooding) depending on where the circulation core tracks. In 1988, I chased Hurricane Gilbert in the region and had a tornado hit about 1/4 mile from where I was staying in SA.

Warren

[John Peters]

I looked at the latest models at the weather underground. The BAMM, GFS and NOGAP computor models show dean moving over yucatan as a catagory 4 and then reentering the gulf and quickly becoming a cat 5. These runs show DEAN heading for the south texas coast or into old mexico. The GFDL and UKMET models show DEAN missing yucatan and heading for Houstun northwards. It looks like the worst case scenarios outlined in the UKMET and GFDL models are less likely. Still could dean make a sharp turn to the north once it is in the gulf? Timing seems to have been stretched out as well with a projected landfall thursday.

My next dumb question will be if it makes landfall south of Houston, as a cat 5 and heads towards San Antonio, how strong will it be over SA? Its kinda like one of those plan a trip north or buy plywood and stay questions.

depends on forward speed and intensity at initial landfall. You have a 15kt+ forward motion and cat 5 landfall, i wouldn't be surprised if you experienced some 75 mph+ gusts. If dean is moving slower when it makes landfall, it will have more time to weaken, and torrential rain will become your biggest issue.

Your biggest problem in SA would likely be tornadoes (and flooding) depending on where the circulation core tracks. In 1988, I chased Hurricane Gilbert in the region and had a tornado hit about 1/4 mile from where I was staying in SA.

Warren

didn't Gilbert produce an F-3 tornado or two? Or is this a different storm I am thinking of?

[cedwards]

It look slike a nice eye forming based on visible sat pics.
If I was on the Texas coast, I would be preparing now.
My parents live near Corpus Christi only a few blocks from the water. They already have plywood (from previous years) and are ready to board up and have a place inland to go if they have to.

[Gene Moore]

[quote=John Peters;didn't Gilbert produce an F-3 tornado or two? Or is this a different storm I am thinking of?[/quote]

I saw a video taken near Del Rio of a wedge tornado produced by Gilbert. Warren, do you have any video or stills of the storms, tornadoes or structure that came from this Gilbert tornado outbreak? Was the wedge your video? I for one have seen very little visual documentation of this event. Few tropical tornado outbreaks are photogenic except the supercells way out on the spiral bands.

The area around San Antonio was ravaged by tornadoes during Allen, that was in 1980. A much weaker storm with landfall of less intensity than its previous cat-5 status. If this next storm passes near San Antonio with heavy rains it will be horrific, Uvalde a small town between Del Rio and San Antonio recently had 17 inches of rain, now we have this latest event to keep streams full. It could shut down all of south Texas.

Gene Moore

[MClarkson]

160230 1447N 06247W 6970 02865 9691 +126 +126 151093 100 096 009 00
160300 1448N 06246W 6935 02951 9757 +109 +109 151113 115 096 010 03
160330 1450N 06244W 6942 02988 9826 +089 +089 147103 105 096 046 00


115 knots at 700mb and 96 of the SFMR. Pressure continues to deepen modestly, down to 963. Looks like a 100 knot cat 3 to me.



12z GFS is in the central yucatan yet again. The consistancy of the GFS runs over the last 2 days is impressive, especially if it ends up verifying. The 06z HWRF is over the northern yucatan, the GFDL splits the uprights into the GOM. Both models continue to call for epic central pressures, also supported by the SHIPS and LGEM models which have been in the 125-140 knot range lately.

[Paul Redmond]

With all the rain from July and the tropical depression on top of it, historic flooding is a very real and frightening scenario. If my memory serves we are 18 inches above normal for the year according to the NWS, at the airport at least. I am sure that it is much higher for some areas around here, such as up by Lake Johnson, Uvalde, other parts of the hill country, not to mention the coastal region. Oh, and the drought is officially over.

[MClarkson]

GFDL says: Hi New Orleans, hows it going

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/hur_nested/storm_1/12/images/hur_msl_108m.gif

[Blake Michaleski]

:eek:

That's the last thing we need over there...

oh and its now a major hurricane with an initial intensity of 125kts.

[Paul Redmond]

It seems that GFDL is the only one pointing to New Orleans, and completely missed the Yucatan crossing. I think that run can be ruled out.

[Jeff Snyder]

How many Cat 3s do we usually see that don't have a clear eye? I can think of many Cat 1 and Cat 2 hurricanes that don't have much in the way of a clear eye, but not too many major hurricanes come to mind. There have been signs of an eye for the past 2 days, but one has yet to clear out. Recon found an inner and outer eyewall, and visible sat hints at an eye. The other sat imagery (IR, H2Ov, etc) hint less so, but we may see it clear out later this afternoon.

Model consensus continues to show Dean moving over the Yucatan, landfalling near Cancun as a strong Cat 4-5 storm, before moving into the Bay of Campeche. As noted above, however, there are a couple of models that suggest that the hit to the Yucatan may be more of a "skirt" or "miss" altogether (GFDL and NOGAPS, namely).

Purely based on anecdotal evidence, it does seem like a lot of storms tend to "split the goal posts" between Yucatan P. and Cuba. In the cases I'm remembering, earlier forecasts showed the storm(s) moving over western Cuba, only for the storm to instead shift west enough to split the two land masses. I'm not sure if there's anything to this (I don't think there is), but it's interesting anyway.

[cedwards]

:eek:

That's the last thing we need over there...

oh and its now a major hurricane with an initial intensity of 125kts.

I think you meant to type 125 MPH.
Dean looks quite impressive on Satellite. nice clear eye visible (http://hadar.cira.colostate.edu/ramsdis/online/trop_ge_storm_relative_0.html). It does appear to be shifting a little farther north. This could be a temporary wobble. too early to tell if it is a real turn.

[Bob Schafer]

Anyone remember Ivan?

http://www.nhc.noaa.gov/archive/2004/IVAN_graphics.shtml
(Dial-up warning: pretty big loop)

Go to the 9-10-04 11AM graphic. At the time, it seemed impossible for Jamaica to avoid anything but a catastrophic event. Sustained winds were 145mph, and landfall was but hours away. There was no way Jamaica had any chance of redemption.

Ivan missed Jamaica (essentially). It was a miracle, and the Jamaicans thanked God for sparing them. Speculation had it that the mountains of Jamaica "pushed" Ivan away.

Now look at the forecast track (3 or 5-day cone) for Ivan post-Jamaica at that same time, 040910, 15Z. At that time, Ivan seemed like he had a date with the FL gulf coast. Tampa Bay was sweating. We all know where Ivan made USA landfall after Jamiaca's "punt".

Dean is currently bearing down on Jamaica. Might we see something similar happen with Dean? If Dean gets punted by the Jamaican mountains, then what happens to his track? If Dean actually gets punted north of Jamaica, that could really be interesting.

Bob

[Warren Faidley]

RE: SA, most of the tornadoes were brief, dropping from low clouds moving very fast and impossible to chase or detect (e.g., wall clouds, etc.), at least in the metro area. It might be easier now with onboard radar. It has been my experience that tornadoes near the main circulation core (once inland) are rather difficult to chase and see. Jim? I don't recall any "wedge" reports, but that might have occurred in isolated cells away from the core or in the bands.

FYI: I did an extensive ground survery in 2000 of the area between Corpus-Brownsville and Corpus-Houston. Between Corpus and Brownsville, Highway 77 could be a serious problem if you were trapped on that lonely highway with a Cat-4+. I don't recall many places worth shooting in that area and there was little infrastructure, at least in 2000. In addition, ALL gas stations along the highway in towns like Armstrong were closed. The area between Corpus and Houston is also a challenge. Locals may know more and please post and correct me if you know of any new survivable vantage points in that area.

Warren

[MClarkson]

It takes a very powerful storm to completely clear out an eye at all times.


The GFDL is a right outlier by a good margin. Yes, it is not as likely to occur, but I wouldnt throw it out completely. It is the GFDL...

[Blake Michaleski]

I think you meant to type 125 MPH.


You are correct Charles.... 125 mph.;)

edit: it appears in a rush i saw the flight level data of 124 kts and then read 125mph surface winds and accidentally mixed them up somewhere between my brain and my fingers on the keyboard.

[Bob Schafer]

How many Cat 3s do we usually see that don't have a clear eye?


How's this? Vis sat shows the eye is still filled in with clouds, but Dean has become quite symmetrical.

[MClarkson]

looking better now... eye pretty clear on infrared, getting symetrical. Plane is about 100nm out.


...plane is in the eye, picked up 700mb winds of 130 knots in the NW quad... typical reduction to surface=115 knots, cat 4. Might find something stronger in the NE quad. Also 123kt on the SFMR. Cat 4 for sure.

[MatthewCarman]

NOAA/NWS saying this is only a Cat 3 hurricane but some strengthining is expected. We now have a very strong hurricane in the atlantic. If it strengthens to a Cat 4 it will become a major hurricane.

Edit: Looks like Jamaica could be hit in the next few days. Anyone going to fly down and watch this Hurricane?

[MClarkson]

NHC just upgraded dean to a 4, and anything 3 or higher is a 'major hurricane'

[cedwards]

Jim Leonard (http://www.cyclonejim.com/), George Kourounis (http://www.stormchaser.ca/), Brad Riley (http://www.canechase.com), and Peter Rowe (http://www.stormchaser.ca/Angry_Planet/About_The_Producer.html) will be flying down in the morning.

[B Ozanne]

FYI: I did an extensive ground survery in 2000 of the area between Corpus-Brownsville and Corpus-Houston. Between Corpus and Brownsville, Highway 77 could be a serious problem if you were trapped on that lonely highway with a Cat-4+. I don't recall many places worth shooting in that area and there was little infrastructure, at least in 2000. In addition, ALL gas stations along the highway in towns like Armstrong were closed. The area between Corpus and Houston is also a challenge. Locals may know more and please post and correct me if you know of any new survivable vantage points in that area.

Warren

Bret 1999 hit that area as a cat 4 and went largely unnoticed due to the small population an desserted coastline.

[mcrowther]

Jim Leonard (http://www.cyclonejim.com/), George Kourounis (http://www.stormchaser.ca/), Brad Riley (http://www.canechase.com), and Peter Rowe (http://www.stormchaser.ca/Angry_Planet/About_The_Producer.html) will be flying down in the morning.

Flying into where? Jamaica or the Yucatan?

[cedwards]

They are going to Jamaica. They aborted the Yucatan plans last night for fear that Dean may go just north of there. Also, Jamaica will be hit in the day time

[Gabe Garfield]

Dean appears to be rapidly strengthening. The latest Vortex data message has Dean's central pressure to 936 mb. This is 10 mb down from the last fix. Also, max flght level winds are up to 138 kts (158 mph). If this trend continues, it's possible that Dean could near Category 5 status a lot sooner than expected.

Gabe

[Mike Smith]

145 mph, strong CAT 4.

[Mike Umscheid]

They are going to Jamaica. They aborted the Yucatan plans last night for fear that Dean may go just north of there. Also, Jamaica will be hit in the day time

Wow! I wish them luck... Why do I have this feeling that this will be an upper 100s storm when it hits Jamaica... this ain't no chicken dinner, they better not make any mistakes...

[MClarkson]

they know what they are doing and they are going to have a very fun time unless the storm veers away(like ivan)

how much does a last minute flight to jamaica cost?

last minute flights to houston are 500$... I guess thats not that bad.

....i need a few more promotions I think though.

[MatthewCarman]

I will pray this thing moves north east and misses Jamiaca,The United States or any other country. The last thing we need is another Katrina on our hands. If anyone does chase this please be safe and remember not to go joy riding in the middle of this thing.

Image may be old but is a good satalite shot of Dean:

http://i9.photobucket.com/albums/a58/Teemster/Weather%20and%20Storms/OSEIiod7.jpg

[Brandon Clement]

they know what they are doing and they are going to have a very fun time unless the storm veers away(like ivan)

how much does a last minute flight to jamaica cost?

last minute flights to houston are 500$... I guess thats not that bad.

....i need a few more promotions I think though.

$615 round trip. I shouldn't have looked because now I am tempted.

http://www.kayak.com/s/flights.jsp?searchid=69NFpFrajrPzChgwpGIE&completed=true

[Brandon Clement]

Make that $415

http://www.continental.com/web/en-US/apps/booking/flight/searchResult1.aspx?SID=E47F1F4E357B42629F69144BBD3 B37BD

[MClarkson]

A rental car in kingston is 50$ a day:P

I wonder if the airlines are gonna cancel flights tomorrow... they might...

[Jeff Piotrowski]

The new 0Z GFS has Dean very close or just North of Jamaica at 48 hour.
Then heads for Cancun at 72-84 hr time frame.

[MatthewCarman]

People are saying this "will" become a Cat 5 Hurricane. That is a big assumption but I have to agree. I think it will happen tommorow or Sunday. Anyone else think this?

[Justin E. Reed]

Either way, some people are gettin their a$$es beat by this monster. Im thinkin a lower TX hit. It'd be best for a Kennedy County landfall, considering not even 1,000 people live there, and its between Corpus Christi and Brownsville, so, not too bad.

[Gabe Garfield]

People are saying this "will" become a Cat 5 Hurricane. That is a big assumption but I have to agree. I think it will happen tommorow or Sunday. Anyone else think this?

It's a pretty big deal when you're forecasting a storm to reach Category 5 intensity, but I don't think that it's unwarranted in this case. Most models forecast Dean to approach or exceed the Cat 4/5 threshold by Monday morning. This seems reasonable given the favorable upper-air pattern (upper-low to the NE; ridge directly overhead; upper-low to the NW) and the very high upper oceanic heat content near
Jamaica.

Upper Oceanic Heat Content:
http://www.aoml.noaa.gov/phod/dataphod1/work/HHP/NEW/2007228ca.jpg

Gabe

[Mark Farnik]

At this point it looks almost dead certain that Dean is going to devastate Jamaica on Sunday night. :( This storm has got its act together much more quickly than everyone anticipated and by the time it reaches Jamaica, if it continues on this rapid intensification trend, it could easily be a Cat 5 by tomorrow morning.
The best case scenario would be Dean landfalling on Jamaica during an ERC, a la Katrina. While Dean would probably only weaken to a low end Cat 4, 140 mph winds are a lesser evil than 160 mph winds. But if Dean hits Jamaica right after it completes an ERC or in between ERC's, extreme 160+ mph sustained winds with gusts over 180 mph are well within the realm of possibility.:eek: Also, Dean's windfield has increased dramatically in the last 12 hours, with hurricane force winds now extending over 85 miles from the center and tropical storm force winds over 220 miles out from the center, and it continues to expand with little signs of slowing any time soon, so it will siginificantly impact a much larger area wherever it makes landfall.

Looking ahead, call it a gut feeling, I suspect Dean's encounter with Jamaica is going to nudge his path more to the north than the NHC and the models anticipate and Dean is going to take a slightly sharper right turn than forecast, which would cause the storm to scrape by or just miss the Yucatan, hopefully sparing Cozumel and Cancun, which are still recovering from the desctruction wrought by Wilma two years ago. But while possibly sparing the Yucatan from absolute devastation, this deviation would shift the landfall about 100 miles to the north, which would shift the bullseye from Brownsville/Matamoros to Corpus Christi. Also, if Dean's eye spends less than 6 hours over the Yucatan, the disruption to the storm would be minimal and he would be back to his full fledged vicious self in no time. But if Dean somehow manages to thread the needle through the Yucatan Channel, God help the Gulf Coast.

The bottom line attm is this: with nothing but practially non-existent shear, limited land interactions and simmering SST's ahead of him, Dean is likely going to become one of the most intense Atlantic hurricanes on record. Once he recovers from his encounter with Jamaica and moves over the torrid waters of the western Caribbean, Dean may very well challenge Wilma's status as most intense Atlantic hurricane on record in the Monday/Tuesday timeframe. And realizing that this is only the 'D' storm and it's only mid August, one has to wonder just how bad it's going to get once we hit mid to late September...

[MClarkson]

Think of it this way. Dean has a few days to play with these warm waters, and there is nothing to prevent it from becoming a 5 at some point. Dean will likely cycle eyewalls for the next few days, varying between a upper 3 and a 5.

The current satellite image is the last for a few hours due to the nightly eclipse. Looks decent. Cloud tops have warmed slightly and the CDO pattern is a little less symetrical, but the eye is nearly perfect, a good indicator of an epic storm. It looks like outflow to the southwest might be impeded slightly, but is still excellent everywhere else. After this pass the plane is coming home I think, so Dean will be on its own for a few hours(although you might be able to get a low angle shot from goes-west) Then we get the satellite back around 07z and another plane should be there around 12z.


passing through the northeast eyewall the plane has just found 154 knot flight level winds, which would reduce to a standard surface estimate of 138 knots, borderline cat 4/5. SFMR was not working well during that pass.

050330 1506N 06627W 6944 02705 9478 +103 +103 096136 148 999 999 05
050400 1507N 06627W 6971 02758 9990 +082 +999 089150 154 121 034 05
050430 1508N 06627W 6991 02795 9990 +075 +999 086143 146 112 040 01

[Brandon Clement]

At this point it looks almost dead certain that Dean is going to devastate Jamaica on Sunday night. :( This storm has got its act together much more quickly than everyone anticipated and by the time it reaches Jamaica, if it continues on this rapid intensification trend, it could easily be a Cat 5 by tomorrow morning.
The best case scenario would be Dean landfalling on Jamaica during an ERC, a la Katrina. While Dean would probably only weaken to a low end Cat 4, 140 mph winds are a lesser evil than 160 mph winds. But if Dean hits Jamaica right after it completes an ERC or in between ERC's, extreme 160+ mph sustained winds with gusts over 180 mph are well within the realm of possibility.:eek: Also, Dean's windfield has increased dramatically in the last 12 hours, with hurricane force winds now extending over 85 miles from the center and tropical storm force winds over 220 miles out from the center, and it continues to expand with little signs of slowing any time soon, so it will siginificantly impact a much larger area wherever it makes landfall.

Looking ahead, call it a gut feeling, I suspect Dean's encounter with Jamaica is going to nudge his path more to the north than the NHC and the models anticipate and Dean is going to take a slightly sharper right turn than forecast, which would cause the storm to scrape by or just miss the Yucatan, hopefully sparing Cozumel and Cancun, which are still recovering from the desctruction wrought by Wilma two years ago. But while possibly sparing the Yucatan from absolute devastation, this deviation would shift the landfall about 100 miles to the north, which would shift the bullseye from Brownsville/Matamoros to Corpus Christi. Also, if Dean's eye spends less than 6 hours over the Yucatan, the disruption to the storm would be minimal and he would be back to his full fledged vicious self in no time. But if Dean somehow manages to thread the needle through the Yucatan Channel, God help the Gulf Coast.

The bottom line attm is this: with nothing but practially non-existent shear, limited land interactions and simmering SST's ahead of him, Dean is likely going to become one of the most intense Atlantic hurricanes on record. Once he recovers from his encounter with Jamaica and moves over the torrid waters of the western Caribbean, Dean may very well challenge Wilma's status as most intense Atlantic hurricane on record in the Monday/Tuesday timeframe. And realizing that this is only the 'D' storm and it's only mid August, one has to wonder just how bad it's going to get once we hit mid to late September...

Andrew, Camille and Katrina were all August Hurricanes so it is not that uncommon to get strong hurricanes this time of the year. The F storm is next in line but everything before it was junk with the exception of Dean.

Jamaica didn't make Gilbert make any sort of turn north and Dean's track, projected track and intensity are nearly identical to Gilbert.

I'm not saying it wont happen just that it is pretty unlikely.



On September 3rd, a westward moving tropical wave showing no signs of organization emerged
off the northwest African coast into the North Atlantic. Over the next several days, a broad area
of low pressure formed whose circulation extended nearly to the equator. An organized center
was not evident until it approached the Windward Islands on the 8th. By the 9th, it had developed
into the 12th tropical depression of the season 400 miles east of Barbados.

The depression moved west-northwest at 17 mph, reaching tropical storm strength over the
Lesser Antilles on the afternoon of the 9th. Rapid strengthening ensued on the 10th, bringing
Gilbert to hurricane-force that evening. The system continued its trek west-northwest, passing
over Jamaica as a major hurricane on the 12th. After it emerged into the northwest Caribbean
Sea, Gilbert rapidly intensified into a category 5 hurricane, with recon reports ranging between
882-885 hPa for the hurricane's surface pressure on the afternoon of the 13th. It moved into the
Yucatan peninsula, becoming the first category 5 hurricane to make landfall in the Atlantic Basin
since Camille in 1969.

Gilbert tracked west-northwest through the Gulf of Mexico as a category 3 hurricane, making its
final landfall in northeast Mexico just north of La Pesca on the afternoon of the 16th. As the
weakening system moved across Texas and Oklahoma, heavy rains fell along its path, as it
accelerated northeast thru the Mid-Mississippi Valley into the Great Lakes late on the 19th/
early on the 20th. Below is the track of this cyclone, provided by the National Hurricane
Center.

http://i136.photobucket.com/albums/q168/bclemms/gilbert1988trk.gif

http://www.hpc.ncep.noaa.gov/tropical/rain/gilbert1988.html


I found this model of Gilbert. Pretty similar circumstances too. You have the big Bermuda high, Low pressure over the Gulf out in front. Not exactly the same but pretty darn close.
http://i136.photobucket.com/albums/q168/bclemms/gilbertmodel.jpg

More models, Satellite shots and plenty of words :) Large file warning (PDF). The screen shot above is on page 54.
http://www.aoml.noaa.gov/general/lib/lib1/nhclib/nwstechmemos/techmemo45.pdf

[Blake Michaleski]

As mentioned in the latest discussion, Bouy 42059 should see some extreme winds here shortly.

Winds are already gusting to over 48 kts.

http://ndbc.noaa.gov/station_page.php?station=42059

[MClarkson]

good point, this bouy could take a direct hit in 2 hours or so. Think it survives? Waves are allready 27 feet.


00z hurricane runs are in. Not much change for either of them. The HWRF seems to have a better handle on the intensity in the near term. Both take the storm just north of jamaica, then GFDL goes well north and the HWRF goes for cancun, in much better agreement with the global models.

Edit: GOES-east is out of eclipse and the CDO pattern is more symetrical, the eye still nearly perfect.

[John Peters]

CDO looks a bit disrupted in recently VIS images. Perhaps the storm ingested some dryer air? Otherwise it's possible that we are seeing the beginning of an eyewall replacement cycle - there are signs of concentric eyewalls on the IR images.

800 AM NHC Advisory keeps the storm at 150 mph sustained/930 mb CP

[Marko Korosec]

What impresses me the most is the pressure drop in the last 24h... 46hPa from 09z yesterday!:eek: That was some rapid intensification, from 976hPa to 930hPa at 09z this morning.

According to latest dropsonde data from 1212z SP is at 926hPa with 145kt FL winds. Looks like its going through eyewall replacement cycle, indeed.

[John Peters]

What impresses me the most is the pressure drop in the last 24h... 46hPa from 09z yesterday!:eek: That was some rapid intensification, from 976hPa to 930hPa at 09z this morning.

According to latest dropsonde data from 1212z SP is at 926hPa with 145kt FL winds. Looks like its going through eyewall replacement cycle, indeed.

actually based on the most recent satellite images, the storm probably ingested some dryer air - it appears that CDO is becoming more organized again, and the onset of eyewall replacement cycles are usually associated with a rise in pressure (initially).

[Gene Moore]

RE: SA, most of the tornadoes were brief, dropping from low clouds moving very fast and impossible to chase or detect (e.g., wall clouds, etc.), at least in the metro area. It might be easier now with onboard radar. It has been my experience that tornadoes near the main circulation core (once inland) are rather difficult to chase and see. Jim? I don't recall any "wedge" reports, but that might have occurred in isolated cells away from the core or in the bands.

FYI: I did an extensive ground survery in 2000 of the area between Corpus-Brownsville and Corpus-Houston. Between Corpus and Brownsville, Highway 77 could be a serious problem if you were trapped on that lonely highway with a Cat-4+. I don't recall many places worth shooting in that area and there was little infrastructure, at least in 2000. In addition, ALL gas stations along the highway in towns like Armstrong were closed. The area between Corpus and Houston is also a challenge. Locals may know more and please post and correct me if you know of any new survivable vantage points in that area.Warren

As for your comments on highway 77, totally true and a bad road to be on during a big event. This road will flood, there is no help anywhere close if a chaser gets trapped by high water and as Warren mentions there is no place to hide. Tim Marshall got pinned down on that road during a night hurricane, probably the one your were discussing. That said, if the eyewall is just north of Brownsville chasers will go for that road. I'll also include that south TX has been very aggressive about closing roads in the last 5 years.

Off topic: On your SA comments.... I wasn't sure where you were in the storm when the tornadoes were reported. I'll agree the ones near the center are almost impossible to catch unless the camera is running when one screams by. As for the wedge report, it was real and I saw the video and read documentation. And true, it was from a spiral band supercell away from the main circulation.

Gene Moore

[Marko Korosec]

actually based on the most recent satellite images, the storm probably ingested some dryer air - it appears that CDO is becoming more organized again, and the onset of eyewall replacement cycles are usually associated with a rise in pressure (initially).
According to the latest dropsonde data at 1340z it appears that pressure slightly rised to 929hPa, not sure if that came from ERC or from some dry air intrusion before.

I am thinking where it will go over Jamaica...or it will pass it just along the south/north coast...hope people are prepared there...it doesn' look good.

[John Peters]

According to the latest dropsonde data at 1340z it appears that pressure slightly rised to 929hPa, not sure if that came from ERC or from some dry air intrusion before.

I am thinking where it will go over Jamaica...or it will pass it just along the south/north coast...hope people are prepared there...it doesn' look good.

yeah, hard to tell based on the satellite images whether the CDO/eyewall symmetry was disrupted by an eyewall replacement cycle or dry air intrusion... looks like it is possible that the storm is developing concentric eyewalls.

Look at this image of floyd on the morning of sept 13, 1999. The storm displays a similar erosion of CDO on its western side; however, floyd regained symmetry later in the day and intensified.
http://www.atmos.umd.edu/~stevenb/hurr/99/floyd/floyd124.n15.sep13_1305.gif

[beaudodson]

Just posted 15 new (large) Gempak Images for those interested

http://www.beaudodson.com/blog/blog3.htm

[Brian Stertz]

Looks like another hit on the Cancun-Cozumel Mexico area again. This time it could be even worse unfortunately. Hurricane Wilma was real bad to Cozumel according to my friends pictures and this time....Dean looks like it will pass overhead...or possibly just north based on the NHC forecast track. At any rate, Cozumel should get hammered again....and Dean looks to be a more progressive forward system than Wilma.

[beaudodson]

Live info from Jamaica (if anyone knows of any ham nets online can you post the links)

http://stormcarib.com/reports/current/jamaica.shtml

[rdale]

Any thoughts to breaking this up into FCST / NOW / REPORT / DISC threads from here on out now that we have chasers en route?

[Mikey Gribble]

Does anybody know anything about the options in northern Mexico? It looks like there is some sort of a bay in the general area where Dean is now forecast to make landfall by NHC.
http://travels.davidmlawrence.com/Mexico/Tamaulipas/images/NMEXICO_STEXAS.png
I'd rather not chase in Mexico, but I'm not sure I'll have a choice.

[Bill Tabor]

Chase Mexico during a strong hurricane....is this an intelligence test? I wouldn't go down there under normal situations considering corruption and lack of infrastructure much less during a major hurricane. :D But that's just me. I suppose there are those that go to third world countries during canes and survive but you definitely have to be in the know and prepared for the unexpected. Good luck if you give it a shot. Will be interesting / entertaining to see how you Mexico chasers prepare and how you fare. Keep us posted.

[HAltschule]

I tend to agree. Hopefully those chasers in Jamaica will survive and be OK. But I do not agree with being there in the first place. Not when you have a storm of this magnitude. Given the infrastructure of Jamaica...I would plan on being stranded for 2-3 weeks after the storm has passed. I would also make sure you have enough food and supplies for 2-3 weeks. Hopefully you will be safe and survive the storm.

BTW...did anyone else see the mostg recent GFDL max. sustained wind speed of 177 knts when the storm is between Jamaica and the yucatan? Whew.

[Jeff Piotrowski]

The 12Z HWRF model has shifted slightly back south. Compared to the 6Z run now brings the center of Dean on the South side of Jamaica by Sunday evening moves WNW along the coast as it heads toward Grand Cayman on Monday

http://grib2.com/animate/hwrfjava.php3?fcsthour=42&type=1000-500_SLPTHKPRP&loop=NOLOOP


The 6Z GFDL has Dean at 900 mb with winds to 177 Knots just before it makes landfall near Cancun.

http://moe.met.fsu.edu/cgi-bin/gfdltc2.cgi?time=2007081806-dean04l&field=Sea+Level+Pressure&hour=Animation

[John Peters]

[COLOR=black]The 6Z GFDL has Dean at 900 mb with winds to 177 Knots just before it makes landfall near Cancun.

http://moe.met.fsu.edu/cgi-bin/gfdltc2.cgi?time=2007081806-dean04l&field=Sea+Level+Pressure&hour=Animation

lol, 177 kts = 200 mph! I tend to think GFDL overestimates wind speeds a bit, while HWRF underestimates min central pressure.

I'm still not too impressed with dean's appearance. I think that the region of CDO with colder cloud top temps needs to expand and become more symmetric on the western side before dean strengthens any further. I also think that interaction with the higher elevations of Hispaniola may slightly disrupt the storms circulation; to what degree will depend on how far south the center passes. Honestly i don't think that dean is going to reach cat 5 before Jamaica. Best chances for an intensity peak are in the higher SSTs west of Jamaica into the Gulf (if the storm does not landfall on the Yucatan)

[Kurt Wayne]

Chase Mexico during a strong hurricane....is this an intelligence test? I wouldn't go down there under normal situations considering corruption and lack of infrastructure much less during a major hurricane. :D But that's just me. I suppose there are those that go to third world countries during canes and survive but you definitely have to be in the know and prepared for the unexpected.

I know there have to be many dedicated weather professionals in the Caribbean and Latin America...but I always am concerned about the populace as well and how well they're able to be warned about events like this, particularly in Mexico given that its a larger nation that would have (I'd think) larger pockets of people who might be more isolated from news.

Then again, "First world" Canada, at least some stations around the Elie, MB tornado of this past June (you have to listen to the radio/audio portion of this one, as well as the reaction of "Bill and Ted" on their trans-Canada highway adventure), (http://www.youtube.com/watch?v=xCI1u05KD_s) seemed to have a few clueless media personnel as well during a major weather event. :mad:

[mcrowther]

So did Jim L and crew make it into Jamaica?

[MClarkson]

Jamaica and the Yucatan get hit by hurricanes all the time. They are not unprepared and their infrastructure is not that bad for resisting hurricanes. Both Jamaica and Cancun are difficult to surge. They are certainly safer and better prepared(Cancun especially) than lets say... New Orleans. Yes, the chasers may get stuck for a few days until the airports resume normal operation, but they know what they are doing.


12z GFDL is much closer to the model consencus now, its still the right outlier but not by much.


keep in mind that the GFDL wind readouts at at 35m and must still be reduced for a good surface estimate.

[Rocky Rascovich]

As far as I know they are on their way. Latest advisory still has Dean at 150mph. The course still seems fairly steady at 275-280deg.

I've been pouring over lots of data and have been focusing on a combo of an interaction with the storm and Hispanola and that cold core upper low which actually seems to be moving faster than anticipated; now NW of EYW. With these two players influencing the storm, I'm still in a quandry over the exact path I think it will take.

Either way, whoever gets to Jamaica will be in for a show, but still this hunch tells me that they will escape the worst of it. If I was there, I'd be on the north coast around Ocho Rios to Port Maria.

[Mikey Gribble]

I know that Mexico isn't known for it's sound engineering and infrastructure practices, but if that is where Dean wants to go, then we don't have much choice. I am far from being certain that I'm going anyways. I doubt I'd make that treck for a night time landfall and I definitely won't go unless it is a high end cat. 3 at least (I'm talking about northern Mexico, not the Yucatan). I'll see if I can dig up some topo maps and more detailed information on northern Mexico for those that might chase Dean once he crosses the Gulf (I'll post it on here later).
Here is a good link for high res. visible satellite loops for Dean http://hadar.cira.colostate.edu/ramsdis/online/trop_ge_storm_relative_0.html
I updated my tropical cyclone page, so if anybody is interested in inaccurate forecasts, then this is your place
http://www.loadedgunchasing.com/TropicalCyclonePage.html

[Justin Turcotte]

I know that Mexico isn't known for it's sound engineering and infrastructure practices, but if that is where Dean wants to go, then we don't have much choice.

Cancun is a modern resort city built pretty sturdy... at least the tourism infrastructure. That said, not much is gonna hold up very well in what is essentially a three hour EF2 tornado. Cancun also has the famed "7" row of resorts which essentially sit on a spit. The "7" comes from the shape of the spit. Storm surge there would not be the monsterous 25+ feet like the U.S. Gulf coast since some of the water could go around the Yucatan but I suspect direct hit there would still produce tremendous surge damage. Now the buildings arn't so good in towns south of the Rio Grande and I wouldn't want to be outside with tin flying everywhere. One bit of potential good news is the GFS doesn't want to bring a tremendous amount of moisture into central Texas. Hopefully that is the case.

[MClarkson]

Those modern hotels in cancun will survive anything. Cancun cannot suffer devestating surge due to the convex shape of its coast and the bathymetry. Also the hotels are concrete and steel, meaning they will outlast the eyewall of even a 5. Sure the windows may get punched out in spots and they will suffer rain damage, but on the downwind side a chaser would survive. Cancun is one of the best prepared cities you will find anywhere, not surprising since they get hit so often.

[Kurt Wayne]

How prepared are gulf coastal cities farther north as Tampico and Veracruz?

[cedwards]

Don't forget that the turist district of Cancun is only PART of the city. The part where the locals live is not as well built. They will have quite a bit to deal with.

[Justin Turcotte]

If you're a hurricane junkie the Eastern US Weather Forum is blazing on Dean. A mix of mets and weenies there but plenty good stuff posted every minute.
http://www.easternuswx.com/bb/

[Reed Timmer]

We just arrived at a "hurricane-proof" hotel in Runaway Bay, Jamaica, just west of Ocho Rios. This place supposedly has bullet-proof windows, and a very solid structure. The only problem is they're turning off the wifi in 3 hours!

I've never been to Jamaica before...and this place is spectacular.

As expected, people do not seem to be taking this storm seriously at all. We didn't see a single house that was boarded up, or any sign of a cat 4-5 hurricane arriving in less than 24 hours. This could potentially be a very bad situation for Jamaica.

[beaudodson]

Jamaica and the Yucatan get hit by hurricanes all the time. They are not unprepared and their infrastructure is not that bad for resisting hurricanes. Both Jamaica and Cancun are difficult to surge. They are certainly safer and better prepared(Cancun especially) than lets say... New Orleans. Yes, the chasers may get stuck for a few days until the airports resume normal operation, but they know what they are doing.


12z GFDL is much closer to the model consencus now, its still the right outlier but not by much.


keep in mind that the GFDL wind readouts at at 35m and must still be reduced for a good surface estimate.

I would expect to be stuck in Jamaica for longer than a few days (but who knows). One of the main government officials was just on television and said they would likely be without power for more than a MONTH. If a Cat 4 or 5 hits this island - head on - then they are going to have serious problems. Way more than any hurricane in recent memory for that island. I would certainly not want to be around to see the aftermath. Best of luck to those who went to the island. It will be an interested 48 hours ahead.

[MClarkson]

One of their priorities will be to reopen the airports.



have fun Reed, i am quite jealous!

[Dean Meece]

Great streaming radio station out of Kingston, Power 106 FM, had it on all day. Has all the curfew information, banks shutting down ATM's at 7PM tonight, power to be shut off tomorrow 10AM. Mandatory evacuations.

http://www.surfmusic.de/radio-station/power-106-fm,7582.html

This seems to be a sports television station, but occassionally has some items on regarding the storm.

http://www.jumptv.com/en/channel/cvmtv/

-Dean

[Jim Zandonai]

The Grand Caymans took a hit a couple years ago too and took alot of time to fix up.. As far as Cancun goes the major hotel chains spent millions after Wilma replacing glass with 'hurricane standard glass' I guess. The Marriott and Ritz took months to re-open during this fix.Should be interesting to see how it holds up. Dean looks impressive here as it heads for Jamaica.

[MClarkson]

The new plane is in the eye, the central pressure xtrap is lower than it was before(918mb), but there is a double wind maxima and a very wide windfield, indicating the probable start of an eyewall replacement cycle.


EDIT: drop in the eye confirms 923mb.

[George Kourounis]

I just arrived in Jamaica with Jim Leonard. Currently Dean is at 920mb and looks great on satellite. It's going to get a bit wild here tomorrow evening.

The guests at the hotel here are starting to get worried, especially since we showed up, a lot of them tried to get out but the airport was flooded with vacationers trying to flee. It's amazing how many people have no clue what is about to happen here...
George Kourounis
www.stormchaser.ca (http://www.stormchaser.ca)

[Marcus Opitz]

damn, I wonder If I can get in there tomarow.....or in that case, grand caymon.

[Jim Leonard]

Grand Cayman would be a long shot at this late hour. The authorities on that island will probably shut down up 24 to 36 hours before the storm hits. I hear here in Jamaica the is a 48 hour curfew in effect beginning tonight island wide.

[Linda Kitchen]

All you chasers be careful! I hope that your not stuck there for long. Jim where on Jamaica are you?

[Justin E. Reed]

So much for my spring break trip to Montego Bay. I already cancelled and got my money back!

[Jeff Piotrowski]

The 18Z GFDL & HWRF and BAMM models are better agreement. The models now show the core of the Dean about 20-30 miles south of Jamaica.

The 18Z GFDL that has been to right of all other model now is in agreement over the next 60 hours. The GFDL does over estimate the winds. Dean still could make a cat 5 before it makes landfall near Cozumel.

[Mike Umscheid]

Last 3 hours worth of loops certainly looks like quite a bit of longitude being chewed up with not much latitude... it's looking like a heading of 275 or 280 now instead of the 285 to 290. If this trend continues through the night, it will be harder and harder for a direct hit on Jamaica... even the southernmost Portland Point. I really don't see much reason why it shouldn't continue a 275-280 heading... which would quite likely spare Jamaica a landfalling eye... most of the latest guidance suggest this as well... that's a hell of a nice ridge directing this thing to the west... I even think Cancun and Cozumel will be spared the brunt... Nevertheless, still some tremendous impacts on Jamaica tomorrow, obviously

[Mikey Gribble]

I was watching that too Mike, but now that the heaviest convection is North of the eye it is wobbling back to the North. Although I'm sure most of the people on here know, I figure it is worth mentioning that hurricanes tend to wobble in the direction of the deepest convection. If you watch the latest infrared loop it shows this quite well.
http://www.ssd.noaa.gov/goes/flt/t1/loop-avn.html

[Mike Umscheid]

I was watching that too Mike, but now that the heaviest convection is North of the eye it is wobbling back to the North. Although I'm sure most of the people on here know, I figure it is worth mentioning that hurricanes tend to wobble in the direction of the deepest convection. If you watch the latest infrared loop it shows this quite well.
http://www.ssd.noaa.gov/goes/flt/t1/loop-avn.html

It seems to be wobbling a little more now, you're right, the last two frames at 0145 and 0215 UTC show a wobble more to the northwest. I tell ya, any wobble to the northwest at this stage is that much more worrisome for Kingston... Yikes.

[Justin Turcotte]

TPC may have jumped the gun revising their track south a tad. Dean went right through the earlier forecast point and then took that brief w/sw jog and is now wobbling back at a decent northwest angle toward the next original forecast point. The early 00z guidance all were a tick south and that is probably what the TPC bit on. I've seen too many of these storms wobble off a highly clustered path too many times, even 12 hours out. We shall see with this one but Jamaica has had reasonable success deflecting these things in the past.

[mcrowther]

I just arrived in Jamaica with Jim Leonard. Currently Dean is at 920mb and looks great on satellite. It's going to get a bit wild here tomorrow evening.

The guests at the hotel here are starting to get worried, especially since we showed up, a lot of them tried to get out but the airport was flooded with vacationers trying to flee. It's amazing how many people have no clue what is about to happen here...
George Kourounis
www.stormchaser.ca (http://www.stormchaser.ca)

I am now thinking that the storm may miss the island to the south- but you still should get a good show.

[MClarkson]

Latest HWRF takes the storm well south of Jamaica. GFDL takes it south of the island, but still pretty close. Both then strengthen the storm a bit more and landfall south of cozumel.


Recon just made another eye pass. Pressure is up a few mb since a few hours ago, but that is expected with the ERC ongoing. Im actually surprised at how the pressure hasnt really risen despite the replacement cycle starting at least 6 hours ago.

[Mikey Gribble]

It now looks like Jamaica may miss the worst of it. Don't get me wrong, they are going to take a pounding, but last night it was looking like the eye would make a direct hit on the eastern part of the island. Now it looks more like Dean will skirt the southern tip of the island. That is good news for those with interests in Jamaica.
The track could still shift very easily. I don't have much time to look at data right now, but the heaviest convection has consistently been on the N and NE side of the storm (over the last hour or two) and I wouldn't be surprised to see Dean start cheating back to the North a bit over the next couple hours as a result.

[John Peters]

Over the last few hours dean's eye has expanded considerably... I'm wondering if this is the end of the ERC?

[Mikey Gribble]

I've been told this site has radar from Jamaica, but I can't verify that because I haven't gotten the page to fully open yet (I'm connected through my cell phone though). http://www.metservice.gov.jm/radarpage.asp (http://www.metservice.gov.jm/radarpage.asp)

I also updated my page and forecast for the three people that actually look at it (one of which is my mom).
http://www.loadedgunchasing.com/TropicalCyclonePage.html

[cedwards]

I've been told this site has radar from Jamaica, but I can't verify that because I haven't gotten the page to fully open yet (I'm connected through my cell phone though). http://www.metservice.gov.jm/radarpage.asp (http://www.metservice.gov.jm/radarpage.asp)


I have been having the same problem. Yesterday the radar loaded fine.

[Brian Emfinger]

I have been having the same problem. Yesterday the radar loaded fine.

Hey, where exactly on Jamaica is the group thats down there? Its going to be really close with the eye itself maybe just grazing the southern coast. That last little wobble nearly was enough but it looks like they will need another wobble to get in the eye (depending on where they are).

[Danny Neal]

Hey, where exactly on Jamaica is the group thats down there? Its going to be really close with the eye itself maybe just grazing the southern coast. That last little wobble nearly was enough but it looks like they will need another wobble to get in the eye (depending on where they are).

Initially I heard they were on the north shore. But they may have relocated when the storm itself started sagging south

[Warren Faidley]

Hopefully they will get some action before sunset in about 4.5 hours. The last report I saw was 9 mph from the NW. I know how frustrating it is to go that far and have to sit there outwaiting darkness. I'm gald they are in a group. Some areas of Jamaica are scary even w/o a storm. I think the winning location for chasing this storm will be along the E. Mex. coast, but at the present forward speed, it will likely strike at night. Unfortunately, major storms striking that region can kill hundreds or thousands from inland flooding.

Warren

[beaudodson]

There is one chaser in Cancun - he may move south. He is posting reports on this thread:

http://www.easternuswx.com/bb/index.php?showtopic=139960

His web-site is Icyclone:
http://www.icyclone.com/

His name is Josh Morgerman

[B Ozanne]

Kingston is reporting 70kts gusting to 100kts. This was a TAF ob on wunderground.com.

[Warren Faidley]

Eye just made what appears to be a substantial wobble to the N/NW on IR image, so it should be getting pretty exciting there about right now!

Warren

[MClarkson]

MKJP 192100Z 14070KT 1000 BKN010 SCT016 OVC080 XX/XX Q0992


If they got a position further south, they could get some excellent shots as the eyewall scrapes by. They have a bit of light left.

[Marko Korosec]

From the latest satelite scans it seems that its turning more NW-wards than W-wards. Also Kingston reporting 80mph gusts right not at 4pm local time.

Guys there in Jamaica are making some good footage now.

PS: could someone explain what this "wobble" means, please? And why this happens? Thanks!

[Warren Faidley]

Here is a list of live web cams in some general areas of tropical interest.

http://www.caribbeantravelforums.com/Caribbean_Cams.htm

The Kingston camera is down. Duh.

Maybe there is another one I don't know about? The live TWC footage looks rather benign, except for the usual overdone antics of the reporters.

Warren

[B Ozanne]

Note to hurricane chasers: Any country that pre-emptively shuts down their power supply may not have adequate infrastructure.

How far south of Kingston did the eye pass?

Edit: Aside from some cloud top warming I don't see any major geography induced disruptions to the storm.

[MClarkson]

The TWC guys are in montego... well north of the eyewall, they will get nothing unless they turn on a couple of their fans again.

Mesoscale wobbles are generally a function of the short timescale of convection, especially while replacement cycles occur, eyewalls contract, other structure changes etc.

Trochoidal wobbles are the result of the eyewall itself slowly rotating around the exact center. They dont always stay lined up, the atmosphere is rarely perfect.

[MClarkson]

MKJP 192200Z COR 10099OO120KT 0KM BKN010 BKN012CB OVC080 XX/XX Q0994




if that is correct, and I have little reason to think otherwise... woa!

[B Ozanne]

I'm not near TWC right now. How did they end up in Montego Bay? Were they being cautious or did they blow the forecast? I don't think they are going to see too much action on that side of the island.

[B Ozanne]

MKJP 192200Z COR 10099OO120KT 0KM BKN010 BKN012CB OVC080 XX/XX Q0994

if that is correct, and I have little reason to think otherwise... woa!

I saw that on some other forum. Where did they get it from?

[MClarkson]

that is the metar for kingston international airport

you can find it from adds.aviationweather.gov

...the only thing is it looks a little like a guestimate with a partially broken sensor, the pressure is wrong, t/td have failed...


MKJP 192300Z E11099OO180KT 0KM BKN008 BKN010CB OVC080 24/24 Q0998


I think we can throw out those metars now.

[Aaron Kennedy]

http://weather.noaa.gov/weather/current/MKJP.html

MKJP 192300Z E11099OO180KT 0KM BKN008 BKN010CB OVC080 24/24 Q0998

I'd say the instrument is suspect given the location of the eye wall and Kingston and the latest ob (200+mph).

[Justin Turcotte]

Communist Cuba has better public radar data than Canada and Dean shows up quite well...
http://www.met.inf.cu/asp/genesis.asp?TB0=PLANTILLAS&TB1=RADARES

[B Ozanne]

http://weather.noaa.gov/weather/current/MKJP.html

MKJP 192300Z E11099OO180KT 0KM BKN008 BKN010CB OVC080 24/24 Q0998

I'd say the instrument is suspect given the location of the eye wall and Kingston and the latest ob (200+mph).


On Mount Washington our station manual allowed us to estimate wind speeds in case of instrument failure. We were really good at estimating wind gusts, especially since we had the data to validate.

Could they be estimating wind? My guess is they aren't very good at it.

[Warren Faidley]

I know it might be a long time before anyone hears from JL and the others, but please post ASAP when someone does to make sure they are OK.

Thanks.

[Miriam Lawrence]

There's been some discussion/disagreement on Easternuswx about the behavior of the ULL in the Gulf, and whether or not it will move out fast enough. Some folks speculating that it may be slowing or stalling. Wondering what ya'll think, looking at the data? Anyone questioning the accuracy of the consensus track?

[Justin Turcotte]

The new TPC path puts Dean over or very near Pemex Cantarel Production Area, one of the biggest oil fields on the planet. Fortunately this area is fairly protected by the Yucatan but I'd think the workers would need to evacuate, effectively shutting the place down for a few days. Oil prices are down in early trading which could be for a variety of reasons.
http://www.eia.doe.gov/emeu/cabs/images/cantarell.jpg

Jamaica streaming radio: http://www.go-jamaica.com/power/

[cdcollura]

Good day all,

Dean has been tempting me for a trip to Jamaica on Friday 8-17 but I cancelled it with fear the Island would be missed to the south.

The hurricane track was SUPPOSED TO develop a WNW / NW movement, but Friday and Saturday, I did not see that as Dean possessed a more W motion (or maybe slightly N by W - like 275 or 280 degrees or so).

This indeed did happen on Sunday 8-19, but was a very close call. I hope who was down there (Jim L and others) stayed safe and got good footage.

I also opted a no-go on the Yucatan since the coarse keeps wanting to go south (storm is due west, not WNW) and might actually go into extreme N Belize where a trip to Mexico may not work out all that well.

Also, it will be a night landfall (like 4 AM or so Tuesday morning) - Screw that.

[John Peters]

Latest satellite images (as indicated by recent NHC forecast discussion) are looking more impressive than earlier this morning. IR cloud top temps seem to be cooling, and the outer eyewall is becoming more defined. Over the next few hours, I'd expect the eye to redefine and the storm to intensify to category five status, especially considering the increasing SSTs as it approaches the Yucatan.

[Gabe Garfield]

Latest satellite images (as indicated by recent NHC forecast discussion) are looking more impressive than earlier this morning. IR cloud top temps seem to be cooling, and the outer eyewall is becoming more defined. Over the next few hours, I'd expect the eye to redefine and the storm to intensify to category five status, especially considering the increasing SSTs as it approaches the Yucatan.

I agree. The satellite presentation is becoming downright scary. The CDO is becoming *very* symmetrical and it finally has "the look" of a Category Five storm. The next recon will be amazing, no doubt.

I am praying earnestly for residents in the Yucatan, as this has the potential to be a catastrophic event with great loss of life.

Gabe

[Brian Stertz]

Looks as though the real danger zone will be south of the Cancun-Cozumel area on the Yucatan between Tulum and Chetumal. This area stands the greatest risk of catastrophic damage etc. It looks like there are some smaller coastal towns on some major points into the Caribbean that will be hit badly. It would have been downright scary had this deepening Dean slammed into the resort areas as it first appeared.

[Jim Bishop]

Not sure if anyone on this boards has been following, but there's a chaser on the easternuswx board who is enroute to Chetumal, Mexico to intercept Dean. I find this pretty interesting. I'm not sure any news outlets are willing to go to those lengths. It looks like he's going to pay a local to drive him down there. Well, at least he won't be alone!

http://www.easternuswx.com/bb/index.php?showtopic=139960

[Howard Robinson]

Not sure if anyone post this, but I have a link to Mexico Radar. Dean should come into their radar range soon.
http://smn.cna.gob.mx/radares/rad-canc.jpg

[Warren Faidley]

You have to prey for anyone who trys a nightime, coastal intercept of a Cat-4/5 in a strike area with little or no substantial infrastructure -- in Mexico! I have a bad feeling this is going to cause a sig. loss of life in Mexico.

Warren

[John Peters]

Latest satellite image is stunning - CDO has become perfectly symmetrical and the eye is very well defined. Looks similar to Rita near that storm's respective peak in intensity.

You have to prey for anyone who trys a nightime, coastal intercept of a Cat-4/5 in a strike area with little or no substantial infrastructure -- in Mexico! I have a bad feeling this is going to cause a sig. loss of life in Mexico.

Warren

I agree warren, considering the forward speed of this thing, it probably won't weaken much before landfall. Storm surge in the northern eyewall is going to be utterly devastating - this coupled with 140 kt winds will create one of the most hellish landfall scenarios imaginable.

[Bill Hark]

I know it might be a long time before anyone hears from JL and the others, but please post ASAP when someone does to make sure they are OK.

Thanks.


Jim Leonard and the others including George Kourounis intercepted Dean in Jamaica. They are doing well this morning. Apparently, they saw some wild waves and damage. Many roads are impassable and most power is out.

Bill Hark
Kour

[Mike Hollingshead]

Couple strange parallel lines in that eye at the moment. They've made a complete revolution like that. Or maybe 2 revolutions. Playing the loop makes them appear like they are moving clockwise. Lol maybe they are moving that way. If you frame by frame it, trying to see them turning that way it looks more like almost one rotation, but if you see it going the other way frame by frame it looks like 2. Those two lines have to be moving clockwise.

[John Peters]

I have no doubt in my mind that dean is now a category 5 storm. 1645Z vis shows some of the most impressive storm structure i have ever seen.

[Dan Robinson]

You have to prey for anyone who trys a nightime, coastal intercept of a Cat-4/5 in a strike area with little or no substantial infrastructure -- in Mexico! I have a bad feeling this is going to cause a sig. loss of life in Mexico.

I agree also. No disrespect toward anyone going to Mexico for this, but I hope that anyone going is prepared not only for the storm itself but for the humanitarian disaster to follow. They aren't going anywhere for a long time and will need at least 2 weeks of food and water. If not they will be suffering incredibly after the storm is over.

I draw the line when it comes to a storm like this, in that type of country and at night nonetheless. Not worth the risk in any way. What would one hope to accomplish by doing this? I have a feeling that anyone going to the Yucatan right now hasn't thought about everything they need to be thinking about. As with most chasing ventures, aside from the few minutes of fame and one or two stock video sales one might see if they survive, no one really cares in the end. I guess that is a lesson to be learned the hard way.

[HAltschule]

Outer Bands now visibile here on Cancun, MX Doppler Radar imagery.

http://www.passco.com/cancun.htm

[John Peters]

latest advisory still pegs Dean as a 150 mph cat. 4 with 924 mb central pressure (estimated). Any word from the reconnaissance aircraft yet?

[MClarkson]

The plane just made a pass through the eye, it is having comm. trouble and some equipment trouble and I wouldnt expect much flight level data. From the one set of obs it did send back it looked like the storm has not intensified, despite its satellite appearance.

EDIT: However I think it will intensify today and perhaps the recon missed the highest winds on their first pass.

[Robert Dewey]

I agree also. No disrespect toward anyone going to Mexico for this, but I hope that anyone going is prepared not only for the storm itself but for the humanitarian disaster to follow. They aren't going anywhere for a long time and will need at least 2 weeks of food and water. If not they will be suffering incredibly after the storm is over.

I completely agree. Look at how bad New Orleans suffered after Katrina, and that was only a CAT 3. If the United States isn't prepared for that, you have to believe that Mexico isn't.

As with most chasing ventures, aside from the few minutes of fame and one or two stock video sales one might see if they survive, no one really cares in the end. I guess that is a lesson to be learned the hard way.Not exactly sure of the motives, but some of these chasers aren't doing it for money. Apparently, "Hurricane Josh" (from the Eastern Wx forum) owns an advertising agency, and money isn't really an issue for him. I can't imagine that he's doing this to make a quick buck if that is indeed the case.

Some people just like the adrenaline... and what would make your adrenaline higher than a CAT 5 'cane in Mexico?

[Marcus Opitz]

From the looks of the sat pic, it looks larger and more defined than ever before. On appearance it rivals many super typhoons in the pacific.

[Marcus Opitz]

I completely agree. Look at how bad New Orleans suffered after Katrina, and that was only a CAT 3. If the United States isn't prepared for that, you have to believe that Mexico isn't.

Not exactly sure of the motives, but some of these chasers aren't doing it for money. Apparently, "Hurricane Josh" (from the Eastern Wx forum) owns an advertising agency, and money isn't really an issue for him. I can't imagine that he's doing this to make a quick buck if that is indeed the case.

Some people just like the adrenaline... and what would make your adrenaline higher than a CAT 5 'cane in Mexico?

I think some good knowledge of jungle survival would be highly recommended as well!

[John Peters]

The most recent HWRF run puts dean into the Yucatan at 873 mb :eek:

I think it's quite possible that Dean won't become a cat 5 before landfall. It seems like the storm has had a lot of trouble maintaining a stable eyewall and symmetric CDO since the eastern caribbean.

Both HWRF and GFDL indicate that the storm could re-intensify to cat 3 before the second landfall.

[MClarkson]

The further south Dean tracks, the less prepared and more vulnerable the populations. Cancun could have taken this storm without too much loss of life... I am not sure what will happen in Belize and the southern Mexican Yucatan.

[Bill Hark]

I really hope that "Hurricane Josh" doesn't vanish after the area is hit by a CAT 5, either from storm surge or the increase in lawlessness during the aftermath. If he comes through, I can't wait to see his video and stills.

I won't criticize his decision to go though I think the risk is very great. I wouldn't do such a chase on my own.

Bill Hark

[Howard Robinson]

Looks like the outer rainbands are on Cancun radar now, and current track puts it over Cancun in a few hours.

[Perry Williams]

Based on a new vortex fix (1923z) which finally came across the wire, Dean is on the verge of being a cat-5. Central pressure listed as 918 mb, and max flight level winds in the NE eyewall of 151 kts.

URNT12 KNHC 201945
VORTEX DATA MESSAGE AL042007
A. 20/192320Z
B. 18 DEG 05 MIN N
083 DEG 39 MIN W
C. 700 MB 2399 M
D. 120 KTS
E. 060 DEG 15 NM
F. 151 DEG 151 KTS
G. 060 DEG 15 NM
H. 918 MB
I. 9 C/ 3037 M
J. 19 C/ 3043 M
K. 18 C/ NA
L. CLOSED WALL
M. C18
N. 12345/7
O. 0.03/1 NM
P. AF303 1404A DEAN 0B 15
MAX FL WIND 151 KT NE QUAD 1918Z

[MClarkson]

The pressure is down to 918mb and FL wind max was 151kt... high end Cat 4. The generally westward track continues, the eye and CDO could stand to be a little more symetrical...

[cdcollura]

Good day all...

I love chasing hurricanes, and been through many bad ones as well.

I have Andrew 92, Katrina 05, Charley 04, and many others under my belt ... But although I am down-right CRAZY, I never want to even be labeled as STUPID.

Here are my NEGATIVES on why I am not just jetting to the Yucatan, renting a car / SUV, and chasing Dean.

1). Night landfall (like 4 AM or so).

2). Storm core keeps shifting more W (not the expected WNW) on each advisory / forecast package.

3). Landfall may be on (or even south) of Mexican / Belize border.

4). If that verifies ... Jungles, little or no road networks.

5). You cannot bring 2 weeks of food, water, and survival gear on an airplane.

6). Anarchy and corrupt government, looting, disorder afterwards.

7). I do not have a gun, and will not buy one to protect myself there AFTER the storm.

8). Started a new job, and being stuck in the jungle for 2 weeks with no comm whatsoever will not explain why I should not be fired as I come back sometime in September.

9). Basically, Chris Collura would essentially disappear from the USA for 2 weeks or so.

10). I have not watched enough "Survivorman" on DISC yet.

11). "Dean" is my middle name ;-(

12). Parking garages above 30 feet MSL are hard to find on the east side of the bay of Chetumal. Surge is another issue, as the photo ops we had in Katrina in 05 won't happen since it will be dark.

13). Winds sustained at 150-160 MPH (this is at-least) and a 30% rule on gusts (near 200 MPH) - This is basically an EF-5 tornado (over 200 MPH peak winds) about 30-40 miles wide and at night - THINK about it!

Just my thoughts. But remove some of these "negatives" and I might re-consider (won't happen in 12 hours) ;-(

[John Peters]

Based on a new vortex fix (1923z) which finally came across the wire, Dean is on the verge of being a cat-5. Central pressure listed as 918 mb, and max flight level winds in the NE eyewall of 151 kts.

URNT12 KNHC 201945
VORTEX DATA MESSAGE AL042007
A. 20/192320Z
B. 18 DEG 05 MIN N
083 DEG 39 MIN W
C. 700 MB 2399 M
D. 120 KTS
E. 060 DEG 15 NM
F. 151 DEG 151 KTS
G. 060 DEG 15 NM
H. 918 MB
I. 9 C/ 3037 M
J. 19 C/ 3043 M
K. 18 C/ NA
L. CLOSED WALL
M. C18
N. 12345/7
O. 0.03/1 NM
P. AF303 1404A DEAN 0B 15
MAX FL WIND 151 KT NE QUAD 1918Z

Thanks for the info Perry. What does 151 kts translate to at the surface?

[Jeff Snyder]

Thanks for the info Perry. What does 151 kts translate to at the surface?

151kts leads to an ESTIMATE of ~135kts at the surface. It is very important to remember, however, that this is a rough estimate. The wind profile near hurricane eyewalls can be very complex, and they can vary from storm to storm (and from time to time in the same storm). Some studies have shown that the proper reduction factor is actually closer to 0.65-0.75. From what I've seen, it's certainly more likely that the 0.9 reduction factor leads to an overestimate much more often than an underestimate. Fortunately, we have dropsonde and SFMR data that can help corroborate an intensity estimate derived from a Fl-level wind reduction.

[cdcollura]

Good day all,

Thanks for the info Perry. What does 151 kts translate to at the surface?

151 Knots is almost 174 MPH ... The surface correction is usually 90%, so 174 * 0.9 is about 157 MPH.

Call it 160 MPH on the next advisory (usually the advisories round up or down each 5 MPH), and voila, you have a minimal cat-5 (over 155 MPH) ;-)

The 90% is for a well-mixed eyewall boundary layer over a marine (ocean) environment. Over land, or when cool air is involved, this can drop to 50% (also common over cooler N atlantic waters).

Over the W Caribbean, water near 90 F, no shear, it should be 90%.

[Bob Schafer]

Is anyone able to decode what the "894" at the end of this dropsonde data implies? There's been some noise about this on easternuswx.com. Thanks.

http://www.nhc.noaa.gov/text/MIAREPNT3.shtml?

[Gabe Garfield]

Just as an FYI, the last Atlantic Basin hurricane to make landfall as a Category Five hurricane was Andrew in 1992. Even though we've had several Category Five storms since Andrew, most were weakening upon landfall. It is very likely that this will not be the case with Dean, as it appears that he will be on the upswing at landfall.

Gabe

[John Peters]

I still think it's possible that dean will not become a category five before landfall. The most recent forecast advisory suggests the formation of concentric eyewalls once again. This may inhibit further strengthening of the inner eyewall. Reconnaissance data has also suggested that 130kts is somewhat generous of an estimate. Recent IR imagery has shown some asymmetry of the coldest CDO cloud tops (similar to behavior the storm has been exhibiting throughout the caribbean).

[cdcollura]

Very little is understood about eyewall replacement cycles.

The constant re-structuring of a hurricane core makes a 5-10 MPH change nearly impossible to predict with current tools and technology.

This is where the term "fluctuations" in strength of a hurricane that has peaked at max intensity come into play.

[Perry Williams]

Good day all...

I love chasing hurricanes, and been through many bad ones as well.

I have Andrew 92, Katrina 05, Charley 04, and many others under my belt ... But although I am down-right CRAZY, I never want to even be labeled as STUPID.

Here are my NEGATIVES on why I am not just jetting to the Yucatan, renting a car / SUV, and chasing Dean.

1). Night landfall (like 4 AM or so).

2). Storm core keeps shifting more W (not the expected WNW) on each advisory / forecast package.

3). Landfall may be on (or even south) of Mexican / Belize border.

4). If that verifies ... Jungles, little or no road networks.

5). You cannot bring 2 weeks of food, water, and survival gear on an airplane.

6). Anarchy and corrupt government, looting, disorder afterwards.

7). I do not have a gun, and will not buy one to protect myself there AFTER the storm.

8). Started a new job, and being stuck in the jungle for 2 weeks with no comm whatsoever will not explain why I should not be fired as I come back sometime in September.

9). Basically, Chris Collura would essentially disappear from the USA for 2 weeks or so.

10). I have not watched enough "Survivorman" on DISC yet.

11). "Dean" is my middle name ;-(

12). Parking garages above 30 feet MSL are hard to find on the east side of the bay of Chetumal. Surge is another issue, as the photo ops we had in Katrina in 05 won't happen since it will be dark.

13). Winds sustained at 150-160 MPH (this is at-least) and a 30% rule on gusts (near 200 MPH) - This is basically an EF-5 tornado (over 200 MPH peak winds) about 30-40 miles wide and at night - THINK about it!

Just my thoughts. But remove some of these "negatives" and I might re-consider (won't happen in 12 hours) ;-(

I agree with you 100%......which is why I never even considered chasing Dean once it became apparent it would remain south of the Rio Grande. The aftermath of a borderline cat-4/5 hurricane in an area you aren't familiar with (and where you aren't a citizen) could be just as dangerous IMO as the hurricane itself.

[George Kourounis]

Here's a pic of the surge coming in along the Jamaica coastline.
More pics online here:
www.stormchaser.ca (http://www.stormchaser.ca)

http://www.stormchaser.ca/Dean/Dean_02.JPG

[beaudodson]

Josh made it to the hotel - he is in Chetumal, Mexico and posting

http://www.easternuswx.com/bb/index.php?showtopic=139960&st=660&gopid=2073150&#entry2073150

[Marcus Opitz]

latest update from the nhc raises the winds to 155 mph...very close indeed...

[B Ozanne]

It looks like north of Chetumal there is very little along the coast until you get to Cozumel.

Any news out of Jamaica?

[Marcus Opitz]

nhc reports that winds are now 160 mph per 835pm update....

[B Ozanne]

Dean is now a Cat 5 with winds of 160mph. Update just issued by the NHC.

[John Peters]

Pressure is down to 915 mb (via recon. aircraft). What a monster. God have mercy on anyone in the path of this storm.

[Brian Stertz]

DATA FROM THE AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT CURRENTLY INVESTIGATING HURRICANE DEAN INDICATE THAT MAXIMUM SUSTAINED WINDS HAVE INCREASED TO 160 MPH...MAKING DEAN A POTENTIALLY CATASTROPHIC CATEGORY FIVE HURRICANE ON THE SAFFIR-SIMPSON HURRICANE SCALE.



Hurricane Dean now hits the charts as a Cat. 5....watch out Yucatan and NE Belize Coast. This one may rip the hurricane flags right off the flagpole. :eek:

[rdale]

The GFS model...which was dead on right earlier in the season this far out, now has progged what looks to be a major hurricane making landfall along the East Coast. This afternoon's run brings onshore over Charleston, SC.

Charleston, Yucatan... they sound similar at least ;> What's a few thousand miles when it comes to forecasting...

[Bill Tabor]

This Hurricane Josh scenario is interesting. I hope the guy fares ok, as it sounds a bit tough. I went over to the forum board and here is his most recent post from 2 minutes ago:

9:20 pm CDT

I'm overwhelmed by the response to this thread. (IMG:http://www.easternuswx.com/bb/style_emoticons/default/smile.gif) I really am.

I'm going to keep a stiff upper lip for y'all, but I won't deny some concern Re: the way this is going on. I'm going to get what I've wished for for twenty years-- since I was a baby weenie on Long Island-- and suddenly, I'm not sure I want it.

But what's done is done. It is what it is, I've made my choices, and I will live with them.

I used to drink a lot during chases-- was hammered during Bret 1999 in TX-- but I gave up alcohol long ago, and so these days, my best way for getting rid of nervous energy is running, and I just went on a 25-minute run-- along the bay. It's still calm-- and I can see the moon a bit. A couple of families were hanging with their kids at the waterfront. Two men sat on a bench smoking. There's something very stoic about the Mexicans-- they don't overreact to things, I've noticed. Perhaps it's because they've all led hard lives? I'm mightily impressed, and their cool vibe is keeping me cool, too.

I just got back and noticed the N wobble. I'm f*cking glad about that-- as long as I'm S of the eye, I'm cool. I just don't want to be in the right-front quad with this one. I never thought I'd hear myself say that about a 'cane. I'm humbled tonight as this monster appraoches.

And yet it's still so calm outside. It's hard to believe what's coming. I almost don't... Like the satellite images are all make-believe.

[Brandon Clement]

This Hurricane Josh scenario is interesting. I hope the guy fares ok, as it sounds a bit tough. I went over to the forum board and here is his most recent post from 2 minutes ago:

Been there done that. Luckily the ones I thought were too much weakened before coming ashore. Lili scared the hell out of me. I only live about 4 hours from the target for Lili. When I left the house she was a weak 2, when I got to the target, found a hotel and checked in she was a 4 and the forecast was talking about a solid 5 moving into a very low lying SW La. I really started getting worried when I saw Jim Cantore 20 miles farther inland than I was. Luckily it weakened and turned out to be the chase I had the most fun.

I don't think he is going to be quite so lucky.

[John Peters]

Based on the most recent dvorak images, i would conclude that the storm has continued to strengthen since the last advisory. The area of coldest cloud tops in the CDO has become very symmetrical around the now very-well-defined eye. Let's hope for this guy's sake that the slight jog to the north will spare him the northern eyewall. I wouldn't be supprised if this storm produced some of the most substantial storm surge in history.

dvorak IR loop:
http://www.ssd.noaa.gov/goes/flt/t1/loop-bd.html

[Brandon Clement]

Latest recon

000
URNT12 KNHC 210029
VORTEX DATA MESSAGE AL042007
A. 20/2346Z
B. 18 DEG 17 MIN N
085 DEG 00 MIN W
C. 700 MB 2359 M
D. 121 KTS
E. 318 DEG 9 NM
F. 047 DEG 156 KTS
G. 318 DEG 08 NM
H. 914 MB
I. 9 C/ 3047 M
J. 21 C/ 3053 M
K. 17 C/ NA
L. CLOSED WALL
M. C16
N. 12345/7
O. 0.02/2 NM
P. AF303 1404A DEAN 0B 30
MAX FL WIND 162 KT NW QUAD 2358Z

Would put surface winds at 165mph

http://www.nhc.noaa.gov/text/MIAREPNT2.shtml?

[John Peters]

Based on the 914 mb, Dean has now tied Janet as the 10th most intense hurricane ever in the atlantic basin.

[cdcollura]

Josh - Hang on and be safe.

let me know if you see a faint stadium in moonlight and stars during the calm - Just make sure you shield your face after that 20 minutes of calm (oh, and face the other side of the wall your hiding behind = Wind shift) ;-)

Wish I was there with you - Good luck!

[MClarkson]

The IR Sat finally shows the classic, epic cat 5. Eye is nearly perfect, so is the CDO, nearly symmetrical thick and cold. There is a very slight dry slot to the north, that is it. Certainly the structure is better looking than when the last plane left. I agree with John, the storm has strengthened since the last plane left 4 hours ago. Another should be there in 1:5h or so, and I would think Dean is at <910mb. We'll find out when they arrive.

[Warren Faidley]

Does anyone know where "Josh" is actually located? Is he in a hotel on the beach (sounds like it). In what town?

Warren

[Helen Rossington]

What time is landfall expected? I am getting confused here with all the time conversions - can someone post it in UTC (Z) please, thanks!

[David Wolfson]

Hi Warren, courtesy of the other board...
http://www.easternuswx.com/bb/index.php?s=&showtopic=139960&view=findpost&p=2074291

[Greg Campbell]

Does anyone know where "Josh" is actually located? Is he in a hotel on the beach (sounds like it). In what town?

Warren

Warren,

Josh mentioned being in a 'block long' three story building at
18.50023N 88.29743W

I think he's in here: (Google Earth) http://members.cox.net/geonerd/Josh.kmz

[Warren Faidley]

Thanks, I've been reading his blow-by-blow (no pun intended) posts on the noted forum. Looks like he is going to take a direct hit, according to the guys who are monitoring the Cancun radar site. Either way, looks like an eyewall experience at night. I'm guessing his connection will go soon, as I think they turn off the power in Mexico in advance of hurricanes. I remember going insane when Andrew hit at night and I could not shoot anything until daybreak!

Does anyone know the ocean geology of that coastal area and the storm surge potential?

Warren

[MClarkson]

Its a steep coast, not quite as resistant to surge as say, cancun, but still youd expect about twice the surge if this storm was landfalling on the US gulf coast.

plane is approaching the eyewall, ~15 minutes till the eye.

[MClarkson]

xtrap 907mb, flight level wind max 156kt

[John Peters]

xtrap 907mb, flight level wind max 156kt

is it me, or is 156 kt extremely low for a Central press. of 906 mb!?

[MClarkson]

Its reasonable, it supports a surface intensity of 135/140 knots typically. This is the planes first pass, they probably havent sampled the strongest winds yet, and they have many passes left on this mission.

[Warren Faidley]

RE: Storm surge: From HHC:

STORM SURGE FLOODING OF 12 TO 18 FEET ABOVE NORMAL TIDE LEVELS ALONG WITH LARGE AND DANGEROUS BATTERING WAVES IS POSSIBLE NEAR AND TO THE NORTH OF WHERE DEAN MAKES LANDFALL ALONG THE EAST COAST OF THE YUCATAN PENINSULA.

[Jason A.C. Brock]

I am up late and monitoring Dean. I was wondering if anyone has some quick links.

1. This Hurrcane Josh blog (also wondering when his last post was and if hes ok)

2. ANY radar near the Landfall area

3. Updated net info from the Hurricane Hunters (maybe even a link to their HAM frequencies linked online).

4. Any TV stations reporting this live or even AM FM radio stations or any kind of local HAMS in the area.

It is interesting to note the low lying area north of Chetumal that looks like a river or canal. Anyways it looks possible that water could be pulled South from Isla de Techal AS storm surge pushes in there and then follows this feature South toward Chetumal. You can see it on Google earth pretty well. This is going to be major but if this thing was moving like 5 mph....I cant even imagine.....I cant even imagine as it is anyways....

[MClarkson]

The plane circled around in the eye a few times, presumably because they missed the drop. at 0633z they dropped a 909mb, but with 27 knots of winds recorded at the surface indicating they did not hit dead center. The actually central pressure was likely a few mb lower.


The plane is moving in for another pass.

EDIT: Through the eye, 164kt fl winds, similar central pressure xtrap

[John Peters]

there is buzz about a new central press. over on WX Eastern of 907 mb. I'm not sure how accurate this is.

[MClarkson]

the latest VDM confirms 907mb. This matches exactly with the 909mb drop that missed by a little and a flight level xtrap of 905.


We could be seeing a landfall pressure <910mb. That is historic. Not many canes have done that. The eyewall is just moving onshore now, the middle of the eye should be onshore in an hour or so.

[John Peters]

the latest VDM confirms 907mb. This matches exactly with the 909mb drop that missed by a little and a flight level xtrap of 905.


We could be seeing a landfall pressure <910mb. That is historic. Not many canes have done that. The eyewall is just moving onshore now, the middle of the eye should be onshore in an hour or so.

*Edit
1)1935 labor day (892 mb)
2)Dean (905-909 mb)
3)Camile (909 mb)
4)Katrina (920 mb)
5)Andrew (922 mb)

[MClarkson]

000
UZNT13 KNHC 210715
XXAA 71078 99186 70871 04587 99907 27206 09009 00/// ///// /////
92/// ///// ///// 85576 24620 06509 88999 77999

http://www.nhc.noaa.gov/reconlist.shtml


that is the latest eye drop

[Jason A.C. Brock]

http://en.wikipedia.org/wiki/Hurricane_Camille

Some great links to info on all the Canes and more mentioned by John


Does anyone Recall where Rita ranked as far as its lowest pressure?

[John Peters]

http://en.wikipedia.org/wiki/Hurricane_Camille

Some great links to info on all the Canes and more mentioned by John


Does anyone Recall where Rita ranked as far as its lowest pressure?

Wilma (882)
Gilbert (888)
Labor Day (892)
Rita (895)

[MClarkson]

New eye pass, 161 knots at flight level, extrap 903mb


A category 5 intensifying as it landfalls. Good thing it chose a relatively unpopulated area.

[John Peters]

000
URNT15 KNHC 210734
AF306 1504A DEAN HDOB 27 20070821
072500 1859N 08712W 6961 02824 9645 +118 +118 101109 110 079 000 00
072530 1857N 08712W 6970 02793 9621 +119 +119 100115 117 082 001 03
072600 1856N 08713W 6960 02778 9579 +129 +116 102123 124 087 000 00
072630 1854N 08713W 6963 02736 9524 +148 +099 102131 134 096 000 00
072700 1853N 08714W 6968 02679 9463 +161 +095 105142 145 105 000 00
072730 1852N 08714W 6955 02651 9406 +163 +102 106146 151 110 000 00
072800 1850N 08715W 6956 02583 9358 +141 +128 107157 161 123 018 00
072830 1849N 08715W 6959 02515 9302 +122 +122 114144 149 122 018 00
072900 1848N 08716W 6971 02433 9206 +150 +150 110123 136 116 003 00
072930 1846N 08716W 6971 02362 9114 +177 +159 104093 102 101 001 00
073000 1845N 08717W 6953 02332 9036 +216 +130 102063 077 112 001 03
073030 1843N 08717W 6962 02313 9028 +217 +127 100026 037 035 001 03
073100 1841N 08718W 6972 02314 9038 +216 +127 079003 017 007 003 03
073130 1839N 08718W 6967 02350 9074 +208 +132 268021 026 003 003 03
073200 1837N 08717W 6967 02384 9115 +196 +141 260037 044 035 004 00
073230 1836N 08717W 6960 02434 9178 +175 +151 256057 068 092 007 00
073300 1834N 08717W 6993 02448 9990 +128 +999 256096 110 120 020 05
073330 1833N 08717W 6919 02628 9990 +099 +999 257116 123 122 041 05
073400 1832N 08717W 6982 02618 9990 +087 +999 255116 120 093 042 01
073430 1830N 08717W 6966 02686 9554 +083 +083 259104 108 092 023 05

Is it possible that this thing is bottoming out as the western eyewall is moving onshore? Only other storm EVER that i remember behaving this way was Andrew.

[MClarkson]

000
UZNT13 KNHC 210748
XXAA 71077 99188 70873 04587 99931 26000 ///// 00/// ///// /////
92059 26004 03673 85804 22200 08648 70492 14800 11157 88999 77999
31313 09608 80728


northern eyewall drop, 173knots 59 meters up.