May Chasing 2008

[Paul Sherman]

Well its that time of year again when the Hordes congregate on the Plains in search of Tubes. Will we get a Saturday High Risk like last year when we all got caught in Traffic Jams of Chasers in Kansas or will the Dreaded "DR" Set Up again. Surprised no threads have started on the outlook for Early and Mid May yet as we are coming into the Model Timescales, looking a bit ridgy for the Start of May on current Model Runs, but what do all you guys think ??
Sunbathing around the Hotel Pools or 400-600 Mile Chase days ??

Thoughts

Paul Sherman

[Willie Dines]

I'm on the 50 yard line as to whether it will be a quiet or lively chase month, it's hard to say with Aprill being pretty quiet, but that doesn't mean May couldn't turn out to be a tube fest, I think that it's merely a case of wait and see.

In other words, I'm not going to make any guess' because guess work is useless when it comes to forcasting of any kind and forcasting is most definitely not my fortee, (Although I hope to change that soon).

Willie

[David Drummond]

I know this sounds crappy, but the only way to really know what this May will bring for you in chasing is wait until June 1st. Anything else is an educated best guess.

[Shane Adams]

Couldn't tell ya. All I know is I'm constantly reminded of 2004 at this point.

[Jim Leonard]

One thing Im encouraged about is the dreaded Hudson Bay low has not been the dominate feature so far. Lately the problem is what we see almost every year around this time is these pesky cutoff lows. Hopefully these lows will run they're course soon so we can get a more progressive wave pattern. If one of these gets stuck in the GOM or where the one is now off the south atlantic coast that could shut down the good tropical juice for a week or more or like 2006 over 4 weeks.

[Bill Tabor]

The best cure for a DR May is to chase April when you've got 'em.

[Andrea Griffa]

So far, in the last two days, I saw an omega block that could give us a ridge upon our heads for at least 7 days,starting from april 29th, confirmed by GFS and ECMWF models. I'm anxious to see today's update. To be honest that is the only pattern I didn't want to see, opening the long range page.

Those are long range forecast and I don't believe it will verify at all.

[David Wolfson]

Very encouraging for 4/30 - 5/9! I'm beginning to believe in the long wave trough settling in the west. The models seem to be giving up on the cut-offs embedded in the east and central US solution in favor of progressive short waves riding the western trough and into the eastern ridging. If this proves out it looks like a busy week or two. :)

[Kem Poyner]

Im heading out from Phoenix on May 3rd. I will be out chasing for a couple weeks. I moved my trip ahead to the beginning of May instead my usual late May gig. I have seen so many small tornados and now am a big game hunter. Know where I can find some Elk??!! The Woman can run a little large out there also...can always find....Hey, what happens in Ponca City stays in Ponca City!
Kem

[Kem Poyner]

Mayday Mayday. It looks like May will start off with a bang. Long range forcasts show good possibilities April 30 and May 1. I just have a gut feeling that May is going to be very busy. But it is probably just gas.

[Brendon Lindsey]

Hmm I would be very depressed if there is a good chance on the first of May seeing that I have a mandatory banquet =/... Would be nice if something slowed down or sped up =) for either that Wednesday or Friday.

[Greg Blumberg]

I would love a couple of days 5/7-5/9 to chase before I fly back home. Hoping that the early May will bring at least one nice, chaseable outbreak that's not on an exam day. Right now it looks like that dream looks possible.

[Ian Miller]

I wonder if the patterns are going to push the action northwards again by the end of the month?

[Mike Peregrine]

Thanks to La Nina, we are/have been having what we used to consider a fairly "typical" chase season. Action in the so. plains in March/April. There have been discreet, slow-moving supercells down there too, I've noticed. Not a lot happening this year in the way of fast-moving spring outbreak scenarios. As long as the current trend holds, I would think we'll also see a standard migration of severe northward over the coming month.

[Brandon Sullivan]

Should be out on the plains from at least 5/23 till 6/1. Looking forward to it...

Quick look through 700+ hour forecasts don't impress me though... lol....

But I think that may change. Slight variablility that far out.. :D:D

[Mike Kovalchick]

From Ed Berry's blog site(Dodge City NWS Long range forecaster):

http://weatherclimatelink.blogspot.com/

"Once the tropical convective forcing comes out into the west Pacific, meridionally oriented RWDs are likely, perhaps shifting a trough farther east into the Plains. Given higher latitude blocking forced by zonal mean AAM transport considerations, a cold and wet pattern for much of the lower 48 states focusing on the central states is a forecast option by ~weeks 2-3."

(He is talking about the May 4 through the May 17 time frame)

NCEP forecast for May 5 through May 11(wet & cool) :

http://www.cpc.ncep.noaa.gov/products/predictions/814day/index.php

NCEP forecast for the month of May(Dry in the Plains):

http://www.cpc.ncep.noaa.gov/products/predictions/30day/

I'm heading out in the Plains May 15-May 26 time frame..so far...happily...I don't really know what to expect.

[Chris Hayes]

The first 2 weeks of May arent too big of a concern for me. I don't leave for my chasint trip till the May 9th-12th time frame. Hopefully by the time we get out there, the pattern will be a bit more favorable.

[Andrew Stoller]

On the super long range GFS, once this next trough moves through the end of this week, things stay quiet until about mid May, when a new trough develops out west. It looks to cut off and head south into Mexico almost. Hopefully this pans out cause it looks pretty darn quiet through early May...

[Scott McPartland]

I don't know about it being quiet until mid May neccesarily. The 12Z Euro is just out and that paints an interesting picture for the first week or so of May with another nice looking trough moving in around the 4th/5th, and another one waiting in the wings at the end of the run (the 8th).

The 12Z GFS shows a similar 500 set up for the 5th/6th & 8th. Dave Lewison and myself are considering pulling the trigger on our chase trip this coming Saturday, assuming things continue to look good as we progress throughout this week :)

And if we get lucky, we may not have to do the insane marathon drive from NYC all the way to Kansas this time around! lol. It'd be nice to break up the 1500+ mile drive into two days, sleep is kind of important..

Best of luck to anyone who's chasing this Thursday! I'll definitely be watching the live streaming for sure!

Scott

[Paul Knightley]

Can someone please point me in the direction of the super long range GFS please?

[Dick McGowan]

Can someone please point me in the direction of the super long range GFS please?

http://www.wxcaster.com/conus_0012_us_models.htm

It's out to 384 on here (16 days).

[Paul Knightley]

Ah OK - I've seen a number of locations with 16 day stuff - I was wondering whether it further than that?

[Andrea Griffa]

ECMWF is showing in the last three days a nice dry line pattern on may 4-5 and may 6 in Tx Panhandle.

[Andrew Stoller]

Yea Andrea, the next trough coming though looks better now. Monday might have potential in west Texas.

[Dan Cook]

Well it looks like May's off to a decent start after today.

[jeremy wilson]

And it may get better Dan. Although theres always that 2 week lull in May at some point. It seems like the middle of May is always slow.

[Dan Cook]

And it may get better Dan. Although theres always that 2 week lull in May at some point. It seems like the middle of May is always slow.

Check out the GFS though. Looks like a parade of troughs coming in for the next few weeks.

[Mike Kovalchick]

Ed Berry's lastest long range forecast is out. Sounds like the vacation chasers are going to have a good season!
http://weatherclimatelink.blogspot.com/


...high impact weather situation appears probable (above May climatology) during ~ weeks 2-3.....

[Shane Adams]

Ah OK - I've seen a number of locations with 16 day stuff - I was wondering whether it further than that?

You'll never need further than that, because anything past 16 days won't be there in 8.

[jeremy wilson]

Like always, I wasted alot of my chase funds on March and April, so I hope May has many chaser freindly days so I dont have to be forced to chase in one of my broke periods.

B

[Mikey Gribble]

This IMO has been the worst year for model watching IMO. I've only been chasing for 7 years and I didn't watch the models that closely for the first 2, but I think this season has taken the cake (so far) for poorest model performance. The ECMWF has done OK, but the GFS and NAM have sucked. I can't even bring myself to believe what either is showing 24 hours out, so there's no way I'm believing what they show a week or two out. If I try to post a forecast for several days out on my blog I usually end up looking like an ass when it doesn't verify. I'm about ready to throw in the towel.
The exception to this is when they GFS is consistent in showing a synoptically evident outbreak scenario with a large West coast trough. I'll get on board with those setups a week out, but it doesn't do much good because the devil is in the details and the details haven't been accurate at all this year on the GFS and NAM.

[jeremy wilson]

True dat Mikey. Thats why it would be sweet to chase every setup with finances not being an issue. Not just this year but many past years I've seen so many chasers posting pics of killer high contrast tornados in very iffy setups. I've chased every setup in ok. and tx. this year up until this last week and look what happens,tornados in a super marginal oklahoma setup while i'm sitting at home willing nothing to happen!

[Andrew Stoller]

This IMO has been the worst year for model watching IMO.

And so, with a grain of salt, I'll post that it looks like a new fairly substantial trough :could: be digging into the west by early next week. GFS shows it, but the ECMWF looks to be 180 degrees opposite with just zonal flow - maybe a much less substantial trough.

[Geoff Manikin]

starting to look very favorable for early next week. The 12z GFS blasts the next wave into the Ohio Valley by Tuesday evening, but it's an outlier. The GFS ensembles strongly favor a deep sfc low somwhere over northwest OK on Tuesday afternoon, and the 12z ECMWF seems to favor that as well. Heck, the ECMWF keeps chances on the southern plains into at least Wednesday as well. Monday has potential for far west TX if moisture can get back in time.

[Paul Knightley]

...but there are signs of quite a big ridge developing from the NW after that - ECMWF EPS shows this tending to flatten, and then start to set up a mean west coast trough by around 21st May - just in time for our trip! ;)

[Chris Hayes]

...but there are signs of quite a big ridge developing from the NW after that - ECMWF EPS shows this tending to flatten, and then start to set up a mean west coast trough by around 21st May - just in time for our trip! ;)


I hope you're right about that trough. I've been looking at GFS model runs the past couple days and get sick when I see that west coast ridge/east coast trough setting up. We're leaving for chasecation sometime next week. We have 3+ weeks of chasing to do, so I'm sure we'll get at least a few chase days in.

[Kevin Myatt]

Dave Carroll and I are headed out leading the Virginia Tech/North Carolina-Asheville group (plus two high school students) on Sunday ... you always know when we're headed out because the jet starts taking a southward plunge out of Canada (4 years in a row!)... fortunately we have at least a couple of decent shots before that happens, as we may well try to intercept Sunday's system in the Tennessee/Ohio Valley on the way west to whatever goes down early-mid week in the southern Plains.

After that, if the models are close to right, it looks like a few (or many) quiet days of northerly/northwesterly flow. Maybe we can get a disturbance across Texas with a stalled front or something like that during that time -- a run here or that has hinted at that. And we'll be hoping the Euro is right in scrapping the western ridge sometime during before Memorial Day!

[Dan Cook]

http://www.nco.ncep.noaa.gov/pmb/nwpara/analysis/namer/gfs/12/images/gfs_500_312s.gif

That's a little encouraging at least.

[David Draun]

What is that damned Hudson Bay polar vortex doing still around? Tell that persistent annoyance to look at the calendar and go away. One GFS run even has the 540dam thickness line coming as far south as northern Illinois! Geez, is there going to be mid-May snow? I leave for a one-week chase trip on May 24th, and I hope things will seriously be looking different than this.

[Cstok]

Ok... so I am liking this better than what I have been seeing lately for the week of the 19th. Of course this could (*will*) all change on the next run, but I wanted to get ebodys perspective.
http://www.ecmwf.int/products/forecasts/d/getchart/catalog/products/forecasts/medium/deterministic/msl_uv850_z500!Geopotential%20500%20hPa!240!North% 20America!pop!od!oper!public_plots!2008050900!!cha rt.gif


http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/12/images/gfs_500_252s.gif

[Scott Weberpal]

Looking at that, I'd want to be out 4-8 days following. Looks like a ton of energy is going to spill in from the Pacific. If you're starting your chase vacation after May 22 or so, things look good. Then again, we're talking about the GFS at 240+ hours :)

[Mike Hollingshead]

This pattern is getting amazingly old now. Looks like the Tuesday/Wednesday "system"(strong cold front with it like normal) really plans on smashing the gulf ahead of any future waves. Everytime I see big energy out in the Pacific, that ridge manhandles it into Canada, then it dives se(not good). Half the time these do this they split and shear out as they come out, or the don't amplify till they get just east of the plains. Then they smash the gulf. That Pacific ridge has been a beast. I'm close to writing off May, lol. It'll be nice whenever that pattern changes, but man, it's been so good at only getting dented then quickly transitioning right back.

[Cstok]

From the DDC AFD this afternoon:

MERIDIONAL FLOW WILL SUPPORT RELATIVELY COOL AND QUIET WEATHER INTO NEXT WEEKEND. THE AMPLIFIED UPPER LEVEL REGIME WILL BEGIN TO BREAK DOWN EARLY THE FOLLOWING WEEK...AND A RETURN TO MORE ACTIVE WEATHER IS LIKELY BY 20-21 MAY.



... and there is hope..sort of... for now!

[John MacKay]

While I'm going to KS next weekend (16-18), it wasn't for weather, but I would take advantage of it if it did. About two or three days ago, I knew it would be clear the whole weekend (a nice weekend considering it will be at the same time Phoenix may reach 100 the first time this year), so I guess there are no distractions.

Currently, we have a big severe weather day on our hands. I was strongly considering going today until early on Friday, when my options (either time or the $700+ airfares) didn't seem feasible, with some opportunities later. I then look at today's 0800 Day 2 outlook and saw the bullseye around Atlanta. Then, I found every flight on one airline straight to Atlanta was around $270, coming back early on Monday. I really struggled with pulling the trigger. I decided not to, because there should be some setups on weekends later on in the Plains. I just wish the Thursday setups would push themselves to the weekend sometime.

The Memorial Day weekend possibility would be met with higher fares. I'm more likely to go out on 3-day weekends (like the next three will be for me due to early other Friday off and Memorial Day) than 2-day weekends (like this one).

I just hope this encouraging pattern for the last third of the month keeps trending toward the active side. I'd like a chance at a Memorial Day weekend chase.

[Laura Duchesne]

Just a gut feeling... since winter I`ve been thinking we will get something real good this year. We are leaving on May 25th for a week and a half. It`s hard to go by long range GFS... but I`ve been going down the last couple of years and we have seen tornadoes during that time period (last week of May, first week of June), but mind you, in `06 we had to do a LOT of driving around... north, south, north, south.... it was nice last year because we played the southern plains a lot.

[Mark Farnik]

All I can say in regards to the potential of the active pattern later this month is two things:
- the storm activity really needs to make a major northward shift. I know this has been a great setup this spring for Southern Plains chasers, but its time for the Central and Northern Plains to get in on the act. I'm sick of the prospect of 1500+ mile chases. How about a nice eastern CO/western KS and NE tornadic setup for a change, not counting the April 24th northwest KS storm?

- there had better damn well NOT be a major outbreak on the 23rd or 24th... the 24th is the day of my high school graduation, and that's something I can't miss, seeing as I'm speaking and singing at it, along with hosting 150 + guests at a grad party afterwards, which I have to help my parents prepare for the night before.
If there's going to be a huge chase day, it can either happen the 22nd, so I can be back home by the evening of the 23rd, or on the 25th, which I could leave for as soon as I'm done cleaning up the building we rented for my grad party. Knowing my luck, however, the best chase day of the year will be the 24th....:mad:

After that, I am completely free and clear to chase whenever and wherever for several weeks, and I have a gut feeling the last week of May and first few weeks of June will be extremely active, particularly on the High Plains. Lord knows we're long overdue for bad weather around here, the last few summers have been almost dead quiet in terms of severe weather, especially in north central and northeast Colorado and into northwest Kansas and western Nebraska. It's about time we had a wild summer again...

[Marc Rémillard]

I'm leaving Canada on May 14 with Rejean Boudreau and we plan to stay on the plains for 3 weeks. We'll be there for the 20-21-22ths possible paradise days... I got hope :)

[Paul Knightley]

For a number of days now, both the GFS and ECMWF ensembles (the stuff to look at for days 7 plus!) have been developing mean 500 hPa troughs over the western US. The GFS deterministic runs this morning have begun to trend towards this solution. I think from around 21-22nd May onwards, a rather active pattern should set-up although I do see the risk (beforehand) that a strong cold front could get right into the Gulf. Or I could be wishcasting, since we flight out to DFW on the 19th!

[Dan Cook]

Latest GFS runs shut down the ridge. :)

http://www.nco.ncep.noaa.gov/pmb/nwpara/analysis/namer/gfs/12/images/gfs_500_252s.gif

[Mark Farnik]

That 500 mb map is a thing of beauty! That is a very, very nice trough! Hopefully it pans out, as if the trough is in the posistion advertised on this 500 mb map, it would kick out onto the Central Plains the afternoon of Thursday the 22nd, which would be perfect timing for me! I could leave Wednesday night, chase Thursday and be back home in time for my high school Baccalaureate Friday evening! :D
If the weather gods are inclining their ear unto us, I beg of them on hands and knees, do NOT let this system slow down, as I will erupt into a fit of violent self flagellating frustration if a tornado outbreak occurs the 23rd or 24th...:mad:

[Andrew Stoller]

May 24th: Violent tornadic supercells in eastern CO. Bank on it!

[Scott Weberpal]

May 24th: Violent tornadic supercells in eastern CO. Bank on it!

Are we taking bets on this? ;)

[Mark Farnik]

Very funny, Andrew. Now you've jinxed it!;)
But in all honesty, with my great luck and constant victimization by the strong arm of Murphy's law, this will be the case. I'm not placing any bets on it until the end of next week, I don't trust the models farther than I can throw them more than a few days out, especially this year.
Well, giving further thought to it, that actually might work out nicely IF it goes down. My grad party ends at 3 p.m., so if there's a nice, stout but breakable capping inversion that will hold intiation off until 4 or, preferably, 5 p.m., which will allow greater instability to occur in addition to giving me time to get to wherever I need to be, let the good chase times roll and the highly visible, uber spectacular tornadoes dance across the Colorado prairie!!! :cool:

[Cstok]

OK, we are still about a week out, but I like the changes I am seeing, and reading for middle of next week:

From this mornings AFD from DDC:
WILL FINALLY SEE DEVELOPMENT OF
LEE TROUGH AGAIN BY AROUND TUESDAY OF NEXT WEEK. JUST BEYOND THIS
FORECAST PERIOD...WE MAY BEGIN TO RE-ENTER A MORE CONVECTIVELY
FAVORABLE PATTERN ACROSS THE WESTERN PLAINS WITH A SYSTEM OF SOME
SHAPE OR FORM ENTERING THE INTERMOUNTAIN WEST REGION AND ROCKIES



Also like what I am seeing from the 5/13 00UTC ECMWF:
http://www.ecmwf.int/products/forecasts/d/getchart/catalog/products/forecasts/medium/deterministic/msl_uv850_z500!Geopotential%20500%20hPa!240!North% 20America!pop!od!oper!public_plots!2008051300!!cha rt.giff

The most recent GFS shows this as a closed low coming in a little slower... some time later next week... but again I like the over all changes I am seeing... one concern however will be lack of moisture, depending how deep the prev. front pushes into the gulf.

[Andrew Stoller]

Whew, I don't know. Out past 140 hours on the GFS, a small closed low looks to break out of the ridge, but it's pretty weak and out to 240 hrs, the death ridge is still in place with that friggin pesky Hudson Bay low. No overall pattern breakdown.

[Cstok]

12z GFS run looks a little scarry:
http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/12/images/gfs_500_228s.gif

What I think is intereting is the difference in the ECMWF:
http://www.ecmwf.int/products/forecasts/d/getchart/catalog/products/forecasts/medium/deterministic/msl_uv850_z500!Geopotential%20500%20hPa!240!North% 20America!pop!od!oper!public_plots!2008051300!!cha rt.gif

[Mike Hollingshead]

Dang, last two runs of the ECMWF are screaming welcome to spring in about 9 days. Looks like it wants to make up for some lost time fast, lol. Today's 12z looks rather sweet.

[cdcollura]

Good day all,

Missing the action this week and past week due to move (sold my home).

On the GFS, I see the "sickening" upside-down horseshoe "omega" high sitting over the Rockies past May 14 to nearly May 20 (glad I'm not there)!

Past that time, troughing resumes and I should make my 10-15 day trip then, but need to be back to FL June2 for new job.

[Dan Cook]

Hmm..which model to believe. The GFS is ridge city while the Euro has a nice trough next week..

[Chad Cowan]

Euro has been showing that nice trough digging in mid- to late next week for a few runs now. Moisture and heat will be aplenty, and if we can get a favorable trajectory of that trough there could be 3-4 good chase days as the energy gets cut off and slowly creeps East. The operational GFS has been absorbing that energy into the NW flow, up and around the ridge. Although, the bowl of spaghetti in the GFS ensemble for the forecast period tells me that the operational output is a shot in the dark.

EDIT: New GFS run (14/12z) is more in line with Euro. It takes the trough further south and makes for a very favorable svr-wx setup. Still considerable uncertainty, but this run puts a 987mb low in W KS on Wednesday with 65 dews pushing as far north as NE. It's reassuring to see the GFS trying to be more like its long-range-savvy European counterpart.

EDIT 2: Uhhh, woah. Just looked at the 00z Euro fcst MSLP (http://meteocentre.com/models/ecmwf_amer_00/cep00_9panel.gif)... and um, it's pretty good. 977mb low in wrn NE on Wednesday. So we got that goin for us, which is nice.

[Fabian Guerra]

This sucks. The euro model shows an active 3-4 day pattern next week and the gfs shows...well you know what it shows. I'm in chaser purgatory. I need to figure out by tomorrow whether to take my planned chase vacation next week or change it to the following week. Hell, I may be screwed both weeks which would be par for the course this year.

[Brandon Sullivan]

Lol. I am just sitting here watching the models flip flop.. Still hoping for a nice trough to move in. Get some gulf moisture, and get a good show...

May 23-June 1

Thats my vacation.. Think the ridge should break down and we will be ready for action.

(Cross Fingers):D

[Chris Hayes]

Lol. I am just sitting here watching the models flip flop.. Still hoping for a nice trough to move in. Get some gulf moisture, and get a good show...

May 23-June 1

Thats my vacation.. Think the ridge should break down and we will be ready for action.

(Cross Fingers):D

The models (especially the GFS) do continue flip-flopping on the 2nd half of the month. However the general trend seems to be troughing. Most of the troughing we see on the GFS is positively tilted, but I'll take a positive tilted trough over a ridge any day. Someone in the IRC chat room the other night mentioned about May being April this year, and June possibly being May. This might be the case as we seem to be stuck in an early to mid spring weather pattern. I leave tommorow morning for my chasecation. *crosses fingers*

[Scott Weberpal]

At this point the operational GFS seems to be the outlier and I wouldn't trust what it says. Take a look at the spaghetti plots and ensemble means and the patter begins to look much better by May 21. Some of the more recent runs (ECMWF vs GFS) have been total opposite with the GFS showing ridging through the 192 hr period, and the ECMWF showing a rather large trof across the western US. My chase vacation dates are set and there's no use racking my brain over this, but I still find myself checking the medium range models on a daily basis.

[Mike Hollingshead]

GFS seems to have been fairly consistent in what it thinks for that May 20th on period. Tendency for a sort of little cut off(or almost cut off) and right back to the same east US troughing. The ECMWF has been consistent too, but with a MUCH better look. Give me a consistent ECMWF over the GFS any day.

The 12z ECMWF just came out and still looks phenomenal(at least 3 runs in a row looking similar that I've seen). I was trying to remember the last time a west coast trough looked like that in middle-late May. 2004? I can't think of one time in May 10th through all of June in 2006, nor one time May 6th through all of June 2007. 2005 had a couple decent shots around May 11-12 and again the June 6-10th period, but this just looks better. I almost have to take a double take on this, it seems so foriegn anymore for post 1st week of May.

I'd imagine gulf moisture will be primed by then too. Then given the big trough from hell, we'll still get to deal with all the other things that can go wrong!

[Paul Knightley]

As I work as a meteorologist here in the UK, I have access to the full suite of ECMWF data out to 240 hours. Let's just say that dew points by 240 hours are above 70F all the way from the Gulf Coast to the Great Lakes, with a pronounced dryline through the central Plains every day from next Wednesday to Sat (the furthest the model goes). 850 flow is at times 50 knots plus!
The GFS ensembles keep showing a better chance of a SW trough next week, and the 12Z GFS does, to my eyes, try to trend that way somewhat. I reckon it'll come more into line with the ECMWF over the next few runs.

[Joshua Horenstein]

OMG, I had a flight for fri, but just bit the bullet and had it changed to next Wed, didn't see a point to sitting in the plains under clear skys and NW flow. I need that trough to exist and then arrive on thursday!

[Cstok]

:eek::eek::mad::mad::eek::eek::mad::mad:
http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/18/images/gfs_500_180s.gif


:D:D:D:D
http://www.ecmwf.int/products/forecasts/d/getchart/catalog/products/forecasts/medium/deterministic/msl_uv850_z500!Geopotential%20500%20hPa!192!North% 20America!pop!od!oper!public_plots!2008051412!!cha rt.gif

It all equals complete angst!

[Mike Kovalchick]

Based on the latest 0z ECWMF and the Ensembles Means..I adjusted my departure date for my chase vacation till next Tuesday evening and should be in position to chase Wednesday afternoon assuming there is something actually out in the Plains to chase.

Looks like an excellent possbility of multiple days of chaseable weather and I expect a banner chase vacation this season.(I'll worry about how I'm going to pay the gas bill after I get back. :mad: )

By the way..what is up with the GFS model this year? It's no wonder the dollar is slipping against the Euro! I suspect that I am not the only one who is annoyed by not having full access to the one long range model that is actually useful?

[Dan Cook]

Nice:

http://weather.cod.edu/forecast/ECMWF/ecmwf_850_temp_168.gif

[Jason McKittrick]

I have been watching both the GFS and the ECMWF for the last two weeks, and by my count the ECMWF has had the awesome western US trough for the past 5 consecutive runs ending with 00z today. The only difference has been, where and how strong the lee cyclone will be. The GFS has been showing some tendency to loose the ridging in favor of a trough toward the end of the period. I am currently siding with the ECMWF since it has been so consistent the last few runs, and the GFS just doesn't seem to know what to do with the Pacific energy. Yesterdays 12z run was trending more toward the ECMWF trough and this mornings run cuts off a low over the SW and retrogrades it of the coast. It seems a little late in the year for that to be a realistic solution but then again this whole season seems to be running about a month behind.

All that said I have already cleared my schedule for a multi-day chase and I am considering making motel reservations in Hays for Wednesday night.

[Stan Rose]

Im with you, Jason. Could be part wishcast since this may be one of my few ops to chase this year, but i dont see how you can ignore the EC's consistency, the 12Z GFS is starting to trend to the trough solution, as it has hinted at over the past couple days. SPC acknowleges the EC, but says the odds of severe are "quite low". I beg to differ, and im seriously arranging my schedule to accomodate the potential.

[Mike Kovalchick]

Latest 12Z ECMWF remains excellent for later next week..

Some initial thoughts on the setup from DDC:

http://kamala.cod.edu/ks/latest.fxus63.KDDC.html


"A STRONG UPPER TROUGH WILL DROP INTO THE CENTRAL ROCKIES BY
WEDNESDAY. CYCLOGENESIS WILL OCCUR OVER THE CENTRAL HIGH PLAINS.
THIS SYSTEM WILL INITIALLY BE PROGRESSIVE, BUT WILL LIFT ABRUPTLY
NNE INTO THE NORTHERN PLAINS BY THURSDAY AND FRIDAY. THIS WILL ALLOW
FOR A FRONT TO STALL OUT SOMEWHERE ON THE PLAINS OR FRONT
RANGE. THE SFC DRYLINE WILL BE LOCATED JUST EAST OF THE FRONT.
ISOLATED STORMS COULD OCCUR WEDNESDAY ALONG THE DRYLINE BUT THIS
SEEMS UNLIKELY GIVEN THE VERY WARM MID LEVEL TEMPS. STORMS MAY
DEVELOP ON THE FRONT LATE THURSDAY IN OUR EASTERN COUNTIES.
CONSIDERABLE UNCERTAINTY REMAINS AFTER THURSDAY. WILL THERE BE
ANOTHER DEEP TROUGH DIGGING INTO THE LONGWAVE POSITION OVER THE
WESTERN UNITED STATES? THIS SEEMS LIKELY, BUT THE EXACT LOCATION
OF THIS TROUGH IS IN QUESTION."

[Derek Weston]

GFS has been putting lows in the plain/midwest area with decent moisture the past few days runs... however, most of the lows stink and are lacking. (mid level winds, 850s placement....etc)

[Donald Giuliano]

Ed Berry issued a blog update today, in which he released the hounds--literally.

http://weatherclimatelink.blogspot.com/

Suffice it to say he's going with the ECMWF solution, which looks like a wedgefest for the Plains. We'll be in for quite a ride if it verifies, which I'm gaining confidence in since the ECMWF has been so consistent the last few days.

[Mark Sefried]

The European model is usually my choice of models when it comes to long range. I think I remember seeing somewhere a while ago that statistically the European slightly outperforms the GFS when it comes to long range predictions. With the European being consistant with that western trough and now that the GFS is finally catching on, when they both agree it usually happens. With the predicted pattern change still about a week away, things could still change so I would not bank on anything yet. I have May 20-June 9 off for chasing so for me its just a matter of waiting until the pattern becomes favorable and then leave.

[Mikey Gribble]

The ECMWF has definitely been the best long to medium range model this season. There really isn't any question about that. I am impressed with its consistency too over the last several runs. A negatively tilted trough with a 75kt mid level jet... that is about all you can ask for. Another reason to be optimistic is that although the GFS doesn't look nearly as good, it has been trending towards the ECMWF solution over the last several runs. Given each models performance this year I expect that trend to continue and we could be looking at a good chase day next Thursday.

[Chris Hovanic]

Ed Berry issued a blog update today, in which he released the hounds--literally.

http://weatherclimatelink.blogspot.com/

Suffice it to say he's going with the ECMWF solution, which looks like a wedgefest for the Plains. We'll be in for quite a ride if it verifies, which I'm gaining confidence in since the ECMWF has been so consistent the last few days.

From my experiences reading his blog, Ed Berry is one of the most accurate long range forecasters I've ever witnessed. His knowledge of global circulations and their affect on the 'sensible' weather pattern is really unparalleled in this field.

That being said, it certainly does appear we're headed into an active severe weather period, just in time for my chase vacation (May 27-June 6)!

[Mike Hollingshead]

If GFS has been taking baby steps towards the ECMWF, tonight it up'd the ante with a pretty big step towards it. Still has the trough too far east and progressive, but good sign none-the-less.

[Paul Knightley]

This morning's ECMWF (00Z) run is still consistent with digging a sharp trough into the SW'ern states. 00Z GFS is trying to come into line, although it still makes less of the initial digging. Even so, it presents several chasing scenarios towards and over Memorial Day weekend.

Just for interest, if we pick Friday on the EC we have:

100+ knot 300 hPa jet across E NM, W OK and TX Panhandles

75 knot 500 hPa jet streak in same place.

50 knot 850 flot across western OK into KS

Surface dews 68-70F across the same areas of OK/KS.

Long way off I know, but I just wanted to give you an idea of the parameters currently predicted.

[Paul Knightley]

06Z GFS is very like the recent ECMWF runs, and depicts a major western US trough being carved out.

[Andrew Stoller]

Wow, I hope the ECMWF verifies...nicely negative tilted trough next week.

[Cstok]

Well last night I pulled the trigger and booked to arrive Denver Tuesday evening and position from there for Wed / Thurs / Fri .. action. The models have pulled into tighter agreement and this far out you cant ask for more.

I also like the HWO from DDC this morning:

SEVERE THUNDERSTORMS ARE POSSIBLE ACROSS PARTS OF CENTRAL AND
SOUTH CENTRAL KANSAS THURSDAY NIGHT INTO FRIDAY NIGHT. VERY LARGE
HAIL AND DAMAGING WINDS ARE POSSIBLE. IN ADDITION...THE WEATHER
PATTERN WILL BE FAVORABLE FOR TORNADOES SINCE A STRONG JET STREAM
AND RICH GULF MOISTURE WILL BE IN PLACE. THE BEST CHANCE OF
THUNDERSTORMS WILL BE ALONG AND EAST OF A LINE FROM HAYS TO
COLDWATER.

[Mike Hollingshead]

Yeah, I'm making plans to raid the mini-dv tape section of the local walmart now. They may not have enough for this one! 12z GFS really flying towards the ECMWF now. Funny, now that it does I feel I need to dig up some fashion of caution. The biggest trend for forever has been to be disappointed in the last days before an event. These are pretty big, broad signals though, so it should be fine.

[John Wetter]

Yes indeed, the models are coming together quite nicely on a severe weather solution for the last half of next week. Headed into Memorial day weekend, chasers are sure to be plentiful and gas prices are sure to be high. The devil will of course be in the details, but it's nice to see as I haven't been able to partake in anything yet coming from Minnesota.

-John

[Mikey Gribble]

Yeah the new 12Z GFS is a thing of beauty with good directional shear and excellent speed at all levels. Moisture will be key. Assuming the timing on the GFS is right and Thursday is the first major chase day I think it is reasonable to expect decent moisture (maybe low 60's), but again if the GFS is on with the timing and everything else now then there should be high quality moisture in place by Friday. If either one of the models can come close to verifying (which it is looking more and more likely that it will) then given the quality moisture, strong wind fields, large spatial coverage, and climatology we will likely have a significant severe weather outbreak. Whether or not it is also a tornado outbreak is going to come down to the details. Quality moisture return and directional shear are my two biggest concerns right now. As is typical with these kinds of classic spring setups the day before the day usually has excellent directional shear, but moisture and capping are typically an issue (Greensburg last year was a day before the day event with excellent directional shear). Then on the main day there is typically strong deep layer shear (due to the trough ejecting into the plains), quality moisture, but you have lost some degree of your directional shear. That being said, if we can have decent moisture on Thursday, which we very well may given the 50-70kt LLJ being forecast 24 hours ahead of this combined with quality moisture residing right off shore, and maintain backed low level winds on Friday, then we may be looking at back to back tornado days.
This is definitely the most optimistic I've been for a setup this year when we were still 6 days out. I think half my optimism is a result of this year sucking so bad and there is finally a good trough being consistently shown by the models, but I also think some of my optimism is well placed given the reliability of the ECMWF this year and the fact that GFS is quickly falling in line with it.

[Jason McKittrick]

I am also am looking to load up on mini dv's today. I hope I don't pick the same store as Mike. Also bought my Windex wipes and my rain-x this morning. See you all next week in Kansas.

As fore the outlook it seems to be a little less certain as to which days will be the big days. The ECMWF holds on to the western US trough through next weekend and never really kicks it out. I have informed my chase team that it still looks like a two or three day event. But it now looks like it could just as easily be Fri, Sat, Sun as Wed, Thu, Fri as first thought.

Just looked at the 12z GFS and it is very similar to yesterdays 12z ECMWF with a southern NE event Wed, Western Ks on Thu and potentially a great day over eastern KS & NE on Sat.

That is my 2 cents, gotta go.

[Andrew Stoller]

AHHHHHHHHHHH, I can't wait. I wish tomorrow was next Thursday!

GFS even hinting at possible high plains/northeastern CO action WED (5 days out though - moisture is lacking). Maybe the first chance this year of an eastern CO Limon/I-70 corridor mothership.

[Mike Kovalchick]

AHHHHHHHHHHH, I can't wait. I wish tomorrow was next Thursday!

GFS even hinting at possible high plains/northeastern CO action WED (5 days out though - moisture is lacking). Maybe the first chance this year of an eastern CO Limon/I-70 corridor mothership.

My initials thoughts are that I will making a beeline from Lansing, MI to NE Co or SW Nebraska Wednesday afternoon. Nothing like starting out the chase vacation with an all night 1000 mile journey!

I think we almost to the point of being able to start a forecast thread on this upcoming event now that all the stars have come into alignment.

[cdcollura]

Good day all...

Already pulled the trigger on a chase trip with this active pattern now coming to be ;-)

http://www.sky-chaser.com/drawing/st051908.jpg

The pattern is apparently changing in lieu of nearly all computer models, including the bullish GFS, now showing persistant troughing in the west and ridging to the east.

With cheap airfare to Chicago from FL, I'll spend the 19th with good buddy of mine there then take May 20-21 to go west, maybe W Kansas for the 22 and after that, ??? but with a decent troughing what else can go wrong?

June 1 I return to FL for work (new job) but I just sold my home so I would be bored to tears staying in FL and missing anything in the Plains anyway, so what the heck!

It's coming ... And it looks big!

[Paul Knightley]

A major severe storm outbreak seems increasingly likely later next week across quite a large portion of the Plains.

You've gotta love the ECMWF - that's why we use it at work!

[Mikey Gribble]

I just copied and pasted this from my blog. I made this post earlier so it was based off of the 12Z GFS and yesterday's 00Z ECMWF...


Severe weather outbreak and possibly a tornado outbreak are becoming increasingly likely during the latter half of next week. The GFS has continued to trend towards the ECMWF, while the ECMWF holds pretty much steady from run to run. Both models are similiar with the upper air pattern and strength of the West coast trough, but there are significant differences in timing and evolution of the trough beyond Wednesday. Because of this is is virtually impossible to pin down a time frame right now. The ECMWF has been more accurate this year, but it's timing may be a little too quick this time. It depicts severe weather/chase days on Wednesday and Thursday. The GFS is much slower and stalls the trough over the Rockies as it deepens. I think the more progressive solution of the ECMWF probably makes more sense for several reasons. I also think ECMWF is a little too fast with the trough ejecting into the plains (it has a tendency to be too fast with the progression of closing troughs). And finally I think both the GFS and ECMWF may be a little too strong with the strength of the trough.

That being said, this is mostly speculative and my confidence is fairly low on the timing and evolution of next weeks trough. I am very confident there will be a west coast trough though and climatology in mind it should perk up our spirits. There should also be good moisture over the gulf, which provides another reason for optimism. My best guess at this time is that Thursday and Friday will be chase days, but it could just as easily fall on any other two days between Wednesday and Saturday. I will update the forecast again tomorrow morning.

Now that I've had a chance to see the 12Z ECMWF there isn't so much uncertainty IMO as to what days hold the best potential. The ECMWF is slowing down now and falling in line with the GFS (to some extent since the GFS is still very different with the evolution of the trough) on the timing of the trough affecting the plains. I still think the GFS is out to lunch on it's evolution of the trough and stalling it out over the Rockies, but whatever. Anyways, I think the 12Z ECMWF is fairly accurate now and should be fairly close to what will happen. This is starting to make the timing more clear too and I am fairly confident Thursday and Friday will be the chase days with this system, with Thursday being the day before the day and Friday being the more widespread severe wx event. So we are back to the traditional questions with these scenarios. Moisture return and the cap will likely be the issues on Thursday. The question for the main day (Friday) will likely be directional shear. It is way too far out to be nitpicking on details that are unclear at best, so I will leave it there. You have to like seeing a negatively tilted trough though after the crap we've been dealing with this season.

[Greg McLaughlin]

After a dismal chase season to this point I find it difficult to not get excited about the models this far out. For all of you out there planning your chase vacations over next week into Memorial Day weekend, you might end up striking gold. I am really interested in how the GooFuS has the trough evolving over the weekend. The slow weakening trend favors multiple severe weather episodes over a large portion of the Plains given the forecast broad warm sector to be in place.

You may have a chase in Kansas one day, be in eastern Oklahoma the next, then up in Nebraska/Iowa a day or two later. Unfortunately gas prices will make chase vacations bittersweet for some, but for all of you who are coming out next week, it looks like you picked a good time....assuming what transpires resembles something close to what the models are currently showing. Given favorable climatology I would be shocked if we don't get at least localized tornado events out of this forecast pattern. Lets hope the models aren't jacking with our heads trying to add insult to an already lack-luster 2008 year.

[Derek Weston]

I just copied and pasted this from my blog. I made this post earlier so it was based off of the 12Z GFS and yesterday's 00Z ECMWF...


Severe weather outbreak and possibly a tornado outbreak are becoming increasingly likely during the latter half of next week. The GFS has continued to trend towards the ECMWF, while the ECMWF holds pretty much steady from run to run. Both models are similiar with the upper air pattern and strength of the West coast trough, but there are significant differences in timing and evolution of the trough beyond Wednesday. Because of this is is virtually impossible to pin down a time frame right now. The ECMWF has been more accurate this year, but it's timing may be a little too quick this time. It depicts severe weather/chase days on Wednesday and Thursday. The GFS is much slower and stalls the trough over the Rockies as it deepens. I think the more progressive solution of the ECMWF probably makes more sense for several reasons. I also think ECMWF is a little too fast with the trough ejecting into the plains (it has a tendency to be too fast with the progression of closing troughs). And finally I think both the GFS and ECMWF may be a little too strong with the strength of the trough.

That being said, this is mostly speculative and my confidence is fairly low on the timing and evolution of next weeks trough. I am very confident there will be a west coast trough though and climatology in mind it should perk up our spirits. There should also be good moisture over the gulf, which provides another reason for optimism. My best guess at this time is that Thursday and Friday will be chase days, but it could just as easily fall on any other two days between Wednesday and Saturday. I will update the forecast again tomorrow morning.

Now that I've had a chance to see the 12Z ECMWF there isn't so much uncertainty IMO as to what days hold the best potential. The ECMWF is slowing down now and falling in line with the GFS (to some extent since the GFS is still very different with the evolution of the trough) on the timing of the trough affecting the plains. I still think the GFS is out to lunch on it's evolution of the trough and stalling it out over the Rockies, but whatever. Anyways, I think the 12Z ECMWF is fairly accurate now and should be fairly close to what will happen. This is starting to make the timing more clear too and I am fairly confident Thursday and Friday will be the chase days with this system, with Thursday being the day before the day and Friday being the more widespread severe wx event. So we are back to the traditional questions with these scenarios. Moisture return and the cap will likely be the issues on Thursday. The question for the main day (Friday) will likely be directional shear. It is way too far out to be nitpicking on details that are unclear at best, so I will leave it there. You have to like seeing a negatively tilted trough though after the crap we've been dealing with this season.

Wednesday really looks like a chase day to me and potentially the one with the best directional shear. Eastern half of Kansas area. Should be enough CAPE to get it done... this has been showing up for at least a few runs now on the GFS. Trick seems to be where the best 850s land...

I would definitely be there on Wednesday as of right now.

Directional shear on Fri is hardly there -- but definitely the strongest shear/CAPE setup. Thursday seems rather unidirectional as well. Speed shear will be interesting though. We've seen a few of these sort of setups produce already this season...

Strong enough system, but none of the GFS runs have been knock-my-socks-off sure-fire type setups. Love the CAPE, shear questions abound.

[Mikey Gribble]

You are going off of the GFS Derek and I would advise against that given it's performance as of late. The GFS digs the trough over the central plains on Wednesday and does portray decenet midlevel flow, but I'm not buying it. The ECMWF has been much more consistent with a trough digging over the Rockies and this makes more sense for several reasons. The GFS on the other hand has been all over the place. I obviously don't know what will happen (nobody does), but I fairly certain I'm right on this one.

Even if the GFS verfied (like you are going off of) pull this up and look at the cap that's in place http://www.weather.cod.edu/forecast/
That is assuming the GFS's miracle like moisture return takes place. Right now the GFS has dewpoints sky rocketing on Tuesday. The only problem is that there is nothing there to advect that moisture northward. Logically you won't have a LLJ until Wednesday. With good moisture residing over the gulf, you are going to be hard pressed to get that to central Kansas in 12 hours. This is all assuming the GFS's upper air pattern verifies, which isn't likely either.

Derek said...
"Wednesday really looks like a chase day to me and potentially the one with the best directional shear. Eastern half of Kansas area. Should be enough CAPE to get it done... this has been showing up for at least a few runs now on the GFS. Trick seems to be where the best 850s land..."

You should go back and read my last couple posts Derek. It is very typical to have good directional shear as the trough approaches, but you traditionally have questions regarding moisture return and capping. Check the unbreakable cap out on the GFS too. If you chased Wednesday (if the GFS verified) you would be looking at blue skies. Directional shear is great, but if you don't have a storm it doesn't do you much good. Again this is all based on the notion of the GFS verifying and you are braver than me if you believe that.

Derek said...
"Directional shear on Fri is hardly there -- but definitely the strongest shear/CAPE setup. Thursday seems rather unidirectional as well. Speed shear will be interesting though. We've seen a few of these sort of setups produce already this season..."

Again you should go back and read my last couple posts. You typical loose your directional shear as the trough ejects into the plains. That is normal. That is why I said Thursday (first chase day) would come down to moisture return and the cap and Friday (second chase day) would come down to how good the directional shear is.

Go with whatever you want to, but I would strongly advise against using the GFS on this one. We'll find out by next week what's going to happen, but I am fairly certain Thursday and Friday will be the chase days with this one (not Wednesday).

[Derek Weston]

You are going off of the GFS Derek and I would advise against that given it's performance as of late. The GFS digs the trough over the central plains on Wednesday and does portray decenet midlevel flow, but I'm not buying it. The ECMWF has been much more consistent with a trough digging over the Rockies and this makes more sense for several reasons. The GFS on the other hand has been all over the place. I obviously don't know what will happen (nobody does), but I fairly certain I'm right on this one.

Even if the GFS verfied (like you are going off of) pull this up and look at the cap that's in place http://www.weather.cod.edu/forecast/
That is assuming the GFS's miracle like moisture return takes place. Right now the GFS has dewpoints sky rocketing on Tuesday. The only problem is that there is nothing there to advect that moisture northward. Logically you won't have a LLJ until Wednesday. With good moisture residing over the gulf, you are going to be hard pressed to get that to central Kansas in 12 hours. This is all assuming the GFS's upper air pattern verifies, which isn't likely either.

Derek said...
"Wednesday really looks like a chase day to me and potentially the one with the best directional shear. Eastern half of Kansas area. Should be enough CAPE to get it done... this has been showing up for at least a few runs now on the GFS. Trick seems to be where the best 850s land..."

You should go back and read my last couple posts Derek. It is very typical to have good directional shear as the trough approaches, but you traditionally have questions regarding moisture return and capping. Check the unbreakable cap out on the GFS too. If you chased Wednesday (if the GFS verified) you would be looking at blue skies. Directional shear is great, but if you don't have a storm it doesn't do you much good. Again this is all based on the notion of the GFS verifying and you are braver than me if you believe that.

Derek said...
"Directional shear on Fri is hardly there -- but definitely the strongest shear/CAPE setup. Thursday seems rather unidirectional as well. Speed shear will be interesting though. We've seen a few of these sort of setups produce already this season..."

Again you should go back and read my last couple posts. You typical loose your directional shear as the trough ejects into the plains. That is normal. That is why I said Thursday (first chase day) would come down to moisture return and the cap and Friday (second chase day) would come down to how good the directional shear is.

Go with whatever you want to, but I would strongly advise against using the GFS on this one. We'll find out by next week what's going to happen, but I am fairly certain Thursday and Friday will be the chase days with this one (not Wednesday).



That was going off of the GFS. GFS hasn't been too sharp this spring. Speculative thoughts based on what the GFS was throwing out for the day. Would expect to see plenty more changes between now and then. Didn't look at capping issues. Yeah, certainly seem to be issues those first two days. Be interesting to see how strong the moisture return is. Have noticed that about the way systems tend to unfold. (directional to unidirectional) Sometimes the 'day before' gets some fun, sometimes not. Will just have to see how things evolve.

[cdcollura]

The key point here is that MANY of the models, not only the GFS, but others (like the ECMWF), are showing the trough and looking encouraging. Never look at just one model, but a general "composite" of many models.

Last week, the ECMWF was showing a trough but the GFS a ridge, total opposite, for May 22. Now, closer to the "event", both show a similar trough in that general time frame, and I decided to make plans to get out there at that point.

[Mike Hollingshead]

Hmmm, looking at the 0z ECMWF I may have to become more of a fan in the GFS now(lol "fair weather fan" here). The last ECMWF run leaves that western trough highly blocked in over there by the eastern big trough. Don't exactly want to see that! Now it looks a little like early 07....high plains or bust. All I know is the low level jet is going to be highly confused if it happens like that shows...all backed to se instead of veered to sw or worse. Thursday actually makes me think a lot of March 28, 2007 on there.

Now that we get the big trough, we just need to get the eastern one to be a little weaker. Coming out slow is fine, but at least come out some.

Edit: 12z gfs in....SIGH.

[Jason McKittrick]

I remember seeing someone ask when the last time there was such a strong extra-tropical cyclone in the plains( ECMWF sub 980 mslp prog). Well, I did a little searching on the NOAA Daily Weather map Archive. In the last 10 years I did not find any sub 980 lows. However, there were three sub 990 cyclones.

988mb May 11, 2003
989mb May 11, 2000
985mb May 5, 1999

Two of the three cyclones listed above were accompanied by significant tornado outbreaks. Most will recognize the 1999 date. The cyclone which produce the Moore, OK tornado went on to produce 113 additional tornadoes (SVR Plot data) over the coarse of 3 days and roughly 12 long tracks.

The May 11, 2003 cyclone occurred during the record setting first 2 weeks of May 2003. The specific cyclone listed above produced a significant tornado outbreak across SE Iowa and N Illinois. It produced approximately 63 tornadoes over the three day period and again roughly 12 of these were long track.

The last occurrence May 11, 2000 produced 13 tornadoes, 1 significant and 0 long tracks.

Climatology confirms that as most of us suspect the models are most certainly over forecasting the intensity of the impending storm. All of the occurrences that I found also occurred during the first 2 weeks of May. I think it is safe to say that until the models back off on the intensity forecast that we should be real careful how much we believe.

In my opinion it is likely that we will see a pattern change to a trough in the west. This will be much more favorable for severe weather. The models seem to favor a strong ridge over the eastern US and this should produce an extended period of convection and severe weather over the central and western plains (great chase country). It will take several days to decipher the details and I will not even attempt to do so until Monday.

At this point I am still anticipating several days of good chase opportunities somewhere from central and western Nebraska to the Texas Panhandle. My main concern is the strength of the EML since the preceding airmass has been responsible for such remarkable heat along the west coast and intermountail region.

[Mikey Gribble]

Well after seeing the new runs of the GFS and ECMWF I started to get a little emotional. This is when I always tell myself that you can't get hung up in run to run changes. It doesn't usually work and I still got caught up in each runs changes (which leads to a roller coaster of emotions), but we really know better than to do that. We've all watched trough after trough every spring jump around on the models and after it's all over with and the chase day has come and gone we realize how wasteful it was to get pissed when one run shows something completely different from the last. I know damn well I should just ignore run to run changes and focus on the bigger picture, but I can never seem to do it. Anyways, the latest runs of the the GFS and ECMWF look like crap, but the important thing is that the last 10 runs before this didn't look like crap. All we really know with some degree of certainty is that we are getting ready to have a trough over the Rockies and that is the first prerequisite for getting a chase day. The rest will iron itself out with time.

Derek said...
"Sometimes the 'day before' gets some fun, sometimes not."

Yeah I am a huge directional shear fan, so I am also a huge fan of the day before the day chases. Greensburg last year was a day before the day. When the moisture is there and the cap breaks there are usually pretty good results on those days.

[Michael O'Keeffe]

I'm not concerned about how the latest models haven't looked so good. The last five days have been showing good stuff and one or two runs out of 20 models runs isn't going to hurt anyone. I mean that is a monster system and the models have a harder time trying to place one day let alone 3 or 4 days. I will start to worry by Monday or Tuesday, but as of right now I'm still banking on 3 or 4 good severe wx days from Wed-Sat sometime.

Edit: Just to add a bit more to my rant, I have called off chases 48 hours before an event and then 24 hours later packed and in the car ready to chase, so what I mean by that is models change back and forth all the time and the thing we need to do is worry 5 days down the road.

[Scott Weberpal]

Another thing to note is you shouldn't just look at the GFS and ECMWF without looking at the ensemble means and spaghetti plots. The spaghetti plots and ensemble means also tend to agree with the most recent solution of the operational GFS and ECMWF cutting off the upper low over the southwest. Don't forget, even though this run may have been different than the last 4 or 5, we're getting closer to the event with each run and as we get closer the models will have a better handle, thought they won't have a complete handle until the system is on shore.

[Mike Hollingshead]

Well at least the Canadian model keeps it more of one big solid trough, not shearing out...and moves the east coast blocker a bit more northeast.

Canadian 12z Friday (http://www.weatheroffice.gc.ca/data/model_forecast/colour_images/12_054_G1_north@america@zoomout_I_4PAN_CLASSIC@012 _144.jpg)

I hope it moves real slow and lets a person just find a cheap motel and not rack up a ton of miles. I also hope it has day after day hope so I don't need to drive back home between any, since I can't stand boredom(looking around at plains things).

I'm worried a little at the recent runs though. Seems like it is in the time-frame where it flips back to the crap it had been showing, then continues with that till the event. What it's done today on the GFS is a pretty good move back towards where it had been most of the time...at least generally.

And about not worrying till the few days before...I don't think anyone is anymore worried than anyone else if you are reading the thread in the first place.

[Mikey Gribble]

When I looked at the GEFS ensemble the other day it looked like a spider web, so it wasn't much help. I rarely look at the Canadian just because it is usually all over the place with its ensemble members too.
edit - good point Hollingshead. If you're reading this thread there is some degree of worry in your mind, whether you know it or not lol.

[Chris Hayes]

We're currently heading west on I-70 toward Kansas City where we'll be staying for the night. I look at the situation coming up next week like this. The fact that there will be a big trough over the west is enough to give me hope. It will have to move out sometime. Be it next wednesday, thursday, or whenever. It will move out. If it were possible for it to become a high pressure system, then I'd be really worried ;) I have 3+ weeks to chase this year, and we just left home, so I'm happy to see a more favorable pattern setting up, even if I need to wait a few days to get an even marginal chase in :)

[mcrowther]

New GFS ensembles are a bit better than the Op run:

http://img360.imageshack.us/img360/112/f156av2.gif (http://imageshack.us)
By mcrowther (http://profile.imageshack.us/user/mcrowther)



Bottom line that seems to be emerging: there will be a western trough or closed low. It probably will form close enough to at least give us a shot at storms (probably pretty far west in the Plains), but the quality of those storms from a chase perspective is yet to be determined. I think I will take a break from model watching the next couple of days and see what it looks like by early next week.

[Jason McKittrick]

I sure don't like the trend I am seeing in the ECMWF with a Mississippi Valley Omega block transitioning to a Rocky Mountain Rex block. Starting to look like Thursday may be the best opportunity. Let's hope the current trends don't continue or we will be needing quite a bit of sun screen for our chases next week.:(

[Andrew Stoller]

May 24th: Violent tornadic supercells in eastern CO. Bank on it!

Haaaaaa! Wouldn't it be funny if it actually does happen.

But the 24th is the first day through this multi day event where the GFS shows the dryline backed into the I25 corridor.

In addition, since the system doesn't really eject out much, the models are likely keeping the moisture a bit too far east each day. We could finally get a significant event along the palmer divide northeast towards Last Chance (a southwest flow event with a more classic supercell or two - we seem to get northwest flow monsoon high precipitation supercells more often but they are practically unchasable with blinding rain and embedded monster hail). Every couple of years it happens.

Thanks Mark Farnik! :D

[Mike Hollingshead]

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gefs/06/images/gefs_50d_120m.gif

This is funny to me. Pretty sure by Thursday with what it wants(yeah this from the 6z run, since I'm leaving soon).

Two days later...

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gefs/06/images/gefs_50d_168m.gif


Think the model decided to hammer some down early for memorial day weekend.

[Chris Hayes]

12z ECMWF seems to be more friendly than the previous one. Shows a negatively tilted trough coming into the eastern Rockies and western plains Thursday through Saturday. 18z GFS has a more postive or neutral trough sitting over the Rockies.

[Derek Weston]

Looks like crap on 0z gfs. Got all of the 850 support and decent dews out ahead of the lower level support.... blocked back west. Yuck. Fri in South Dakota looks nice I guess, but besides that, this system is looking kind of sad according to some of the latest runs here. (not sure the ECMWF is offering much more)

[Shane Adams]

I keep seeing this thread and keep thinking the chase day is like tomorrow or something.

[Jason McKittrick]

Better take advantage of any May chase opportunities that come along. I am not sure how many others noticed, but the GFS has consistently been forecasting $5/gallon gas by the first week of June. IE tropical system in the GoM.

[Damon Scott Hynes]

Ping: anyone with more of a brain than I about this--

D4-D6 looks nice for the Front Range, what happens on Sun/Mon? I'd love to be able to walk this system east to Des Moines / Columbia. Mo-ish through Monday good Lord (and the cap) willing.

[Shane Adams]

Ping: anyone with more of a brain than I about this--

D4-D6 looks nice for the Front Range, what happens on Sun/Mon? I'd love to be able to walk this system east to Des Moines / Columbia. Mo-ish through Monday good Lord (and the cap) willing.

All I know is it's Monday and we're talking about stuff for next weekend. With as much as it's changed over this past weekend, I'd wager dollars to dimes what we're currently seeing won't be what actually happens. Sure, there's a huge trough out there and there's gonna be multiple chase days. But where, how concentrated, and how intense? Stay tuned to reality time (Wed evening) for that story.

All I can say is, it's been hard to put much faith in anything so far, because it's all been displaced. I use CoD so I am still waiting on the new WRF updates the rest of you have been pining over the past hour or more, but I wouldn't be at all shocked to see a slight eastward trend with everything and eventually, reality. Regardless, this looks to be the 'po boy's last hurrah, so we're prepared to go camping up the High Plains for a few days if that ends up being the deal. Personally, one day of High Plains stuff would rule, and then it'd be killer to get to move a bit further east for Sat/Sun.

[Chris Rice]

Reality? Is there any good places to hang a hammock in the high plains for some camping if it does end up further to the west, I'm a Missouri boy! LOL!

[Damon Scott Hynes]

All I know is it's Monday and we're talking about stuff for next weekend.

Ain't it beautiful? Fifty years ago we couldn't have pinned this down to this extent, let alone have the luxury of kvetching about how far and how fast the low will move.

Regardless, this looks to be the 'po boy's last hurrah,

I have the luxury of three-day weekends all through May and June, but that doesn't mean I want to go throwing $50s at every Shell station I see :eek: I've made one chase so far this year--drove to Sioux City and waved byebye to the stuff in NW IA. But I'm surprised and somewhat relieved that there haven't been any other days that I'd call marginal--not even close.

Personally, one day of High Plains stuff would rule, and then it'd be killer to get to move a bit further east for Sat/Sun.

I'm with ya on that. Eastern Kansas for Saturday means Steak 'n Shake in Topeka, LOL.

[Jason Caster]

My Chase vacation (5/25 - 6/1) is rapidly approaching and excitement is doubling with frustration. Obviously an amazing setup is being predicted by the models for 5/22 and 5/23. Like others, work keeps me from starting my vacation early, so there-in-lies my frustration.

I'm looking to Sunday (25th) as my first chase day since I fly in to DFW pretty late the evening of the 24th.

It appears I'm not completely out of luck as a cold front will move over the plains to play with some instability. But I have a feeling it will likely cause too much convection with more of the same HP storms we've been seeing thus far and not much potential for nicely defined/contrasted tornados.

I have a good chunk of time for something to form later in the week. I'm still keeping spirits high for my vacation, especially since this could be my first time to ever see a tornado, or even a severe storm over the plains for that matter.

I'll likely be meeting up with Scott at some point so I'm thankful to have his forecasting experience as an extra advantage on the trip.

Good luck to everyone heading out Tomorrow-Thursday. I'll be monitoring everything from work.

-Jason

[Laura Duchesne]

I feel the same way Jason. My chasecation is from the 25th to June 5th. I am not quite sure what to expect this year. At least models point to having moisture in the plains... I just hope there is enough instability to play with and a few dryline set ups. One good thing is we aren't just being limited to one area... we have the entire alley to play in.

[Scott Weberpal]

Fortunately the ECMWF and GFS are both developing another western trof around the 28th/29th. Not all hope is lost after Sunday.

[Jason Foster]

I'm at the point too that I'm just so close to calling off my 2008 chase expedition. Even though this was suppose to be the first year chasing since having the kidney transplant, I'm not convinced that the pattern is going to give me enough sustainable chase days to be worth the $4,000 budgeted for this years trip. Plus, that money could be thrown back into investments and I'd have a much better start to the hurricane season which begins June 1st. So even though I was going to wait until May 30th to call it off, I think I'm sort of doing it now.

So hopefully, the rest of you aren't held back by a cut off date, because I suspect sometime in June (likely late) is going to have to peak in the plains this year.

[Kevin Crawmer]

I wouldn't give up on Monday yet. In Eastern 1/2 of KS: Temps are good. Dews are good. CAPE 4000+. Best forcing appears to be a little to the west of all this. Looks like some morning convection could leave some boundaries too. The winds are not good though. Weak low level winds (40 kt). They are actually out of the south now....earlier runs did not show this. I actually was just skimming an article on high CAPE, low shear days. If it can get some frontal forcing it will be ok.

The GFS has not been consistent with anything beyond Friday with this, so we will see what shakes out of it. I'm just anxious to see some of the photos from this weekend. Isolated storms in a good geographic area? Say it isn't so! Not in 2008!

**I am far from an expert. I'd like to hear other's opinion on this.