WINTER STORM FCST 12/07/07-12/12/07: KS, MO, IA, IL, MN, WI, NE, MI

[Michael O'Keeffe]

It looks like a powerful winter storm will affect us again!!! The HWO in EAX has put out startling news about this weekend. Check it out:

CONDITIONS ARE BECOMING INCREASINGLY FAVORABLE FOR A MAJOR AND
PROLONGED PRECIPITATION EVENT OVER THE ENTIRE OUTLOOK AREA THIS
WEEKEND...INCLUDING THE POSSIBILITY FOR SIGNIFICANT ICE
ACCUMULATIONS. ARCTIC AIR IS EXPECTED TO SURGE SOUTH ACROSS THE
PLAINS AND INTO THE AREA FRIDAY...INTERSECTING A STATIONARY FRONT
OVER SOUTHERN MISSOURI. THIS FRONT WILL SERVE AS THE FOCUS FOR
SEVERAL ROUNDS OF MODERATE TO HEAVY PRECIPITATION FROM LATE FRIDAY
THROUGH POSSIBLY TUESDAY AS A POWERFUL STORM SYSTEM REMAINS LOCKED
OVER THE SOUTHWESTERN STATES. AS A VERY WARM AND UNUSUALLY MOIST
SPREADS NORTHWARD ABOVE THE SHALLOW ARCTIC AIRMASS IN PLACE NEAR THE
SURFACE...SIGNIFICANT ICE ACCUMULATIONS COULD RESULT. ACROSS FAR
SOUTHERN PORTIONS OF THE OUTLOOK AREA...PROLONGED HEAVY RAINFALL
COULD LEAD TO RAPID RIVER RISES AND POSSIBLE FLOODING INTO EARLY
NEXT WEEK.


I could be in for a very looooonng weekend, but hey I don't mind it may keep me out of school and my b-day is on Saturday. I love this stuff, that would be the ultimate present :D

[Joel Wright]

Well, there definitely looks to be another storm for the upcoming weekend. Another icing event may unfold for somebody. There are a lot of things that can change by then. There's two systems that will lay down some snow before this one arrives, so that may end up having at least a minor impact on where this storm tracks. Also, having a snowfield in place will surely have an impact on where the edge of the arctic air entrenches in.

It sure looks like someone may end up with an icestorm though, with the shallow layer of arctic air in place near or over the snowfield, and strong S/SW flow just above the surface feeding in the moisture and warmer air. The severity of the icing will depend on whether or not any one location can stay in the balance of the arctic air at the surface, and WAA regime just off the surface.

[Brandon Sullivan]

Yikes.. Yeah, local WFO is hitting the Ice Storm Wording for this weekend already..

NEW SUITE OF LONG RANGE MODELS ARE ADVERTISING TROUBLING TRENDS OF
PAC NW/GULF OF AK ENERGY DUMP INTO THE SOUTHWEST CONUS...WITH
RESULTANT AMPLIFYING SOUTHWEST UPPER FLOW/STORM TRACK TAKING AIM AT
THE MIDWEST FOR THE WEEKEND. CURRENT SIGNALS OF ENERGY EJECT OUT ACRS
THE REGION AND WARM AIR DRAW ALOFT WITH LINGERING COLD/ARCTIC AIR AT
SFC SPELLS A POTENTIALLY SIGNIFICANT ICE AND/OR SNOW STORM ACRS
PORTIONS OF OR NEAR THE LOCAL FCST AREA SAT INTO SUNDAY BY THE NEW
RUN GFS...ECMWF AND UKMET. ITS JUST THE PHASING AND TIMING ISSUES
STILL TO BE WORKED OUT. WILL UP POPS TO HIGH CHC THRU THIS PERIOD AND
HIT FREEZING RAIN WORDING HARDER...AS OPPOSED TO CHC OF JUST RAIN OR
SNOW.

[Ben Prusia]

EAX is hitting the Kansas City area hard still in their latest AFD.


BOTH OF THESE WAVES OF STRONG FRONTOGENETIC FORCING WILL LIKELY BE CHARACTERIZED BY A NARROW BUT HEAVY PRECIPITATION CORRIDOR. ALTHOUGH TELECONNECTIONS FROM THE 12Z MODEL SUITE CONSENSUS WOULD SUGGEST THAT CENTRAL/SOUTHERN MISSOURI WOULD LIKELY SEE THE HEAVIEST PRECIPITATION THROUGH THE PERIOD...POSSIBLY EXCEEDING 2 INCHES QPF...ANY DEVIATION IN THE STORM TRACK WOULD RESULT IN LARGE SHIFTS IN PRECIPITATION AMOUNTS AND TYPE. AT THIS TIME...SIGNIFICANT ACCUMULATIONS OF SNOW AND/OR ICE ARE POSSIBLE FOR MUCH OF THE REGION...WITH THE PRIMARY FOCUS ALONG AND SOUTH OF THE MISSOURI RIVER FROM LATE SATURDAY THROUGH TUESDAY.

I am not really looking forward to it as I work grave shift on Saturday/Sunday night. GFS has us in the KC area in constant precip from Saturday through Tuesday/Wednesday with a shift in and out of all types of precip from rain to snow and freezing rain. Time to go buy the sand logs.

[BrianBaker]

Definitely looks like a potentially very serious storm for late this weekend. Might need to shift teh zone of interest farther south to include Oklahoma, parts of Arkansas and Texas for this. Believe the arctic front will get past the Red River on this one. Just a feeling that some models are backing up. Interesting to see the 12z GFS start to line up a little better with other models and bring the arctic front farther south. I do believe the NAM may be a bit to fast, however not by much as when cold air starts moving it can move pretty rapidly like on Nov. 29 of last year.

What a way to start finals week if it verifies! :)

[Mike Peregrine]

This week's forecast from EAX (http://forecast.weather.gov/MapClick.php?site=EAX&map.x=133&map.y=151) ... sweet! ...

http://img.photobucket.com/albums/v143/mikeperegrine/KCForecast.jpg

[Jeff Miller]

Winter Storm Watches have been posted for tomorrow for the southern half of the Sioux Falls forecast area, and Snow advisories,Winter Storm and/or Heavy snow warnings are posted for a large part of Northern Nebraska, Wyoming and Western Colorado.

Extremely efficient snowmaking ingredients will be in place as a very cold arctic dome and mid level moisture could produce a 15-20:1 ratio for snow - very fluffy but will pile up pretty quick. Therefore some locations wouldn't be hard pressed to get well in excess of 6" of snowfall with this sort of a situation.

Since this thread also includes up to December 12, we cannot forget another winter storm situation for the Mon-Tue timeframe. Also, as Mike Peregrene alluded to, icing will tend to be quite a problem with periods of intermittent freezing rain or mixed precipitation where mid level warming is maximized in the central Plains. '

Cities right now for tomorrow under the gun for heavy snow would include in Nebraska Sioux City, O Neill, Valentine, Oshkosh, and Rushville.

[Rhyuan Janssen]

I am not quite sure what DSM's thinking is regarding the weekend system. I find it hard to believe that looking at QPF we are in the same if not MORE moisture where I live in Iowa than they are out in the western part of the state yet we are to have ONE inch of snow on Saturday? If we truly have 20:1 ratio's .5 liquid equivalent is NOT one inch :-) I can't imagine we wouldn't reach at least advisory critera during the period.

[Jarrod Cook]

I am not quite sure what DSM's thinking is regarding the weekend system. I find it hard to believe that looking at QPF we are in the same if not MORE moisture where I live in Iowa than they are out in the western part of the state yet we are to have ONE inch of snow on Saturday? If we truly have 20:1 ratio's .5 liquid equivalent is NOT one inch :-) I can't imagine we wouldn't reach at least advisory critera during the period.

It seems a lot of the midwest WFOs don't have a very good grasp on the situation yet - most likely for where precip type lines will be, etc. WFO ILX said in their HWO that a conference call is likely tomorrow for a potential ice storm Saturday/Sunday...yet they don't have any type of winter wx product issued yet. I imagine some products will get issued this evening.

[Jeff Miller]

OMINOUS wording from Springfield, MO where a Winter Storm Watch is in effect from Saturday night through Tuesday for Icestorm conditions and potentially 1" plus of ice accumulations.

This is a 56hr plus winter storm watch, one of the longest I can remember.

[Benjamin Smith]

OMINOUS wording from Springfield, MO where a Winter Storm Watch is in effect from Saturday night through Tuesday for Icestorm conditions and potentially 1" plus of ice accumulations.

This is a 56hr plus winter storm watch, one of the longest I can remember.

And they were hit hard last year with a major ice storm. I have family living down there and the neighborhoods just don't look the same with all those trees missing limbs. Heck, there is still piles of limbs around the city lingering around!!:eek:

[Jeff Piotrowski]

The 12Z models seem to be a little farther south with the freezing line at 12Z Monday before the main rain event starts. It looks like I-44 corridor may have in excess of one inch ice on Monday. The past freezing rain events the 28 temp seems to be the magic temperature with moderate rain for rapid ice accumulation on power lines and trees. This event will be very interesting to watch.

[Ben Prusia]

12Z models are hinting at the I-44 corridor as the major potential player in the ice event. Temperatures are looking to hover around the freezing mark with slightly lower temps to the NW of the corridor. Looks like some convective possibility along and south of I-70 which may enhance precipitation totals. I would hint at areas between the I-44 and I-70 corridors to stand the best chance of significant icing, with areas closer to I-70 having the best chance of sleet/freezing rain while further south more of a solid freezing rain.

Most of the WFO's in the area have already issued Winter Storm Watches including SGF's watch from Saturday Evening through Tuesday, and EAX's watch from Sat Afternoon to Sun Afternoon; TSA and OUN already have watches issued. Most likely we'll see TOP and ICT jump in with advisories for their CWA's within a few hours.

[Mike Peregrine]

Hoping KC dodges the worst of this one - -

Day 2 HPC ice probabilities (http://www.hpc.ncep.noaa.gov/wwd/day2_pice_gt_25.gif) puts the majority of icing to the east and south, but it looks too close to call.

Day 3 (http://www.hpc.ncep.noaa.gov/wwd/day3_pice_gt_25.gif) shows more icing over Oklahoma, with the same areas in Missouri continuing to receive accumulation.

Both NAM and GFS seem to generally agree on the precip outlines, though the timing looks to be varying a bit.

I've seen enough of these now to know that they can easily become a much bigger, or much smaller event than predicted. And that areas riding the forecast boundaries are totally up in the air until it happens. What concerns me is the extended period of precip that looks to be setting up, with the same areas getting several fresh coats. Not good.

[Mike Hollingshead]

Boy, if tomorrow's system slides a bit more south, and the next one a hair north, there's going to be a lot of snow on the ground here. Today's 12z gfs slid it a bit south, putting the 8-10 inch line just north of Omaha for tomorrow's system(we had 5 yesterday). Then comes the following system on Monday, which as it stands now the 18z gfs shows another larger shot of snow just south of here in se NE(1.25 liquid that should be largely snow).

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/18/images/gfs_p36_102m.gif
Surface freezing line during much of that is from about St. Joe to Dodge City.

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/18/images/gfs_pcp_090m.gif
There's 6hr precip with the 850 0c line, which happens to be about 70 miles north of the sfc 0c line. Bye bye Marysville KS.

[Jeff Miller]

While the threat of a severe ice storm situation is quite plausible in the central plains, I wanted to bring up some reasoning discrepencies in the FSD/DMX areas...

Woodbury County, Iowa is under a Heavy Snow Warning for 6-8" of snowfall accumulation. However, if you go one county southeast to Crawford County, Iowa, there is absolutely no warnings, watches, or advisories, even though 3-5" of snow is forecast, at least putting the area and counties directly northeast in a Snow Advisory criteria. I dont often see such a sharp cutoff from a Warning to absolutely nothing like this is. Since accumulations to 6" are certainly possible, I would imagine at the least a Snow Advisory is warranted - but the AFD shows no signs of a warning issuance. I would expect a little better reasoning or collaberation - it seems senseless to forecast up to 6" and not have some sort of advisory up since criteria at least has a chance of being met.

[Mike Hollingshead]

Hoping KC dodges the worst of this one - -

Day 2 HPC ice probabilities (http://www.hpc.ncep.noaa.gov/wwd/day2_pice_gt_25.gif) puts the majority of icing to the east and south, but it looks too close to call.

Day 3 (http://www.hpc.ncep.noaa.gov/wwd/day3_pice_gt_25.gif) shows more icing over Oklahoma, with the same areas in Missouri continuing to receive accumulation.

Both NAM and GFS seem to generally agree on the precip outlines, though the timing looks to be varying a bit.

I've seen enough of these now to know that they can easily become a much bigger, or much smaller event than predicted. And that areas riding the forecast boundaries are totally up in the air until it happens. What concerns me is the extended period of precip that looks to be setting up, with the same areas getting several fresh coats. Not good.

Looks like St. Joe could get some love from this one...at least the 18z gfs thinks so.

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/18/images/gfs_ten_090m.gif

Since they are just north of the sfc freezing line.

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/18/images/gfs_ten_096m.gif

It really doesn't move it 6 hours later either.

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/18/images/gfs_ten_096m.gif

Or during the following 6, lol.

That'd be a big difference between this and that last "ice-storm". It doesn't look to surge anywhere and should actually have some converging sfc winds out of the ne along it, trying to keep it there/below freezing.

[Mike Peregrine]

Hmmm - I was looking at Earl Barker's GFS page. I wonder if it hasn't updated yet or something? If the ones you posted play out, it would be a different story, looks like. Those make it look like NC-NE Kansas into NW Missouri is going to get pounded, which contradicts what we're seeing out of most NWS offices right now. Winter weather just makes me scratch my head. I'm convinced that it's totally a wait-and-see thing. I'm pretty sure somebody is going to get it, though - will be interesting to watch and see who.

[Michael O'Keeffe]

Well Mike I think the NWS is looking at the WRF which is making the areas between 1-70 and I-44 looking to be in line for a major ice storm which has already been said I think.

[Jeff Snyder]

While the threat of a severe ice storm situation is quite plausible in the central plains, I wanted to bring up some reasoning discrepencies in the FSD/DMX areas...

Woodbury County, Iowa is under a Heavy Snow Warning for 6-8" of snowfall accumulation. However, if you go one county southeast to Crawford County, Iowa, there is absolutely no warnings, watches, or advisories, even though 3-5" of snow is forecast, at least putting the area and counties directly northeast in a Snow Advisory criteria. I dont often see such a sharp cutoff from a Warning to absolutely nothing like this is. Since accumulations to 6" are certainly possible, I would imagine at the least a Snow Advisory is warranted - but the AFD shows no signs of a warning issuance. I would expect a little better reasoning or collaberation - it seems senseless to forecast up to 6" and not have some sort of advisory up since criteria at least has a chance of being met.

Jeff, what is the timeline for the snowfall up there, though? Most of the time, advisories (winter weather, dense fog, etc) are not issued much more than 12 hours ahead of time (many times issued ~6 hrs before the event starts, sometimes issued after an event starts). For significant events, though, winter storm watches may be issued ~24 hours ahead of time, especially for particularly dangerous events (big ice storm, first major winter storm, big storm over a holiday when lots of people will be traveling, etc). In this case, the heavy snow warning doesn't actually start until 9 am tomorrow, and it may be a bit premature for a winter weather advisory to be issued if it doesn't start for 15 hours. If ~6" snows look likely after tonight's models, I would expect to see at least a snow advisory issued with the morning forecast package (i.e. issued with the 3-4am forecasts).

[Jeff Miller]

Jeff, what is the timeline for the snowfall up there, though? Most of the time, advisories (winter weather, dense fog, etc) are not issued much more than 12 hours ahead of time (many times issued ~6 hrs before the event starts, sometimes issued after an event starts). For significant events, though, winter storm watches may be issued ~24 hours ahead of time, especially for particularly dangerous events (big ice storm, first major winter storm, big storm over a holiday when lots of people will be traveling, etc). In this case, the heavy snow warning doesn't actually start until 9 am tomorrow, and it may be a bit premature for a winter weather advisory to be issued if it doesn't start for 15 hours. If ~6" snows look likely after tonight's models, I would expect to see at least a snow advisory issued with the morning forecast package (i.e. issued with the 3-4am forecasts).

I totally agree with you on the timing aspect. I guess my concern is the public who would look at that (on a TV graphic) and see a heavy snow warning to the west and nothing for them potentially making them think "it's going to miss us" and be lax about the system. Of course we know that weather knows no man-made criteria, however I would think at least a mention of potential advisories or warnings should have been included in the evening AFD.

[rdale]

That's why we NEVER show NWS information on our forecast maps... It's my forecast - why would I advertise one made by another entity that only adds confusion! People understand "6 inches of snow coming" -- not "heavy snow warning" :>

[Mike Hollingshead]

http://weather.cod.edu/forecast/ECMWF/ecmwf_850_temp_96.gif

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/18/images/gfs_850_090m.gif

Check out the 850 0c line on both of those for 12z Tues. The last one, the 18z gfs was a nudge north from earlier thoughts. The 12z ecmwf however is a lot further north than that. ecmwf has it just south of Sioux City while 18z gfs has it down near Nebraska City.

[Bill Schintler]

An extended period of light mixed winter precipitation will affect eastern Iowa beginning Saturday afternoon and lasting through the day Sunday. Below are forecasts for specific locations:

Cedar Rapids:
Light snow will start at 5:30 PM CST Saturday and continue until 6 PM Sunday. Total snow accumulation through Sunday evening: 3.0 inches.

Iowa City:
Light snow will start at 5:30 PM CST Saturday, change to sleet and snow at 9:30 PM, and continue until 6 PM Sunday. Some freezing rain may mix in with the sleet and snow Sunday morning. Total snow and sleet accumulation through Sunday evening: 1.5 inches.

Marengo:
Light snow will start at 5:00 PM CST Saturday, change to sleet and snow at 8 PM, and continue until 5 PM Sunday. Some freezing rain may mix in with the sleet and snow Sunday morning. Total snow and sleet accumulation through Sunday evening: 2.0 inches.

Paris, IA:
Light snow will start at 5:15 PM CST Saturday and continue until 6 PM Sunday. Total snow and sleet accumulation through Sunday evening: 3.0 inches.

Synopsis:
Analysis indicated H3 height falls over the WRN CONUS with 140kt H3 flow from UT through the SRN Great Lakes. H7 WAA had commenced in SWRN KS, while at the SFC, high pressure was established from MT into ERN SD and STG NERLY flow was pushing into KS and NE.

Discussion:
A continuation of the very active winter WX pattern is in store for the next several days. First, SFC high pressure will shift slowly off to the N as SRLY flow aloft increases ahead of developing SFC low pressure in the WRN high plains. Winter WX FCST is challenging for the weekend as high-amplitude SWRN CONUS trough will eject a succession of compact ULVL SHWVS towards the CNTRL Plains and upper-Midwest. Each piece of ULVL energy has varying degrees of isentropic lift, frontogenetical forcing, and TROWAL features. Precipitation should develop over the area Saturday afternoon as a lead H5 wave approaches the area. Precipitation rates will be strongest late Saturday evening within the right-entrance region of a 120kt H3 jet, isentropic lift, and H8-H7 frontogenesis. Following a lull in the precipitation Sunday morning, a second impulse will affect the area Sunday on a more SRLY trajectory. Looking ahead, yet another piece of energy will affect the area Monday evening.

One FCST certainty is that an arctic airmass is becoming entrenched at the LLVLS across the area, maintaining a NWWRD slanting baroclinic zone oriented parallel to the ULVL flow. This frontal SFC will shift very slowly SERD over the next few days as the cold dome expands and the jet stream shifts slowly SWRD, Meanwhile, moisture in parcels that is running well above seasonal norms will follow isentropic SFCS NW of this feature in response to ULVL forcing. MDL confidence (GFS, NAM, UKMET, and NGM) remains low with regard to handling of kinematic details of the aforementioned ULVL waves and a coupled H3 jet structure, as well as to the thermal profile of the atmosphere, therefore weighted ensemble PROGS were favored except for SFC/LLVL temperatures where the cold GFS was favored. Latest trends have indicated a delay in the precipitation onset as well as less QPF. MDL soundings suggest primarily snow N of I-80, while some sleet will mix in further S. Cold layer appears sufficiently deep so that liquid precipitation should refreeze before reaching the ground. MDL confidence is also low with QPF, and may be too high as banded or convective features and strong omega in DGZ will be short lived if at all. In summary, it looks like an extended period of light snowfall and sleet in the area Saturday afternoon and again Sunday.

- bill
8:37 PM CST, 12/07/07

[Mike Hollingshead]

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/00/images/gfs_p60_090m.gif

Yikes. That second shot Wednesday morning really helps crank up the precip totals.

Interesting that through 84 hours NAM has a more northerly precip track.
http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/nam/00/images/nam_p60_084m.gif

It's much different than the GFS with the system at 84 hours. Shearing it out pretty good while the GFS continues a stronger storm.

http://www.rap.ucar.edu/weather/model/eta84hr_500_wnd.gif
http://www.rap.ucar.edu/weather/model/gfs084hr_500_wnd.gif

I have no idea which is more likely to be correct. I guess the old 12z run of the ecmwf leans towards the nam's more sheared system by 12z Wednesday.

[Michael O'Keeffe]

Here is an image of the latest QPF model for the Monday night into Tuesday night timeframe. It is indicating over 2.5" of precip for my area and points west. I think anywhere between I70 and I35 from KC to Topeka south to Emporia and back to KC area in for a VERY damaging ice event. The latest forecast from the NWS EAX is saying there is a 100% chance of freezing rain Monday night and Tuesday before tapering off late on Tuesday.

http://i84.photobucket.com/albums/k3/wolverines028/fill_98qwbg.gif

[Joel Wright]

Someone's going to get hammered tomorrow night into Tuesday morning. Look at all the QPF forecasted right in the area where forecast soundings indicate freezing rain. There may be areas from northeast KS, into northwest MO, and into extreme southern IA that receive over an inch of glaze by noon Tuesday. Some of that may extend further east into north-central IL too.

To me it looks like Salina, up through the St. Joseph MO area, and up towards Lamoni IA is going to be in the midst of the heaviest glaze band.

[Joel Wright]

The 00z models seem to slow the monday night system just a bit, but other than that I don't see too much of a difference from previous runs. Maybe just a slight nudge northward of the heaviest QPF.

It's sure looking like a very damaging icestorm with ice accumulations/glaze approaching 1" in a band from northeast Kansas, through northwest MO, through southeast IA, and into northern IL.

Here in the Quad Cities area of NW IL, we're looking to receive 0.50-1.00" of glaze depending on what model you look at. That would rival and possibly exceed the last icestorm we just had last weekend.

The only saving grace with this particular storm is the lack of wind associated with it. The storm system on December 1st brought 40mph winds during the event. This one will have considerably less wind. On the flip side, unlike that icestorm which was quickly followed by thawing temps which helped melt ice off of everything, this one will actually have colder air surging in after the precip quits...

[Mikey Gribble]

Wichita may end up dodging a bullet on this one if the NAM is to be believed. The last few runs have been keeping us barely above freezing. The 00Z run only has us dipping below freezing for a few hours early Tuesday morning.
The system does look like it slowed down a bit from previous runs, but I haven't been watching it that closely. The NWS has been keeping our temps well below freezing in the forecast. I haven't forecasted nearly enough to second guess them, but right now I'm thinking that if ICT gets below freezing then we are just barely going to get there. Aside from the surface temperatures being slightly to warm the ICT sounding is definitely going to be freezing rain. We got pretty much all sleet out of the storm that just exited our area, but the cold air in forecast sounding for ICT in this event should be shallow enough to keep the precip. in liquid form. I always feel like sleet is a waste of a winter storm. I just don't like it for some reason. Ice sucks too, but it makes things a little more interesting (so long as I don't have to drive in it). Anyways, I'm hoping our temps drop a bit more than the NAM is forecasting because I want a good winter storm.

[Jim Zandonai]

Looks like late tonight and Tuesday is going to be another Icy event in N.IL.
Here in RFD looks like we will be on the north edge of the significant precip again.
At this time KLOT has held off with the warnings probably due to timing and any slight shift to the south or north would make a big difference.
I wasnt worried about Ice last time but our power was out for 15 hours..although it was windy then too. This time its going to be close again. Just south of us though is going to be a mess.

[Joel Wright]

Looking at the potential for a very damaging/devastating icestorm later tonight and tomorrow. Still looks like the best icing will occur from the Salina KS area, northeast to near St Joseph MO, up towards Lamoni IA, to just south of the Quad Cities, and up towards NIU/Dekalb IL. Folks along this line should easily see 3/4" glaze, with additional amounts where some thunderstorms occur. With this much ice, widespread power outages and significant damage to trees and powerlines are a given. Wind will be almost non-existent with the storm, which does help somewhat. However, given the magnitude of the glazing, it's not much consolation.

Anyone who lives in these areas needs to start your preparations, as we may be losing electricity for awhile.

Warmer air will try to sneak northward, and should have at least some success. Areas like Kansas City, Quincy/Peoria IL should spike above freezing early Tuesday morning helping to alleviate the ice buildup there. The GFS and GEM both show this, and have proven with past icestorms to be pretty good at forecasting the surface freezing line in these events.

[Bill Schintler]

A major ice storm will affect much of Eastern Iowa along and south of US-30 from late Monday evening through Tuesday afternoon. Ice accumulations in excess of 0.5 inches will cause widespread power outages and damage to trees, as well as causing a major travel hazard. The heaviest ice accumulations will occur along and south of I-80 in eastern IA. A silver lining in all of this is that winds will remain light for the duration of this event. Below are forecasts for specific locations:

Cedar Rapids:
Sleet and freezing rain will start at 12:30 AM Tuesday. A changeover to snow will occur at 3 PM Tuesday. Precipitation will end at 7 PM Tuesday. Total ice accumulation: 0.20 inch. Total sleet: 0.30 inches. Total snowfall on top of the ice and sleet: 1.5 inches.

Iowa City:
Freezing rain will start at 11:45 PM tonight. Thunderstorms are possible between 3 AM and 9 AM, resulting in enhanced icing rates. Sleet will mix with the freezing rain during the afternoon Tuesday. Total ice accumulation: 0.7 inches.

Marengo:
Freezing rain will start at 11:30 PM tonight. Thunderstorms are possible between 3 AM and 9 AM, resulting in enhanced icing rates. Sleet will mix with the freezing rain during the afternoon Tuesday. Total ice accumulation: 0.6 inches.

Synopsis:
UA analysis this morning indicated a 140kt H3 speed max over AZ ejecting ahead of persistent WRN CONUS trough. A sharp, E/W-oriented H85-H7 baroclinic zone as well as SFC high-pressure were noted in IA. WV imagery also indicated potent NRN-branch SHRTWV over WY/ID/MT.

Discussion:
SFC high pressure will move E of the area today, with STG mid-level WAA developing. Another round of SHRTWV energy will eject NE from the SWRN CONUS trough and bring a good chance for winter WX. By 06Z, a 50kt LLJ will develop and H85 temperatures will reach +5C along I-80. Moisture will increase with PW values two- to three-times seasonal norms S of the H8 WF. MDLS (NAM, GFS) show strongest forcing developing from 06Z Tuesday through 15Z Tuesday between US-34 and I-80 in ERN IA. Moderate H7-H8 sloping frontogenetical forcing between I-80 and US-30 will be collocated with isentropic lift and omega beneath the right-entrance region of a 150kt H3 jet. A large part of this frontogenetical forcing (and strengthening of the thermal gradient) should be due to horizontal deformation acting on the thermal gradient. All of this points to some elevated convection in the S. Meanwhile, the aforementioned SHRTWV in the NRN branch of the jetstream will provide a reinforcing shot of shallow CAA. MDLS are indicating storm total QPF ranging from 0.50 inch to 1.05 inch by Tuesday afternoon, while locally higher amounts may occur along and S of I-80 where any convection or banding of the precipitation occurs. MDL soundings show all FZRA S of I-80 and N of US-34with SLT mixing in further N. Latest MDL trends suggest a more NRLY trajectory but with less mid-level WAA. A change to all RA is indicated further S, but this is discounted as MDLS are underestimating the shallow arctic AMS.

- bill
10:00 AM CST, 12/10/07

[Rhyuan Janssen]

I am still crossing my fingers for the more northerly trajectory as I live on 20 and if it all stays 30 on south I will miss it by about 30 miles....as it stands now I expect a good deal of sleet again where I am.. like last time...

[Joel Wright]

I don't usually post quotes from the NWS on ST, but I thought this latest statement from DVN was particularly ominous...

A SIGNIFICANT ICE STORM WILL AFFECT THE AREA TONIGHT THROUGH
TUESDAY EVENING. PREPARATIONS FOR THIS ICE STORM SHOULD BE
COMPLETED BY THIS EVENING. THE PROBABILITY IS HIGH THAT POWER
INTERRUPTIONS...POSSIBLY FOR AN EXTENDED PERIOD OF TIME...WILL
OCCUR DURING THIS STORM.

FREEZING RAIN WILL QUICKLY DEVELOP THIS EVENING AND BECOME
WIDESPREAD AFTER MIDNIGHT...AND CONTINUE THROUGH TUESDAY. THE ICE
ACCUMULATION THAT OCCURS WILL BE ON TOP OF THE LIGHT ICE
ACCUMULATION ALREADY ON TREES AND POWER LINES. ICE ACCUMULATIONS
OF ONE HALF TO ONE INCH ARE EXPECTED. ISOLATED THUNDERSTORMS ARE
ALSO POSSIBLE LATE TONIGHT INTO TUESDAY MORNING IN MOST OF THE
WARNING AREA...WITH BEST CHANCES MAINLY SOUTH OF AN OTTUMWA IOWA
TO PRINCETON ILLINOIS LINE. ICE ACCUMULATIONS OF AN INCH OR MORE
ARE POSSIBLE WHERE THUNDERSTORMS DO OCCUR.

Reading some of the posts from the ongoing NOW thread only makes the above statement scarier. The models have been pretty persistent with their QPF forecasts, so at this point it's looking like much of the area's in for a very bad icestorm. The icestorm on Dec 1st gave us about 3/4", and caused widespread power outages and tree damage. I can't even imagine what 1"+ ice accumulations would do.

[Jesse Risley]

It looks as if NE Missouri, SE Iowa and extreme West Central Illinois are going to get socked with a fairly heavy glaze. Based on the latest QPF forecasts + the threat of convection, I wouldn't be suprised if a few locations exceed the predicted 1" total accumulation of ice.

The big question for the southern and eastern areas of the predicted ice accumulations will be how quickly the cold layer erodes. It looks as if the freezing line will remain southeast of the IL river for much of the day on Tuesday.

It noted this was part of the LSX discussion earlier today:
"OBVIOUSLY WE WILL NEED TO WATCH (http://www.crh.noaa.gov/glossary.php?word=WATCH) SURFACE TEMPERATURES THROUGHOUT THIS ENTIRE EVENT...AS ONLY 25 TO 50 MILES WILL BE THE DIFFERENCE BETWEEN SIGNIFICANT AND POSSIBLE CATASTROPHIC ICE ACCUMULATION AND JUST PLAIN OLD RAIN."

[Rhyuan Janssen]

I am wondering what this afternoon's package will bring about. Reading Kansas City they now are considering making "MAJOR CHANGES TO THE AREAS WHICH WILL RECEIVE HEAVIEST ICE." I am hoping they are going to jump on the northward trend bandwagon and shove everything north. The NWS forecast for one county to the north of me is 2-4 inches of sleet! I am surprised Lacrosse has not issued if that is true. DSM saying now there is a definate trend northwestward with heaviest precip but do not know how far north it will go..as long as it goes far enough north to be over my house I will be a happy camper!

[Mike Peregrine]

That latest update by EAX is definitely an attention grabber! Anxious to see what they come up with this afternoon. They are also lowering the POPS quite a bit to the south, sounds like ... and it at least makes it sound like they're expecting more warm air advection than they previously thought. I'll definitely be refreshing that page a few times until some clarifications are made and it's expanded on a bit -

[Mikey Gribble]

I did some forecasting this morning and my thinking was that Wichita would dodge the bullet for the most part. I was thinking we would stay below freezing over night and get a good glaze of ice, but by tomorrow morning we will come back above freezing a degree or two and quickly melt off the ice we have. The NWS have been consistent in keeping us at a high of 30 between now and Wednesday morning though, so that is the only thing shaking my confidence. I'm about 60-40 we'll get above freezing tomorrow morning. I also think the bulk of the precipitation will hit us tomorrow and if it happens after we clear freezing we should get off relatively easy. The Hutchinson to Topeka area is going to get hammered. I wouldn't be surprised to see somebody in that area get > an inch of ice. That will be a crippling event for people in that part of the state.
Anyways, I'm hoping we stay below freezing because I would love a good ice storm, but I'm doubting our chances of that happening. Time will tell.

[Dick McGowan]

http://www.weather.cod.edu/forecast/ETA/SP/etaSP_0_prec_24.gif
http://www.weather.cod.edu/forecast/ETA/SP/etaSP_2_temp_24.gif

Looks like it may be further north now by 12z, I do not want this ice storm!
It will be a real PITA to get to work and finals.

[Mike Peregrine]

Just took a look at the latest EAX web briefing (http://www.crh.noaa.gov/eax/?n=webbriefing) ... the graphics they are using now are really indicating the bulls eye moving off to the north. Topeka to St. Joe looks to be the hot spot (good call Joel!). Not good for the family, but I'd still rather STJ take the hit than KC. Also - doesn't look to me like anything is going to seriously get underway till much later on.

[Dick McGowan]

When did they start doing these "web briefings?" I noticed Topeka has one up too:

http://www.crh.noaa.gov/top/?n=winterweatherbriefing

[Rhyuan Janssen]

ZOOT! Lacrosse is going to issue Winter weather adivsory... here's to hoping DSM will do at least the same... I am still keeping my fingers crossed for Winter Storm warning..might be a big hopefull there however...

[Mike Hollingshead]

Just took a look at the latest EAX web briefing (http://www.crh.noaa.gov/eax/?n=webbriefing) ... the graphics they are using now are really indicating the bulls eye moving off to the north. Topeka to St. Joe looks to be the hot spot (good call Joel!). Not good for the family, but I'd still rather STJ take the hit than KC. Also - doesn't look to me like anything is going to seriously get underway till much later on.

Looking at the satellite loop and last couple radar scans, I bet it starts lighting up pretty soon in ne KS. Dang temps are bugging me, already at 30 in so many areas, but then again there is some sunshine in that area. I may hedge my bet for worth hit area just west or northwest of St. Joe. Heading that way now, just incase it does light up sooner, as it appears it will.

[Rhyuan Janssen]

I am glad to see that QPF has upped my amounts by quite a bit...I was sitting on the line of .1 and now I am on the line of 1.0! If this holds true I would expect to reach warning criteria on something...be it snow or ice...

[Mike Peregrine]

Looks like a lot of the thinking in here is reinforced by the latest outlook language out of EAX --

OVERNIGHT...AREAS NORTH OF A KANSAS CITY TO MACON LINE WILL LIKELY EXPERIENCE THE HEAVIEST FREEZING RAIN ACTIVITY...ALTHOUGH THE ENTIRE REGION WILL EXPERIENCE FREEZING RAIN DURING THE NIGHT. AREAS NORTH OF AN ATCHISON KANSAS TO UNIONVILLE LINE ARE EXPECTED TO SEE AT LEAST HALF AN INCH OF ICE OVERNIGHT WITH ISOLATED SPOTS POSSIBLY SEEING CLOSE TO AN INCH OF ICE WITH THE THUNDERSTORMS. FROM KANSAS CITY TO KIRKSVILLE AND MACON AROUND A QUARTER INCH OF ICE IS EXPECTED TONIGHT WITH ONE TO TWO TENTHS OF AN INCH POSSIBLE SOUTH OF THE MISSOURI RIVER.

Mike H better get himself to St. Joe. Have fun because I'm not going near that place tonight. Will be bad enough down here, from what I can tell. Radar is really starting to fill in across Kansas-

http://img.photobucket.com/albums/v143/mikeperegrine/kansasradar.jpg

[Joel Wright]

Hey Mike H, St. Joseph may be a good spot, but even there it may rise above freezing for a time tomorrow morning. I'm sure they'll still get a lot of ice though. If I were you I would consider maybe staying in Mound City along I-29. They should be just far enough north to stay locked into the subfreezing temps for the whole storm. Ideally, between Mound City and St. Joe would be the best spot in my opinion, but obviously the hotels would be sparce in that area I'd imagine. I think St. Joe or Mound City would be a great place to set up though. You should have easy access to the best ice band in either of those two locations...

[Chad Cowan]

END OF THE WORLD:
http://www.hpc.ncep.noaa.gov/wwd/day1_pice_gt_25.gif

[Michael O'Keeffe]

You guys are looking mostly at the night aspect of the storm. Once the sun rises that heavy band will move south of an Atchinson to Macon line including the KC metro area dumping an additional 1/4-1/2" of ice for areas brining the total ice storm totals to over an inch possibly for areas along the I70 corridor.

So with that 1/4"-1/2" overnight tacked on to the additional 1/4"-1/2" during the day we could still see the blow while areas north of Atchinson to Macon line including St. Joe will see maybe a 1/10 of an inch of ice, but a 1/2" of sleet. So with that said I still think KC will need to take extreme precaution because though we may not get the worst during the morning commute the rush hour drive home could be VERY treacherous.

Just my 2 cents.

[Joel Wright]

18z models look even wetter to me. 1.5" accumulations (no joke) are not out of the question for the people hit the hardest. It looks like moderate to heavy supercooled rain will almost train over the same areas for 12hrs or more later tonight. Still looks like Salina through St Joseph (or a hair north of there) to Lamoni, to near the QC, and on towards NIU/Dekalb.

The GFS surface 0° looks nearly the same as previous runs. Maybe just a HAIR further south than this mornings cycle. Really doesn't look like sleet will factor in across the heavy band of ice, as this area will have a rather thick layer of relatively warm air above the VERY shallow, but cold arctic airmass. Yee haw! Here we go...

[Rhyuan Janssen]

My local forecast has up to .5 of ice and then up to 5 inches of sleet!! That would be incredible! I still think some changes will occur with morning package if the trends continue to do this north shift thing.

[Charles Kuster]

Lincoln won't see as much ice as locations further to our south, but we are still under a winter storm warning. We should see freezing rain tonight which should transition over to sleet and snow during the early morning hours. Both the NAM and RUC have the 850mb freezing line passing us between 12:00am CST and 6:00am CST (probably around 2-5am). However, we could see a decent amount of ice before this occurs. NWS has increased our ice accumulations from .2"-.4" to .3"-.5" and locations just to our south are forecasted to potentially receive more than .5" of ice. Precip is increasing over KS and spreading to the north quickly, so our precip could begin within several hours. Stay safe everyone. :)

[George Limpert]

The temperature is creeping up in Columbia. The RUC seems a little warm compared to surface observations, but seems to have a better handle on temperatures than the latest GFS. For the next few hours, the RUC keeps temperature advections at the surface rather weak over central Missouri. I'm not expecting the temperature to go above freezing in Columbia until possibly 2 or 3 AM. The 21Z RUC would take it above freezing around midnight, but that run of the RUC seems to be a degree or two too warm at the surface. The winds do become southeasterly this evening in response to pressure falls to the west. Radar trends over west central Missouri show echoes developing aloft. I think we'll see a lot of cold rain and possibly some thunder in Columbia tomorrow morning.

[Bob Johnson]

Didnt get ice from this storm at all. Stayed NW of me here in ORD. Was quite a storm in Quads area.

[Tyler_Costantini]

We lost power Sat 12-9 ~4am cst restored to my home in Pittsburg, KS @ ~ 5:30pm cst last night Wed 12-12. We kept the house warm enough to live in with a 5kw generator I only ran it every 4 -5 hours or so I only had 15gal of gas and with the amount of damage i wasn't sure when we would have power restored. We lost large limbs and one tree in out yard. According to NWS Springfield we received 1.5" + honestly in not sure how to properly measure ice.

Anyway I wanted to post a report and let everyone we made it through ok.
I hope everyone made it through the storm safely.
here is a link some of the pictures it took in and around Pittsburg, KS
http://www.tornadonerds.com/gallery/main.php?g2_itemId=17638