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

 

[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 ... sweet! ...

 

[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!!

 

[Jeff Piotrowski]

Ice Storm

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 puts the majority of icing to the east and south, but it looks too close to call.

Day 3 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.