Corn Belt Region Watch out for Wednesday and Thursday!!!

[Gothpunk-IL-WX]

ETA and UKMET and GEM are tending to bring a band of Heavy Snows as of the 00UTC runs to bring a heavy deformation zone setup for Eastern Kansas, south central Missouri, Central/southwestern Illinois and Indiana, Michigan areas by Morning Thursday starting as early as after midnight Wednesday Night. Heavy precipation may still be falling as the storm phases with the cold air faster then previously forecasted, which may result in a 50-100 mile band of very heavy snows possibly up to 8-12 inches in any of these areas. This is still about 3 to 4 days out but the confidence is building that these areas could possibly see the heaviest and greatest risk of snow and sleet. The cities within the greatest risk area include but may change are: Springfield, MO, St. Louis, MO and surrounding metro areas by Wednesday Night/Thursday Morning time frame, Springfield and Lincoln, IL and into Indianapolis and Detriot by thursday Afternoon. The Storm should end west to east by Thursday Midnight for the midwest and most of the Great Lakes. This Storm will probably be not remembered for much icing or super heavy rains, although some T-storms and heavy rains upto 2 inches are possible, but not nearly the 4-7 inches of rain that some areas picked up last week. The storm maybe more know for it's potentially heavy snows. After this storm the Sibarian Airmass arrives and puts the midwest all the way into the Northeast and Mid-Atlantic in the Deep Freeze. Temperatures may be below freezing even in the deep south. There's still alot of uncertainly with this storm, and confidence is still very low, but slowly rising. Ethier way the warm-up will never reach the levels that were expected a week ago or even just a few days ago in the midwest, although the northeast may get one "hot" day for winter standards and same with the Southern Great Lakes and Ohio River Valley Regions. Then the Chill and snow arrives for at least a good week or so. More as models come more into agreement and we get closer to this interesting event.

[Gothpunk-IL-WX]

GFS is also slowly following closer to the ETA, although it is not as aggressive with QFP amounts and Phasing as the ETA, but still we have to watch this developing storm.

[PurdueWx80]

I disagree. Most of the precipitation will be pre-frontal, and with temperatures ahead of the front likely to be in the 50's and 60's as far north as the Great Lakes, there will be little to no snow along or behind the front itself. The only hazard with this front will be damaging winds as an 80-90 kt jet at 850 may be transferred to the surface if deep convection develops. Regardless, there will be widespread winds gusting over 30 kt outside of precipitation, with 40-50kt likely in rainfall and thunderstorms. There will also be very brisk winds in the Plains behind the front with the massive high coming down and the associated tight pressure gradient between it and the rapidly deepening surface low over the Lakes. This storm will be known more for it's rain and wind in the Midwest than anything else, and in fact, I see little to no snow outside of widespread flurries with the upper system (and of course in the Plains...i.e. MN and the Dakotas). (There could potentially be a very narrow band of light snows if a secondary low forms on the front in association with the vort max rounding the bend - this weak low is progged by the Eta, although the one in the northern Plains would be the primary system. In any case, there could be a small deformation zone with this...right now I don't see it happening but it would mean places in IA, far northern IL and WI could see a light dusting to a couple of inches). The massive temperature gradient will also be quite shocking, with temps in the 60's one day, with 10's or 20's the next (and wind chills below zero). As I alluded to two weeks ago, and reiterated last week, major flooding will once again become an issue with the high-PW air and high QPF expected. The Wabash River crested 9 feet above flood stage here (considered a moderate flood)...and has slowly fallen over the last couple of days. Moderate to major flooding will continue in the middle and lower OH river valley, and will eventually make it to the Mississippi. After this week, flooding will become less of an issue with the pattern change leading to colder/drier weather.

EDIT - Let me clear this up just a bit...What I laid out above is what I see happening, but there is still some uncertainty until the upper low over the PacNW is ejected into the southern Plains. There is still discrepancy among the models, the UKMET is further south and east with the low...also shows phasing...the 00Z GEM shows phasing and a very intense low, although the details are difficult to see given VERY fast flow and 24-hour model time intervals...the 00Z Euro has less phasing early on which equals a weaker solution, with no big storm in the Lakes/northern Plains at all. I do believe the mesoscale models will do a much better job of picking out the details once the system is within about 48 hours. It appears a couple jet feature will exist, so there are a number of ingredients which spell out a strong surface system...it's track will more or less be determined by the upper system that comes out of the SW.

[IWXSkywarndork]

Good discussion both of you guys. However, the local NWS mets (IWX) seem to be leaning towards Purdue's forecast. I'd love to see that arctic air move in before the final wave moves through Indiana Wednesday night. But it looks like just some flurries for me on Thursday with the bottom dropping out tempwise.

The one thing I would disagree with in Purdue's discussion is the temps, a least here in Northeast IN. We have an inversion set up here, and there is a lot of snow and ice on the ground. I don't think anywhere north of I-70 will see 60 degrees on Wednesday, and most areas will only make it into the lower 50's. South of there though, it's wide open.

Either scenario, however, is not good news for the Ohio Valley, as they can't handle any more precip. Flooding issues are going to magified as there may be some impressive rainfall amounts, especially with any convection Wednesday afternoon/evening.

[IWXSkywarndork]

Wow, did I bust on my temperature prediction. It hit 65 on my weather station here in Huntington, and it is still 60 degrees as I type this at 4:30 AM. Guess I'll leave the forecasting to the experts.

[Gothpunk-IL-WX]

Seems that my forecast is trying to come true! This is a storm of weather extremes. Snowfall amounts I'm not even going to guess on, but if I had to make a rough estimate I'd say 1-3 inches is possible in the Saint Louis, MO metropoliation area and a 75-100 mile band lining toward the east northeast direction. Precipation will end by Early afternoon in St. Louis, MO and later on in the day points north and east of that.

[PurdueWx80]

See http://www.spc.noaa.gov/products/md/md0080.html to explain this:

[PurdueWx80]

Another mesoscale discussion graphic from the storm prediction center -



I'm right on the edge of the heavy snow projection....temps falling around 3 deg/hour now so we should switch over within the next 2-3 hours!

[PurdueWx80]

By the way, areas that do see 1-4" of snow can chop off 10-20 degrees from their projected overnight lows as the arctic high and airmass come down. Don't be surprised to see areas in a narrow strip between St. Louis, Chicago and Detroit go to at least -10F if not colder this weekend.