2/10/07-2/13/07 FCST: Midwest (WINTER PRECIP)

[Brandon Sullivan]

Latest models have been consistent in advertising a strong low pressure system to eject northeastward from the south west CONUS. Models have still not resolved on a solution, with system still 84 + hours out, still time to resolve the issue.. Heavy rain could be a threat anywhere south of LSK IND SGF line.. With a sleet snow mixture north of that line. Until you reach the all snow line somewhere around and north of an IND EAX line.. NOTE: this is with current model data.. Also, ECMWF is somewhat different from other members in that it pushes the all snow line further north. Moisture and Forcing don't seem to be lacking in this system. Wouldn't be surprised to see a good 6+ up to maybe 8-12 based on current parameters.. This main snow axis would likely fall 100 miles on either side of a Kirksville, Mo - Lincoln, IL line. Will wait for more model runs. But will be worth watching.

 

[Robert Dewey]

I'm keeping an eye, but not focusing on it too much. A lot can change, and I don't really keep up with things beyond days 3 and 4. It's kind of weird talking about 8-12 inches being "a lot" given the +25 inches in 6 hours over parts of NY.

 

[Brandon Sullivan]

Well, looks like im still talking to myself. This system is making big trouble for all the models. IT still hasnt been agreed upon the track/timing/speed/strength. All I can say is central IL has a good shot of 6+ if it keeps the current AR TN track. More north, more snow, south less than 2. At least we know not to expect no 7 feet like NY.

 

[Jesse Risley]

It looks more and more like a "wishcast" to me...I'm still not seeing the odds in favor of a good dumping on west central IL or NE Missouri...time will tell!

 

[Robert Dewey]

KIND:

EVEN THOUGH THERE IS STILL SOME DIFFERENCES BETWEEN ENSEMBLE
MEMBERS...MODELS HAVE BEEN TRENDING FOR A STRONGER SOUTHERN STREAM
SYSTEM AND ALSO TRACKING IT FARTHER NORTH. NAM IS MUCH TOO STRONG
AS IT GIVES 10 TO 20 INCHES OF SNOW ACROSS OUR REGION.

I still wouldn't discount the NAM. It has been right way too many times this winter. With that said, the 00Z is rolling in now and it will be interesting to see if things are indeed deeper and further north.

 

[Robert Dewey]

It's interesting to see how far north the 00Z NAM has pushed the system without moving the -10C isotherm at 850MB. Just looking at the mid level lift and thermal profile, we'd probably be looking at snow ratios of 25:1 or 30:1 here in southern lower MI. NAM spits out 0.50 to 0.75 inches of QPF along the -10C 850MB isotherm, so that area would probably see anywhere from 10-20 inches if the NAM is believed.

I'm willing to bet that the 00Z GFS and GEM models are also further north. That will probably be the up and coming trend through the next 60-84 hours.

 

[Mike Hollingshead]

KUCHERA METHOD FORECAST SNOW TOTALS VIA NAM

10 TO 1 RATIO FORECAST SNOW TOTALS VIA NAM

Not that these are worth a whole hell of a lot, but they are fun to look at. If it is going to be cold forever it may as well snow and if it is going to snow it may as well be heavy.

GFS quicker and weaker.

 

[Robert Dewey]

GFS quicker and weaker.

Yeah, but it's been trending north/west and stronger. I think the "trend is the friend" in this situation.

I just can't shake how similar the trends were with the ice storm several weeks ago. Models were really far southeast, with the NAM trending further northwest. It was discounted by the HPC, but then the GFS jumped on the bandwagon and there wasn't anything left to discount lol. Not only did the NAM correctly predict the northwestward trend, it actually under-forecasted it.

I have a feeling this might be the case with this system. The GFS will probably start to slow it down, the Euro and Canadian models will pick up the NAM trend, and then we'll have model war.

 

[Brandon Sullivan]

It' s Coming.

Wow. How the models have changed. Time has taken its toll and models finally coming together. At least on the broad scale features. Obviously, trend has been north, especially the NAM. Thermal profiles north of I 70 should support an all snow event.. maybe a few brief periods of sleet.. This system is going to be in a favorable setup for deep cyclogenesis. Given the fact that ageostrophic flow is well above normal. So could be a similar setup to Dec 1st. Also, tightening pressure gradient, could see near blizzard conditions.

Believe the below image compliments model output data quite well, and is small enough to not fill the page up, so opted to include it for a better idea of axis of threats.

One more good full day to really analyze the system. Most likely see headlines out tomorrow morning. Always love getting woke up by NOAA at 3:30 AM. Lets see how it plays out!

 

[Dan Cook]

DVN's talking about blizzard like conditions here.

 

[Brandon Sullivan]

Its on its way!!

All seems to be shaping out well and I am being put under a winter storm watch. WSW details says 6-10+ in my area. Lots of blowing snow a BIG concern.. I wouldn't be surprised at some sort of a blizzard product. Models honestly haven't changed much. All in all.. looks to be another big snow maker. As Robert said earlier, hard to see this as a lot compared to NY. But O well. I still don't want to get over confident, knowing what has happened before.. But I'm getting a good feeling. Have to start watching the system and comparing it to how the models predicted it. DVN AFD says blizzard warning will be needed if NAM or Canadians verify. Which I see as very possible. NAM even trended it FURTHER north this morning!!.. Noted that the HPC used the GFS for their model of choice this morning... It does have good run to run consistency. But general trend of all models is north... Dry wedge hinted at sometimes in models is all but gone. DVN and ILX both issuing WSW.. DVN goes into effect at 12Z Monday. and ILX at 18Z Monday. This may be one thing models are yet to fully resolve.. Looking at the new NAM coming in.. It is somewhat different on placement of the QPF.... But good to note that GFS and NAM are virtually in agreement.. Note that the surface gradient on this system is somewhat stronger in the new models.. Ill get some more and be back later... Keep your eyes in the sky and the ears to noaa.. shes a coming.

 

[Robert Dewey]

12Z GFS and GEM models caught the northward trend. GFS and GEM models now the most aggressive as the NAM has eased off a bit. GFS paints up to 0.75 inches of QPF along the -10C 850MB isotherm with a very tight QPF gradient. I'm still expecting high snow ratios, on the order of 30:1 given the Arctic airmass in place. GFS also kicks up SFC winds a bit, so it will definitely be a "true" winter storm.

One thing that worries me with these events is the amount of low level dry air. However, the models do show a nice banded event setting up prior to the main storm system, so this might work well in terms of moistening the airmass.

With the current trends... I'm going to say that someone within the IL/IN/MI/OH area will end up with close to 24 inches of fluff IF these trends continue. Any warming in the lower levels or reduction in QPF would obviously hinder that amount significantly.

 

[Brian Stertz]

Looks like the heavy snow band will setup across far NE Kansas into NW/NC Missouri Monday evening - Tuesday morning. Both the ETA and GFS support this trend. The GFS is a little heavier with the snowfall than the ETA (2-4" in the KC Metro and 4-8" along & north of a Topeka KS to Chillicothe MO line).

A lot will be dependent on the wet-bulbing effects by late Monday afternoon and into the evening hours. I would think that by 9-10pm tomorrow night, the KC Metro will change over to all snow from the wintry mix earlier in the day.

http://grib2.wxcaster.com/wxcaster4/CONUS1_ETA212_SFC_ACCUMSNOWFALL_48HR.gif

http://204.2.104.196/gfs/WINTER_GFS0P5_SFC_ACCUM-SNOW_51HR.gif

 

[Robert Dewey]

Decided to make an outlook map outlining where I think the heaviest snow will setup. Basically, I think somebody in that zone will see up to two feet of snow... With several locations hitting 12 to 18 inches. The outlined area is broad, which is a good indication of uncertainty; I don't expect that entire area to be affect, rather a more narrow band will likely setup somwhere within that zone.

 

[Jesse Risley]

Well you guys win for now, but I'm gonna be skeptical until tonight. I do notice that recent model trends are showing that dry air undercutting snow totals should not be as big of an issue as one thought. However, if this low pressure system tracks 20-50 miles further south than anticipated, the northern fringes of your maps are going to get a dusting at best. I'm not sure lower MI is gonna get much action outta this one..but we might be digging out again here in western IL.