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

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Norman, OK
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.
 
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.
 
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!
 
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.
 
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.
 
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.
 
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.

Feb10pm.jpg



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. :p Lets see how it plays out!
 
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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.
 
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.
 
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
 
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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.
 

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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.
 
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.

That is correct. Storm track to the north means southern edges get cutoff, storm track further south means northern edges get cut off.

You also need to remember that 0.25 inches of QPF at a 30:1 snow ratio is around 7 inches of snow... So while areas to the north only receive 0.25 inches of QPF at 7 inches of snow, areas further south will need 0.70 inches of QPF to attain that same 7 inch snowfall total.

As of the 12Z models, KPIA to KDTW will likely see the worst of the storm as a combination of wind and fluffy snow create low visibility and cold wind chill values.
 
As of the 12Z models, KPIA to KDTW will likely see the worst of the storm as a combination of wind and fluffy snow create low visibility and cold wind chill values.

Well if that holds true it looks like Brandon and I will see another snow today tomorrow and/or Tuesday!:) However, I'm guessing it's gonna be another long school year that doesn't end until after Memorial Day. This is starting to remind me of the winter of 1993-1994 in North Central IL. Long range models are also forecasting an active March too.

It also looks like the KPIA-KDTW area would be most impacted by a jet streak..so I'm guessing your snow totals could be more accurate than current WSW predictions if that holds true.
 
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I think the heaviest snows will evolve out of the big surge of moisture moving north late Monday night and especially Tuesday. A large area of heavy rain and thunderstorms will develop Monday night down south near the organizing surface low, and bulge north rather rappidly later in the night into the colder air in place to the north and reinforce the ongoing snowfall. I think the heaviest band will set up from eastern IL into northwest Ohio. This area could see up to a foot of snowfall.

Snow to water ratios will likely be near 10:1 in this heaviest band. To the north the ratios will be higher, say up to 20:1, but moisture will be much less impressive and the precip will be fighting dry air trying to fight in from the northeast.

I think the "jackpot" band of snow will line up roughly from Lafayette to Fort Wayne IN, to Bowling Green OH. 10-12" first guess along this line.

Further back to the west in Illinois, Missouri, and Iowa, moisture looks to be lacking a bit, but upper dynamics and slightly higher snow to water ratios will help offset that a bit I think. There is a closed low above 700mb, so that's good. I think the snows in these areas will be fairly "bandy", with large areas of just light snows in between.

Time will tell and I'm looking forward to later model runs.
 
Looks like yet another ice event for winter 06/07 taking shape, along the Ohio River this time. I almost don't want to look at models until the day of the event - it's all where the freezing lines at the surface and aloft set up, almost impossible to pinpoint now.

Just a side note - we have a real 'weather bubble' here, called the warm wedge. From the looks of the NWS watch/warning map, the warm wedge is giving Charleston, WV a bit of 'Norman, OK syndrome' as the only location in the storm swath outside of the winter storm watches.
 
FWIW, KIWX is says that areas in the watch should expect in excess of 12 inches. Their AFD states 12-16 inches, locally higher. It will be interesting to see how this evolves. The 18Z NAM is further northwest than the 12Z run, and the 18Z GFS is pretty close to the 12Z GFS (perhaps a touch further southeast with the QPF).
 
You also need to remember that 0.25 inches of QPF at a 30:1 snow ratio is around 7 inches of snow...

That ratio might be a little high given cold temps in place. I'm intrigued by the northward motion but not ready to ignore the dry air hanging around and being advected in on the northeast winds...
 
Wow. :eek: This system is slowed by the models yet again! Honestly though... I still see the same effects. Note that some WFO trimming the snow totals due to a slight temperature inversion. Thus, could see some mixed precip.. How much however remains to be told. I am still confident that the area should see warning criteria snow.. Blizzard conditions will be marginal.. My normal model site seems to be down. So I am using a new model source.. so interpretations a little different. After seeing the new models.. I do agree with Joel on the heavier snows in E IL.. This most likely due to the more southern track the storm is forecast to take. Now dipping into N Texas rather than going through central OK. Looking at the SREF, that prediction seems to be right on. It has changed before so I wont be surprised to see it change again.. Well be around watchin it.
 
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.

I aggree with you on that, Even Northern Indiana has everything going up calling for up to 15 inches for my area tomorrow through tuesday evening.
not sure if I can post the link to the Page in this forum, so I Will hold off till I know
 
It seems like I am caught in the middle. I don't know if thats a good thing or a bad thing. Snow Advisory to my north tonight, Winter Storm Watch to my south. City of Chicago currently off scott-free right now. I am more interested in the possible lake effect band the south side of Chicago and NW Indiana might be getting. East-Northeast winds are expected to blow up to 35 mph. Everyone here and in the media are mentioning a mainly south of I-80 snow event and that will be the case if the Storm continues on its current forecasted track. Well now I have given up on all hope of the storm track to move 50 miles to the north and give me 8-12 inches of snow. Alot can still change but, I have seen this types of storms come and go and they usually hold true to what is currently forecasted. I have focused on some lake effect for the City of Chicago, South Subs, and NW IN eventually later on Tuesday night into Wednesday. Anyone else concerned about this? I know this is mainly focused about the main system so I am kind of skeptical. Will it be historical? hell no! But maybe a nice band can form over the southside and drop 8-10 of its own! Hmmm?
 
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