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

[Robert Dewey]

So far, the 12Z NAM, NGM, and GEM are a touch further south as the high to the north appears to be a bit stronger. QPF still on the order of 0.50 to 0.75 across southern lower MI, with +1.00 amounts just to the south in IN/OH. On the other hand, the 09Z SREF has pushed the 1.00 inch QPF isoline further north, and increased the deviations to 0.25 to 0.50 inches across lower MI.

While this isn't what I would call a major shift, it does push the highest snowfall totals southward by about 25 miles. The next few runs of the models will really start to define where the heaviest snowfall totals will be confined, but right now it looks like northern IN and northwestern OH will see the most.

As it stands now, I expect around 8-12 inches between FTN and DTW, 12-18 inches DTW to DFI, with isolated 24 inch amounts (closer to DFI). Of course, I'm not taking into account mesoscale factors such as CSI, potential banding, etc., and there are several synoptic-scale variations that could push that heavy snowband further north/south.

 

[rdale]

Drop those numbers by a third and I'll go with your forecast too, due to the cold temps and dry air at the onset I think ratios will be 20:1 or less...

 

[Jesse Risley]

As it stands now, I expect around 8-12 inches between FTN and DTW, 12-18 inches DTW to DFI, with isolated 24 inch amounts (closer to DFI). Of course, I'm not taking into account mesoscale factors such as CSI, potential banding, etc., and there are several synoptic-scale variations that could push that heavy snowband further north/south.

I'll agree with the 8-12" totals, but I expect that anything over 15" will be very sparse and highly localized at best.

 

[Robert Dewey]

Drop those numbers by a third and I'll go with your forecast too, due to the cold temps and dry air at the onset I think ratios will be 20:1 or less...

I could see < 20:1 along the very northern fringe of the precipitation shield, but I still think 25:1 will be found where you have the best combination of strong vertical lift coupled with those cold temperatures. Obviously that's not going to cover the entire area; more like a 25-35 mile wide band.

I've also seen Alberta Clippers drop through with temps in the 10-15F range with QPF on the order of 0.25-0.35, outputting nearly a foot over southeast MI. That happened in 2004, I believe - you can look through the archives at the NWS DTX website (or clicking here). While origin of the system might also play a role in "seed type", I strongly believe temperatures around 15F with strong vertical lift will yeild ratios around 25:1.

I'm always watchful of the dry air to the north... I've seen it kill too many "good" winter storms. However, I think this current system is really helping out in that department, not to mention some modification of the northeasterly flow from Lake Huron. The NAM indicates RH falling to around 60% in the 1000-850MB layer briefly as this first system passes through.

Just south of the border, the models are in good agreement and have been very consistent in showing +1.00 QPF amounts (even the typically-dry NGM). Barring any significant changes, I still think 12-18 inches will actually be quite common in a narrow band stretching from NE to SW across northern IN and northwestern OH, with isolated 24 inch amounts.

Don't quote me on the location, however

 

[Robert Dewey]

12Z FSL WRF models coming in... They maintain their previous strength and track. The 12Z GFS appears to be further south, which agrees with the trend found on the other three models. I'm going to lean with the majority of the models, but won't rule out a further north track like the FSL WRF.

The rest of the WRF models are in... They all take the system further northwest, and are slightly stronger (in some cases, quite a bit stronger). It appears as though these models don't phase with the Atlantic system quite as fast as what the operational models are suggesting, which would account for the deeper / further north system. For example, the Millersville University WRF iteration takes a < 996MB low just east of CLE, and outputs 0.75 inches of QPF across much of the area southeast of LAN to FNT. The FSL WRF is a bit further north than that, pushing the 1.00 inch isoline towards DTW.

I'm still going to side with the operational models and see what the 18Z suggests.

Also, BUFKIT is showing snow ratios of 20:1 to 30:1 for DTW based on the thermal profile depending on the method;

Snow growth zone: 10:1 onset, 30:1 during heaviest QPF
Maximum thermal temperature: 20:1 to 25:1
SFC temp: 30:1

One thing to factor in will be the wind. BUFKIT shows solid 40KNTS in the mixing layer, which could shear the snow crystals resulting in slightly lower ratios.

 

[Chris Hayes]

Cleveland NWS is painting a pretty picture for much northern Ohio with 7-14 inches total snow accumulation. Winter storm warning for tommorow through wednesday. Calling for 5-9 inches of snow here tommorow, with several more inches tommorow night. Some sleet could mix in, but it doesnt appear as if it will cut down on snow accumulation a whole lot. Lots of blowing and drifting will be occuring tommorow through wednesday. Deffinately looking like the best winter storm for northern Ohio since at least 2003.

 

[Andrew Pritchard]

http://grib2.wxcaster.com/wxcaster4/CONUS1_ETA212_SFC_ACCUMSNOWFALL-KUCHERA_36HR.gif

While that model is likely overdoing the snowfall totals a little, it pretty much sums up my belief that the heaviest totals should be in a band from eastern Missouri into Ohio, with the heaviest being in eastern Illinois into central Indiana.

Moisture obviously isn't an issue with this system, and that in combination with the strength of the system, jet streaks further enhancing the lift over the area, among other ingredients coming together should produce a long period of heavy snow right here in central and eastern Illinois into central Indiana last late tonite into Tuesday. I don't think amounts of a foot or more are out of the question. 8-10 inches should be the average across the central part of Illinois, with 12-16 in eastern IL.

Finally, winter shows it's head where I live...

 

[Robert Dewey]

The trend here in MI is for less and less QPF. The 18Z NAM really takes off with the 500MB vort center with even less phasing with the northern system. This pushes the system further south yet again...

MKX says they are a bit concerned that the northern stream might actually absorb the system a bit more, pushing it further north. The models seem to disagree, but I'm not the one with the met degree

I'm still going to say 12-18 inches south of the MI border, but lower things for MI; 8-12 inches DTW to the border, 6-8 inches DTW to PTK, and 4-6 inches PTK to FNT. That's due to the new 18Z NAM, and I'm pretty sure the 18Z GFS will follow. The 00Z runs will probably be very representative of what actually occurs.

 

[Andrew Herron]

I agree with Robert but it looks like we're going to get the bulk of the system on Wednesday. Looks like the closest we're going to come to .50 QPF is at 00Z Wed with the main system in Ohio and skirting along the southern border of Lake Ontario.

Looks like we're going to once again just get clipped by this bugger.

 

[rdale]

18Z GFS confirming the drier outlook, checking Canadian GEM (which I love around here) also puts me on that bandwagon.

Our main met called in sick (sure ;> ) so my final call for Lansing is 2-4" (NWS saying 4-7".)

 

[Robert Dewey]

Maybe I should stop following this system, so that way it can jog back to the north. GFS is nearly consistent with it's previous run, didn't really see a big QPF jump... But it wasn't too wet to begin with.

Either way, the system looks really impressive on the NEXRAD and WV loop. With 24-36 hours left before the event completely unfolds, I won't totally write it off for DTW northward (00Z models will decide that).

 

[Brandon Sullivan]

Ok.. System looks to really beginning to get its act together and ready to release it's wrath that wiil strecth from IA/IL/MO all the the way ENE up throught NY. I dont really think that freezing rain will be too much of a concern. At least for my area in W central IL. I think CAA will kick in a cool the troposhphere before or shortly after the snow begins to fall... Still think the heaviest snow threat is across northern mo into west central il !!! THAT IS FOR TONIGHT S ACCUMS...!!! THE heaviest snow axis should then slide eastward from there on tuesday. As this is where the cyclonic branch of the "conveyer belt" will setup.. System will be a two punch ordeal.... # 1 will be the deformation zone precip.. # 2 will the warm conveyer belt setup.. This system still showing lightning into central KS.. and with the elements in place.. may even see some thunder snow... will keep an eye on this feature

 

[Joel Wright]

Well the storm's getting closer. Overall the models have been pretty consistent with the main features. There's been a few tweaks here and there, mainly with the timing details, but overall roughly the same as 24hrs ago.

The heaviest band of snow from this storm still looks to fall along a line from Lafayette to Fort Wayne IN, to Bowling Green OH during the day tomorrow and tomorrow night. Still looks like a nice solid 10-12" with a few very lucky spots up to 16" if they can manage to get stuck under a strong band for a length of time. I think those kind of amounts will be very isolated though.

Back here in northern IL into IA the moisture won't be as impressive, but as the upper level dynamics pass through there should be enough lift to induce some pretty respectable snows. I'm calling for about 5" of 14-17:1 snowfall to water ratio snow here at my house by tomorrow night.

A big factor we're going to have to deal with, especially later in the day tomorrow, is the winds. Winds may gust to 35mph or a bit higher at times tomorrow afternoon and night. Blowing and drifting is something we'll be dealing with many many hours, and maybe even a day or so after the snow has stopped falling.

 

[Andrew Herron]

One last look at the modes before bed. We're definetely getting clipped here in SE Michigan. I think the heaviest stuff is going to stay south of I-94 with no more than 5" north of that. It looks the like the backend of the system is going to give us more moisture and by Wednesday night expect about 6" overall with localized amounts of up to 10".