2/5/08-2/6/08 WINTER STORM NOW: KS,MO,IA,NE,IL,WI,MN,IN,MI,OH

[Joel Wright]

Figure I'd start a NOW thread since the winter weather aspect of the storm is becoming more widespread now.

A large shield of heavy precip has moved across much of MO into parts of IA and now IL through the morning hours, dumping up to an inch of rain on KC. Meanwhile, just north into far northern MO and southern IA a small area of heavy snow fell. This area of precip is expanding as it pushes eastward. Back to the west, the precip across KS is lighter, but with the upper energy hanging back still, this whole are should get invigorated later today, and especially tonight.

Here in Erie, a mix of sleet and snow has moved in. Most likely this will change over to rain here shortly, since it's still too warm to support snow. Thickness values are still rather high, with 850mb temps still hovering around 3°C.

The true snow/mix line is out in eastern IA, and extends down to near the KC area. Some areas in northwest MO northwest of that line are still experiencing some light rain, but any burst of moderate precip would rapidly change it over to snow.

The snow/mix line should push ever so slightly southeast with each passing hour.

 

[Robert Dewey]

Not sure what we're going to get between the Detroit and Flint area. NAM is predicting incredible QPF amounts, though, for a lot of areas.

I've always had trouble with these type of events... the latest 18Z NAM shows us kissing the 0C to -3C 850MB isotherm, which would indicate snow to me; but that's marginal temperatures at best, and definitely wouldn't take into account any warm layers that sneak in.

Both NAM and GFS are trending slightly colder, with the 18Z NAM continuing the trend.

 

[Mike Kovalchick]

Temps have dropped to 35 in Lansing. Looks like the fun should arrive here towards midnight. 18Z NAM paints about 2" liquid equivalent to fall-mostly snow-especially Lansing Northward. The NAM QPF fields have been overblown most of the Winter it seems but you would think just by chance it would get it right sooner or later!

 

[Robert Dewey]

From what I've found, personally speaking, is that the NAM is usually 2-3 times actual amounts. So, I fully expect at least 0.75 to 1.15 inches of QPF over much of southern lower MI.

 

[Joel Wright]

I'm getting a little concerned with my own forecast at the moment. We weren't really supposed to have any snow until after sunset, and yet it's been snowing heavily now for a half hour. Picked up a quick 1/2". If this were to stay all snow it's downright scary how much could fall looking at all of the model QPF forecasts. NAM/GFS paint 1.50" right over me...

 

[Mike Kovalchick]

From what I've found, personally speaking, is that the NAM is usually 2-3 times actual amounts. So, I fully expect at least 0.75 to 1.15 inches of QPF over much of southern lower MI.

Upstream radars look very impressive to say the least. Perhaps the NAM might be on to something? I see the local NWS calling for upto 9" and locally higher amounts. Climatology in this area would tend to rule out much over a foot except very locally. I assume the OZ runs will tell the tale.

 

[cstrunk]

In St. Joseph we picked up about 1-2" of snow/sleet earlier in the day. It then switched to rain and it's been lightly raining or misting since then. We're sitting at 32 degrees and the light rain is starting to freeze on trees. I'm sure it will be switching back to snow within the next hour or two. A little heavier precip looks to be heading our way... but as has been mentioned, the storm hasn't wound up for round 2 yet, and I expect it to look a lot more menacing for this area by 7-8 PM.

 

[Robert Dewey]

Upstream radars look very impressive to say the least. Perhaps the NAM might be on to something? I see the local NWS calling for upto 9" and locally higher amounts. Climatology in this area would tend to rule out much over a foot except very locally. I assume the OZ runs will tell the tale.

I hope it is!

As DTX notes, there is quite a deep (and very strong) layer of instability present... and with winds stationary to the boundary, this is a perfect setup for a stationary band of extremely heavy snowfall.

DTX is going with around 8 inches here, but notes that amounts could be MUCH higher if such a band sets up - which is exactly what the 18Z NAM is hinting at.

EDIT: 18Z NAM snow algorithms are through the roof with +18 inch amounts (though, I've seen this before without verification) - http://wxcaster4.com/nam/CONUS1_MESO-ETA212_SFC_ACCUMSNOWFALL-KUCHERA_60HR.gif

I'll be more inclined to jump on the bandwagon if the 18Z GFS continues with a cold trend.

 

[Chad Cowan]

EDIT: 18Z NAM snow algorithms are through the roof with +18 inch amounts (though, I've seen this before without verification) - http://wxcaster4.com/nam/CONUS1_MESO-ETA212_SFC_ACCUMSNOWFALL-KUCHERA_60HR.gif

I'll be more inclined to jump on the bandwagon if the 18Z GFS continues with a cold trend.

I was about to post the exact same map... that's a scary sight for us here in Chicago. I'm not sure my shoes can handle any more of this. I might need to brush up on my pole vaulting skills to get over these snow packed curbs.

I'm hesitant to jump on the big totals here, the 12z NAM put the +6" totals north of Chicago and I'm a bit wary of these off hour runs.

 

[Joel Wright]

The heavy snow from earlier rapidly switched back over to just rain and sleet once the higher reflectivities moved on an hour and a half ago or so. We still picked up a quick .7" of snow in less than an hour. For a time the flakes were half-dollar size. Very cool to see. (Of course as I type this some snowflakes are suddenly mixing in again lol).

NWS DVN is forecasting a band of up to 18" of snow right through the heart of the area, from southern IA into northern IL. That seems a little bullish, but if we can get some thunder involved then I guess anything's possible.

Precip behind the first wave has really decreased, but the main upper support is still way out in New Mexico! I expect a few more waves of precip before the whole momma shoots out late tonight. That's when things should really come together.

 

[Jim Zandonai]

Well looking at the current radar I see a huge amount of thunderstorms to our south and some snow to the north..So far we had about 2" . What I see though are huge gaps in the snow shield over NW MO and around there..that means time without snow..Now It could fill in which is the idea behind the huge snowfall totals and extended period of snow..History shows me that whenever we have had amount of a foot or near that its been a steady snow shield of moderate to heavy snow with no let ups.. I just dont see it getting to a foot here.. yes I see energy behind it but most of that huge swath is almost east of us so am I missing something ?
I could be wrong we could get a snow burst etc but that area to the west is really going to have to fil lin and increase in intensity ..for now I'll stick with the lower end of the forecast around 9

 

[Joel Wright]

00z models rolling in looking pretty ominous. They continue to slow the storm down, keeping heavy snow in place longer for the areas impacted. I completely agree with DVN and other surrounding offices with the 12-18" snowfall potential.

The majority of the upper level energy will finally kick out later tonight, and develop a very intense, banded area of heavy snow in the deformation zone area from NW MO into IA. This will then SLOWLY progress eastward laying down a lot of snow in it's path. The heaviest snow will probably fall from Williamsburg IA to Rockford IL, to the extreme southeast tip of WI. My particular area will probably see a foot of snow, maybe a bit more if thunder gets involved. The heaviest may end up just a tad north of my exact location, but I'll be damn close.

Already heavier precip is beginning to organize in KS. This is the sign that the upper energy is beginning it's kick eastward.

Hey Jim, you may well be in the heart of where the heaviest snow falls man!

 

[Jim Zandonai]

Well Joel you may be right.. Winter Weather forecasting and Snowfall amounts have always been a headache in forecasting..but with all that incredible action to the south its hard to concentrate on this event..
Good Lord what an event ..esp for FEB. The bad news is there are injuries and fatalities..
Lets see how many days to Spring ?

 

[David Draun]

Wow, this system has really slowed down, I guess that happens when a low begins to close off. The main snow event for areas east of I-39 isn't supposed to start until much later tomorrow morning. Mostly rain and sleet changing to light snow overnight for the Chicago metro.

 

[Robert Dewey]

I'm not sure that it has really slowed down, rather it looks like more emphasis is being placed on deformation snows rather than the initial surge of moisture. Convection really limited the northward extent of precipitation this evening.

All of the models agree on very heavy snows setting up from NW MO northeastward through NY by the time it's all said and done.

http://wxcaster4.com/nam/CONUS1_ETA212_SFC_ACCUMSNOWFALL-KUCHERA_60HR.gif