4/10/07 FCST: SD/NE/MN/IA/WI/IL/IN/MI (WINTER PRECIP)

[Joel Wright]

Wow, didn't think we'd have to make another one of these threads again this year.

It's looking more and more likely that a band of heavy wet snow will set up from South Dakota all the way east through the cornbelt Tuesday through Wednesday.

So far the models have been a little erratic with the storm track. So it's probably a bit early to pinpoint exactly where the heaviest band will end up. The majority of them place the heaviest band across the northern half of IA through northern IL, then up into southern MI.

I was planning on going out and buying a new car today, but now with this storm coming in I'm not so sure.

 

[Brandon Sullivan]

Brr.. ya, I was hoping not to see another one of em either.. Oh well..

Some of this mornings models paint an impressive 12-15 inch band across IA/MN border.. Hopefully it will stay north of I 80.. I'm hoping we don't have an ice storm setup.. Which doesn't look too likely now.. Will have to monitor.... Hopefully we can chase next Friday and forget all about this..

Yuck!

 

[David Draun]

One of the latest runs of the GFS paints and ugly picture of possibly a FOOT OF SNOW in the Chicago area in the Tuesday-Wednesday time frame. Now the GFS is totally cold-biased, but right now it is nailing this cold air. I'm definitely concerned about this one. And it will likely be the heavy heart attack snow should this come to fruition. Ugh, go away winter.

 

[Joel Wright]

Well, the last few model runs have the system considerably less organized. Instead of a band of heavy snow just north of a potent surface cyclone, they're showing more of a broad area of lighter snows to the north of a much weaker low center. Still a ways out so things may go back the other way. I still wouldn't be surprised to see a band of heavy snow lay out somewhere if the system ends up being more organized than currently progged.

Looks like you folks up in MN and WI have the best shot of anything white coming from this system of any consequence...

 

[Robert Dewey]

Reading some of the discussions, the GFS doesn't really line up with any of the other models. I see the NAM looks closer to the GFS, though...

I'm not convinced either way yet - it could be something big, or it could be nothing at all. I'm not willing to give a higher probability to either outcome.

 

[Bill Schintler]

Eastern IA winter weather update

Two winter storms will affect the Eastern Iowa area this week. The first will start to day as light rain and showers spread over the area from the west later this afternoon with a changeover to snow Wednesday morning after which several inches of snow are likely. A second storm will bring a mix of winter precipitation to the area Friday. The following are some specific are forecasts for the Tuesday/Wednesday storm:

Cedar Rapids:

Light rain will begin at 3:30 PM today. Rain will then continue through the evening and overnight hours and then change to snow at 7 AM Wednesday. Snowfall will continue through 10 PM Wednesday evening.
Total snowfall: 2.5 inches (Eastern IA Airport), 3.5 inches on northern CR.
Total liquid precipitation (including melted snow): 1.18 inches

Iowa City:

Light rain will begin at 4 PM today. Rain will then continue through the evening and overnight hours and then change to snow at 9:30 AM Wednesday. Snowfall will continue through 10 PM Wednesday evening.
Total snowfall: 1.5 inches
Total liquid precipitation (including melted snow): 1.20 inches

Marengo:

Light rain will begin at 3:30 PM today. Rain will then continue through the evening and overnight hours and then change to snow at 7:30 AM Wednesday. Snowfall will continue through 9 PM Wednesday evening.
Total snowfall: 2.0 inches
Total liquid precipitation (including melted snow): 1.17 inches

Mount Vernon:

Light rain will begin at 4:30 PM today. Rain will then continue through the evening and overnight hours and then change to snow at 8:30 AM Wednesday. Snowfall will continue through 10:30 PM Wednesday evening.
Total snowfall: 2.0 inches
Total liquid precipitation (including melted snow): 1.10 inches

Synopsis:

Complicated coupled jet structure with strongest H5/H7 height falls occurring over ERN WY/ WRN Dakotas; while H85 height falls were diving SE towards ERN NEB ATTM. At the SFC, an elongated area of low-pressure was deepening from SERN CO into NWRN MT with strongest pressure falls of -0.003 in/hr noted over OK. A couple of areas of precipitation were ongoing. The first, in NRN IA/SRN MN, was apparently in association with an area of H7 frontogenesis and isentropic upglide along 290K – 295K SFC’s. In NRN NEB, precipitation was falling along a developing SFC WF. Models have initialized well to SFC and UA features but are a few degrees cool with 2m temperatures.

Discussion:
A very difficult forecast indeed… The primary concern is the exact track of the SFC low and attendant temperature structure and timing. Up until this morning, models have been all over the place with the evolution and track of the SFC low; and today the NAM and GFS have finally come into decent agreement. The consensus is trending towards a single low along with a more southerly track then earlier indications, the implications of which are both more QPF and colder temperatures. Current track is from S of STL to S of ORD during the day Wednesday. Dry air near the SFC will need to be overcome before precipitation will start. CAA starting early Wednesday should be sufficient for a changeover to snowfall in most areas. QPF in excess of 0.3 inches after changeover to snow suggests several inches of snow despite low snow/water ratios.

[FONT=&quot]- bill[/FONT]

 

[Joel Wright]

Well, good thing I'm hungry because it looks like I'm going to have to eat my words.

The storm system is not only much stronger/more organized, but it's also tracking further south again per latest data. A rather wide band of heavy wet snow will in fact set up from the northern third of IA into southern WI, and perhaps a bit south if trends continue.

Areas from Sioux City IA towards Dubuque IA, and up towards Madison WI may see over 10". Wow.

 

[Josh Richardson]

Winter Storm Warnings are in effect now as well as Heavy Snow Warning just off to my north. As Joel stated 10" will be very likely across the northern third of the state with locally heavier amounts up around a foot or more near the IA/MN border.

 

[Danny Neal]

I am hovering right along that tricky freezing line. Winter Weather Advisory here, snow advisory to the north side, and Winter storm warning to my west and north. I really pray this system stays to the north....will make work hell for me. Hard to believe....it is 51 degrees here and we are talking 3-5 inches of snow potentially.

 

[Jim Zandonai]

This is about as depressing as it gets especially since we were watching thunderstorms and record warmth not long ago..besides near record cold crushing early blooms now we are on the edge of a Winter storm Warning in Rockford area. Even though it wont be around long its still going to be a slippery/wet mess. Looks like its set to give us some heavy wet snow esp. NW of us. The good news is the weekend storm should give us mostly rain but even then not much of a thunder threat even though we should see 60 next week.
What a disappointing April,that mountain of cold air sure put a lid on things everywhere.Then again up here April is real finicky anyway. At least Heat seems to be rebounding next week !