Sunday Snow, and What Happens Next

Ten days ago, I posted a blog about the possibility of a winter storm late this weekend.  While it won't have nearly the intensity that models were suggesting back then, we are definitely getting snow tomorrow.

Here's how this morning's GFS model sees accumulations in Wisconsin.  The last 4 runs of this model have increased snow totals, but have kept the bulls eye in southwestern Wisconsin.

And here's how the National Weather Service sees it:

Judging from the storm's current intensity, I favor these 3-4" totals.  Some spots may hit 5".  My guess is that the National Weather Service will issue a Winter Weather Advisory for our area at or before the 3:30pm forecast later today.

UPDATE (2:10pm):  As expected, the National Weather Service has issued a Winter Weather Advisory for south-central and southeastern Wisconsin, in effect from 3:00am to 6:00pm Sunday.  The official advisory calls for 3-4" of snow.  Here's the statement from NWS (click to enlarge):

So, our first measurable snow will come exactly one week after the 11/26-27 prediction I made all the way back on October 24th.  Not bad.

Snow will start early in the morning, probably before sunrise, while temperatures are still in the mid to upper 20s.  That will allow for accumulation on all surfaces.  So if you're headed to Green Bay for the game, be aware that road conditions will make bad traffic even worse.

So tomorrow's snow will make it look like winter...but it'll take a couple more days to really feel like winter.  Here's the cold front that goes through on Tuesday:

That cold front will do two things: (1) pull in the season's first real rush of arctic air, and (2) prevent that other low (the one in the above map centered over Tennessee) from impacting our weather all that much -- or at least that's how it's looking at the moment.  That's the low we had all been watching the last few days, and the one Accuweather meteorologist Bernie Rayno recorded a video about yesterday.

Let's talk about that cold first.

By Wednesday morning, that arctic air spills into the west.  This map shows temperature anomaly (departure from average) in degrees Celsius for Wednesday morning.

As that cold air continues to settle in and push eastward, our temperatures here in southern Wisconsin will drop into the 20s for daytime highs, and the lower teens for nighttime lows.

Brrr.

Models see a second major cold push around December 14th (give or take):

If that materializes, we'd see our first sub-zero temperatures of the season -- perhaps well below zero.

As for additional snow beyond tomorrow, well, much depends on which models and patterns you believe.  ECMWF still seems to favor some snow on Thursday, so we'll keep an eye on that.  There is another shot at snow next weekend.  As long as that cold air stays in place, chances for snow will continue at a pace of 2-3 storms per week.

Drive safe tomorrow, and as always, let me know if you have any questions!

~Scott