The (Major?) Winter Storm I'm Watching...

For the last few days, weather models have been suggesting a big storm in the middle of the country for late next weekend into early the following week (12/3-12/5).  I want to show you what that looks like in this morning's 06z GFS model run.

I'm going to show you 5 images that represent a period from next Saturday afternoon into Monday afternoon, the 5th.  Click on any map to enlarge.

Take a look at this low pressure in northern Mexico...

It moves east toward the Gulf of Mexico and starts to tap an endless stream of moisture...

Then it starts to head northwest, producing heavy rain and thunderstorms to the east/warm side of the low, and snow to the west/cold side of it.

The exact track of the low determines where the heaviest snow falls.  If this low was 75 miles further to the east, it would place Madison/New Glarus in the path of very heavy, prolonged snow.

After the low passes, it pulls cold air in from the north (remember that winds circulate counter-clockwise around a low), throwing down more snow on the back side of the storm.  It's amazing how this one low pressure system and a trailing cold front can produce precipitation all the way from Canada to the Gulf!

If this storm was happening tomorrow, I'd be predicting two FEET of snow for parts of Wisconsin.  And then, with those two highs to the west and fresh snow cover, I'd be predicting a pretty cold week.

So this will be fun to keep an eye on over the next 7-10 days.  It may not materialize, but conditions should be favorable for this kind of whopper in this time period.  Currently, storms are not tracking far enough east to put southern Wisconsin in the snow zone.  But as cold air continues to push into the middle of the country, that should slowly change.

It's a fun time of year to be a weather geek!

~Scott