BIG TEMPS AND THEN THE CRASH....
It was another amazing weekend of weather around the central Midwest. Sunday's highs were generally in the range of 55-60 degrees over my area. 70s made it as far north as Missouri. Here's what temperatures looked like at 4:00 Sunday afternoon , already down a couple of degrees from the highs.
The warmth is being transported northward by a developing storm that tracks across Minnesota Monday. As it races northeast it will deepen rapidly during the day, Here's the storm at noon progged to eventually reach a pressure around 974 MB. Snow is falling from the Plains to northwest Minnesota. In the warm sector a few showers and storms are trying to get get their act together ahead of the cold front.
Temperatures in front of the storm will be unseasonably warm in Monday from my area southeast. Gusty SW winds of up to 35mph will send highs near or above 60 degrees. The GFS has 67 in Cedar Rapids. The all-time record high for the day and entire month of December is 69 in Cedar Rapids. We're talking some rare air here.
Personally, I'm not so sure we will get that warm as clouds, precipitation, and the speed of the front could be detriments. The 3K-NAM has only 60 as it puts into play some of these factors.
Personally I think low to mid 60s look good which should keep most areas short of records. However, a little slower on the front or slightly more sunshine and the game is on.
While the storm is a potent one, it will travel fast and have a limited window of time where it can generate and produce precipitation. The 3k NAM shows this for total precip. My northern counties are most favored for any significant rain.
Some nice totals are showing up in Wisconsin where more than 2" could fall in a narrow band. Here's a larger perspective of the 3k NAM.
Snowfall finally returns to the upper Midwest with amounts that look like this on the cold side of the system.
Following the storm, the long awaited turn to colder weather finally arrives. The 500mb jet goes from this mild pattern Monday.
To this frigid 500mb flow Friday.
Friday's highs on the GFS
The bottom line is that temperatures from Monday to mid-week are going to red line. Readings will be 30-40 degrees colder Wednesday through the coming weekend. The party is just about over for this round of beautiful late fall weather. Roll weather...TS