A SHIP PASSING IN THE NIGHT...
Winter has finally made it's way back to the Midwest and now that it has, we'll see plenty of it in the next two weeks. Here's the PRISM temperarures departures for January to date. Nationally, readings are running 5.82 degrees above normal.
SInce 1981, the only other January that was warmer was 1996 with a mean departure of 6.6 degrees.
ARE YOU READY FOR THE FLIP?
For more than a week I've been telling you a major change was coming and the wheels are turning. By January the 500mb jet stream pattern evolves into a strongly amplified northwesterly flow.
Look at the 10 day temperature departures that creates on the GFS, EURO, and Canadian for the period January 28-February 7th. Confidence is high that we are headed for a big chill.
The Climate Prediction Center shows the Arctic hounds howling over the NC United States.
According to the EURO, the peak intensity of the cold occurs the morning of February 1st when lows of 10-19 below are depicted.
Readings like that are 31-36 degrees below normal.
A SHIP PASSING IN THE NIGHT
The storm which gets the ball rolling for the transition to cold is what you might call a ship passing in the night as it quietly embarks on its journey out of Texas. Since late last week models have been attempting to come together on the amount and placement of phasing between a closed upper air low in the southwest and a northern stream trough digging southeast. Light snow develops in my area late Tuesday night and continues from time to time into Wednesday night. There is now good consistency that the surface low clips the bootheal of Missouri and then heads towards EC Indiana. For my region, that implies the worst of the snow (5-9 inches) would fall well to the southeast. As a result, winter storm warnings (pink) and a winter storm watches (blue) are in place roughly south of a line from Tulsa to St. Louis and on to Detroit. Winter weather advisories (purple) reach up to the border of SC Iowa. I fully expect winter weather advisories will be issued for at least the southeast half of my area at some point by the NWS.
Despite the track being as far southeast as indicated, there has been a slight NW shift on some of the lighter snows pushing as far west as Cedar Rapids and Dubuque where an inch is so is possible. Further SE, amounts of 2-3 inches could work their way into SE Iowa and WC Illinois, especially SE of the Quad Cities. The CAMs (convective allowing models) have noted that trend Monday eveing with the 3k NAM most bullish and furthest NW with a 2-5 inch snow band from NW to SE. That is currently the heaviest solution and an outlier. Here's what models are suggesting for accumulations. At the very least, 1-3 inch snows look widespread with 1-4 inch totals starting to look more likely with the heavier amounts favored in the southeast half.
The 3K NAM
The 12k NAM
The SREF MEAN