WINTER RETURNS WITH A VENGEANCE

After an exceptional 3-week period of cold and snowy weather February 27th to December 16th, winter just packed up and left. The upper level steering currents were completely re-aligned and much of the last 10 days have been spent in the 30s and 40s, and the 20–25 inches of snow that fell in the wintry stretch was essentially wiped out by the warmth. Here's the temperature departures across North America over the past 10 days. More than 90 percent of the continental U.S. has enjoyed above normal temperatures.

Here's the 500mb upper air pattern that has driven old man winter north of the border.

I think we all knew this was too good to be true, and it was just a matter of time before we got a reality check, and that time is rapidly coming. Check out the change in the 500mb pattern that evolves by the end of December. The warm upper level ridge over the middle of the country is crushed and forced west in a weaker state. A strong NW flow is established over the upper Midwest, and that effectively puts an end to the mild weather we've recently come to know.

In fact, New Year's Day itself, the GFS shows temperatures as much as 25 degrees below normal.

At midnight New Year's Day, the EURO has temperatures ranging from -6 north to +4 in the far south.

The cold comes with a pretty good breeze, and wind chills of 10 to 20 below are on the table. Welcome to 2026!

One ingredient that always enhances cold is snow, and after the prolonged snow layoff, there's some of that in the forecast as well. The system that initiates the change is still to the west, in the organizational stages, Saturday. That ensures another mild precipitation free day Saturday. Highs have a good chance of reaching 50-55 in the south, with 45 to 50 more likely north of I-80.

Saturday night, low pressure begins to take shape over Kansas, pulling Arctic air into its center. Meantime, warm moist air starts streaming into the system from the Gulf of Mexico. This sets the stage for rapid intensification, and the storm deepens from 1002mb Saturday night to 980mb Sunday night as the low tracks towards Chicago and SW Michigan.

Initially, rain spreads into the area Sunday, with temperatures that range from the upper 30s NW to the upper 50s SE at noon. Readings should look similar to this.

Here's the surface map at noon Sunday, with the low just SE of Burlington.

Sunday at 6:00pm temperatures are free-falling and below freezing west of the Mississippi as the low deepens near Chicago.

The surface map at 6:00pm Sunday has the low down to 994mb, with snow beginning to move into my western counties.

At midnight, strong N/NW winds are blowing, with temperatures in the mid to upper teens.

At midnight, the low is in Michigan, down to 985mb. Strong NW winds and light snow is spreading southeast. In the NW some moderate snow looks possible.

Snow accumulations remain a bit up in the air, but they could be enough to cause some real issues in the N/NW half of the region, where blowing and drifting could be become a problem Sunday night thanks to sharply colder air and wind gusts to 40mph+. The EURO is further south on the track, with 1-3 inches of accumulation possible in the NW. The GFS and NBMv5 are further north with the track and lessen the amounts to 1-2 inches in that same general area. The raw model output, not an official forecast, currently looks like this. This is some of the data forecasts will be derived from in the next 24 hours.

The EURO

The Canadian RDPS

The GFS

The NBMv5, a blend of 30 models and ensembles.

As it stands now, this is going to be a very significant winter storm over parts of the upper Midwest, and its strength has grown steadily stronger in recent model runs the past 24–36 hours. Since my area is more or less on the southeast fringe of the snow band, future runs will be very critical in determining the eventual impacts locally. A further shift southeast would mean greater impacts that would extend further SE in my area. I doubt that will happen. A shift further NW (possible with a strengthening storm) would keep snow accumulations minimal, but there would be plenty of wind and cold as the system passes to the northeast. Travelers to the west/northwest Sunday should be prepared for rapid changes to wind, cold, and snow Sunday afternoon and night. Things could get pretty ugly in the NW half of Iowa, much of Minnesota, and NW Wisconsin. Winter is coming back with a vengeance. Roll weather...TS