FRESH SNOW PROJECTIONS

The first of two clippers is bearing down on the region as it zips steadily southeast. The atmosphere is in the process of saturating and snow should begin soon in my western counties in Iowa (if it hasn't already) and spread across the rest of the west and south into Illinois by 3 to 4:00pm. Here's the latest radar around 12:30pm.

In my northeast counties, dry air remains firmly in place, forcing the snow band to largely avoid this part of my area. As a result, accumulations here will be little more than a dusting to an inch. Further southwest the forcing will overcome the dry air and a 1-3" snow is expected (with some isolated 4 in totals SW of the Quad Cities). The counties in blue below are under a winter weather advisory for hazardous travel this afternoon and evening. I could see the advisories extended a county further southwest towards Ottumwa and Keokuk based on this morning's data.

Here's the official NWS snowfall forecast through tonight. I'll show the raw model output later.

After this system departs, another clipper tapping Arctic air will streak through the region Saturday, depositing another swath of snow. It is likely to be just a bit further southwest in track than today's event. The NWS forecast for it looks like this.

Combined, the two clippers should spread a fairly widespread 4–7 inches of snow over my western and southern counties. Amounts of an inch or less falls in the far N/NE where the dry air essentially wins out. Here's the official NWS total snowfall projection for the two events.

Now the raw snowfall output from this morning's model runs. The main feature that stands out is that the raw model guidance shows higher totals that are further NW into SE Iowa and WC Illinois. I suspect there could be a 6 to 8 inch total fall from the two events from a line roughly extending from Washington to Burlington in Iowa on to Monmouth, Illinois and points southeast. That's the total from today through Saturday evening. There are even some higher amounts than that shown due to the high snow ratios in place by Saturday. That's not out of the question, but not fully on the table yet.

The EURO

The GFS

The 3k NAM

The NBMv5, a blend of 30 models and ensembles.

The 10k RDPS Canadian

The 12k NAM

The HRRR, most likely too bullish and too far northeast. Not likely...

Following the snow, bitter cold temperatures and wind chills settle in Saturday night and Sunday. These are lows by Sunday morning. Most spots 10 to 15 below zero. Headlines for dangerous cold will be issued.

Wind chills of 25 to 30 below are common on the EURO early Sunday.

Anyway you slice it, snow, cold, or both are going to get you between now and the end of the weekend. Nobody should be surprised. Stay safe and keep in mind, much warmer weather is on the table next week. Roll weather...TS