Sunday, December 21, 2014 2:40 AM
Prepared by Bob Weisman
Professor of Earth and Atmospheric Sciences
Saint Cloud State University
Earth and Atmospheric Sciences Department
Saint Cloud and Vicinity Forecast
Storm Gets Stronger Faster, But Too Much Warm Air for Huge Snowstorm
Continued Spotty Drizzle and Melting
On the day with the least amount of daylight (December solstice at 5:09 PM CST), we will again be mostly without sun. The low clouds have remained stuck over Minnesota through the past day and are locked in overnight (see Colorado
State RAMDIS Western US Fog/Reflectivity Product). Once again, they are producing a combination of fog, although the south wind blowing at 10 MPH has kept the fog from getting very dense (see UCAR
Minnesota surface chart loop). The low clouds and fog have produced an "exciting" temperature trend, since temperatures barely budged yesterday from a 32 degree high to a 30 degree low (see NWS: Last 72 hours of St. Cloud Observations).
We do have another weak disturbance moving over top of the low clouds (see infrared loop from College
of DuPage Satellite and Radar Menu). The main thrust of this system will be to push through northern Minnesota into southwestern Ontario early this morning. There have been some overnight radar echoes (see NWS
Upper Mississippi Valley radar loop) and some spotty freezing rain to our north. That's where roads are partly covered with snow and some ice. We will mostly stay in the low clouds and the drizzle today. There could be some slippery sidewalks and driveways early this morning, but temperatures should climb a degree or two above freezing.
Stronger Storm Develops Earlier on Monday, So Slushy Snow Best Bet
The storm system crashing the West Coast (see infrared loop from College
of DuPage Satellite and Radar Menu) is the one making forecasting so difficult late this week. The scenario has changed again with a more southern storm track from North Dakota into Iowa favored. The storm is also forecast to do most of its intensifying over Iowa. That should allow a plume of steady precipitation to develop tomorrow morning near the Minnesota-Iowa border, then push into central Minnesota by midday. It looks like our best chance of precipitation will be between tomorrow midday and early morning Tuesday. However, having a stronger storm earlier means that the air will have trouble producing snowfall during the day tomorrow. Right now, it looks like the St. Cloud area may be cool enough (ground temperatures of 34 degrees) to allow some slushy accumulation tomorrow afternoon. . So, I have a forecast of 1-2 inches of wet snow by evening. Tomorrow night, the temperatures will fall back below freezing, allowing a better chance of accumulating snow. We might see another 1-3 inches overnight, bringing the storm total to between 2 and 5 inches of new snow. In the Twin Cities, it should stay warm enough during the daytime to allow any wet snow to melt on contract with the ground until late afternoon. There could be 1-3 inches of new snow overnight. Conditions look to be similar to here in Little Falls.
Right now, the most prolonged period of accumulating snow could be in northeastern Minnesota. The Arrowhead is under a winter storm watch for the potential of more than 6 inches of new snow.
Monday night and Tuesday morning could be difficult commutes, Monday with the falling, accumulating wet snow, and Tuesday morning since temperatures will be below freezing, so there could be ice lurking underneath any snowpack.
Ground and Air Travel Problems to Our East Next Week
After the storm strengthens over Iowa tomorrow, it will move into the Great Lakes states, but not get much stronger. Instead, a second storm system is expected to swoop into the Southern Plains by Wednesday, then move into the Ohio Valley and Ontario. This storm will likely cause a mess of air travel problems with rain in all of the East Coast hubs on Wednesday and Thursday. There could also be some snow inland, which would make travel worse. There are some forecasts that strengthen the storm as it moves into Quebec, which would cause wind problems out East as well.
Ground and Air Travel Links
Meanwhile, the air behind this storm won't be that much colder than what we've had. Temperatures may climb back above freezing on Tuesday with just some occasional light snow or flurries. On Wednesday and Thursday, temperatures look like they will be in the 20's. As long as skies stay mostly cloudy, low temperatures likely won't drop out of the 20's, so it will remain seasonably mild, although a bit on the dreary side.
Winter Resumes Late Next Week??
The active weather pattern will continue next week with the possibility of a Plains storm developing late in the week. At this point, it looks like the storm will track far enough to our south and east to do little here, but it could bring a combination of heavy rain and severe weather to the East Coast. However, the most important weather feature will likely be a developing storm in the Gulf of Alaska. This storm is likely to turn the upper level winds around to northwest-to-southeast flow from northern Canada into the eastern two-thirds of the US. There is finally a strong forecast high pressure area pushing into the Northern Plains by next weekend, which would bring in some really cold air. There could be a turn to some colder weather on Friday, but the mother lode would come in over the weekend.
That will bring an end to the relatively mild conditions we've seen since the first week of December. Over the past two weeks, St. Cloud has had 10 days with an average temperature at least 10 degrees warmer than average. A lot of this has been produced by slightly mild high temperatures and temperatures not dropping much overnight.
See Forecast Below
Ground and Air Travel
Sunday 12/21: Mostly cloudy with fog and spotty drizzle, which could be freezing drizzle early in the day. High: between 33 and 36. Winds: SE 8-15 MPH. Chance of measurable precipitation: 10%.
Sunday Night: Cloudy with drizzle or freezing drizzle and continued mild. Perhaps some steady rain in the early morning hours. Low: between 32 and 35. Winds: SE 10-20 MPH. Chance of measurable precipitation: 30%.
Monday 12/22: Spotty morning light rain mixed with wet snow, becoming a steady wet snow by midday. Between 1 and 3 inches are possible by evening. High: between 32 and 34. Winds: SE-E 10-20 MPH. Chance of measurable precipitation: 80%.
End of "Reasonable" Forecast Certainty
Monday Night: Wet snow likely throughout the night. Another 1-3 inches will accumulate by morning. Ice will form underneath the snowpack. Windy and turning cooler. Low: between 26 and 31. Winds: E-NE 10-15 MPH. Chance of measurable snowfall: 90%.
Tuesday 12/23: Occasional snow continues, breezy, but seasonably mild. Another dusting to an inch is possible. High: between 30 and 33. Winds: N-NW 10-25 MPH. Chance of measurable snowfall: 70%.
Tuesday Night: Occasional light snow or flurries, windy, and colder. Low: between 20 and 25. Winds: NW 10-25 MPH. Chance of measurable snowfall: 50%.
For Entertainment Purposes Only.
Wednesday 12/24: Cloudy, breezy, and a bit colder. High: between 25 and 30. Winds: W 5-15 MPH. Chance of measurable snowfall: 20%.
Wednesday Night: Cloudy, less windy, and still relatively mild. Low: between 20 and 25. Winds: SW 5-10 MPH. Chance of measurable snowfall: 20%.
Thursday 12/24: Partly sunny, breezy, and seasonably cold. High: between 24 and 28. Winds: W-NW 8-15 MPH. Chance of measurable snowfall: 10%.
Extended: Turning much colder late next week??
Forecast Confidence (10 - "Know what gas will
cost next week, Bob?"; 0 - "Been a victim of road rage lately, Bob?"): 7 Sunday, 6 Sunday night and Monday, 5 Monday night, 4 Tuesday and Tuesday night, 3 Wednesday through Thursday.
Yesterday's High: 32°F; Overnight Low (through 2 AM): 31°F
St. Cloud Airport Precipitation: Trace; SCSU Precipitation (Through 2 AM Sunday): Trace
Normal Temperatures for December 21 - High: 23°F;
Next Update: Monday, December 22, 2014 8:00 AM (or as needed)
Let me know what you think about this forecast and discussion by emailing SCSU
meteorology professor Bob Weisman. Please note that I make the forecast, not the weather!
Are you interested in studying meteorology? If so,
go to the Earth and Atmospheric Sciences Department home page.