Thursday, December 18, 2014 10:45 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
Blue Skies Return
A day with both moon and sun yesterday. After no sunshine for 9 days, the high pressure area associated with this typical December air mass pushed right over Minnesota, clearing out the skies. (see infrared loop from College
of DuPage Satellite and Radar Menu). The high temperature yesterday only reached 20 degrees (see Yesterday's
High Temperature Map from NWS/SUNY-Albany), 4 degrees cooler than average. But at least there was sun.
Temperatures early this morning had widely fallen to near zero in central Minnesota (see NWS Aviation Center Minnesota map). St. Cloud had some low clouds during the evening hours (see NWS: Last 72 hours of St. Cloud Observations), so temperatures were still holding in the lower teens, but skies cleared out again after midnight, thanks to the high pressure right over us (see NWS
HPC Latest North American zoom-in surface map). So, we should make down into the single digits again by sunrise.
Split Flow Keeps Us Mostly Precipitation-Free Through the Weekend
We will continue this week in the northern branch of a double storm track. The southern track, moving from the West Coast through the central and southern Plains then into the Northeast, continues to hog all of the best moisture. This morning, a West Coast storm has emerged in Kansas (see water vapor loop from College
of DuPage Satellite and Radar Menu), producing thunderstorms from Missouri to Arkansas (see NWS National radar loop) with some moderate snow in eastern Kansas, southern Nebraska, and western Missouri, including the Kansas City area (see NWS Aviation Center Central Plains map). There's even been some mixed precipitation in southwestern Missouri. The heavy rains are expected to hit south Texas today, where the really humid air is (dewpoints in the 60's on the NWS
HPC Latest North American zoom-in surface map)
There is actually a nearby storm in the northern branch of flow across North America. Note the counterclockwise circulation that has pushed from Montana into northwestern North Dakota overnight (see water vapor loop from from College
of DuPage Satellite and Radar Menu). However, so little moisture has made it this far north that this system can do little but produce low clouds. Note the mostly white area of low clouds on the Colorado
State RAMDIS Western US Fog/Reflectivity Product with only a little bit of higher clouds (dark areas over the white). That storm system will push over us today, so we won't have quite as much sun as we did yesterday, but these low clouds won't be capable of doing much more than cutting down on our sunshine.
We may have more trouble seeing as much sun during the rest of the week as the next system pushing into British Columbia right now (see water vapor loop from College
of DuPage Satellite and Radar Menu) gets into the Northern Plains by tomorrow. Still, these systems will be quite dry, with only a few flurries possible. Temperatures will become milder, although not to the ridiculous level of last weekend. Look for highs in the low to middle 30's over the weekend with lows staying in the 20's. These conditions could bring back the low clouds at times, but I'm hoping we can salvage at least some sunshine surrounding the December solstice, the day in the Northern Hemisphere with the fewest hours of daylight. It will take place on Sunday at 5:03 PM. On that day, there will be only 8 hours and 43 minutes of daylight. After the past week, any sunshine looks good.
Thawing to Disappear Next Week?? With Potential Travel Problems???
The long-range forecasts are changing the steering winds early next week to more of a northwest-to-southeast flow pattern. Often, these changes are more reliable than the typical long range, but that's only when a strong high pressure develops in northern Canada. Instead, the forecasts say that the main weather maker is a Pacific storm that moves into the Plains on Sunday and strengthens dramatically as it moves over the Great Lakes on Monday and Tuesday. Some of the long range forecasts are hinting at low pressure deep enough to break records in northern Michigan. This storm would be so strong that it would be able to pull some of the really cold air in extreme northern Canada (see NWS
HPC Latest North American zoom-in surface map) into the eastern two-thirds of the US. I'm much less confident about long-range major storms than strong cold highs. On the other hand, the computers have had a pretty good winter, nailing the series of intense storms in eastern Canada and Greenland about 10 days ago.
If we're talking about a storm slowing down and strengthening over Wisconsin and Michigan, then some of Minnesota could be under the threat for some significant snowfall Monday into Tuesday. However, the timing of the storm would be crucial, since there won't be a lot of cold air or a great deal of moisture to work with as the storm gets going. So, where and how much is still questionable.
If any kind of major storm develops over the Plains early next week, just the winds alone could play havoc with flight schedules at major hubs like Chicago, Detroit, and eventually the East Coast cities on Christmas Eve into Christmas Day. Again, it's too early to panic, but this weather situation has to be watched.
See Forecast Below
Ground and Air Travel
Thursday 12/18: Mostly cloudy with occasional light snow or flurries this morning. Between a dusting and a few tenths of an inch are possible. Maybe some afternoon sunny breaks. High: between 20 and 25. Winds: SE 5 MPH. Chance of measurable snowfall: 10%.
Thursday Night: Increasing clouds with a chance of flurries late, and not as cold. Low: between 14 and 18. Winds: SE 5 MPH. Chance of measurable snowfall: 10%.
Friday 12/19: Mostly cloudy and seasonably mild. A chance of a few flurries. High: between 25 and 30. Winds: S 5-10 MPH. Chance of measurable snowfall: 20%.
Friday Night: Cloudy and milder with a chance of flurries. Temperatures holding between 25 and 30. Winds: SE 5-10 MPH. Chance of measurable snowfall: 20%.
Saturday 12/20: Partly sunny, breezy, and milder. Perhaps a stray flurry. High: between 32 and 36. Winds: SE 8-15 MPH. Chance of measurable snowfall: 20%.
End of "Reasonable" Forecast Certainty
Saturday Night: Cloudy, breezy, and milder. Maybe some patchy fog. Low: between 25 and 30. Winds: SE 8-15 MPH. Chance of measurable snowfall: 10%.
Sunday 12/21: Sunshine through high clouds, breezy, and milder. High: between 35 and 40. Winds: SW 5-15 MPH. Chance of measurable snowfall: 10%.
Sunday Night: Cloudy and continued mild. Low: between 25 and 30. Winds: SE 8-15 MPH. Chance of measurable snowfall: 10%.
For Entertainment Purposes Only.
Monday 12/22: Cloudy, windy, and colder with a good chance of snow. High: between 30 and 35. Winds: NW 15-25 MPH. Chance of measurable snowfall: 50%.
Extended: Lingering snow on Tuesday???? Turning much colder and windy in the run up to Christmas. Ohio Valley and Great Lakes major storm causing some problems with central and northeast airline hubs?
Forecast Confidence (10 - "Know what gas will
cost next week, Bob?"; 0 - "Been a victim of road rage lately, Bob?"): 8 Thursday, 7 Thursday night, 6 Friday through Saturday, 5 Saturday night and Sunday, 4 Sunday night, 3 Monday, 2 Tuesday
Yesterday's High: 20°F; Overnight Low (through 7 AM): 9°F
St. Cloud Airport Precipitation: None; SCSU Precipitation (Through 2 AM Thursday): None
Normal Temperatures for December 18 - High: 24°F;
Next Update: Friday, December 19, 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.