Thursday, March 26, 2015 3:39 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
Low Snow Totals Don't Affect Ground Water
The minor snowfall yesterday still left St. Cloud more than 11 inches behind on snowfall for the cold season (30.1 inches actual, 41.6 inches average). For the year so far, there has been only 0.80 inch of precipitation, more than an inch and a half behind the average of 2.46 inches (difference shown in brown on lower graph from National Weather Service). That's why the US Drought Monitor has been showing Minnesota and parts of neighboring states in severe drought classification.
However, it's not as bad as it seems. The snowless winter has occurred while the ground has been frozen. On the average, the ground doesn't get moisture from the snowpack, since the ground is frozen and frost doesn't leave until after the snow has melted. So, ground moisture is literally frozen in place during the winter. And, in central Minnesota, that moisture is high, thanks to the 4th wettest year in St. Cloud records. As long as the ground is frozen, the dried plants at the surface can't tap that deep moisture.
Frost is Just About Out of Ground!
The good news is that, in the past week, the ground has thawed in central Minnesota. At the MnDOT site in Otsego, the blue curve is the deepest depth of the frost in the ground. The red curve is the depth to which the top has been thawing. When they meet, as they did early this week, the frost is out. In Otter Tail, there's less than half of foot of frozen ground left. Because of the recent snowfalls across southern and southeastern Minnesota, there's still a foot and a half in frost left in the Rochester area. We are keeping below freezing temperatures at least overnight through the end of the work week this week, but when we warm up this weekend and especially next week, plants should start to green up as they tap the ground moisture. This should help ease the fire danger we've been seeing on warm, windy days since the snow melted.
Lake Levels Affected
Now, the snow melt does have a major effect on river and lake levels. On the latest Minnesota Dept. of Natural Resources streamflow map, there are a few yellow stations (streamflow a bit below average) and a few scattered reds (streamflow in lowest 10%). Lakes up north and the Minnesota River Valley had the least snow during the winter, so they could really use some spring rain. The snow levels in the Arrowhead were a little on the low side, but there was average snowfall on the south shore of Lake Superior, so we'll see how that develops.
Now, Back to Your Regularly Scheduled Weather Discussion
Right now, we are in a cold interlude in the wake of the non-storm from Tuesday night into Wednesday. Colder air was pulled into Minnesota on strong northwest winds. That kept high temperatures in the middle to upper 30's in most of central Minnesota (see Yesterday's
High Temperature Map from NWS/SUNY-Albany), a good 5 degrees colder than average. The cold air came with very strong winds created by the pressure difference between the departing low pressure system, now over northern Ontario (see NWS
HPC Latest North American zoom-in surface map) and the cool high now on the Alberta-Saskatchewan border. The top wind gust in St. Cloud was 45 MPH at 1:48 PM (see NWS: Last 72 hours of St. Cloud Observations). Alexandria (49 MPH) and Coon Rapids (48 MPH) had the highest gusts around midday.
The winds and the leftover moist air from both the Monday night and Tuesday night precipitation to our south kept the low clouds in all day (see infrared loop from College
of DuPage Satellite and Radar Menu). They are just starting to break up overnight (see Colorado
State RAMDIS Western US Fog/Reflectivity Product). However, clouds and wind have kept low temperatures mostly to the 20's (see NWS
Aviation Center Minnesota map). We will see more sunshine today, although some low clouds will form as the day goes on. It will be breezy with northwest winds at 10-20 MPH, but not nearly as blustery as yesterday. And, temperatures will recover slightly to around 40 degrees or a bit higher.
The cold high pressure area will move over us tonight, so look for lows to bottom out in the low to middle teens. The cooler than average weather will continue into early Saturday as highs tomorrow stay in the upper half of the 30's to near 40 and lows again Friday night drop to the upper teens to lower 20's.
Cold Eases Over the Weekend, Really Warm First Half of Next Week
Over the weekend into early next week, the air flow from the West Coast into the Central US will become more west-to-east, allowing the air warmed by its trip over the Rockies to get into Minnesota. After the cold start on Saturday, temperatures will climb back into the 40's. A warm front will pass early Sunday morning. A few scattered rain showers are possible overnight (yes, I said rain, since ground temperatures will likely remain above freezing), then when the skies clear out by midday Sunday, temperatures will return to the 50's. It will be another blustery day with northwest winds of 15-30 MPH with higher gusts possible.
Even warmer air moves in for the first half of the work week. Winds will be relatively light on Monday (and strong winds help to produce the warmer temperatures), so I don't think we'll quite make it out of the 50's on Monday. However, with a strong west to northwest wind on Tuesday, we could see middle or even upper 60's.
The next cold front looks to push through Wednesday morning. With that timing, temperatures may be held to the 50's to start off April. It does look like the southern portion of the stream of cooler air will move back into Minnesota for the second half of next week. We are close to the boundary, so I expect a lot of up-and-down temperature forecast changes from one computer run to the next, but overall, we should have temperatures closer to average from Thursday into next weekend. At this point, however, I don't see really cold air moving back in.
Where the Tuesday night storm had access to better moisture, there was severe weather, including a handful of tornadoes in Oklahoma and Arkansas yesterday afternoon. In the Tulsa area, a tornado ripped through a mobile home park, killing at least one person. The Oklahoma City suburb of Moore, which was decimated by a May tornado a couple of years ago, had extensive damage from a tornado yesterday, but not approaching the devastating levels of 2 years ago.
See Forecast Below
Thursday 3/26: Sunshine returns, still breezy, and cold. High: between 38 and 43. Winds: NW 8-15 MPH. Chance of measurable snowfall: 10%.
Thursday Night: Partly clear, diminishing wind, and colder. Low: between 12 and 18. Winds: NE 5 MPH. Chance of measurable snowfall: 10%.
Friday 3/27: Sunny, less windy, but still cold. High: between 35 and 40. Winds: SE 5 MPH. Chance of measurable snowfall: 10%.
Friday Night: Partly clear, breezy, and not quite as cold. Low: between 17 and 22. Winds: SE 5-10 MPH. Chance of measurable snowfall: 10%.
Saturday 3/28: Sunshine through high clouds, windy, and more seasonable. High: between 40 and 45. Winds: S 10-20 MPH. Chance of measurable snowfall: 10%.
Saturday Night: Cloudy, breezy, and milder. A chance of rain showers late. Low: between 32 and 37. Winds: S-SW 8-15 MPH. Chance of measurable rainfall: 30%.
Sunday 3/29: Morning clouds with a lingering rain shower, afternoon sunshine, turning blustery and warmer. High: between 50 and 55. Winds: NW, increasing to 15-30 MPH with higher gusts in the afternoon. Chance of measurable snowfall: 10%.
End of "Reasonable" Forecast Certainty
Sunday Night: Partly clear, slowly diminishing wind, and still relatively mild. Low: between 25 and 30. Winds: NW 5-15 MPH. Chance of measurable precipitation: 10%.
Monday 3/30: Sunny, not as windy, and warmer. High: between 52 and 58. Winds: E 5-10 MPH. Chance of measurable snowfall: 10%.
Monday Night: Clear, light wind, and mild. Low: between 30 and 35. Winds: S 5-15 MPH. Chance of measurable precipitation: 10%.
Tuesday 3/31: Toasty Tuesday. Sunny and very warm. High: between 64 and 68. Winds: S 5-15 MPH. Chance of measurable snowfall: 10%.
For Entertainment Purposes Only.
Extended: Maybe a rain shower Tuesday night or Wednesday morning. Breezy, but not quite as warm Wednesday with highs in the 50's. More seasonably cold late week and weekend???
Forecast Confidence (10 - "Know what gas will
cost next week, Bob?"; 0 - "Been a victim of road rage lately, Bob?"): 8 Thursday through Saturday, 7 Saturday night and Sunday, 5 Sunday night through Tuesday.
Yesterday's High: 38°F; Overnight Low (through 3 AM): 27°F
St. Cloud Airport Precipitation: None; SCSU Precipitation (Through 4 AM Thursday): None
Normal Temperatures for March 26 - High: 44°F;
Next Update: Friday, March 27, 2015 8:00 AM (or as needed)
Ground and Air Travel
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!
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