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Friday, May 25, 2012 5:22 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
Synopsis: Today's the Dry Day
Eighth Wettest May With More Rain To Come
The rainfall beat continued yesterday in much of Minnesota. The bulk of the showers fell from the morning through the middle afternoon (see NWS: Last 72 hours of St. Cloud Observations) with another .79 inch after 7 AM yesterday and a total of 1.74 inch since Wednesday night. That brings St. Cloud's May rainfall to 6.67 inches, which ranks as the 8th wettest May in St. Cloud records. St. Cloud was not even close to the heaviest rain seen over the past couple of days with swaths picking up 3-5 inches. And, we could still see another 1-3 inches of rain over the weekend, so we could actually get close to the wettest May in St. Cloud records: 9.68 inches in 1912.
There are no widespread flood watches or warnings right now, although the Mississippi River at Aitkin is expected to leave its banks over the next couple of days. but most reports show high river levels.
But, for now, we are in the midst of a break in the rainfall, which we badly need. The upper-level low pressure system is moving right over central Minnesota (see water vapor from College
of DuPage Satellite and Radar Menu), so it will move to the east later this morning. With all of the moisture along the ground, we will likely see a mixture of clouds and sun, but we will warm up into the upper 60's to near 70.
More Heavy Rain Possible, Especially Saturday (All Day) and Sunday (Late Day and Overnight)
The passing of this low pressure system has pushed the front to Missouri and Kansas (see NWS
HPC Latest North American zoom-in surface map), with showers and thunderstorms are still to the north of it in Nebraska and Iowa on the NWS
Upper Mississippi Valley radar loop. But, this front will begin to move northward again as the next low pressure system along the California-Oregon border (see water vapor from College
of DuPage Satellite and Radar Menu) moves into Montana by tomorrow afternoon. This will pull that front northward again, setting us up for more chances of showers and thunderstorms.
One round will develop overnight tonight from northern Iowa into Minnesota with the storms spreading into our area late night tonight through tomorrow morning. The front will get hung up in southern Minnesota tomorrow, so there will be another wave of showers and thunderstorms from tomorrow afternoon through tomorrow night. Some storms could produce large hail, but the biggest problem will continue to be heavy downpours over our waterlogged area.
There are mixed signals for Sunday's forecast, which all depends on how far northward the warm front will move. Most of the computer forecasts now have it hanging up somewhere in central Minnesota. So, I'm not forecasting temperatures pushing to near 90. It will also affect the timing of showers and thunderstorms. Storms will linger around the warm front and points northward on Sunday morning, so I have that chance here, but I expect the storms to move northeastward, allowing us to see some sunshine for a while midday and into the afternoon on Sunday. Still, the main low is forecast to push into Minnesota late in the day, triggering a line of showers and thunderstorms. These storms will have the best chance of developing "conventional" severe weather (large hail, damaging winds, maybe a tornado near the warm front) late Sunday afternoon into Sunday evening, especially where the warm and cold fronts meet. However, our biggest problem will be the possibility of more heavy rain on top of the current waterlogged ground and perhaps another half-inch of rain tomorrow. Some areas could see another 1-3 inches of rain. Now, the St. Cloud area and points west may luck out with the late Sunday rain as some of the computer guidance says that, with the warm air aloft, widespread thunderstorms may not develop until Sunday evening and, by that time, the cold front could be off to our east. But, I'm not going to count on that.
Can we at least salvage Monday? A lot of people are keeping rain in the forecast on Monday as the cool air aloft combines with the wet ground to produce numerous showers, especially in the afternoon. However, I'm looking at the forecast conditions with an eye towards showers and it seems to me that the southern half of Minnesota won't cool off enough to produce widespread showers. We will have a lot of clouds and perhaps a sprinkle, but I don't think it will be as wet as Saturday or late Sunday.
Review of Dry and Wet Periods Through the Weekend
Still with the recent rainfall and more rain on the way, most areas will have wet grounds over the weekend, even when it isn't raining. So, either make sure your tent has a well insulated bottom or adjust your plans. Again, the best chance of rain will be from late tonight into tomorrow morning, from tomorrow afternoon through Saturday night and perhaps into early Sunday, and again late Sunday afternoon or Sunday night.
Our temperatures will continue to be in the 60's to near 70 tomorrow as we stay mostly cloudy with those rain chances. Since I don't expect the warm front to make it through here on Sunday, look for highs in the upper 70's to lower 80's at best, but it will feel quite humid. Monday will be a cooler day with highs back down in the 60's.
In northern Minnesota, the warm front will hang around, so they are likely to see more widespread rain more frequently than us, with rain likely throughout tomorrow and tomorrow night into Sunday morning and again rain likely Sunday night through Monday. The Boundary Waters may have a delayed start to the rain tomorrow, but the rain will tend to linger longer. Since the warm front won't get through northern Minnesota, east winds will keep temperatures along the North Shore in the 50's at best and maybe some 40's during the rainy periods. Highs will be in the 60's tomorrow inland and perhaps the lower 70's on Sunday.
Still Need Rain Up North But Perhaps Too Much On the Way
On the precipitation front, this US Drought Monitor actually shows the areas of moderate drought spreading from the Red River Valley across northern Minnesota and along the Minnesota-Iowa border. This doesn't include rain over the past two days or what is to come over the weekend. It will look strange to show much of the state dry in areas that may have flooding problems over the weekend or early next week. Note that on this week's report on rainfall from the State Climatology Office, the heaviest rainfall since the start of the growing season has mostly missed the northwest. These reflect last week's heavy rain across Minnesota with more than an inch in many areas from the Arrowhead through central and southwestern Minnesota. Note that Lake Winnibigoshish and points northwestward missed the heavy rainfall.
Working On Very Warm and Wet May
As noted above, St. Cloud rainfall through midnight is 6.67 inches, which ranks as the 8th wettest May in St. Cloud records. Between April 13 and May 24, the St. Cloud Airport has picked up 9.24 inches of rain. The average amount for the period is 3.94 inches, so rainfall has been more than five and a quarter inches above average for the past 5 weeks. Note that, at its worst, the dry spell from mid-summer through last fall had us around 6 inches of rain behind.
At this point, the spring (March-May) rainfall stands at 10.42 inches, not enough to crack the 10 wettest springs. However, note that another inch would push St. Cloud into at least a tie for 10th place. One inch is one of the more conservative forecasts of rainfall this weekend.
Temperature-wise, it doesn't seem like it, but the average May temperature is still hovering around 60.6°F, more than 5 degrees warmer than normal and stands just outside the 10 warmest Mays. However, the spring (March-May) 2012 temperature stands at 50.7°F, which would beat St. Cloud's previous warmest spring (1977) by 0.7°F. These humid days with the warm low temperatures are very efficient at keeping our average temperature up.
Links:
Surface
Satellite
Radar
Current Watches/Warnings
Road Reports
Climate
Drought
Forecast: Friday: A mixture of sun and clouds and not quite as cool. High: between 65 and 70. Winds: W 5-15 MPH. Chance of measurable rainfall: 10%.
Friday Night: Clear early, increasing clouds late with a slight chance of a late night shower or thunderstorm. Low: between 48 and 53. Winds: NE 5-12 MPH. Chance of measurable rainfall: 20%.
Saturday: Showers and thunderstorms likely, some with heavy downpours, both in the morning and late afternoon. High: between 68 and 73. Winds: E 10-20 MPH Chance of measurable rainfall: 50% in the morning, 50% late in the day.
Saturday Night: Showers and thunderstorms with some large hail possible and heavy downpours likely. Some areas of flooding possible. Low: between 60 and 65. Winds: E-SE 8-15 MPH. Chance of measurable rainfall: 70%.
End of "Reasonable" Forecast Certainty
Sunday: Maybe an early shower or thunderstorm, then mixed clouds and sun, warm, and very humid. A better chance of late day showers and thunderstorms, with large hail, damaging winds, and heavy downpours producing localized flooding possible. High: between 80 and 85. Winds: SW 15-25 MPH. Chance of measurable rainfall: 30% in the morning, 50% late in the day.
Sunday Night: Showers and thunderstorms likely with severe weather possible. Low: between 50 and 55. Winds: W 8-15 MPH. Chance of measurable rainfall: 70%.
Monday: Mixed clouds and sun, breezy, and cooler with a slight chance of a shower. High: between 64 and 68 . Winds: W 10-20 MPH. Chance of measurable rainfall: 20%.
For Entertainment Purposes Only.
Monday Night: Partly to mostly cloudy, breezy, and cooler. Low: between 45 and 50. Winds: NW 8-15 MPH. Chance of measurable rainfall: 10%.
Tuesday: Morning clouds, afternoon sun, breezy, and cooler. High: between 56 and 61. Winds: NW 10-20 MPH. Chance of measurable rainfall: 10%.
Extended: Drier weather continues into Wednesday. Lows in the 40's. Highs near 60.
Forecast Confidence (10 - "Know what gas will
cost next week, Bob?"; 0 - "Been a victim of road rage lately, Bob?"): 8 Friday and Friday night, 7 Saturday, 6 Saturday night, 5 Sunday and Sunday night, 4 Monday, 3 Monday night and Tuesday, 2 Tuesday night and Wednesday.
Yesterday's High: 62°F; This Morning's Low (through 5 AM): 50°F
St. Cloud 24-Hour Airport Precipitation (through 5 AM): 0.79 inch (last 2 days: 1.74 inch); SCSU Precipitation (through 5 AM):
0.73 inch
Normal Temperatures for May 25 - High: 71°F;
Low: 47°F
Next Update: Tuesday 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.
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