Friday, September 12, 2025  2:10 AM 

Prepared by Bob Weisman, SCSU Meteorologist and Professor Emeritus

Dog Days of September (?) Ahead

Minnesota is still on track to have a last round of warm temperatures and uncomfortable humidity, beginning this afternoon and continuing well into next week. The most likely temperatures will be in the 80's through much of Minnesota. There is an uncertain chance for a 90 degree high or two in the Minnesota River Valley or southern Minnesota. That will be most likely on Sunday. And, current dew points in the upper 50's (see UCAR hourly dew point chart) will likely ooze into the uncomfortable 60's, as they are in the Dakotas.

The main question through the weekend will be the chance for showers and thunderstorms. There have been quite a few in the Dakotas and northern Minnesota from yesterday afternoon through the overnight hours over the past 24 hours (set number of frames to 200 on the College of DuPage North America clean infrared satellite loop) with storms continuing in northern Minnesota early this morning (see College of DuPage north central US radar loop). These storms have developed on the northern flank of the warm and humid air (see location of warm front on the 4 PM Thursday NWS WPC North America zoom-in map), on the leading edge of where yesterday's 90-degree highs were located. That prime area will move more into Minnesota for this afternoon's and this evening's redeveloping showers and thunderstorms, so I have a 1 in 3 shot at showers and thunderstorms.

After this evening, we will be in the warmer and more humid air, but with a lot of residual clouds, so I don't have highs approaching 90 everywhere, but I have the warmest highs of the next 7 days, because the chance for showers and thunderstorms will be relative small (20 to 30 percent).

The winds won't be that strong through the weekend, so there may be a chance of some areas of dense fog during the weekend mornings. Lows have a better chance of being in the 60's, rather than the 50's.

When we get into next week, the stalled weather pattern with a strong low in the Intermountain Region (counterclockwise circulation on the College of DuPage North America mid-troposphere water vapor loop) and a high across the Plains (switch from southwest-to-northeast flow over the eastern Rockies to northwest-to-southeast flow over the Mississippi Valley) will allow a series of lows to push from the West Coast into Saskatchewan and Manitoba. None of the lows appear to be strong until the middle of the week, so Monday through Wednesday will have uncertain chances for showers and thunderstorms, but the chances appear to be better than over the weekend. I am still leaning for a better chance of storms on Wednesday, but that depends on having a stronger low nearby. I am keeping high temperatures in the 80's through Tuesday, but that could be cooler if we have more thunderstorms over us or near us, so that the clouds persist longer. The dew points in the 60's will likely continue through at least mid-week.

I am no longer sure about a cool down for the second half of next week, since the computer forecasts are now inconsistent about a stronger cold front bringing in cooler and drier air after Wednesday.

Detailed St. Cloud, MN, and Vicinity Forecast

Confidence Level: "The Bugs Are Waiting for Me to Mow the Lawn"

Friday 9/12/2025: A slight chance for a morning shower or thunderstorm. Otherwise, partly sunny, breezy, and warmer with uncomfortable humidity. Maybe a scattered late day shower or thunderstorm. High: between 78 and 83. Winds: SE 8-15 MPH. Chance of measurable rainfall: 20% during the morning, 30% during the late afternoon.

Confidence Level: "Extra Bugs Will Come From Every Home on the Block to Hover Around My Head"

Friday Night: Partly clear, breezy, warmer, and uncomfortably humid. A chance of a shower or thunderstorm. Low: between 62 and 67. Winds: SE-E 5-10 MPH. Chance of measurable rainfall: 30%.

Saturday 9/13/2025: Mixed clouds and sun, breezy, warmer, and uncomfortably humid. A slight chance for a late day shower or thunderstorm. High: between 80 and 85. Winds: E-SE 8-15 MPH. Chance of measurable rainfall: 20%.

Saturday Night: Partly clear and very warm. Uncomfortable humidity. A chance for a shower or thunderstorm. Low: between 62 and 67. Winds: SE 5-15 MPH. Chance of measurable rainfall: 30%.

Sunday 9/14/2025: Mixed clouds and sun, windy, very warm, and uncomfortably humid. A chance for a late day shower or thunderstorm. High: between 82 and 87. Winds: SE 10-20 MPH. Chance of measurable rainfall: 30%.

Confidence Level: "Enough Bugs Will Fly into My Mouth to Throw Off My Diet"

Sunday Night: Partly clear, still very warm, and uncomfortably humid. A better chance for late night showers and thunderstorms. Low: between 64 and 68. Winds: SE 5-15 MPH. Chance of measurable rainfall: 40%.

Monday 9/15/2025: Mostly cloudy and windy, not quite as warm, but still uncomfortably humid. A good chance for showers and thunderstorms. High: between 80 and 85. Winds: SE 8-15 MPH. Chance of measurable rainfall: 50%.

Monday Night: Continued partly clear, warm, and uncomfortably humid. Uncertain chance for showers and thunderstorms. Low: between 62 and 67. Winds: S 5-15 MPH. Chance of measurable rainfall: 30%.

Tuesday 9/16/2025: Mostly cloudy and windy, not quite as warm, but still uncomfortably humid. Uncertain chances for showers and thunderstorms. High: between 80 and 85. Winds: SE 8-15 MPH. Chance of measurable rainfall: 40%.

Extended: Continued quite humid with a better chance for showers and thunderstorms Wednesday?? Uncertain chances for showers and thunderstorms Thursday and Friday??? Not quite as warm late next week??

Forecast Confidence (10 - "The Rabbits Will Thump Even Though I Fed Them"; 0 - "The Rabbits Will Offer To Groom My Bald Spot"): 7 Friday, 5 Friday night through Sunday, 3 Sunday night through Tuesday, 2 Wednesday.

Yesterday's High: 76°F; Overnight Low (through 2 AM Friday): 62°F
St. Cloud Airport 24-Hour Melted Precipitation (through 2 AM Friday): None; SCSU 24-Hour Precipitation (through 2 AM Friday): None

Next Update: Monday, September 15, 2025 6 AM

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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