Thursday, September 18, 2025  5:40 AM 

Prepared by Bob Weisman, SCSU Meteorologist and Professor Emeritus

Making Up for Drier Past 6 Weeks

The slow-moving western low (see College of DuPage North America mid-troposphere water vapor loop) finally got close enough to Minnesota to produce showers and thunderstorms (set number of frames to 200 on the College of DuPage north central US radar loop). Most of them were in western Minnesota, but there were a few afternoon showers and thunderstorm in central Minnesota. The slow circulation around the low (see College of DuPage North America clean infrared satellite loop) meant heavy rainfall with 0.59 inch at the St. Cloud Regional Airport (see NWS: last 72 hours of St. Cloud observations).

The low will now drift into Minnesota, arriving by tomorrow. So, the chances for showers and an occasional thunderstorm will increase to likely this afternoon through tomorrow. There will be the potential for at least another inch of rain over the next 3 days (see Days 1-3 on the NWS WPC quantitative precipitation forecast). There will be more clouds today (see College of DuPage North America clean infrared satellite loop) than yesterday, so highs will take a step back to the middle to upper 70's. Tonight and tomorrow, when we are closest to the low pressure, we will likely see persistent cloudiness, so highs will probably remain in the upper 60's. The low is expected to ease eastward by Saturday, but whether the low gets out of range for creating a lot of mainly afternoon showers is still a bit more uncertain. I still have a 50-50 chance of showers with highs back in the lower 70's.

From Sunday on, the forecast has changed a little bit. Another low is forecast to move from the eastern Pacific Ocean (see College of DuPage North America mid-troposphere water vapor loop) to the Dakotas by Sunday, but the low is now forecast to push southward more than eastward, so the low would be over Nebraska and Kansas by Monday instead of pushing through Minnesota. That would allow a slow drying over Minnesota, so the chances for rain showers would drop to 1 in 3 on Sunday and 1 in 5 on Monday. And, we will see increasing amounts of sunshine, allowing temperatures to return to the upper 70's on Sunday and range from the middle 70's to the lower 80's on Monday. I still feel the forecast is a little shaky since the scenario has changed drastically.

Relatively cooler air will move in during the middle part of next week, so highs will range from the middle 60's to the middle 70's for much of next week. Hopefully, this would allow some drying, ending the persistent uncomfortable humidity.

Detailed St. Cloud, MN, and Vicinity Forecast

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

Thursday 9/18/2025: A good chance for both early morning and afternoon showers and thunderstorms. Not as warm, but uncomfortably humid. High: between 75 and 80. Winds: ESE 8-15 MPH. Chance of measurable rainfall: 70%.

Thursday Night: Mostly cloudy with scattered rain showers, especially during the evening. Low: between 59 and 63. Winds: E-NE 5-15 MPH. Chance of measurable rainfall: 70%.

Friday 9/19/2025: Mostly cloudy and cooler, but still uncomfortably humid. Occasional showers and perhaps a thunderstorm. Best chance during the afternoon. High: between 65 and 70. Winds: SE 8-15 MPH. Chance of measurable rainfall: 80%.

Friday Night: Mostly cloudy with occasional rain showers, mainly during the evening. Low: between 57 and 62. Winds: SE-S 5-15 MPH. Chance of measurable rainfall: 70% evening, 30% late night.

Saturday 9/20/2025: Lots of clouds with perhaps some early sunshine. A good chance of midday and afternoon scattered showers. Cool and still quite humid. High: between 70 and 75. Winds: S-SW 5-15 MPH. Chance of measurable rainfall: 50%.

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

Saturday Night: Maybe an evening shower. Then, areas of dense fog. Low: between 53 and 58. Winds: S-SW 5 MPH. Chance of measurable rainfall: 40%.

Sunday 9/21/2025: Mixed clouds and more sunshine with a chance for a scattered afternoon shower. A bit warmer and still humid. High: between 75 and 80. Winds: SE 5-15 MPH. Chance of measurable rainfall: 30%.

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

Sunday Night: Partial clearing with some areas of fog by morning. Low: between 57 and 62. Winds: S 5 MPH. Chance of measurable rainfall: 20%.

Monday 9/22/2025: Mixed clouds and sun with more summerlike temperatures and humidity. A slight chance for a shower or thunderstorm. High: between 77 and 82. Winds: S 8-15 MPH. Chance of measurable rainfall: 20%.

Extended: Better chance of Tuesday showers and thunderstorms?? Cooler than average rest of next work week??

Forecast Confidence (10 - "The Rabbits Will Thump Even Though I Fed Them"; 0 - "The Rabbits Will Offer To Groom My Bald Spot"): 7 Thursday through Friday night, 6 Saturday, 4 Saturday night and Sunday, 2 Sunday night and Monday.

Yesterday's High: 85°F; Overnight Low (through 5 AM Thursday): 63°F
St. Cloud Airport 24-Hour Melted Precipitation (through 5 AM Thursday): 0.59 inch; SCSU 24-Hour Precipitation (through 5 AM Thursday): 0.60 inch

Next Update: Friday, September 19, 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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