Wednesday, April 17, 2024 6:00 AM
Prepared by Bob Weisman, SCSU Meteorologist and Professor Emeritus
Thunderstorms In Minnesota, Even Yesterday Morning
The slow moving low pressure system edged from Nebraska into Iowa yesterday (set number of frames to 200 on the College of DuPage continental US mid-tropospheric water vapor loop). Showers and thunderstorms were blossoming in Nebraska and Iowa Sunday night and they pushed into southern and central Minnesota by yesterday morning (set number of frames to 200 on the College of DuPage north central US radar loop). The worst of the storms produced tornadoes in western Iowa, eastern Nebraska, and into Missouri and Kansas with wind damage widespread across eastern Iowa and northern Missouri. Minnesota barely missed the severe weather, but there were plenty of thunderstorms all day with some pea-sized hail briefly in the St. Cloud area around 7 AM.
Would Have Been A Rainfall Record Except Yesterday
But, the dominant Minnesota weather was heavy rainfall. The St. Cloud Regional Airport picked up 1.92 inch of rain through 5 AM with 1.71 inch recorded yesterday (see NWS: last 72 hours of St. Cloud observations). That amount would have broken St. Cloud's record daily rainfall for nearly any mid-April day except April 16 (3.26 inches in 2003). There was 1.74 inch at St. Cloud State University. Redwood Falls had 1.95 inch and Minneapolis-St. Paul International Airport had 1.33 inch. The winds were also quite strong. Both the large pressure difference between the Iowa low and the high over Hudson Bay (a rare 7 isobars, meaning a 28 millibar, 0.82 inch mercury, pressure difference across Minnesota on the 4 PM Tuesday NWS WPC North America zoom-in map), and the thunderstorms, which mix the higher speeds from aloft to the ground efficiently, helped to produce those strong winds. Winds gusted to nearly 40 MPH in between hours in St. Cloud (see NWS: last 72 hours of St. Cloud observations) and reached 45-55 MPH in west central and south central Minnesota and along Lake Superior (set time to 1-4 PM on the NWS Minnesota hourly weather round-up).
Heaviest Rain Now Over, But Showers Will Persist, Especially This AM
As the low moved along the Iowa-Minnesota border Monday night (see College of DuPage continental US mid-tropospheric water vapor loop), the heaviest thunderstorms were mainly in northeastern Minnesota (during the early evening) and southeastern Minnesota into Wisconsin (set number of frames to 96 on the College of DuPage north central US radar loop) with a few scattered showers right in the vicinity of the low center (see Shortwave Albedo loop from Colorado State satellite slider). The slow moving upper air low will spend today drifting from eastern Minnesota into Wisconsin today (see College of DuPage continental US mid-tropospheric water vapor loop). The heaviest rainfall is now over, but there will be more scattered showers in the vicinity of the low, so the rain showers will continue at least through the morning. The showers will be more occasional during this afternoon, but the cold air pocket associated with the low will help clouds quickly fill in any small breaks. It won't be quite as windy as yesterday, but the current east to southeast winds (see NWS Aviation Weather Center METAR map) will shift into the northwest and increase to 15-25 MPH with gusts over 35 MPH, especially this afternoon. The breaks in the rain and the mild start (temperatures in the middle 40's) will allow highs to climb to the near average lower half of the 50's.
Cool With Sunny AM, Clouds and Few Showers Midday and PM Thurs and Fri (Fewer Showers Sat)
Then, we will have to deal and and a second upper air low will drift from Saskatchewan now to western Ontario on Friday (see College of DuPage continental US mid-tropospheric water vapor loop). That will give us more cold air aloft, so we will begin each of Thursday through Saturday sunny, but there will be a lot of midday and afternoon clouds and some scattered showers. The best chance for those showers will be Friday afternoon, when the second low is along the Ontario-Minnesota border, with only a few scattered sprinkles Thursday and Sunday. While the pressure difference across Minnesota won't be as large as yesterday or today, those puffy instability clouds will again mix some higher speed air down to the ground, so there will be wind gusts of 35-40 MPH Thursday and Friday. It won't be nearly as windy on Saturday.
Some of those showers might take the form of snow showers in north central and northeastern Minnesota, with the best chance tonight and Thursday night. A coating may be possible in the Arrowhead.
Potential for Sub-Freezing Lows Increasing Thursday Through Saturday Nights
High temperatures will be near or slightly below average today and tomorrow (lower half of the 50's). Friday will likely be the coolest day with highs in the upper 40's to near 50. Any clear, calm night during this cold period would drop low temperatures into the middle or even the lower 20's. However, the northwest winds will persist the next 3 nights. More clouds tonight will likely keep lows in the upper 30's or even the middle 30's. On Thursday night, we will begin with lingering clouds, but skies could clear late at night. Lows will be around the freezing point. Both Friday night and Saturday night will have a better potential for a sub-freezing low, but the breeze will keep the air stirring on Friday night. Still, we could see a low around 30. Lows are more likely to be in the 20's on Saturday night.
Back to Mid-April Averages (or Better) Sunday into Early Next Week
We will continue with the drier weather from Sunday into early next week. That should allow temperatures to recover past the mid-April averages to the upper 50's and perhaps 60's by early next week. How warm we get depends on how many clouds we will have and that depends on the progress of another Pacific storm due to get close to Minnesota early next week. However, the quick movement of this system on the heels of our drying process will make it difficult for it to produce a lot of rain (see Days 4-7 on the NWS WPC quantitative precipitation forecast).
Detailed St. Cloud, MN, and Vicinity Forecast
Confidence Level: "The Bugs Are Waiting for Me to Mow the Lawn"
Wednesday 4/17/2024: Cloudy with occasional light rain or showers in the morning. Turning breezy and a little bit drier in the afternoon. Seasonably mild. High: between 50 and 55. Winds: becoming NW 15-25 MPH with higher gusts. Chance of measurable rainfall: 70% in the morning, 30% in the afternoon.
Wednesday Night: Partly cloudy evening, then more clouds after midnight with a few light rain showers possible. Breezy and cooler. Low: between 35 and 40. Winds: NW 5-15 MPH. Chance of measurable rainfall: 30%.
Thursday 4/18/2024: Maybe some morning sun, then a lot of midday and afternoon clouds, windy, and seasonably mild. A chance for a brief shower or sprinkle in the afternoon. High: between 50 and 55. Winds: W 15-25 MPH with higher gusts. Chance of measurable rainfall: 20%.
Confidence Level: "Extra Bugs Will Come From Every Home on the Block to Hover Around My Head"
Thursday Night: Cloudy with perhaps a lingering evening sprinkle. Then a chance of clearing late. Breezy, and cooler. Low: between 30 and 35. Winds: W 5-10 MPH evening, 8-15 MPH late. Chance of measurable rainfall: 20%.
Friday 4/19/2024: Morning sun, lots of midday and afternoon clouds with a few scattered showers. Continued windy and a shade cooler. High: between 45 and 50. Winds: WNW 15-30 MPH with higher gusts. Chance of measurable rainfall: 30%.
Friday Night: Perhaps a lingering early evening sprinkle, then partial clearing, still breezy, and colder. Low: between 27 and 32. Winds: NW 8-15 MPH. Chance of measurable rainfall: 10%.
Saturday 4/20/2024: Morning sun, again a lot of midday and afternoon clouds. Only a slight chance of a sprinkle. Not as windy. High: between 47 and 52. Winds: NW 8-15 MPH. Chance of measurable rainfall: 10%.
Saturday Night: Clearing, light winds, and colder. Fog possible in the early morning hours. Low: between 25 and 30. Winds: NW 5-10 MPH evening, 5 MPH late at night. Chance of measurable rainfall: 10%.
Sunday 4/21/2024: Sunny, not nearly as windy, and seasonably mild. High: between 47 and 52. Winds: W 5-15 MPH. Chance of measurable rainfall: 10%.
Confidence Level: "Enough Bugs Will Fly into My Mouth to Throw Off My Diet"
Extended: Slowly increasing sunshine and temperatures Sunday into Monday????
Forecast Confidence (10 - "The Rabbits Will Thump Even Though I Fed Them"; 0 - "The Rabbits Will Offer To Groom My Bald Spot"): 7 Wednesday through Thursday, 5 Thursday night through Sunday.
Yesterday's High: 54°F (set at 6-7 AM); Overnight Low (through 6 AM Wednesday): 43°F
St. Cloud Airport 24-Hour Melted Precipitation (through 6 AM Wednesday): 1.92 inch; SCSU 24-Hour Precipitation (through 6 AM Wednesday): 1.74 inch
April 17 Historical Data | High | Low |
Average Temperatures | 55°F | 33°F |
Record Temperatures | 86°F (1987) | 56°F (1977) |
32°F (1953) | 15°F (1907) |
Next Update: Thursday, April 18, 2024 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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