Tuesday, May 20, 2025  5:30 AM 

Prepared by Bob Weisman, SCSU Meteorologist and Professor Emeritus

Retrieving Labrador (Cool All Week, Wet Through Wed.)

Could I Have Gotten the Hint?

I wanted to be a meteorologist since I was 9 years old. However, I got hints of the public attitude towards my job choice from time to time. One of the strongest clues was during my college graduation ceremony at the University of Massachusetts-Lowell. It was Memorial Day weekend and the ceremony was held at a football stadium. The speaker's podium was covered, but all of the graduates and the audience had no cover. The ceremony was held during a major cool rainstorm. The speeches were still full-length. They didn't have the graduates go up and get their fake diplomas; they just had each major stand up at their seats so the graduates would be recognized. When meteorology was called, the entire audience booed. And yet, I didn't get the idea.

Persistent Rain Today

Today and tomorrow, there would be plenty of booing since the weather will be similar to what I experienced that graduation weekend. The slow-moving storm spent yesterday touring the Black Hills (see center of counterclockwise rotation on the College of DuPage North America mid-level water vapor loop). The leftover Sunday night rain shriveled as it moved into Minnesota yesterday morning, but it allowed the clouds to stay all day. During the afternoon, new showers and thunderstorms developed in southwestern Minnesota and pushed northward (set number of frames to 200 on the College of DuPage continental US radar loop). There are more showers and thunderstorms on the way, which produced many reports of tornadoes (not shown on this graphic yet), large hail and damaging winds from Nebraska and Iowa to Oklahoma and northeast Texas. However, we are on the eastern flank of the low (see 4 PM Monday NWS WPC North America zoom-in map), so our winds are coming from the east to northeast. The very warm and sticky air fueling these storms is only on the ground from eastern Kansas and Missouri southward. Underneath that warm, sticky fuel supply, the combination of the Black Hills low and the Hudson Bay high is bringing in chilly air from Labrador. That means temperatures are in the 40's and even 30's where it is raining in Minnesota (see NWS Aviation Weather Center METAR map).

The leftover storms to our south will get pulled into southern and central Minnesota later this morning, so the most likely time for light to moderate rain will be this morning into the early afternoon. Those storms will weaken, but the Black Hills low will drift into southern Minnesota today, so more rain showers will develop. And, in between the showers, we are likely to have persistent drizzle. That will continue to provide central and southern Minnesota badly needed rain with the potential for over an inch of rain (see Day 1 on the NWS WPC Quantitative Precipitation Forecast) added to the rain we got overnight (half an inch through midnight; see NWS: last 72 hours of St. Cloud observations).

Coolness That Wind Chill Can't Account For

But, it will be a cold rain. The National Weather Service isn't posting the wind chill in northern Minnesota, but temperatures in the upper 30's with an east wind of 8-15 MPH (see NWS Minnesota hourly weather roundup) is producing wind chills between 25 and 35. However, there is a penetrating, bone-chilling nature to breezy, wet air with temperatures in the 30's and 40's that wind chill doesn't pick up. That will be with us throughout the day. The persistent clouds and rain in the air will knock down our temperatures to around 40 with little recovery during the day. So, we may approach St. Cloud's May 20 record cool high of 43 degrees, set in 1931.

Persistent Clouds With Spotty Rain Tomorrow

The heaviest rainfall will likely be over after this afternoon. The best fuel of warm sticky air will likely trigger another severe weather outbreak, this time approaching the parts of the Ohio and Tennessee Valleys hit so hard last Friday (threat ranked as category 3 of 5 by the NWS Storm Prediction Center), but that means the leftover storms will be directed more towards the Ohio Valley and the Carolinas. The upper-air low will drift from Minnesota and Wisconsin, then stall tomorrow. That means there will be pockets of rain showers persisting across Minnesota especially tonight. There will be less steady rainfall tomorrow, but the clouds will persist and there will be occasional drizzle (note the absence of even a quarter-inch contour on the Day 2 NWS WPC Quantitative Precipitation Forecast). The low-level air will continue its path from Labrador, so low temperatures tonight will likely be in the upper 30's. The few drier interludes will probably allow high temperatures to climb at least into the middle 40's and perhaps approach 50. We will have persistent northeast winds, but they won't be as strong as last night or today.

Sunshine Returns Thursday into Weekend, But Still Cool

The painfully slow drying process will continue with the threat of light rain or drizzle easing late tomorrow night. Thursday may actually begin sunny, although there will be enough leftover moisture to fuel midday and afternoon puffy clouds and a widely scattered shower or two. The strong sun will warm the Labrador air, so highs will climb to the middle 60's on Thursday. Still, low temperatures are likely to be in the 30's each night through Thursday night. The high on Friday and Saturday may be limited to around 60, rather than into the 60's.

The long-range forecast for the rest of the Memorial Day weekend has changed a bit. Instead of getting back into the main west-to-east steering winds, it looks like Minnesota, the Great Lakes, and the Northeast will merely have the Hudson Bay high hold on, steering potential storms to our south. This forecast is still shaky, but the latest computer runs show rain chances remaining no further north than Iowa. I would still say the rain chances will be uncertain through the weekend, but the possibility of anything more than some scattered showers are quite small. Highs should have a better chance of climbing into the 60's through the weekend, but lows may remain in the 40's here, which means 30's up north.

Wildfires: Cool Temperatures Help, But Windy Conditions and Missing the Rain Still Could Aggravate Problems

The cooler weather has helped fire fighters bring parts of the northeastern Minnesota wildfires (see location on the North America fire map from fireweatheravalanche.org) under control. The latest status on the National Interagency Fire Center map shows the Munger fire as being mostly contained but the other two fires with less control (also see WCCO-TV site with links to wildfire maps and FOX9 news site). The windy conditions aren't helping (NWS wind advisory continues until early tomorrow), but the much cooler temperatures are. Still, a fire weather watch is in effect today for most of northern Minnesota north of Hwy. 2, where little or no rain is expected. Watch the Minnesota DNR wildfire map for the updated fire danger.

Detailed St. Cloud, MN, and Vicinity Forecast

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

Tuesday 5/20/2025: Cloudy, windy, and chilly with periods of light to moderate rainfall, perhaps becoming more occasional during the afternoon. High: between 42 and 47. (Record cold high: 43 in 1931) Winds: E 15-25 MPH with higher gusts. Chance of measurable rainfall: 100% during the morning, 80% during the afternoon.

Tuesday Night: Cloudy, not quite as windy, but chilly with occasional rain or drizzle. Low: between 39 and 43. Winds: NE 10-20 MPH evening, 8-15 MPH during the early morning hours. Chance of measurable rainfall: 60%.

Wednesday 5/21/2025: Mostly cloudy with persistent drizzle. Some occasional rain showers. Not nearly as windy, but still cool. High: between 45 and 50. (Record cold high: 46 in 1931, 1963) Winds: NE 5-15 MPH. Chance of measurable rainfall: 50%.

Wednesday Night: Cloudy with evening drizzle, then some partial clearing late at night. Areas of fog possible. Still cool. Low: between 35 and 40. Winds: NE 5 MPH. Chance of measurable rainfall: 20%.

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

Thursday 5/22/2025: Finally, a good supply of sunshine with some puffy afternoon clouds, and a slight chance for an afternoon sprinkle. Back to mid-May warmth. High: between 62 and 67. Winds: N 5-15 MPH. Chance of measurable rainfall: 10%.

Thursday Night: Clear, light winds, and chilly again. Perhaps some fog. Low: between 35 and 40. Winds: N 5 MPH. Chance of measurable rainfall: 10%.

Friday 5/23/2025: Sunny in the morning, mixed sun and clouds with a slight chance for a sprinkle during the afternoon. A bit cooler. High: between 58 and 63. Winds: SE 8-15 MPH. Chance of measurable rainfall: 20%.

Friday Night: Partly clear, a bit of a breeze, and not quite as cool. Low: between 42 and 47. Winds: E 5-10 MPH. Chance of measurable rainfall: 10%.

Saturday 5/24/2025: Partly sunny, breezy, and continued cool. A slight chance of a late day shower. High: between 58 and 63. Winds: NE 5-15 MPH. Chance of measurable rainfall: 20%.

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

Extended: Temperatures returning to the 60's over the weekend??? Not much chance for rain???

Forecast Confidence (10 - "The Rabbits Will Thump Even Though I Fed Them"; 0 - "The Rabbits Will Offer To Groom My Bald Spot"): 9 Tuesday, 8 Tuesday night and Wednesday, 6 Wednesday night, 5 Thursday and Thursday night, 4 Friday through Saturday, 3 Sunday and Monday.

Yesterday's High: 56°F; Overnight Low (through 2 AM Tuesday): 41°F
St. Cloud Airport 24-Hour Melted Precipitation (through 5 AM Tuesday): 0.68 inch; SCSU 24-Hour Precipitation (through 5 AM Tuesday): 0.64 inch

Next Update: Wednesday, May 21, 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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