St. Cloud, MN Weather Forecast

Fewer Showers Yesterday

There were still a few scattered showers and thunderstorms yesterday afternoon in the northern third of Minnesota (set number of frames to 200 on the College of DuPage north central US radar loop), but the rest of Minnesota just saw some cloudy periods (see College of DuPage North America clean infrared satellite loop). 

Major Weather Pattern Change to Produce Prolonged Humidity and Heat at Times

However, the major change in flow pattern is underway as storms from the northeast Pacific are moving west to east (see College of DuPage North America mid-level water vapor loop). That low along the West Coast will intensify over the weekend, turning the flow pattern to more southwest-to-northeast. You can see that there are pockets of showers and thunderstorms from Wyoming to Nebraska, Kansas, and Missouri (set number of frames to 200 on the College of DuPage north central US radar loop). They are developing as the uncomfortably, dew points in the 60's, to oppressively humid air, dew points in the 70's (see yesterday's 4 PM CDT NWS WPC North America zoom-in map), gets lifted over the cooler and drier air to the north. 

Forecasts of Heat, Severe Weather, Rain Conflict, Which Is Why Sunday and Forward are Uncertain

So, we will spend the next several days either within the oppressively hot and humid air (potential high temperatures well into the 90's with Florida-like dew points in the 70's) or on the edge of that air, subject to strong showers and thunderstorms, especially overnight. The National Weather Service has red and even purple levels of heat risk across much of Minnesota from Sunday through Thursday. While the forecasters at the NWS Weather Prediction Center put most significant precipitation to our north over the weekend (see Days 3-5 of the NWS WPC quantitative precipitation forecast) with a better chance for significant rain during the middle of the week (Days 6-7) in areas forecast to see extreme heat. And, the NWS Storm Prediction Center has moved its potential severe weather area to North Dakota and Minnesota on Days 4 and 5, despite the extreme heat forecast. Even though a lot of those thunderstorms will occur overnight, there would be the potential for lingering clouds knocking heat temperatures a few degrees cooler during the day. So, these forecasts conflict with each other, which I think is the right forecast, given the typical uncertainty in extreme heat forecasts and thunderstorm predictions along the northern edge of these outbreaks.

Some Chance of Storms Late Today

What does all of this mean, given the continued festival plans? We will have a chance for some late day showers and thunderstorms (1 in 5 shot) today, tonight, and tomorrow afternoon. Today will likely be our last day with relatively dry dew points and highs in the 70's. We will have a shot at 80 degrees tomorrow.

Better, But Uncertain Chance Saturday Night into Sunday Morning

The iffier part of the festival forecast will be from late Saturday through especially Saturday night and into early Sunday. I have a 50-50 shot at thunderstorms. It appears that the severe weather threat will be small Saturday night, but lingering Sunday morning storms could produce severe weather. So, people planning activities from Saturday evening concerts and fireworks to Sunday morning outdoor activities should keep an eye on forecasts and radar with a Plan B in mind.

Tuesday??? Has the Best Chance for Storms, Severe Weather

At this point, the best chance for thunderstorms appears to be Tuesday with the latest forecasts leaning towards Tuesday night rather than Monday night into Tuesday, but I would be on guard for any storms especially overnight to morning from Sunday night forward.

Sunday Through At Least Tuesday Will Have Serious Heat and Humidity (Best Chance Monday?)

Beginning on Sunday, anyone planning outdoor activities should keep in mind steps for mitigating extreme heat and humidity, including having indoor cooling stations and water supplies. The potential for extreme heat is more uncertain on Sunday, but looks more likely on Monday.  I am not sure about going to purple levels during the middle of next week, since a weak cold front could push through Tuesday night. Humidity after the front goes by will continue to be oppressive, but high temperatures may not be quite as extreme. A work day combined with the extreme heat will also produce air quality issues as ozone will likely be generated from vehicle exhaust.

Even if the Tuesday cold front pushes through Minnesota or possibly even hangs up near Minnesota, we will likely continue in the uncomfortable to oppressive humidity for much of next week. The daily threat of thunderstorms (possibly severe) is uncertain. 

While tracking any storms to our south and west, keep in mind the gap shown on radar (for example, the College of DuPage north central US radar) since the Sioux Falls National Weather Service radar is under repair, at least through next Monday.