St. Cloud, MN Weather Forecast

Tuesday's Rain Helpful, But We Need More

While there has finally been significant rain in more of central Minnesota during the past week (set NWS Water Prediction Service Minnesota map to yesterday's date and last 7 days), most of Minnesota has chalked up another month of below average rainfall (see yellow areas when you set NWS Water Prediction Service Minnesota map to yesterday's date, last 30 days, and departure from normal). Today, the US Drought Monitor will update conditions through Tuesday's rainfall. There was enough rain on Tuesday in St. Cloud to push the June total rainfall to 3.25 inches, about a quarter inch above the 2.99 inch average. But, if we don't get much the rest of the month, June will finish behind the average.

Cause of Tuesday, Wednesday Showers Now to Our East

As the festival activities really get going today, the hope through the weekend is that the rain manages to hold off. Today has a much better chance of being dry. The old upper-air low pushed through northern Minnesota into Lake Superior yesterday (see College of DuPage North America mid-level water vapor loop). That means Minnesota will be less influenced by cold air aloft, so we should see far fewer scattered showers and thunderstorms than were seen yesterday across the northern half of Minnesota (set number of frames to 200 on the College of DuPage north central US radar loop). We will have midday and afternoon puffy clouds and perhaps a sprinkle, but most events should go on dry. Temperatures will again be about 5 degrees cooler than average, topping out in the low to middle 70's with still comfortable humidity.

Weekend Begins Very Warm (Hot?) Temperatures, Uncomfortable (Oppressive?) Humidity

I have been noting all week the upcoming change in the weather pattern that will allow very warm air and uncomfortable to oppressive humidity to return to Minnesota for the first time since the first week and a half of June (10 of the first 12 June days had a high of at least 80 degrees). The first chance for an 80-degree high will be Saturday and that's when dew points will climb back into the uncomfortable 60's. After that, central Minnesota will be on the edge or within the really hot and oppressively humid air (see red areas on the NWS Heat Risk forecast Sunday through Tuesday). For the parts of Minnesota getting into the core of the heat and humidity, the National Weather Service would like issue at least heat advisories if not excessive heat warnings.

I Have Small Storm Chances But That Could Change

The changes in the computer forecasts in the past day are pointing towards more of Minnesota being in the oppressive air Sunday through Tuesday. However, there will be showers and thunderstorms, especially overnight, developing on the northern edge of the heat in the area of the warm front. This would create the potential for both severe weather and heavy rainfall (see Days 3-7 on the NWS WPC quantitative precipitation forecast). And, the track record of computer forecasts at pinning down who would be in the northern edge of the heat versus who would have the best chance for showers and thunderstorms isn't very good. That's why the NWS Storm Prediction Center only has a Saturday yellow area for potential severe weather in North Dakota for the next week. The text of the message notes that the Northern Plains and the Upper Midwest would be favored for strong thunderstorms, but the forecast is too uncertain to pin down where this would happen.

Because of the uncertainty, I have put a small chance for showers and thunderstorms (1 in 5) for Friday afternoon and night and a better chance (1 in 3) for mainly Saturday night into Sunday morning, which is the most likely time for the warm front to push into central Minnesota. I still have some chance for Sunday night into Monday storms. There would be some potential for severe storms if the heat is kept a bit further to the south than forecast.

I am also tempering the potential highs on Sunday (near 90) and Monday (low 90's) rather than going with the more extreme highs being forecast (another 5-10 degrees hotter). If the storms stay to our north and we get more deeply into the sultry air, we might have a small chance to get close to some late June record warm highs and lows (would need a high in the 100's or a low near 77 to hit any records).

Friday Small Rain Chance, Saturday Night A Little Iffy, Uncertain Late Sunday

So, Friday's festival activities have a small chance of a brief late day shower or thunderstorm. Any Saturday activity would more likely be at night than during the day. I don't have a great chance of storms right now, but my uncertainty means that those running concerts and fireworks should be alert.

We might have a leftover early shower on Sunday, but there is that potential for extreme heat and humidity Sunday afternoon.

Perhaps Better Chance for Storms Tuesday? 

There are conflicting indications that a cold front could push the most oppressive air out of Minnesota Tuesday night; that's why the NWS Heat Risk forecast focuses more on southeastern Minnesota on Tuesday). That could bring a better chance for showers and thunderstorms, some possibly severe, on Tuesday or Tuesday night. But, the forecasts don't show a strong storm driving the cold front, so it's too early for me to say the next best chance for storms is Tuesday.

At Least Warm and Humid Much of Next Week

Since no system is that strong, we are likely to hold on to the warmer than average temperatures (80's) and uncomfortable humidity for a good chunk of next week's weekdays. I still have an uncertain chance for storms each day. 

The Sioux Falls National Weather Service radar is under repair, so there will be a gap shown on radar (for example, the College of DuPage north central US radar) for any storms headed into Minnesota from the southwest.