St. Cloud, MN Weather Forecast

Leading Edge of Tropical Weather Approaching

We have one last day of merely noticeable to uncomfortable dew points. The dew point climbed into the upper 50's and lower 60's yesterday afternoon (see yesterday's 4 PM CDT NWS WPC North America zoom-in map) after a low 50's start. And, the continued southeast winds will eventually bring in the steamier air from the southern half of Iowa southward (see UCAR hourly dew point chart). 

Thunderstorm Threat Largest Tonight into Tomorrow Morning (Continues in Northern Minnesota Sun Ht-Mon)

The main surge of that Florida-like air will begin tonight, so tonight into tomorrow morning appears to have the best chance for showers and thunderstorms of the next few days. The current storms in the Dakotas (see College of DuPage north central US radar loop) will weaken but new storms will develop in the western Dakotas and Montana late today and push eastward across the Dakotas overnight. There is a small chance of any severe weather reaching northwest Minnesota before 7 AM tomorrow, but strong storms will push into Minnesota for the daylight morning hours, possibly interfering with outdoor plans. During tomorrow, the hot and sultry air will push into southern Minnesota and approach central Minnesota. There will be another round of late day showers and thunderstorms, continuing into Sunday night. The best chance for those storms will be in northern and perhaps central Minnesota.

There will be more chances for storms into Monday morning and again Monday night into Tuesday morning. The latest forecasts show the sultry hot and humid air entrenched in at least southern and central Minnesota, so the most likely spot for storms will be northern Minnesota, Manitoba, and Ontario (see Day 3 of the NWS WPC quantitative precipitation forecast). Those storms will again have a chance to produce severe weather (see updated Day 3 of the NWS Storm Prediction Center convective outlook after 2:30 AM).

Another Good, But Uncertain Storm Chance Tuesday, Tuesday Night?

There are signs that the heat and humidity could edge a bit to the south sometime Tuesday or Tuesday night. A weak cold front will push through parts of Minnesota. That would have the next best chance to produce widespread showers and thunderstorms in central Minnesota, maybe early Tuesday morning with a better chance on Tuesday night. However, this system is forecast to be weak, so I am not nearly as confident in rain as the higher totals on Days 4-7 of the NWS WPC quantitative precipitation forecast suggest. There would also be a severe weather threat, but the NWS Storm Prediction Center forecasters are too uncertain about timing of the front to pin down a severe weather risk area beyond Day 4.

Sultry Air Will Push Heat Index, Air Pollution to Serious Levels Tomorrow PM (S and Perhaps Central) and Most of MN Monday into Tuesday

Within the hot and humid air, thunderstorms will tend to be suppressed except within 50 miles of the warm front. That's because the hot air bubble will feature very warm air (near or above 70 degrees) at 5,000 to 10,000 feet above the ground. So, those areas will have a good chance for maximum sunshine as well as sweltering humidity. Expect the National Weather Service to have heat advisories and excessive heat warnings through much of the Plains as far north as the Dakotas and Minnesota (much of Minnesota shown in the heat risk area Sunday through next week; excessive heat watch already in effect for Wisconsin and Iowa). There will also be air pollution issues as the sunshine turns vehicle exhaust into low-level ozone. These will easily be the most oppressive conditions Minnesota has seen so far this summer. Expect temperatures either in the lower 90's with dew points in the lower 70's or perhaps even in the middle 90's with dew points in to the low to middle 70's in at least southern Minnesota tomorrow and throughout much of Minnesota on Monday. Heat indices should break 100 degrees. Depending on how far southward any storms get late Monday night, parts of Minnesota could see more heat and air pollution issues on Tuesday.

Heat and Sun Safety

You can find safety steps for intense heat and humidity on the NWS heat safety page (kids and seniors are the most vulnerable.)  Also, keep your exposure to ultraviolet sunlight to a minimum (there is no such thing as a safe tan).

Beyond Tuesday, the front will be nearby. We may have slightly cooler temperatures (80's to low 90's), but still Florida like dew points and an uncertain chance for showers and thunderstorms.