Dangerous midweek heat for much of Minnesota

Humidity is on the rise across Minnesota, and will combine with hot weather to create dangerous conditions. Meanwhile, rain is back in the forecast but it brings a significant severe weather risk, especially Monday.

Monday’s forecast

A southerly wind started moving more humid air into the state overnight. Northern Minnesota, where some dew points are still in the 50s as of Monday morning, began the day with most lows in the 50s. 

Southern Minnesota is already more humid, and that helped keep overnight temperatures much higher, in the 60s and 70s with muggier conditions.

The higher dew points spread north through the day, and all of Minnesota is likely to see dew points in the 60s by the afternoon. Highs will be in the 80s north and low 90s south.

The increasing humidity will also make it feel even warmer.

The instability has also increased again, and a band of showers and storms moved into western Minnesota overnight, bringing a swath of rain along with it that even clipped parts of the Twin Cities.

That areas has diminished as of 9 a.m., but more storms will build through the day, especially in the afternoon and evening, continuing into the overnight. Precipitation is possible anywhere, but the best chance is in central Minnesota. 

Unfortunately, that is also the most probable area for severe weather in the evening and overnight, with large hail the primary risk, but damaging winds and isolated tornadoes are also possible.

Hot and stormy

The instability keeps showers and storms across Minnesota through early Tuesday, with more forecast to develop once again, especially late Tuesday and through the day Wednesday.

The risk for scattered severe storms shifts to southern Minnesota Tuesday and to the southeastern corner of the state Wednesday, although isolated strong storms are possible almost anywhere in the state through Wednesday.

Rain totals in general through Wednesday will be about one-half inch or less for most of Minnesota, but those totals are expected to vary greatly, with some spots missing the rain entirely and other areas getting over 1 inch, depending on where exactly the storms track. 

The heat continues to rise through Wednesday, with much of southern Minnesota in the mid and upper 90s by Wednesday, and a few locations, especially southwest, likely to make it into the 100s. 

Humidity also increases, with some dew points back in the low 70s by Wednesday. This mix of hot humid weather has much of southern Minnesota already under either a heat advisory or excessive heat watch Tuesday into Wednesday, for a heat index that is forecast to top 100 at times. 

On Wednesday, locations near the Mississippi River Valley could feel like over 105 degrees.

Fortunately, a cold front finally passes through late Wednesday, dropping the heat and humidity by Thursday. 

Programming note

You can hear my live weather updates on Minnesota Public Radio at 7:48 a.m. Monday through Friday morning.