Severe storms likely across Minnesota on Wednesday

Dangerously hot, too, with the heat index above 105 in some areas

Updated 9:20 a.m.

Wednesday’s weather brings several hazards across Minnesota, from excessive heat to severe storms that are expected to bring damaging winds, large hail and tornadoes.

Wednesday’s forecast

An area of low pressure moves across Minnesota Wednesday, bringing both hot and stormy weather with it. 

Under a predominant wind flow from the south, which is funneling in heat and humidity, all but northeastern Minnesota is starting Wednesday warm and muggy, with temperatures in the 70s.

Other than the northeastern corner of the state (in the 80s), the entire state can expect highs in the 90s Wednesday, with upper 90s and a few 100s likely in southern Minnesota.

Dew points in the 70s also keep tropical moisture levels in the air. That mix of hot and humid weather will put the heat index above 100 for most of southern Minnesota, and many locations, especially near the Mississippi River Valley could feel like over 105 degrees.

weather graphic
Wednesday's forecast heat index temperatures
National Weather Service

Because of the dangerous heat and heat index forecast, most of southern Minnesota is under an excessive heat warning through Wednesday evening.

weather graphic
Wednesday's heat warnings and advisories
National Weather Service

Surrounding areas, where the afternoon heat index will be closer to 100, are under a heat advisory.

Along with the instability from the low pressure, the heat and humidity are already fueling some showers and storms Wednesday morning.

weather graphic
9:00 a.m. Wednesday radar
National Weather Service

There is a risk for showers, storms and possible severe across most of Minnesota at any point Wednesday. However, the highest threat is in the late afternoon and evening, with more numerous and intense severe storms likely as you head farther east.

The marginal and slight areas (dark green and yellow) mean more isolated to scattered severe storms.

The enhanced (orange) is where numerous severe storms are possible, and the moderate (red) area shown in Wisconsin could get numerous, longer-lived, intense storms. 

Damaging wind is the primary concern, and the risk is so high for damaging winds Wednesday along the eastern border of Minnesota and into Wisconsin, that we only see this high of a threat (a 45 percent area) every two to four years.

Hail and tornadoes are also expected.

Stay with MPR News for coverage of the severe weather as it develops throughout the day. 

Pattern change

The cold front with this weather system starts moving into Minnesota Wednesday evening, passing north to south by Thursday morning. Therefore, most of the severe weather should wind-down by late Wednesday, with precipitation clearing overnight.

Under a completely different air mass in place Thursday, the weather will feel noticeably more comfortable.

High will dip back into the 80s, with a few 70s north.  The humidity drops back to lower levels, and the skies stay dry and sunny. However, the shift in the winds is forecast to draw more smoke and haze back across Minnesota Thursday.

Temperatures through the rest of the week remain more seasonably warm for late July with 80s south and a few 70s north. The current average high in the Twin Cities is 83. By the start of August on Sunday, the temperatures might even be a couple degrees below average. 

Here are those forecast highs for the Twin Cities through Sunday:

weather graphic
Twin Cities forecast highs
National Weather Service

Rain chances turn limited again, which means drought conditions are likely to worsen.

Programming note

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

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