Excessive heat Tuesday followed by storms Wednesday

It’s already a warm morning and it will be a hot Tuesday. An excessive heat warning is posted for the Twin Cities and a heat advisory is in effect for many other areas in southern Minnesota. Thunderstorms will temporarily break the heat Tuesday night into Wednesday.

A very hot Tuesday

We’ll have abundant sunshine and hot conditions Tuesday. Temperatures are already starting out in the 70s for most of southern Minnesota. Highs will be well into the 90s for many places.

Dew points in the 60s, even near 70 will create a heat index in the triple digits possibly for some Tuesday afternoon.

Far northwestern Minnesota will have a few morning thunderstorms.

What’s a heat burst?

Redwood Falls experienced a rare phenomena early Tuesday morning, a heat burst.

A heat burst is more common in the desert southwest and occur at night. We had collapsing showers moving across southwestern Minnesota between 4 and 7 a.m. early Tuesday morning.

Dry, warm air at about 3,000 to 4,000 feet up enters the dying storm and the moisture evaporates into it. This rapidly cools the air and it descends quickly. This set up is similar to how microburst (severe storm wind gusts) develop.

As air descends it warms, due to compression. From this height, the air can warm 15 to 20 degrees! Redwood Falls saw their temperature jump from 79 to 95 degrees for just several minutes, then cool back down.

Storms possible Tuesday night into Wednesday

This first bout of heat will be relatively short-lived. Thunderstorms will break the heat along a cool front late Tuesday night into Wednesday.

Some storms could be strong to severe Wednesday. After Wednesday we’re in for a few “cooler” days in the lower to middle 80s. We’ll have abundant sunshine Thursday into early next week with the next blast of heat moving in for the weekend and giving us several days in the 90s potentially.