Heat Storm: 120-degree heat index in Windom; storms brewing overnight

Welcome to the jungle.

Most of Minnesota cooked in brutal July heat Wednesday. We’re riding the northern edge of a deep tropical air mass. Heat index values topped 100-degrees at many southern Minnesota locations.

Heat index values Wednesday afternoon via Oklahoma Mesonet.

The dew point at Windom reached a jungle-like 84 degrees and produced a dangerous heat index of 120 degrees.

Windom’s 84-degree dew point temperature is just 4 degrees shy of the all-time Minnesota state record dew point of 88-degrees in Morehead on July 19, 2011.

After verifying that the dew point sensor at the Moorhead Airport automated station was operating properly, it has been determined that the 88 degree F dew point temperature recorded from 7pm to 9pm July 19, 2011 is the Minnesota state record for highest dew point temperature. The previous dew point temperature record was 86 degrees F set at Pipestone and St. James on July 23, 2005.

Storms brewing

Thunderstorms roll through northern Minnesota and may reach the Twin Cities overnight. The slow-moving nature and heavy downpours prompted the Duluth NWS to issue a flash flood watch for much of northeast Minnesota. There is also a risk for severe storms with large hail and damaging winds.

Twin Cities: Sunrise surprise?

The best chance of storms in the Twin Cities appears to be between about 3 and 7 am Thursday. The front stalls out near the Twin Cities Thursday, and that may mean another batch of storms Thursday afternoon into Friday morning.

Here’s NOAA’s NAM 3 km model.

NOAA NAM 3 km resolution model from Wednesday night to Friday morning via tropical tidbits.

Relief next week

Wednesday marks the 12th day at or above 90-degrees in the Twin Cities this year. Our annual average is 13 days, and we’re still a few days shy of the midpoint of meteorological summer. We stay warm and sticky through the weekend. A significant cool front brings a fresh and cooler Canadian air mass our way by Monday.

NOAA via Weather Bell.

Stay cool and classy Minnesota.