Dangerous heat and humidity will continue

Heat and humidity

Welcome to Miami of the north. This afternoon the Twin Cities and much of Minnesota have been more humid than subtropical Miami.

A dome of hot, extremely humid air has made its way to Minnesota. Our three-day heat wave will feature hot and extremely humid days coupled with very warm nights.

The National Weather Service has issued Excessive Heat Warnings for a very large area of the middle of the country. They are in effect through tomorrow for parts of Minnesota just north of the metro area and until Friday evening for the metro area and points south. A Heat Advisory has been posted for the Duluth area and far northwest for Thursday.

July 20 - heat warnings 2
Excessive Heat Warnings are in effect.

Lows tonight will be mainly in the 70s statewide except for the core of the Twin Cities metro area which might remain in the low 80s. Buildings without air conditioning will cool little overnight.

Thursday will be the hottest day as highs should range from the upper 80s to the upper 90s, and maybe even a few 100s. The blast-furnace heat and abundant humidity will create dangerous conditions for people and pets who are not in air conditioning or at least dense shade.

Friday will not be quite as hot, and the dew point will be lower.

Relief will be on its way for the weekend. By Sunday our temperatures will be back to near normal.

In case you have been wondering, the highest dew point of record in the Twin Cities was 82 degrees measured at 3 p.m. and 4 p.m. on July 19, 2011. Thunderstorms had ended shortly before that time, and the evaporating rain from hot surfaces pushed the dew point up to that sultry 82.

Storms

Some strong thunderstorms could spread from North Dakota across northern Minnesota tonight and continue into tomorrow.

July 20 - tont's slt risk area
The Storm Prediction Center has designated an area of slight risk for severe weather in northern Minnesota tonight.

On Friday, some strong or severe thunderstrorms are forecast for the Dakotas and then possibly into western Minnesota later in the day.

July 20 - Friday fcst map
Forecast surface weather map for Friday. NOAA Weather Predicton Center

The pattern will continue to shift eastward as we get into the weekend. Numerous thunderstorms are likely from later Friday night through Saturday and into Saturday night. The Storm Prediction Center already has forecast a chance of severe thunderstorms around Minnesota and into Wisconsin on Saturday.

July 20 - Saturday severe outlook
There is a fifteen percent chance of a severe thunderstorm within 25 miles of any location in the yellow area on Saturday. NOAA Storm Prediction Center.

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