A sultry then stormy Saturday

Hot and humid

Today will be hot and humid. That's the easy part of the forecast. Expect highs to range from the low 80s in northern Minnesota to the low 90s in the south. The Twin Cities should reach about 90. Dew points across much of the state will climb into the very muggy low 70s.

The National Weather Service has issued a heat advisory for portions of east central and south central Minnesota from the Twin Cities and Buffalo down to Mankato, New Ulm and St. James from 1 p.m. until 6 p.m. today:

June 25 - heat advisory
A heat advisory will be in effect for the area in orange the afternoon. Twin Cities National Weather Service

Thunderstorms

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Strong to severe thunderstorms with heavy rain were ongoing during the night and into the morning in far northern Minnesota. These storms have been tracking to the east-northeast into Ontario. Here is a screen shot of what the Duluth radar was showing around 7 a.m. this morning as the strongest storms with a severe thunderstorm warning for possible damaging winds moved into northern St. Louis County:

June 25 - DLH radar
Very strong thunderstorms were passing through northern Koochiching and northern St. Louis Counties early this morning. Duluth National Weather Service

Severe weather is likely later today

The mugginess, the heating of the day, increasing instability and an advancing cold front from the west will combine to set the stage for numerous strong and severe thunderstorms this afternoon and evening.

Warm air aloft will contain the instability for a while, but that "cap" should be broken early this afternoon. That is when scattered storms should build rapidly in western Minnesota. Storms will intensify and become widespread as they head for eastern Minnesota later in the afternoon. Severe storms are most likely to reach the western metro area around 4 p.m.

Storms will have a chance of large hail and possibly a few tornadoes early in the event when storms are mostly scattered. Then, as the storms transition into clusters and lines as they move into eastern Minnesota, the primary risk will be of damaging winds. Heavy rain is likely, as well.

This could become a significant severe weather event. The Storm Prediction Center has issued an enhanced risk of severe storms area for much of east central and northeastern Minnesota and then all of northwestern Wisconsin. The bullseye could easily turn out to be between the Twin Cities and Duluth.

June 25 - risk areas
An enhanced risk area for today is centered over eastern Minnesota and northwestern Wisconsin. NOAA Storm Prediction Center

Sunday will be a less-dramatic day. Highs should range from around 70 in the north to the upper 80s in the south, and dew points will be significantly lower. A few harmless showers should break out in the north.

June 25 - Sunday fcst map
Forecast weather map for Sunday. NOAA Weather Prediction Center