The heat is on; isolated thunderstorm chances

Nothing says Minnesota State Fair more than hot and humid conditions.

Dewpoints will continue to rise into the mid to upper 60s by Saturday evening. Plenty of sunshine with south-southeast winds 5-10 mph. Look for temperatures to top out in the lower to mid-80s.

There is an isolated rain chance late tonight into early Sunday morning. Most of the Twin Cities will remain dry.

Northwestern Minnesota will see a slight risk for severe storms on Sunday. If the storms hold up, they will move southeast and gradually weaken. Most of the Twin Cities will remain dry with just isolated storm chances.

Several chances for showers for the last full week of August. First one being Monday into Tuesday, and another developing system for late Wednesday into Thursday.

Excessive heat watch issued

The National Weather Service has issued an excessive heat watch from Sunday afternoon through Sunday evening.

“...EXCESSIVE HEAT WATCH IN EFFECT FROM SUNDAY AFTERNOON THROUGH MONDAY EVENING... * WHAT...Dangerously hot conditions possible. Heat index values on Sunday could range from around 100 in the Twin Cities metro, to as high as 110 along and southwest of the Minnesota River in southwestern Minnesota. Heat indices around 105 are possible Monday. * WHERE...Portions of central, east central, south central, southwest, and west central Minnesota. * WHEN...From Sunday afternoon through Monday evening. * IMPACTS...Heat-related illnesses increase significantly during extreme heat and high humidity events. * ADDITIONAL DETAILS...Little relief is expected Sunday night with low temperatures in the low to mid 70s.”

Most of central and southern Minnesota will see temperatures in the low to mid-90s. When combined with dew points between 75 and 80 degrees, we will see heat indices around 100 to 110 degrees.

Monday is shaping up to be the hottest day with temperatures in the mid-90s. Heat index ranges from 100 to 110 degrees are expected.

Stormy Monday; severe possible

A cold front will track southeast across the state on Monday providing relief from the heat. Areas of northwestern Minnesota will see cooler temperatures around the upper 70s to low 80s, but still dangerously hot for central and southern Minnesota.

Showers and thunderstorms will develop late in the afternoon and evening hours. Storm coverage will increase into the overnight hours. The Storm Prediction Center has issued a slight risk of severe for most of central and southern Minnesota. Main threats include large hail (greater than 2 inches), and damaging winds. A tornado cannot be ruled out, given the atmospheric set up.

Rollercoaster of temperatures

Highs temperatures behind the cold front will be in the low to mid-80s for Tuesday and upper 70s to low 80s on Wednesday.

We are still on track to see a significant cooldown by Labor Day weekend. Forecast models are pointing to highs in the low to mid-70s — very fall-like weather. The start of September will be cool with highs 10-15 degrees below our average.

Don’t fret, we will see the return of warmer temperatures.

I’m not quite ready for fall…