Dangerous heat Thursday, then a big humidity drop this weekend

Significant rainfall remains elusive

People swim at a beach.
Beach-goers enjoy unseasonably warm water at Lake Nokomis beach in Minneapolis on Tuesday.
Tim Evans for MPR News

After another dangerously hot and humid day Thursday, Minnesota finally sees some slight relief from the record-setting heat. 

The heat wave that has gripped Minnesota since last week has been one for the record books all across the state. This hot stretch has included (among other records) numerous record highs, warmest lows, and “earliest in the season” records.

Here are just a few of the noteworthy records:

weather graphic
Notable heat wave records
Minnesota DNR

The Twin Cities is also in the midst of a record for the most consecutive low temperatures at or above 70 degrees so early in the season, a run that is at eight days including Thursday morning.

Thursday’s forecast

Minnesota began the day warm and muggy again, with most of the state starting Thursday in the 60s or 70s.

Our heat wave continues with central and southern Minnesota seeing highs in the 90s, and a few 100s possible west. 

weather graphic
Thursday high temperatures
National Weather Service

Dew points have also stayed elevated, predominantly in the 60s, and that high moisture content in the air is making for the muggy morning and will keep the day sticky.

The combination of the heat and high humidity has much of the state under a heat advisory as the heat index could top 100 degrees. 

weather graphic
Thursday heat advisories and warnings
National Weather Service

For the Twin Cities and surrounding counties, the heat advisory that has already been in place the past few days is upgraded to an excessive heat warning from 11 a.m. until 8 p.m.

Be very careful outside Thursday, keeping any strenuous activities in the mornings and evenings when it is not as hot. Hydration, breaks and shade are very important if you need to be outside.

Skies stay mostly sunny to party cloudy again, but much like Wednesday, there will be enough instability for a few isolated showers and storms to develop, especially in the afternoon and evening.

Both western and east-central Minnesota may see isolated severe storms, with high winds and large hail as the primary risks. 

Some relief ahead

weather graphic
Forecast storm position Friday morning
National Weather Service

In contrast to the mostly isolated storm activity Minnesota has seen recently, a weather system starts moving across the state early Friday that brings more clouds across the entire state and showers and thunderstorms that move west to east during the day. 

Unfortunately, moisture is fairly limited with the system, and most places can expect under one tenth of an inch. There will be isolated higher amounts with some thunderstorms, and possibly in western Minnesota.

The combination of the rain, clouds, and a cold front moving through will already put much of Minnesota in the 80s by Friday.

Southeastern Minnesota, including the Twin Cities, will likely still see some low 90s Friday, with the 80s arriving Saturday. 

Although that is still well above average, it offers some relief from the excessive heat.  More significantly, that cold front plunges the dew points dramatically, from muggy 60s and low 70s, to dry 40s by Saturday afternoon.

weather graphic
Forecast dew points Saturday afternoon
National Weather Service

The lower humidity reduces the risk of heat illness during outdoor activities. It also allows the overnight temperatures to start dropping back into the 50s and 60s, which will be a huge relief to those without air conditioning.

Highs are forecast to make it back into the 90s for central and southern Minnesota already again on Sunday. Next week stays above average again with many highs in the 80s and low 90s, but it currently looks like the heat is less likely to be as record-setting as the past week has been.  

Programming note

You can hear my live weather updates on Minnesota Public Radio at 7:49 a.m. Monday through Friday morning.

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