Summerlike weekend gives way to a September reality check next week

Much colder air on the way late next week?

Sunflowers and a September sky at the Weather Lab
Sunflowers and a September sky at the Weather Lab
Paul Huttner | MPR News

Get ready for some big changes in our weather picture across Minnesota in the next week.

As I posted earlier today, we begin with thunderstorms and a severe risk across Minnesota Thursday. Friday brings lingering showers in the morning, with a gradual clearing trend from west to east through the afternoon.

Summery weekend ahead

The last weekend of astronomical summer lives up to its name this year. High pressure shifting into the Great Lakes brings a warmer southerly flow to Minnesota. Highs Saturday will reach the 70s across most of the state, with a few spots near 80 late Saturday afternoon.

Forecast high temperatures Saturday
Forecast high temperatures Saturday
NOAA

Sunday brings even warmer air, as the thermal ridge with this warm spell approaches.

Highs will reach the July-like upper 80s and maybe even 90 degrees in parts of southern Minnesota.

Forecast high temperatures Sunday
Forecast high temperatures Sunday
NOAA

Sunday also brings a more humid air mass to Minnesota. Dew points will reach the muggy upper 60s in some areas.

Dew point forecast for 5 pm Sunday
Dew point forecast for 5 p.m. Sunday
NOAA

I predict longer lines at your local Dairy Queen Sunday.

September’s other colder weather shoe

Next week starts warm. But a potent system will shove a cold front through Minnesota late next week. Scattered rain and thunder arrive Tuesday and Wednesday.

By late next week highs will not climb out of the 50s in northern Minnesota, with 50s and 60s in the south.

Forecast high temperatures Wednesday
Forecast high temperatures Wednesday, Sept. 22
NOAA

Some forecast models continue to crank out temperatures in the 30s (and possible frost) up north by late next week.

NOAA GFS temperature forecast for 7 am Friday September 24
NOAA GFS temperature forecast for 7 a.m. Friday, Sept. 24
NOAA via tropical tidbits

The longer-range outlook suggests we will likely still see more 70s and possibly 80s in late September.

Stay tuned.

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