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Signs of cooler air ahead in early September

Steamy weekend ahead

NOAA 8 to 14-day temperature outlook
8 to 14-day temperature outlook
National Oceanic and Atmospheric Administration

Many of the forecast models we use each day run out to 240 hours. It doesn’t take long to do the math. That’s 10 days. That means September is beginning to creep into the medium-range forecast models.

I wrote earlier Wednesday about another steamy weekend ahead for Minnesota.

Now let’s take a look at next weekend as September dawns.

The upper-air pattern across North America favors warm and humid air into next week. But there are signs the jet stream may buckle late next week and send the first real taste of cooler September air toward Minnesota.

On the map below, check out the National Oceanic and Atmospheric Administration’s Global Forecast System model upper-air pattern from this Saturday through Sept. 2. See how the warm colors linger most of next week? But then a pocket of cooler air slides into the Upper Midwest by around Labor Day.

NOAA GFS upper air forecast
Global Forecast System upper-air forecast from Saturday through Sept. 2
NOAA, via Tropical Tidbits

NOAA’s eight to 14-day outlook at the top of this post reflects the trend toward cooler-than-normal temperatures.

Wednesday’s runs have pushed the arrival of the noticeably colder air back a day or two, but forecast models have cranked out highs in the 60s south to 50s north in the early days of September.

The good news for summer weather lovers? It looks like we’ll heat up again after this brief cool snap.

Preview of coming attractions.