Patchy frost tonight; warming up and turning more humid this weekend, 80s return on Sunday

A frost advisory has been issued for northern Minnesota from Midnight tonight to 8 AM Saturday (blue area on map).

Temperatures as low as 32 will result in frost formation.

Some locations in this frost advisory include International Falls, Bigfork, Hibbing, Cook, Crane Lake, Orr and Isabella.

Frost could kill sensitive outdoor vegetation if left uncovered.

Mean dates for the first 32 F freeze of the season (1991-2020 climate period).

International Falls, MN: September 15
Ashland, WI: September 24
Brainerd, MN: September 25
Duluth, MN: September 30

Frost Advisory (blue area on map)

Much warmer temperatures arrive this weekend into early next week, with Sunday and Monday looking like the warmest days in the Northland, with widespread 80s on Sunday, and 70s and 80s for Monday. As for Saturday’s high temps, not too shabby, mid 60s to low 70s.

Mean dates for last 80 F day of the year (1991-2020 climate period).

International Falls, MN: September 14
Duluth, MN: September 15
Hibbing, MN: September 18
Ashland, WI: September 22
Brainerd, MN: September 26


Along with the warmer temps this weekend will come an increase in humidity on Sunday and Monday as dew points rise into the 60s.

60 degree dew points are pretty unusual this far north in mid September.

Loop below shows the dew point temperature anomaly valid from 7 AM Sunday, September 19, 2021 thru 7 AM Tuesday, September 21, 2021.

We’ve got the first snowfall of the season coming to portions of the Rockies this weekend/early next week, although this won’t be a major winter storm, with only a few inches of snow accumulation expected.


Rain chances return to the Northland in the Sunday night-Tuesday morning time frame.

Northern Minnesota has the greatest chance for showers and thunderstorms Sunday night, and then will see rain chances gradually increase farther east sometime Monday or Monday night.

Forecast map for Monday morning, September 20, 2021.

An early look at how much rain we could get with our next system shows a potential for widespread 1″+ amounts, with 2″ of rain possible over parts of northern Minnesota the way it looks now, again this would be in the Sunday night-Tuesday morning time frame.


Leave a Reply

%d bloggers like this: