Cool temps tonight-Thursday night with isolated showers possible Thursday; rain chances increase Sunday-Monday

Could see some patchy frost early Friday morning in far northeast Minnesota, and also in parts of northern Wisconsin (away from Lake Superior) Note: Frost is not expected in Duluth or Superior.

Source: 18z NAM-WRF model;

The ridge is our friend as it will keep the rain away from most of the Northland through Saturday morning. Some rain could begin to affect far western areas along and west of a line from Walker to International Falls Saturday afternoon or Saturday night, but there is a chance that the entire area stays dry until Sunday thanks to that upper level ridge. Eventually we will see the trough across the Northern Rockies make its way into the upper Midwest later this weekend which will increase the chance for getting some rain, this is most likely to happen in the Sunday-Monday time frame.


Potential is there for a cool final week of August with a large portion of the U.S. forecast to have below normal temperatures next week (blue and green colors on map) What this means for us in the Northland would be highs in the 60s and lows in the 40s (could end up being even a little cooler) Note: The coolest temps look to arrive mid to late next week.

Source:; 12z European Ensemble model

Note: Not quite record cold in Hibbing this morning but the low of 38 degrees was good for 3rd lowest minimum temperature on record for August 21. The record low for August 21 is 27 degrees set in 2004.

…Cooling Degree Day stats for the summer of 2019, stats below are from June 1 through August 20, 2019…

Note: Cooling degree days are defined as the number of degrees by which the average daily temperature is higher than 65 degrees, it’s also a measurement to quantify the demand for energy needed to cool buildings.

Note: CDD=Cooling Degree Day

Brainerd, Minnesota

  • CDD: 407
  • Departure: +66 above normal

Duluth, Minnesota

  • CDD: 322
  • Departure: +152 above normal

Ashland, Wisconsin

  • CDD: 227
  • Departure: +33 above normal

International Falls, Minnesota

  • CDD: 156
  • Departure: +2 above normal

Hibbing, Minnesota

  • CDD: 81
  • Departure: -41 below normal

Note: Duluth has had 241 more cooling degree days so far this summer compared to Hibbing, and this shows up nicely in the average temperature and number of 80 degree days, with a warmer summer in Duluth compared to Hibbing. The average temperature so far this summer at Duluth 67.0 degrees (+3.5 degrees above normal) while at Hibbing the average temperature so far this summer 61.5 degrees (-0.7 degrees below normal) 42 days at or above 80 so far this summer at Duluth while Hibbing has had 31 days at or above 80 so far this summer.

Low temperature forecast for Thursday morning, August 22. Source:

High temperature forecast for Thursday, August 22.

…Weather Summary…

Keeping an eye on an isolated frost threat, isolated Thursday sprinkles, and rain chances late this weekend.

The majority of the Northland should stay dry through Saturday morning, but there is one exception, that being near Lake Superior where we could see a few light rain showers pop up on Thursday due to the proximity of an upper level low/trough sitting to our north combined with an easterly wind coming off Lake Superior which could cause a few lake induced rain showers to develop with air/water temp differences of around 10 degrees (H85 temp +5C; water temp around +15C)

Partly to mostly cloudy skies are expected tonight and Thursday with lows tonight in the 40s and 50s, highs Thursday in the 60s to around 70 degrees. North winds will shift to the east on Thursday at 5 to 15 mph.

Even cooler temperatures are forecast for late Thursday night-early Friday morning with some 30s possible in far northeast Minnesota and in parts of northwest Wisconsin (away from Lake Superior) if temperatures can drop into the 34-38 degree range, then we could see some patchy frost between 3-6 AM Friday, again this would be in far northeast Minnesota (Arrowhead region) and interior portions of northwest Wisconsin.

Winds will shift to the south this weekend with milder temperatures returning to the Northland along with a better chance for some rain by late this weekend. Highs Friday mid 60s to lower 70s, highs Saturday mainly in the 70s, highs Sunday in the 60s and 70s.

Forecast for Duluth and Superior

.Tonight… Partly cloudy. Low 50 to 55. Wind north to northwest 10 to 15 mph.

.Thursday… Partly to mostly cloudy. An isolated shower possible. High 63 to 68. Wind east 10 to 20 mph. Note: June 23 was the last time when the high temperature didn’t hit at least 70 degrees in Duluth (nearly two months ago)

.Friday… Partly cloudy. High 65 to 70. Wind east 10 to 20 mph.

Normal temperatures for August 22

  • High 73
  • Low: 54
  • Sunrise Thursday 6:15 AM CDT
  • Sunset Thursday 8:07 PM CDT

Thanks for reading!

Leave a Reply

%d bloggers like this: