Dense Fog Advisory issued for the North Shore and Twin Ports. Update on the active weather pattern which will be with us for the next 5 days

The good news is that this should be our last dense fog advisory for a while at least, and wow what a streak this has been.

A Dense Fog Advisory is in effect for the North Shore and Twin Ports until 10 AM Sunday.

Visibility to a quarter mile in dense fog.

Hazardous driving conditions due to low visibility.

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The first of three strong low pressure systems over the next 5 days will be affecting the Northland tonight and Sunday.

Tonight’s low continues to deepen over eastern South Dakota, and this low will head NE reaching northwest Minnesota late Sunday afternoon. Warm air ahead of the low, colder air behind it, it’s a clash of the airmasses!

Ingredients are there for the development of severe thunderstorms which could include a couple tornadoes this evening over parts of eastern South Dakota into west-central Minnesota.

There’s plenty of wind shear in the atmosphere, with easterly winds near the surface, veering SE at 850mb, and SW or SSW at 500mb. We’re also seeing a decent amount of speed shear where the wind speed increases with height.

0-1 KM shear is sitting in the 20-25 knot range late this afternoon, while Effective Storm Relative Helicity was in the 200 m2/s2 to 300 m2/s2 range, both parameters are in the favorable range to where we could see a few tornadoes through this evening. Again this would be for southeast North Dakota, eastern South Dakota and west-central Minnesota.

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  • Tonight’s low over eastern South Dakota heads NE and moves over northwest Minnesota Sunday afternoon.
  • A second low tracks from the Southern Plains on Sunday to the Midwest and Lower Great Lakes for Monday and Tuesday.
  • A third and final low heads northeast out of the central Rockies in the Tuesday-Thursday time frame.

Tonight’s low and the third low (middle of next week) will track in a favorable direction to bring some rain to northeast Minnesota and northwest Wisconsin, but that second low early in the week should pass too far SE of us to give us a lot of rain, but we could still see a little rain out of that one in the late Monday-Tuesday time frame, with those rain chances looking highest in northwest Wisconsin and Arrowhead of Minnesota.

Occasional showers and some thunderstorms are likely in northeast Minnesota and northwest Wisconsin tonight and Sunday. Note: Timing for when we could see some heavy downpours and stronger storms in our area is from late this evening into Sunday morning.

18z/1 PM NAM 3km model simulated radar forecast ending 7 AM Monday, October 11, 2021.

Rainfall totals of an inch or more are expected across north-central into northeast Minnesota by Sunday evening, while lower amounts generally in the 0.10″ to 0.40″ range are expected in northwest Wisconsin.

Tim

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