Update on tonight’s rain and a look ahead to a threat for some severe weather on Thursday; Warming trend midweek-weekend (record warmth possible Sunday, Sept. 19)

There’s quite a bit of weather going on in the Northland this week, including multiple rain chances, possibly some severe weather late this week, and warmer temps which looks to peak on Sunday, that’s when we could tie or break record high temperatures in the Northland.

MRMS radar loop ending at 5:10 PM Monday, September 13, 2021 — Rain is steadily advancing east-northeast out of the eastern Dakotas and west-central Minnesota late this afternoon.

18z NAM 3km model simulated radar forecast valid from 7 PM this evening to 7 PM Tuesday. Steadiest rain this evening and overnight, rain moves out of the area from W-E early Tuesday morning. Most of the day Tuesday looks dry across the Northland, but we could see a few isolated pop-up showers Tuesday afternoon.

Note: Rain moves into Duluth and Superior ~8 PM to 11 PM tonight, rain diminishes ~4 AM to 6 AM Tuesday.

Highest odds for over a half inch of rain with tonight’s system remains over southern portions of the Northland including east-central Minnesota and northwest Wisconsin per Euro ensemble model.

HREF model agrees quite well with the Euro ensemble model on where the highest rain totals will be for tonight/early Tuesday morning — Parts of northwest Wisconsin and far eastern Minnesota could see a half inch to over an inch of rain tonight including for cities such as Pine City, Hinckley, Siren, Hayward, Spooner, Shell Lake and Hurley. Rain totals taper off farther north, with anywhere from a trace to less than a quarter inch of rain expected for northern Minnesota into the Arrowhead.

Here in Duluth and Superior we could see between a quarter to as much as a half inch of rain by Tuesday morning.

  • Rain tonight
  • A few isolated showers Tuesday afternoon
  • Showers and thunderstorms possible Thursday
  • Rain chances return early next week

So overall we’re looking at a potentially wetter pattern for northeast Minnesota and northwest Wisconsin over the next week with above normal precipitation possible (green colors on map)

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…Severe Weather Potential Thursday…

The synoptic setup for Thursday includes a cold front (blue line) which will move east across the upper Midwest. Southerly winds ahead of that front will pull warm and somewhat humid air northeastward, while cooler/drier air pushes SE behind the boundary.

Primary concerns at the moment include

-Moisture (not enough?)
-Timing and capping (too warm aloft for storms to develop?)
-CAPE (not enough instability/fuel for storms?)

A strong low level jet looks to be in place ahead of a cold front on Thursday, this combined with strong winds aloft and a decent amount of wind shear certainly warrants keeping an eye on Thursday’s forecast in the days ahead. Stay tuned.

Note: The pink outlined area on the map is where there could be an isolated severe thunderstorm risk Thursday afternoon and evening, but that area could shift around a bit over the next few days.

…Midweek/Weekend warmup…

Long range computer models continue to be in good agreement on how the pattern will setup later this week into the weekend. It’s a pattern which could produce some very warm temperatures across the upper Midwest including here in the Northland especially this weekend, with Sunday (September 19) looking like the warmest day.

Here are the Record High Temperatures for September 19

Looking over the record highs for this coming Sunday, every location but Duluth does have a pretty good chance at tying or possibly even setting a new record high temperature for September 19th. As for Duluth, very doubtful that will hit 90 degrees on Sunday, although it still looks warm with highs possibly getting into the 80s.

Duluth, MN: 90 set in 1984
Brainerd, MN: 88 set in 1940
Ashland, WI: 87 set in 1985
Hibbing, MN: 87 set in 1984
International Falls, MN: 86 set in 1970

Note: Warmer than average temps in orange and red colors on the maps below, with below average temps in blue and green colors.

Tim

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