105 FXUS63 KDLH 161923 AFDDLHArea Forecast Discussion National Weather Service Duluth MN 223 PM CDT Tue Sep 16 2025
.KEY MESSAGES...
- Isolated showers and storms are possible through tonight, with a few strong thunderstorms possible in the Arrowhead.
- Warm to hot temperatures continue today and Wednesday, then a return to more seasonal temperatures.
- On-and-off shower and storm chances through the week and into the weekend.
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.DISCUSSION... Issued at 223 PM CDT Tue Sep 16 2025
A warm air mass lingers this afternoon as a cool front in northwest Minnesota slowly enters the area. Low-end amounts of mainly speed shear with slight directional sheer combines together with a notably unstable airmass aloft to create a 5-10% chance of strong thunderstorms in the Arrowhead this evening directly ahead of the advancing cool front. If a strong thunderstorm can form, the primary hazard would be small hail and heavy rainfall, with gusty winds to 50 mph as a secondary hazard. At this point the main time period of concern would be around sunset through the early overnight hours before the front pushes eastward into an area of even less favorable shear profiles late tonight. The chance of precipitation forecast for this evening and overnight remains capped around 20-30% for this low-confidence thunderstorm environment later tonight.
Expect another day of warm to hot temperatures south of the Iron Range and especially east-central MN and all of northwest Wisconsin Wednesday as the cool front stalls out. Temperatures will cool to near or slightly below normal for Thursday. An easterly wind over Lake Superior will especially be notable for typical lake breeze locations Thursday and Friday. This late work week time period will feature multiple low-end chances of additional rain showers as the stalled and slowly weakening frontal boundary sits across the general US Hwy 2 corridor and low pressure over the Great Plains lifts moisture northward.
This similar pattern lasts into the weekend even as the closed low breaks down since the a cutoff low over Quebec moves into the Canadian Maritimes. At this point the highest confidence rainfall would be Saturday into Saturday night with the better Plains forcing entering the area before ejecting eastward into Ontario. Westerly flow aloft with near-normal temperatures helps to keep at least a mild pattern over the Upper Midwest into early next week.
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.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/... Issued at 1225 PM CDT Tue Sep 16 2025
Isolated thunderstorms this afternoon mainly in far northern Minnesota will be monitored for any TAF amendments that may be needed, especially near Hibbing. Isolated thunderstorm chances last into tonight with a strong thunderstorm possible into the Arrowhead ahead of an advancing cool front. Areas of fog again produce a few hours of expect IFR to LIFR visibility 09-14Z.
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.MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/... Issued at 141 PM CDT Tue Sep 16 2025
Light southerly winds under 10 knots persist through tonight before becoming light and variable Wednesday. Expect a notable uptick in northeasterly winds Wednesday night, with gusty to strong easterly winds Thursday morning onward. A few gusts to 30 knots are possible (30-40% chance). The resultant elevated waves and gusty winds linger into Friday. There is a fair chance of needing some Small Craft Advisories Thursday.
For the open water discussion, refer to the NWS Marquette Area Forecast Discussion at weather.gov/mqt.
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.DLH WATCHES/WARNINGS/ADVISORIES... MN...None. WI...None. MARINE...None.
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DISCUSSION...NLy AVIATION...NLy MARINE...NLy
NWS DLH Office Area Forecast Discussion