361 FXUS63 KMQT 071851 AFDMQTArea Forecast Discussion National Weather Service Marquette MI 251 PM EDT Tue Oct 7 2025
.KEY MESSAGES...
- A widespread freeze/frost is expected for inland areas tonight. A freeze warning and frost advisory have been issued.
- Frost and/or freeze conditions will be possible again Wednesday night.
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.DISCUSSION... Issued at 251 PM EDT Tue Oct 7 2025
A cold front pushed pushed through the western U.P this morning and was now located over the central portion of the U.P. A few light sprinkles have been reported along the front but no appreciable precipitation is expected as it continues to push east through the rest of the U.P this afternoon. Behind the front winds shifted to the west-northwest and were gusty, especially over the Keweenaw. Temperatures were in the 50s in the west and low to mid 60s in the south central and east.
The main challenge with the forecast for tonight is how cold it will get and coverage of lake effect clouds/showers. A secondary cold front will drop south through the U.P this evening bringing another surge of cooler air into the region. 850mb temps will drop to around -2C resulting in 850mb-lake deltaTs of -15C or so. Clouds will develop over the lake this evening and deepening inversion heights to around 7kft should result in scattered lake effect showers. Sub- cloud dry air will likely limit the precipitation intensity, however, a convergent wind pattern over central portion of the lake should help focus a few bands of light showers, mainly east of Marquette. While the showers will be light and generally not impactful, lake effect clouds are expected to develop over the western U.P as well. Some model guidance brings these clouds well inland, through the interior of the U.P but feel this is a bit overdone and even a short period of clear skies should allow for temperatures to plummet over the interior with otherwise optimal conditions for strong radiational cooling. Kept the temperature forecast in-line with previous trends and left the frost/freeze headlines in place.
Temperatures warm into the 50s for Wednesday. Deep mixing and a dry airmass will bring RH over the interior down as low as 30% but winds should be light, limiting fire weather concerns.
Wednesday night looks like a good setup for strong radiational cooling over much of the U.P as winds become calm over much of the area and a cool, dry airmass remains in place. This should expand frost and/or freeze conditions closer to the Lake Superior shoreline and across much of the eastern U.P away from Lake Michigan. Used the 25th percentile of the NBM for overnight lows, bringing many areas away from the shorelines down into the upper 20s.
The trough axis shifts east of the area late in the week as a ridge of high pressure builds into the western U.S. This will result in temperatures warming into the 60s across the U.P late this week into early next week, several degrees above seasonal averages. A shortwave will move through the Upper Great Lakes on Thursday night into Friday under northwest flow aloft. This brings a chance for precip back into the area but nothing widespread at this time. The ridge will shift east over the weekend and break down with the chance for showers coming back into the forecast for late Sunday into early next week.
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.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/... Issued at 156 PM EDT Tue Oct 7 2025
VFR conditions prevail during the 18Z TAF period. Northwest winds remain elevated this afternoon between 10-15 kts in the wake of the cold front now progressing over the eastern UP. Gusts are expected up to 30 kts at CMX and around 20 kts at SAW until sunset when winds shift more northerly and diminish. At that point, a colder airmass passes overhead and lake effect cloud cover returns. Best coverage will be at SAW where a few sprinkles could be seen and periods of high-end MVFR cigs can`t be ruled out (15-25% chance). CMX may see broken skies at times, but confidence was too low to include, especially given VFR cigs should persist. Mostly clear skies are expected at IWD. Skies scatter out Wednesday morning as high pressure centers overhead.
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.MARINE... Issued at 251 PM EDT Tue Oct 7 2025
Northwest winds will gust to 30 knots through this evening over the central and western portion of the lake as a cold front exits the area. Expect winds to diminish quickly overnight with light winds expected for Wednesday. Southerly winds will develop on Thursday into Friday in response to a low pressure tracking through Ontario. Winds will increase to 25 kts over the west on Thursday and up to 30 kts lake wide Thursday night. Expect light winds on Friday and Saturday, generally below 15 kts.
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.MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... Frost Advisory from midnight tonight to 10 AM EDT Wednesday for MIZ001-003-006-007-014-085.
Freeze Warning from midnight EDT /11 PM CDT/ tonight to 10 AM EDT /9 AM CDT/ Wednesday for MIZ002-004-005-009>013-084.
Lake Superior... None. Lake Michigan... None.
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DISCUSSION...NL AVIATION...77 MARINE...NL
NWS MQT Office Area Forecast Discussion