799 FXUS63 KDTX 130305 AFDDTXArea Forecast Discussion National Weather Service Detroit/Pontiac MI 1105 PM EDT Fri Sep 12 2025
.KEY MESSAGES...
- Low chance (15-20%) for isolated to scattered showers tomorrow morning into early afternoon.
- Much above normal highs with continuing dry weather next week.
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.AVIATION...
SE Mi conditions become increasingly influenced by a combination of weather components but still result in VFR late tonight and Saturday. Surface high pressure building toward the New England states reaches back into the Great Lakes to maintain warm and dry air in the low levels. Low pressure developing in the Plains has a warm front extending into the Midwest but makes little eastward progress during the early weekend period. The system produces showers and thunderstorms to the north and east of the warm front but which only graze northern and SW Lower Mi. This leaves just low probability for a stray shower along the SE Mi terminal corridor, although a considerable virga signal is expected on radar. Otherwise, mid and high clouds increase coverage and thicken during the day and then break up late. Wind is light and lake breeze augmented from the south into Saturday evening.
For DTW/D21 Convection... Thunderstorms are not anticipated through Saturday.
THRESHOLD PROBABILITIES...
* None.
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.PREV DISCUSSION... Issued at 321 PM EDT Fri Sep 12 2025
DISCUSSION...
Western periphery of high pressure and build up of a 586dam ridge brings another round of dry weather and mostly sunny skies. Ongoing showers and convection over northern Minnesota into Wisconsin will wane leading into the night as it targets the U.P. and northern lower Michigan. A secondary response just south of the ongoing activity, fueled by unbalanced flow on the nose of a jet, which will strengthen tonight, will sustain adequate moisture transport for nocturnal convection. A convectively enhanced shortwave will sustain activity into Michigan despite the disconnect with instability. Showers and any embedded storms will be entering a non-conducive environment for sustained activity with poor mid-level lapse rates and very little to no elevated instability. The expectation is for this feature to path into SE MI through tomorrow afternoon and early evening, but for coverage to wane as it moves across the cwa. Will continue to maintain around a 15-20% chance for PoP, favoring more isolated to scattered coverage of showers, with a very low chance for an embedded thunderstorm. Otherwise, mid to high based altostratus to cirrus will fill in through the day until the shortwave has cleared.
A deep trough extending through the western CONUS will amplify ridging downstream into the Great Lakes starting Sunday and into early next week. A rex block pattern then forms and holds through the midweek period, again with high pressure holding over the Great Lakes. This will bring yet another round of extended dry weather and above normal temperatures. There is moderate to high confidence to see highs aoa 80 degrees through the entire forecasting period, outside of the lakeshore and inland Thumb region, where weak gradient flow will allow a lake breeze to develop near peak heating hours. This will moderate high temperatures by several degrees holding temperatures just shy of the 80 degree mark.
MARINE...
Departing high pressure has led to light southeast flow and dry weather across the Great Lakes this afternoon. Glancing influence from Hudson Bay low pressure Saturday and a cold front Saturday night lead to low coverage of light showers throughout the day and evening hours. High pressure then builds across Ontario Sunday into early next week, while upper level ridging slides in from the Plains. This brings a seasonably warm airmass into the Great Lakes, while reinforcing dry and favorable marine conditions.
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.DTX WATCHES/WARNINGS/ADVISORIES... MI...None. Lake Huron...None. Lake St Clair...None. Michigan waters of Lake Erie...None. &&
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AVIATION.....BT DISCUSSION...AM MARINE.......MV
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NWS DTX Office Area Forecast Discussion