823 FXUS63 KDTX 151800 AFDDTXArea Forecast Discussion National Weather Service Detroit/Pontiac MI 200 PM EDT Wed Oct 15 2025
.KEY MESSAGES...
- Dry weather and normal mid October temperatures resume this afternoon through Thursday.
- Warmer air but a more active rain pattern is expected late Friday through this weekend.
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.AVIATION...
Varying levels of clouds this afternoon as we deal with the lingering mid clouds from the system that passed through the area this morning and moisture advection off Lake Huron resulting in some CIGS around 2-3kft. Expectations are for high pressure to continue building into region with northerly winds bringing increasingly drier air into lower MI. Clouds should decrease in coverage after peak heating today going clear overnight. Signal still there for some patchy lake stratus to move ashore off Lake Huron Thursday morning with some cirrus possible by the afternoon.
For DTW/D21 Convection... The high pressure dominated weather pattern does not support thunderstorms today and tonight.
DTW THRESHOLD PROBABILITIES...
* Moderate for ceiling at or below 5000 ft this afternoon, low this evening and tonight.
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.PREV DISCUSSION... Issued at 356 AM EDT Wed Oct 15 2025
DISCUSSION...
Mid-level fgen engaging a swath of moisture along an elevated frontal slope is driving scattered coverage of light rain across the area early this morning. Upper jet forcing has begun to depart east and system-relative progs will increasingly favor isentropic descent over the next few hours - this will support gradual shrinking of saturation depth and decreasing probability for rain through the rest of the morning. The parent wave exiting east will drive the elevated front south and allow cooler, drier air to settle across the area today. Clouds will gradually clear from north to south with mostly clear skies expected by this evening. The Thumb will take the most direct cold advection which keeps highs around or just shy of 60. Elsewhere, lower to mid 60s will be common.
High pressure building in across the northern Great Lakes maintains clear skies and very light wind overnight to bring favorable radiating conditions and a cooler start to Thursday morning. Outside of Metro Detroit and immediate lakeshore communities, guidance offers lows in the mid to upper 30s - supportive of some patchy frost, especially inland. The complicating factor to temps dropping further will be weak moisture flux off Lake Huron as northerly gradient flow stays active around the high pressure up north. This may bring in low stratus and/or fog, or at the very least slightly higher boundary layer moisture that would raise the floor for low temps. Low confidence exists in more than just patchy coverage of frost at this point, exhibited by HREF and REFS offering only 10 to 30% probability for lows below 35F for isolated locations.
The pattern aloft becomes increasingly amplified by Thursday as a deep cutoff low migrates across the high plains and another upper low digs south from Quebec. This leaves the Great Lakes within the strengthening ridge between, marked by stable and dry conditions Thursday into early Friday. The ridge axis passes overhead early Friday with a slug of mid-level moisture then riding in along an elevated warm front. This brings increasing cloud cover through the day and a chance of rain mainly across the north at first, then spreading south Friday night. Higher confidence exists for a period of wet weather Saturday into Sunday as the deep troughing to the west eases in, taking on a negative tilt over the region and bringing increasing likelihood for a dynamic low to track nearby. This brings relatively high confidence for some much needed rainfall and potential for gusty winds.
MARINE...
A cold front will move across the Great Lakes this morning which will maintain northeast flow through the early afternoon, with backing wind direction to the northwest by the evening hours. This has allowed wave heights to increase in the outer Saginaw Bay and Lake Huron shoreline, where Small Craft Advisories are in place. Lingering rain showers also remain possible through the morning with the frontal passage. High pressure will then quickly build in later today and hold through Thursday, which will decrease wind speeds and thus wave heights through the afternoon. Light winds and dry weather continues tomorrow.
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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.....DRK DISCUSSION...TF MARINE.......AM
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NWS DTX Office Area Forecast Discussion