FXUS63 KDTX 251321 AFDDTX Area Forecast Discussion National Weather Service Detroit/Pontiac MI 921 AM EDT Sat Oct 25 2025 .KEY MESSAGES... - Seasonally cool and dry weather this weekend into early next week. && .UPDATE... There remains fairly good consensus, supported by recent water vapor trends, in a rapid weakening of an inbound mid level short wave over Wisconsin. In fact, cross sectional analyses even shows some weak subsidence persisting in the mid level through the day. This is supportive of just some high clouds from this system being the main impact to Se Mi. There has been a persistent region of strato cu across the northern portions of the forecast area this morning. The 12Z DTX sounding indicated these clouds trapped under a deep inversion based near 5k feet. With weak flow and little thermal advection across the inversion expected across the thumb region today, it may prove difficult for a late October sun angle to mix these out. The morning forecast update will be issued to make some minor subtle adjustments to the cloud trends (a bit of an increase in the thumb) and corresponding forecast highs. && .PREV DISCUSSION... Issued at 649 AM EDT Sat Oct 25 2025 AVIATION... An area of surface high pressure slides northeast across the region today supporting VFR conditions. Clouds exist with varying heights and coverage as the day progresses, but bases are expected to hold at or above 4 kft AGL. Morning satellite imagery showing persistent stratocumulus cloud over most TAF sides gradually erodes toward the northeast. Some renewed cumulus development is likely through the daytime heating cycle before a disturbance aloft drops in from the upper Midwest bringing patches of denser mid and high cloud. Light winds, generally AOB 5 knots, veer easterly throughout the day until a subtle boundary settles across Lower Michigan. This yields a more northeasterly trajectory into Sunday morning which reinforces a rather dry airmass and favorable aviation conditions. For DTW/D21 Convection...No thunderstorm activity expected this TAF period. DTW THRESHOLD PROBABILITIES... * Low in ceilings at or below 5000 feet today. PREV DISCUSSION... Issued at 304 AM EDT Sat Oct 25 2025 DISCUSSION... Dry airmass is in place with sprawling high pressure over the Central Great Lakes this morning. An upstream upper level wave is tracking into the Western Great Lakes, which is dampening in the process. This is accompanied by the 500 MB shortwave trough axis swinging through southern Lower Michigan late today/this evening. Prospects for showers is very low, but can't entirely rule out light sprinkles with a narrow strip of mid level forcing/modest 850-700 MB Theta-E ribbon tracking along and south of M-59. With an increase in mid to high clouds today and limited mixing, not looking for maximum temperatures to be much warmer compared to yesterday. Subsidence kicks back in for Sunday as heights build, and an upper level ridge center lifts through the Western Great lakes and reaches James Bay late Monday (576 DAM at 500 MB). Southeast Michigan looks to remain under the influence of this ridge through Tuesday morning, but then there is a growing consensus regarding the upper level low/energy over New England. This will track to the west into the Central Great Lakes, becoming absorbed with the digging jet energy/trough over the Central Plains on Tuesday-Wednesday. As this system closes off at 500 MB, a dive to the southeast is expected into the Tennessee Valley before a turn to the northeast. Deformation axis may impact southeast Michigan on Thursday (see 00z ECMWF AIFS/Ukmet), while operational Euro/Canadian/Icon models are mostly glancing blows across far eastern Areas. Still too many upper level wave interactions to contend with this far out. MARINE... Surface high pressure builds as it slides east across the Great Lakes this weekend. A prolonged period of northwest flow comes to an end as winds begin to shift to the east today and tonight. As the high moves into Quebec early next week, the gradient once again tightens to increase east flow toward 10-20 knots sustained to start the work week. Elevated waves are expected as flow will be directly onshore for much of the local shoreline, which will likely require Small Craft Advisories early next week. The next chance for widespread precipitation holds off until mid-week. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...None. Lake Huron...None. Lake St Clair...None. Michigan waters of Lake Erie...None. && $$ UPDATE.......SC AVIATION.....KGK DISCUSSION...SF MARINE.......MV You can obtain your latest National Weather Service forecasts online at www.weather.gov/detroit.