


Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI
Issued by NWS Detroit/Pontiac, MI
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939 FXUS63 KDTX 132348 AFDDTX Area Forecast Discussion National Weather Service Detroit/Pontiac MI 748 PM EDT Sun Jul 13 2025 .KEY MESSAGES... - After a dry early week period, showers and thunderstorms return Wednesday through Thursday. - An uptick in heat and humidity occurs Tuesday as high temperatures reach around 90 Tuesday afternoon. && .AVIATION... Mostly VFR conditions expected throughout this TAF period. Light winds out of the west will continue through the night with BKN high clouds streaming northward associated with a system across the Ohio Valley. The sky will be clear of clouds late tonight and and through much of tomorrow. Pockets of hazy skies from Canadian wildfire smoke will remain over the area into tomorrow, especially to the north. Will carry VFR VSBY to highlight this with potential for occasional MVFR VSBYs. For DTW/D21 Convection...No thunderstorms expected this TAF period. THRESHOLD PROBABILITIES... * None. && .PREV DISCUSSION... Issued at 240 PM EDT Sun Jul 13 2025 DISCUSSION... Last vestiges of moisture axis/cold front roughly along ADG-PHN line still just enough to touch off isolated showers with weak low level convergence around. Dry mid levels will tend to inhibit development and should prevent EQL from reaching -20 C isotherm as MLcapes are hovering around 500 J/kg, higher on Canadian side. Surface dew pts started the day around 70 degrees but in the process of slowly mixing down as dry air over Western Great Lakes (see 12z GRB sounding) moves east over southern Lower Michigan tonight into Monday. Modest 500 MB height rises into Tuesday (591 DAM) with deep moisture then ramping up/returning for mid week period, as PW Values push to 2 inches on Wednesday. A couple of waves of moisture/disturbances moving through Tuesday night-Friday morning time-frame will support a few rounds of showers and thunderstorms. Euro ensembles now indicating 24 hr QPF probability of half an inch or more around 40 percent. Bulk of stronger westerlies/0-6 KM bulk shear looks to be over the northern Great Lakes during the mid weak period, thus prospects for any severe storms looks low, but there is some indications MLcapes exceeding 1500 J/kg which would put isolated severe into play with the average mid level lapse rates. Regardless, those decent capes will be conducive to localized heavy rainfall within the moisture rich environment. MARINE... A stray shower or rumble of thunder is possible this afternoon and evening near Lake St Clair, western Lake Erie, and far southern Lake Huron. Otherwise, dry conditions and light winds prevail today and through the early week period as high pressure builds over the Great Lakes. The next chance for showers and thunderstorms will enter Wednesday and Thursday as a prefrontal trough and cold front move across Michigan. This will bring the potential for some localized stronger wind gusts with any thunderstorm activity. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...None. Lake Huron...None. Lake St Clair...None. Michigan waters of Lake Erie...None. && $$ AVIATION.....AA DISCUSSION...SF MARINE.......AM You can obtain your latest National Weather Service forecasts online at www.weather.gov/detroit.