


Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI
Issued by NWS Detroit/Pontiac, MI
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979 FXUS63 KDTX 121917 AFDDTX Area Forecast Discussion National Weather Service Detroit/Pontiac MI 317 PM EDT Sat Jul 12 2025 .KEY MESSAGES... - Temperatures in the mid 80s tomorrow, upper 80s Monday, then reaching around 90 degrees on Tuesday. - Dry start to the week, but showers and thunderstorms likely return Wednesday-Thursday. && .DISCUSSION... Broken line of strong to marginally severe thunderstorms went up on the prefrontal trough around noon, earlier and more extensive than many of the hires solutions. Dew pts dropping into the mid to upper 60s and surface ridging moving in late this afternoon has pretty much ended the severe threat, as mid level cold pool and much better wind shear over Western Great Lakes will not arrive in time before the sun sets. Still, the cold front may be able to muster a couple more showers and thunderstorms in the evening with some residual low instability left over. Upper level trough axis swings through tomorrow, but extremely dry mid levels (40-50 C dew pt depressions at 700 MB) look to prevent any activity from going up, except perhaps right near the southern Michigan border. Upper level ridge (591-592 DAM at 500 MB) axis then builds over the region early next, promoting dry but hot weather, with temps likely reaching 90 degrees on Tuesday. A wet pattern then looks to be setting up for Wednesday-Thursday as moisture streams up from Gulf Coast States/Southern Plains, in response to a fairly strong upper level wave/trough swinging through the northern Rockies and into the Western Great Lakes by Thursday. Euro ensembles indicating at least a 60 percent chance of a tenth or inch or more of qpf in Wednesday-Thursday time frame. && .MARINE... The thunderstorm threat has generally receded although some isolated development remains possible through the evening hours. Otherwise, dry conditions prevail in the wake of the ongoing cold front passage which brings light winds with gust potential holding below 20 knots. The next chance for showers and thunderstorms will arrive through the midweek period by Wednesday as an upper-level disturbance arrives over the Great Lakes. && .PREV DISCUSSION... Issued at 156 PM EDT Sat Jul 12 2025 AVIATION... Several gravity waves emanated away from the trough over the Midwest this morning initiated convection a few hours earlier than anticipated today. With the lead line exiting the area at press time, we look toward the next few hours for any additional convection. The next line has initiated over MBS and will now work eastward but confidence in how this line will act over the next few hours is low. Will hedge the tempo forward in time a few hours thinking that this next line may be the final chance this evening as drier air is spreading across SW Lower toward the area which will further lower chances. So, tempo TSRA through about 20-21Z with only isolated activity after that. The cold front will work through tonight possibly touching off a few showers, otherwise expecting a sct low VFR/MVFR deck tonight before skies improve Sunday. Gusty winds this afternoon will decrease and turn westerly tonight with the frontal passage. For DTW/D21 Convection...There remains a chance of thunderstorms this afternoon mainly before 21Z. Only isolated activity is expected this evening with mainly dry conditions tonight. Gusty winds will be the primary threat with any storm. THRESHOLD PROBABILITIES... * Low for ceiling 5000 ft or less outside of thunderstorms today and this evening. Moderate with the cold front late tonight. * Low for thunderstorms this afternoon. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...None. Lake Huron...Small Craft Advisory until 10 PM EDT this evening for LHZ421-422. Lake St Clair...None. Michigan waters of Lake Erie...None. && $$ DISCUSSION...SF MARINE.......AM AVIATION.....DRK You can obtain your latest National Weather Service forecasts online at www.weather.gov/detroit.