


Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI
Issued by NWS Detroit/Pontiac, MI
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335 FXUS63 KDTX 061726 AFDDTX Area Forecast Discussion National Weather Service Detroit/Pontiac MI 126 PM EDT Sun Jul 6 2025 .KEY MESSAGES... - Hot and muggy conditions persist today. - Showers and thunderstorms move in from the northwest today with potential for torrential rainfall and isolated marginally severe wind gusts during the afternoon and evening hours. - Drier, a bit cooler, and less humid with time Monday and Tuesday. - Shower and storm potential return mid-late week. && .AVIATION... Breezy southwest winds prevail ahead of a cold front progged to slowly drop south across the area late tonight and into Monday morning. Wind gusts at YIP/DTW/DET have been overachieving, given the ample sunshine during the late morning/early afternoon hours. Showers and storms have developed across portions of central and western Michigan early this afternoon. These storms are expected to move east-northeast across the area with additional development into the evening hours. The environment is favorable for clusters of storms with water loaded updrafts capable of producing stronger outflow winds and heavy rain. Cannot rule out a microbursts or two as well, especially if we get any stronger, elevated thunderstorm cores. Convection will wane in intensity and coverage around/after 02Z this evening. The above mentioned cold front is progged drop through the Tri-Cities and Thumb region between 00-02Z. With the front being slow to clear the area tonight and into Monday morning, there will be a linger chance for showers and a few isolated storms overnight. The front moves into the MBS area between 00-02Z this evening, helping spread northerly winds and MVFR to IFR stratus into the area. FNT/PTK will see a similar wind shift and arrival of low stratus between 03-06Z, and DTW/DET/YIP between 07-09Z. Northerly winds will prevail behind the front. IFR stratus will gradually lift into the MVFR category through late morning Monday as daytime heating and mixing increase, then ceilings are expected to gradually scatter out by early Monday afternoon. For DTW/D21 Convection...Widely scattered convection is expected this afternoon and evening, with the peak window for impacts across the airspace between roughly 20Z and 02Z. For DTW, as showers/storms move in from the west the main window of concern is 22Z and 02Z. Isolated microbursts and gusty thunderstorm outflow winds will be possible this evening with any stronger, more organized clusters of storms. Lingering low probability for thunderstorms overnight between 08-12Z, followed by a cold front passage and switch to north winds. THRESHOLD PROBABILITIES... * Medium for thunderstorms between 22Z and 02Z this evening, the low overnight and into early Monday morning. * High for ceiling below 5000 ft between 06Z and 18Z Monday. && .PREV DISCUSSION... Issued at 304 AM EDT Sun Jul 6 2025 DISCUSSION... Prototypical early July heat and humidity entrenched locally early this morning, fortified by light southerly flow beneath lingering lower amplitude ridging. General stability likely to hold through the morning period as daytime heating gains traction, with attention focused on an inbound elongated mid level trough and associated weak cold frontal boundary. Notable increase in both forced ascent and moisture quality as these features arrive from northwest to southeast coincident with peak heating. This will serve as the focus for a scattered to numerous coverage of showers and thunderstorms to emerge during the afternoon and evening hours. Prospective mlcape peaking in excess of 1500 J/kg supportive of some healthier updrafts. Rather muted deep layer wind field inherent within this summer pattern will offer some limitation to potential convective organization overall, but an isolated damaging wind gust threat will exist as the elevated PW content encourages greater precipitation loading and wet microbursts within any deeper updrafts. Slow storm motion also brings potential for localized regions of torrential rainfall. Peak afternoon temps ranging from mid 80s north to around 90 degrees south. Gradual decline in convective potential with time tonight, although lower end chances remain as the slow moving front continues to engage a moist and weakly unstable profile. These conditions persist into Monday morning before the front clears the region to the south. Increasing influence of high pressure centered to the north for the latter half of Monday. After any lingering early day showers exit, looking at notably less humid conditions with a modest reduction in temperature with this post-frontal airmass change. This lends to highs ranging from mid 70s to lower 80s. Maintenance of deep layer stability held within existing surface ridging and generally zonal mid level flow means benign conditions with standard airmass modification Tuesday. Dry with seasonable temperatures overall this period. Another lower amplitude mid level wave likely to induce modest height falls as it traverses the great lakes within the Wed-Thu window. Defined sources of upward vertical motion relative to the diurnal heating cycle remain ill-defined at stage. However, some degree of troughiness even absent of more meaningful forced ascent will establish a background environment supportive of convective potential with a focus on the typical peak heating period. Outgoing forecast continues to highlight a broader precip mention across this entire period as offered by NBM output at this stage. Conditions otherwise marked as seasonable by July standards through the latter half of the week. MARINE... Low pressure will continue to move across the northern Lakes today. The strengthening southwest winds are expected to continue through about mid morning with the strongest gusts, around 20kts, occuring over the central portions of Lake Huron. Due to shoreline effects, the Saginaw Bay continues to have the potential to reach/exceed 25kts through mid morning today with waves approaching 3-4ft. The Small Craft Advisory will expire at 10 a.m. and expect that to work well as winds decrease around that time. A cold front sagging south from the aforementioned low gradually crosses Lower MI today. In advance, scattered to numerous showers and storms are expected. Severe storms not generally expected however an isolated strong storm can`t be ruled out. Behind the front, mainly for Sunday night and Monday, northerly winds may increase a bit for the Saginaw Bay and southern Lake Huron basin with some gusts to 20kts. A few showers/storms look to linger into Monday for the southern Great Lakes as the front is slow to fully vacate. High pressure then briefly follows late Monday through Tuesday before unsettled weather returns midweek. HYDROLOGY... Scattered to numerous thunderstorms are forecast this afternoon and evening amidst hot and humid conditions. Thunderstorms will move rather slowly and be capable of producing torrential downpours. Localized areas may experience over an inch of rainfall in less than an hour which may lead to flooding of urban areas, small streams, and otherwise poorly drained areas. The main threat for flooding will be between 3 PM and 9 PM, until the supporting cold front exits toward the southeast. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...None. Lake Huron...None. Lake St Clair...None. Michigan waters of Lake Erie...None. && $$ AVIATION.....JA DISCUSSION...MR MARINE.......MR HYDROLOGY....KGK You can obtain your latest National Weather Service forecasts online at www.weather.gov/detroit.