


Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI
Issued by NWS Detroit/Pontiac, MI
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713 FXUS63 KDTX 270402 AFDDTX Area Forecast Discussion National Weather Service Detroit/Pontiac MI 1202 AM EDT Fri Jun 27 2025 .KEY MESSAGES... - Yet another round of thunderstorms is likely Friday as a cold front moves through Lower Michigan. There is a Marginal Risk of severe intensity during the afternoon and evening. - High temperatures increase back to the upper 80s to 90 degrees Friday and Sunday after a brief cool down Saturday. && .AVIATION... There remains a low potential for convective development overnight, mainly across FNT/MBS, as ongoing activity across both southwest lower MI and WI spill northeastward with time. Otherwise, moist low level environment will again offer a higher probability for lower stratus develop, featuring a cloud base ranging from lower VFR to MVFR. Confidence in occurrence remains higher from PTK northward. Inbound cold front will provide the focus for potential shower and thunderstorm development during peak heating. Southwest wind gusts ahead of the front reaching the 20-25 knot range in the afternoon, in addition to the stronger/gustier winds in any thunderstorm. For DTW/D21 Convection... Thunderstorm potential between 18z and 22z Friday. THRESHOLD PROBABILITIES... * Low for thunderstorms Friday afternoon. * Moderate in ceilings aob 5000 feet late tonight and again Friday afternoon. && .PREV DISCUSSION... Issued at 417 PM EDT Thu Jun 26 2025 DISCUSSION... An interesting progression of thunderstorm development from this morning continues to unfold across the area this afternoon and evening. Broad scale support for nocturnal/elevated convection late last night resulted in storms grazing the Tri Cities and Thumb around sunrise this morning. The larger scale support, mainly near the entrance region upper jet circulation, helped the 850-700 mb theta-e ridge percolate over southern Lower Mi all morning until becoming surface based toward noon. A messy multicell convective mode dominated since then and which has migrated south of the Ohio border after forecast issuance. Lingering severe potential, for mainly damaging wind and heavy rainfall, has shifted farther north to the hybrid marine layer/surface front. This has released new storms where MLCAPE projections show a 2000 J/kg instability axis through early evening. In all cases, precip loaded damaging wind gusts are the primary severe hazard followed by heavy rainfall. Hail is a distant third given the deep moisture profile and low CAPE density in the mid levels. The ongoing storms across Lower Mi are expected to dissipate with the loss of heating tonight, in time to look toward the Midwest where another low pressure system is interacting with the resident surface front across the Great Lakes. Surface based storms out there are also expected to diminish/dissipate on the downward side of the heating cycle followed by a new transition to low level jet forced convection tonight. The surface low moves into NW WI while pulling the front back north into northern Lower Mi late tonight and Friday morning. This presents a dry warm sector scenario for SE Mi and a more favored nocturnal MCS track north of the Tri Cities late tonight into Friday morning. Yet another round of thunderstorms is likely for SE Mi Friday afternoon as the WI surface low continues into northern Ontario while dragging a cold front across Lower Mi. The solid warm sector in place over the area is HREF projected to build SBCAPE up to around 2000 J/kg ahead of the front. Bulk shear is also advertised to be on the low side, however a deeper dive into model soundings indicates unidirectional mid level flow around 35 knots with some dry air around the 500 mb level. The big CAPE helps with the lower end wind field for storms evolving into line segments along the front with damaging wind potential the primary hazard, as good or better than SPC`s Marginal Day 2 outlook for our area into Friday evening. The Friday cold front ushers weak high pressure into the area for Saturday, slightly cooler and a little less humid. This reverses Sunday as the next low pressure system moves into the Great Lakes and brings highs back up near 90. The front associated with this system leads to a larger scale pattern shift resulting in at least lower humidity with greater staying power next week. MARINE... Marine conditions remain unsettled in terms of thunderstorms this afternoon through Friday while wind and waves are otherwise subdued outside of the storms during this time. The current center of low pressure in the Midwest moves eastward along a frontal zone that has been wavering across Lake Huron and Lower Michigan over the last couple days. The low moves across the Straits Friday and pulls a weak cold front southward through Lower Michigan and into the Ohio valley Friday night. Light wind and favorable weather follow with weak high pressure Saturday followed by another low pressure system entering the northern Great Lakes during Sunday through Sunday night. This system brings a stronger cold front into Lake Huron and Lower Michigan to start next week. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...None. Lake Huron...None. Lake St Clair...None. Michigan waters of Lake Erie...None. && $$ AVIATION.....MR DISCUSSION...BT MARINE.......BT You can obtain your latest National Weather Service forecasts online at www.weather.gov/detroit.