


Area Forecast Discussion
Issued by NWS Grand Rapids, MI
Issued by NWS Grand Rapids, MI
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693 FXUS63 KGRR 120743 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 343 AM EDT Sat Jul 12 2025 .KEY MESSAGES... - Severe Weather chances this Afternoon - Showers and Thunderstorms return mid-week && .DISCUSSION... Issued at 343 AM EDT Sat Jul 12 2025 - Severe Weather chances this Afternoon Shortwave trough axis goes negative tilt as it swings through today with conditional severe threat across the eastern zones this afternoon. Main threat will be isolated downbursts with deep layer shear once again a limiting factor for persistent, organized convection, despite 1500-2000 J/kg CAPE across the area from LAN to JXN. Severe threat winds down in the late afternoon and early evening as storms shift east. - Showers and Thunderstorms return mid-week Zonal flow with weak sfc ridging brings fair weather for Sunday through Tuesday then rain chances returns for mid-week with the approach of a weak shortwave trough. Showers and storms become more widespread on Thursday as a cold front moves through. Severe weather threat also increases as forecast deep layer shear is progged to be over 30 knots along with sufficient instability for organized storms. && .AVIATION /06Z TAFS THROUGH 06Z SUNDAY/... Issued at 130 AM EDT Sat Jul 12 2025 Scattered thunderstorms and MVFR conditions will be across Lake Michigan and near MKG through about 08Z but chances of thunder in other areas of western Lower Michigan are low overnight. Some light fog could also bring patchy MVFR conditions through sunrise. Showers and thunderstorms are expected to flare up Saturday afternoon over roughly the eastern half of Lower Michigan with some isolated IFR conditions in heavy rain along with winds gusting over 30 knots and small hall in stronger storms. && .MARINE... Issued at 343 AM EDT Sat Jul 12 2025 Scattered thunderstorms today could bring wind gusts over 30 knots otherwise winds should be below 25 knots through the weekend and into early next week. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ DISCUSSION...Ostuno AVIATION...Ostuno MARINE...Ostuno