


Area Forecast Discussion
Issued by NWS Grand Rapids, MI
Issued by NWS Grand Rapids, MI
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417 FXUS63 KGRR 121806 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 206 PM 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 /18Z TAFS THROUGH 18Z SUNDAY/... Issued at 204 PM EDT Sat Jul 12 2025 Have removed any mention of storms from the TAF`s as the frontal boundary has moved to the east. There is still a small chance some showers and storms form later this evening but it should be north of all the TAF sites. Only MKG has any chance and that would mainly been MVFR from showers. Otherwise VFR will dominate the forecast with gusty winds decreasing early this evening and becoming calm after sunset. && .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...Air Quality Alert from midnight tonight to noon EDT Monday for MIZ037>040-043>046-050>052-056>059-064>067-071>074. MARINE...None. && $$ DISCUSSION...Ostuno AVIATION...Ceru MARINE...Ostuno