638 FXUS63 KGRR 270745 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 345 AM EDT Mon Jul 27 2026 .KEY MESSAGES... - Waiting on the storms today - Next chance for rain end of the week && .DISCUSSION... Issued at 345 AM EDT Mon Jul 27 2026 - Waiting on the storms today As suspected, the convection in this northwest flow regime has vastly underperformed so far for Lower Michigan despite the hi res convective models insisting on bringing it in. So we wait to see when and if we get anything. Latest trends show an uptick in the storms across northern Minnesota, but that`s a long way off and the rain across Wisconsin is decreasing as it crosses Lake Michigan so we will continue to wait. If the storms do finally get here, hail and downburst winds will be the main threats. Whatever convection does reach us today should be pushing south this evening with some lingering showers possible after midnight as a surface low and trailing front clears the forecast area. Surface high builds in with fair weather for Tuesday and Wednesday. - Next chance for rain end of the week An upper level shortwave trough rounds the top of the western CONUS ridge and cuts off across the Great Lakes on Friday and Saturday with showers and thunderstorms possible for those two days. && .AVIATION /06Z TAFS THROUGH 06Z TUESDAY/... Issued at 158 AM EDT Mon Jul 27 2026 VFR conditions expected overnight then thunderstorms could bring brief IFR/MVFR conditions between 10 and 14Z from MKG to AZO. Not much confidence in timing and coverage of storms, so expect amendments as needed as storms approach. Another batch of storms expected late afternoon into the evening, with current forecast probabilities highest between 22Z and 02Z. These storms could have winds over 40 knots and hail. && .MARINE... Issued at 345 AM EDT Mon Jul 27 2026 Thunderstorms could bring heavy rain, hail and high winds today and this evening then north winds and waves will increase after midnight. A SCA/BHS has been issued from late tonight to Tuesday night as high pressure builds in. Conditions will improve on Wednesday under high pressure. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...Beach Hazards Statement from late tonight through late Tuesday night for MIZ037-043-050-056-064-071. MARINE...Small Craft Advisory from 4 AM Tuesday to 2 AM EDT Wednesday for LMZ844>849. && $$ DISCUSSION...Ostuno AVIATION...Ostuno MARINE...Ostuno

NWS GRR Office Area Forecast Discussion