822 FXUS63 KGRR 121930 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 330 PM EDT Fri Jun 12 2026 .KEY MESSAGES... - Dry weather continues through the first half of tomorrow - Showers and storms possible late Saturday with fold front - Cooler and drier weather through early next week && .DISCUSSION... Issued at 240 PM EDT Fri Jun 12 2026 - Dry weather continues through the first half of tomorrow The reprieve from any showers and storms will be short lived. A large upper level low will continues is trek through central way through Canada tomorrow. A short wave trough and a corresponding low will move along the southern gradient of that system. Models are in fair agreement on the track of this system. Near normal temperatures will continue with fair weather tonight and through most of Saturday. - Showers and storms possible late Saturday with fold front The above mentioned upper level low will sweep a cold front through the region Saturday evening. Latest timing continues to delay frontal passage. First round of CAMS has convection reaching the shores of Michigan tomorrow evening. The best moisture are instability remains in the Great Plains, However there is a mid level short wave with a weak low level jet that could aid in storm development along the frontal boundary. With The daytime temps 5 to 10 degrees above normal, in the 80s, and dewpoints in the 60s the airmass will aid convection development. Due to those considerations, SPC has included much of Lower Michigan in a marginal risk tomorrow evening. This system so far looks weaker and does not contain the forcing as last night`s. Latest models actually has the wave elongate as it moves eastward and deepen as it advects into the Mid Atlantic. So expect another round of showers and storms tomorrow evening, especially along the I 94 corridor. - Cooler and drier weather through first half of the week Downsloping flow in the wake of the cold front will bring 850 temps of +4C overhead Sunday. This will drop highs 5 to 10 degrees below normal. So a return of cool spring greets us this week as we stand on the edge of summer. The week ahead should have daytime highs in the 70s with lows in the 50s which is around 5 degrees below normal. Next chance for rain is midweek from shortwave that should clip the Great Lakes. && .AVIATION /18Z TAFS THROUGH 18Z SATURDAY/... Issued at 240 PM EDT Fri Jun 12 2026 VFR conditions will continue through the TAF period. Gusty winds will slacken overnight as the inversion envelops the region. This inversion will break down with more gusty winds by 17Z on Saturday. The next concern for reducing cigs and vsbys will be Saturday evening around 00Z Sunday. && .MARINE... Issued at 240 PM EDT Fri Jun 12 2026 Waves continue to calm this evening. This will be short lived and the approaching front will bring strong southwesterly flow that will increase winds and waves early Saturday. There is a good chance for small craft conditions Saturday into Saturday night. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ DISCUSSION...Ceru AVIATION...Ceru MARINE...Duke/Ceru

NWS GRR Office Area Forecast Discussion