442 FXUS63 KGRR 070511 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 111 AM EDT Mon Sep 7 2026 .KEY MESSAGES... - Chances for Rain late Tuesday into Wednesday and again next weekend && .DISCUSSION... Issued at 232 PM EDT Sun Sep 6 2026 - Chances for Rain late Tuesday into Wednesday and again next weekend Fair weather continues through Labor Day into most of Tuesday. There could be some shallow fog late tonight into early Monday morning as light winds and clear skies result in radiational cooling. Lows will drop into the upper 40s and lower 50s by daybreak across much of the forecast area. An Omega block across the CONUS breaks down early this week as a low across the Pacific NW kicks east and flattens the upper high, with surface low pressure tracking across southern Canada. Return flow of moisture and a surface cold front should kick off some showers and thunderstorms late Tuesday into Wednesday. Shear profiles suggest organized convection is possible if instability is sufficient Tuesday evening ahead of the front. A zonal flow pattern across the northern CONUS should allow a quick progression of a shortwave trough from the Pacific NW into the upper Great Lakes by next weekend with increasing chances for showers and thunderstorms late Friday into Sunday. && .AVIATION /06Z TAFS THROUGH 06Z TUESDAY/... Issued at 109 AM EDT Mon Sep 7 2026 Latest IR loop shows abundant cirrus spilling over the ridge in place across the Great Lakes. We`ll see those high clouds throughout the TAF period. It`s possible some shallow fog develops around sunrise at LAN/JXN this morning, but confidence wasn`t high enough to include in the TAFs. && .MARINE... Issued at 232 PM EDT Sun Sep 6 2026 Light offshore winds, generally less than 15 knots, can be expected through Labor Day under high pressure. Winds will increase on Tuesday as the high moves east A Small Craft Advisory will be needed for Tuesday afternoon through Wednesday night. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ DISCUSSION...Ostuno AVIATION...04 MARINE...Ostuno

NWS GRR Office Area Forecast Discussion