469 FXUS63 KGRR 210556 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 156 AM EDT Sun Jun 21 2026 .KEY MESSAGES... - Rain Chances Tonight and Wednesday && .DISCUSSION... Issued at 155 AM EDT Sun Jun 21 2026 - Rain Chances Tonight and Wednesday The Great Lakes region will continue to be in a fast quasi-zonal flow regime on the southern edge of persistent upper troughing across eastern Canada this week. This will keep temperatures below normal with fast-moving shortwave troughs bringing the chance for rain tonight and again on Wednesday. The best chance for rain tonight will be across southern Lower Michigan as low pressure tracks across northern Indiana and Ohio. An area of mid-level frontogenetic forcing brings steady rain across the I-94 corridor with QPF close to an inch by the time the rain ends on Monday. There will be a sharp gradient to the north with around a quarter inch along I-96 and less than a tenth of an inch north of there. A weaker low follows for Wednesday in northwest flow and precip amounts will probably be less than a quarter inch. && .AVIATION /06Z TAFS THROUGH 06Z MONDAY/... Issued at 156 AM EDT Sun Jun 21 2026 Except for the possibility of shallow ground fog before sunrise, VFR conditions are expected this morning before clouds and rain move in from the southwest this evening. MVFR conditions in showers and lowering ceilings are expected this evening and patchy IFR is possible, especially across southern Lower Michigan. && .MARINE... Issued at 156 AM EDT Sun Jun 21 2026 Fairly tranquil conditions today then winds and waves will increase tonight as low pressure passes just south of Lake Michigan. A SCA will be needed for Monday. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ DISCUSSION... AVIATION...Ostuno MARINE...Ostuno

NWS GRR Office Area Forecast Discussion