911 FXUS63 KGRR 120553 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 153 AM EDT Sun Apr 12 2026 .KEY MESSAGES... - Excessive rainfall threat this week && .DISCUSSION... Issued at 151 AM EDT Sun Apr 12 2026 - Excessive rainfall threat this week Sunday through Thursday holds the potential for more flooding rains as Plains lows track into the Great Lakes. This is similar to the synoptic pattern that brought flooding earlier this month and could also result in severe weather at times. The first batch of rain is currently across Wisconsin associated with an area of warm advection/isentropic ascent. Expect some elevated convection persisting into this morning north of a warm front, across the northern half of the forecast area. Surface- based instability is limited until the front pushes north on Sunday afternoon. Another round of rain and embedded thunderstorms then follows for tonight along the front trailing the sfc low tracking into southern Canada. Model soundings show deep moisture and this is reflected in precipitable water of 1.5 inches. MBE vectors are less than 5 knots during this time indicating any persistent updrafts will result in flooding rains. There is only a short lull before a series of surface lows move along a baroclinic zone aligned from the Southern Plains to the central Great Lakes from Tuesday into Thursday. The wet pattern should continue even beyond that as all model guidance depict a significant low arriving by next Saturday. && .AVIATION /06Z TAFS THROUGH 06Z MONDAY/... Issued at 151 AM EDT Sun Apr 12 2026 Showers move through overnight but he steadier rain is expected to stay mostly north of central and southern Lower Michigan through the afternoon. MVFR conditions are possible overnight in rain showers near MKG and GRR. Rain spreads in from the east late Sunday afternoon and evening with MVFR and patchy IFR possible. LLWS can be expected overnight into Sunday evening. && .MARINE... Issued at 151 AM EDT Sun Apr 12 2026 No changes to the SCA, but it may need to be extended beyond Monday afternoon as southwest winds of 25 knots are forecast for Monday night and Tuesday. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...Small Craft Advisory until 4 PM EDT Monday for LMZ844>849. && $$ DISCUSSION...Ostuno AVIATION...Ostuno MARINE...Ostuno

NWS GRR Office Area Forecast Discussion