662 FXUS63 KGRR 111045 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 645 AM EDT Sat Apr 11 2026 .KEY MESSAGES... - Excessive rainfall potential next week && .DISCUSSION... Issued at 156 AM EDT Sat Apr 11 2026 - Excessive rainfall potential next 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 last week that brought flooding and could also result in severe weather at times. The first batch of rain moves in late tonight with an area of warm advection/isentropic ascent. Expect some elevated convection persisting into Sunday morning along and north of a warm front. Surface-based instability is limited until the front pushes north on Sunday afternoon. Another round of rain and embedded thunderstorms then follows for Sunday night 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 pattern could continue even beyond that as both the GFS and ECMWF depict a significant low arriving by next Saturday. && .AVIATION /12Z TAFS THROUGH 12Z SUNDAY/... Issued at 645 AM EDT Sat Apr 11 2026 VFR conditions through this evening with light winds early this morning going southeast AOB 10 kts later today. && .MARINE... Issued at 156 AM EDT Sat Apr 11 2026 After a lull in the winds and waves today and tonight there will be a chance for south gales late Sunday into Sunday night. Winds and waves will remain hazardous to small craft through at least Wednesday. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ DISCUSSION...Ostuno AVIATION...Ostuno MARINE...Ostuno

NWS GRR Office Area Forecast Discussion