385 FXUS63 KGRR 241044 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 644 AM EDT Thu Sep 24 2026 .KEY MESSAGES... - Dry through Tuesday - Chances for rain mid next week (Tues night through Wed Night) - Slightly above normal temperatures through the 7 day forecast && .DISCUSSION... Issued at 328 AM EDT Thu Sep 24 2026 - Dry through Tuesday High confidence in dry fall weather today through Tuesday. BUFKIT overviews show little in the way of moisture through the depth of the atmosphere through next Tuesday. Ensemble data from both the GFS and ECWMF show no members with any precipitation into next Tuesday, so 80 members indicating dry. That is an emphatic statement that dry weather will continue into early next week. - Chances for rain mid next week (Tues night through Wed Night) Major model discrepancies arise mid next week when looking at the GFS and the ECWMF. The GFS is bringing a deep fall low (989mb) right through the western Great Lakes during the Tuesday and Wednesday time frame, whereas the ECMWF has some weak surface troughing (1012-1014mb). Interestingly, both bring locally heavy precipitation to the area during this time frame. With the GFS the rain is driven by the deep low and a strong cold front. In the ECMWF the rain is driven by overrunning of a warm front. Low confidence to say the least out at this range in the forecast, but we will continue to monitor trends to see if we can get better agreement. - Slightly above normal temperatures through the 7 day forecast Normal highs for this time of year are in the upper 60s for the most part. MOS guidance and 850 temperatures around +10C indicate that we will likely be a bit above normal for highs in the lower 70s. Lows will dip into the 40s into next Monday. && .AVIATION /12Z TAFS THROUGH 12Z FRIDAY/... Issued at 644 AM EDT Thu Sep 24 2026 High confidence in VFR weather the next 24 hours. High pressure will bring mainly clear skies and fair weather today. Some FEW-SCT clouds around 5,000 feet are expected today with some cirrus moving in tonight with BKN bases around 20,000ft. Winds will be from the east today at 5-15 knots. && .MARINE... Issued at 328 AM EDT Thu Sep 24 2026 Surface high pressure will remain entrenched across the Great Lakes region through the remainder of the work week, the weekend and into early next week. High confidence in lighter winds and limited waves through that time frame. Waves are expected to be less than 2 feet into at least Monday. The next chance for higher winds and waves does not come until Tuesday and especially Tuesday night next week. That said, the system potentially bringing us wind during that time frame, in the GFS, is not handled the same in the ECMWF. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ DISCUSSION...Duke AVIATION...Duke MARINE...Duke

NWS GRR Office Area Forecast Discussion