501 FXUS63 KGRR 291725 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 125 PM EDT Tue Sep 29 2026 .KEY MESSAGES... - One more sunny day - Showers, isolated thunder, Wed-Fri - Cooler weekend, frost/freeze potential && .DISCUSSION... Issued at 258 AM EDT Tue Sep 29 2026 - One more sunny day High pressure over Michigan will drift east today and that will help high clouds to the west to move overhead later this afternoon. Another mostly sunny day is anticipated, once the morning fog burns off by mid morning. While much of the fog this morning will be shallow in low lying areas and river valleys, some of may be dense in spots prior to burning off. normal high temperatures are around 70, but we`ll see highs in the mid to upper 70s today. - Showers, isolated thunder, Wed-Fri High confidence that we`ll see light to moderate rain Wednesday into Friday. GFS and ECMWF are and have been in pretty good agreement since last week in showing a cold front move east across southern Canada into Lower MI and then stall out, as a southern stream low develops in New Mexico and moves northeast. This low will not only draw Gulf moisture northward, it`ll also be entrained by moisture from the tropical system that moved across Baja CA. We anticipate this to be a slow moving system, because the frontal boundary will become more or less parallel to the upper flow and the frontal boundary over the cwa will act as a conduit for a lot of the moisture. Instability is pretty low which make thunder chance around 15 percent or so. Thus, we`re looking at mostly a light to occasionally moderate rainfall. QPF from Wednesday to Thursday is roughly 1-2 inches, highest over the western cwa. - Cooler weekend, frost/freeze potential The cold front will move through the cwa Friday, essentially ending the rainfall. H8 temperatures fall from 16c on Thursday to 6c by Saturday morning . That means the highs in the lower to mid 70s early in the week will be closer to 60 over the weekend. If skies can clear at all, we`ll be looking at lows in the mid 30s over the northern cwa Friday night and Saturday night and lower 30s along US-10 Monday night; frost and freeze headlines may be needed then. && .AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/... Issued at 125 PM EDT Tue Sep 29 2026 Expect VFR with a few afternoon cumulus clouds at 4,000 feet. VFR continues well into tonight, with higher altitude ceilings trending MVFR from northwest to southeast during the daytime Wednesday. Not expecting fog tonight given the clouds and winds below 1,000 feet. The winds at 1,000 feet should be about 200 degrees at 20 to 25 knots, between 04 and 14 Z, which would lead to there being about 20 knots of LLWS below 1,000 feet. Light to occasionally moderate rain will spread over much of Lower Michigan on Wednesday, affecting northwest sooner southeast later. && .MARINE... Issued at 258 AM EDT Tue Sep 29 2026 High pressure will begin move east today and south flow will increase tonight ahead of the next cold front. We`ve issued a small craft advisory and beach hazards statement north of Grand Haven for winds and waves valid from late this evening through Thursday morning. South winds will gust to 25 knots and waves will increase to 3-6 feet. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...Beach Hazards Statement from 10 PM EDT this evening through Thursday morning for MIZ037-043-050. MARINE...Small Craft Advisory from 10 PM this evening to 8 AM EDT Thursday for LMZ847>849. && $$ DISCUSSION...04 AVIATION...CAS MARINE...04

NWS GRR Office Area Forecast Discussion