446 FXUS63 KGRR 230533 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 133 AM EDT Wed Sep 23 2026 .KEY MESSAGES... - Showers possible through far southern Michigan tomorrow - Fair, dry with warming weather into next week && .DISCUSSION... Issued at 255 PM EDT Tue Sep 22 2026 - Showers possible through far southern Michigan tomorrow Michigan currently is at an impasse between two systems. A low, cycling along the Iowa, Illinois and Wisconsin borders is bringing southerly moisture northward into lower michigan. A large upper level high remains entrenched over Ontario and Quebec. Michigan lies in between these systems. The pressure gradient along their boundary is creating gusty surface winds out of the east. Expect these winds to continue through the evening, dampening briefly overnight, before strengthening again tomorrow. The upper level high pressure will shift eastward as a ridge of high pressure builds front the south. This will drive the previously mentioned low to the south east. As it moves east there is a slight chance that some of the precip bands on the periphery will infiltrate Michigan with a slight chance of bringing light rain to the southern tier or two of Michigan tomorrow afternoon. Latest models continue to shift the low southward, so these precip chances continue to dwindle. - Fair, dry with warming weather into next week The models are in fair agreement through the mid to long range. The ridge building from the south should become a full fledged rex block high late this week, into the weekend. The low will continue to advect eastward and given the latest trends is tracking to close off as it begins its trek up the northeastern seaboard. The high pressure will simultaneous keep this low from retrograding, and stop an upper level wave from intruding into the Great Lakes region. The below normal temperatures will slowly warm through the weekend, with above normal temperatures, peaking into the low 70s, are trending into next week. && .AVIATION /06Z TAFS THROUGH 06Z THURSDAY/... Issued at 133 AM EDT Wed Sep 23 2026 We are starting off this forecast period with a broken stratocumulus deck at around 3500-4000 ft along the I-94 terminals, while the I-96 corridor has only sct-bkn 20k ft clouds. This should hold stable most of the night without much change. We will see them advance a little north during the daylight hours, bringing the bkn040 deck into KGRR and KLAN. We are likely to see some MVFR conditions along the I-94 corridor with ceilings expected to drop to around 2500 ft for a few hours. Winds will become gusty a bit one last day to around 20-25 knots. These lower clouds should all rotate out of the area by 00z Thu, and we could even see skies go mostly clear at all of the terminals. The ENE winds will hold up again one last night around 5-10 knots. && .MARINE... Issued at 254 PM EDT Tue Sep 22 2026 Strong offshore winds will continue the the evening hours. waves remain calm and should continue through Thursday, before winds settle down a bit. The offshore component should keep the winds just below criteria. High pressure will build over the region late this week and through the weekend which will create lighter winds by Friday. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ DISCUSSION...Ceru AVIATION...NJJ MARINE...Ceru

NWS GRR Office Area Forecast Discussion