957 FXUS63 KGRR 291917 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 317 PM EDT Thu Oct 29 2026 .KEY MESSAGES... - Scattered Showers and Isolated Storms along and south I 94 today - Decreasing chances for rain for this weekend - Change in Pattern with chances for rain next week && .DISCUSSION... Issued at 235 PM EDT Thu Oct 29 2026 - Scattered Showers and Isolated Storms along and south I 94 today The stalled frontal boundary remains draped across southern Lower Michigan. Latest mesoanalysis shows 30kts of shear through the lowest row of counties in MI. While there is very little SFC based CAPE, there is enough instability aloft that coupled with the boundary and the shear to allow for storms to develop along the cold front. These storms are not expected to become severe but given the time of year and the height of the -10C, small hail is possible. The main area of concern is along and south of the I 94 corridor. Expect scattered showers and isolated storms moving from west to east through the afternoon hours before the cold front moves eastward early this evening. Temperatures will drop behind the front with Min T`s dropping below freezing tonight along the US 10 corridor. Elsewhere Mix temperatures will be in the mid to upper 30s. - Decreasing chances for rain for this weekend Models are becoming in good agreement for the upcoming system. High pressure at the surface through the mid levels will dominate the pattern through the eastern half of the US. That high will stymie the approaching upper level perturbation making its way through the Great Plains. The overall pattern has a negatively tilted ridge that will extend through the upper mid west into Canada this weekend, along with an upper level short wave that will move through the Great Lakes this weekend. That perturbation will move through Saturday into Sunday but most mid range guidance has the best moisture bifurcating Southern Lower Michigan. That said, there remains a chance that scattered light rain showers are possible Saturday, mainly through the southwest. The better instability with that upper level trough could arrive late Sunday into Monday. NAEFS ensembles has a broad area of slightly anomalous PWATS moving over Lower Michigan late Sunday into Monday. The best moisture is to the southeast, however a negatively tilted mid level shortwave could bring enough instability for showers and perhaps a storm Sunday night into Monday morning. - Change in Pattern with chances for rain next week The pattern is coming into a bit of focus through the first half of next week. As we know, the models do better with high pressure, and as there is a stronger ridge Monday and tuesday, that is allowing for more consistency in the trends. That said, Monday is looking drier, with converging lows moving through the region on Tuesday. The best moisture remain north of southern Lower but scatter showers are possible early Tuesday from warm air advection out ahead of an approaching system. From then on out the ensembles and resulting guidance diverge on any coherent solution. There remains the potential for a frontal pattern with the chance for showers and storms moving through the Great Lakes, Wednesday and Thursday. Temperatures will remain above normal through the period with highs in the mid to upper 60s. && .AVIATION /18Z TAFS THROUGH 18Z FRIDAY/... Issued at 141 PM EDT Thu Oct 29 2026 A cold front is presently crossing the terminals with MVFR cigs, sub-fuel alternate at times, accompanying it. Included is widely scattered showers, with a thunderstorm expected to travel in the vicinity of AZO/BTL over the next 30-45 minutes. After the front skies clear out with mostly clear skies overnight into Friday. Winds gust to around 20 knots this afternoon before diminishing this evening. Winds will start from the west shifting to northwesterly. && .MARINE... Issued at 257 PM EDT Thu Oct 29 2026 Westerly flow is weakening but it is strong enough and winds will be 10 to 20 kts with gusts upwards of 25 through the rest of the afternoon into the early evening. Expect waves north of South Haven and south of Pentwater to be in SCY criteria through the first half of tonight. Winds and waves will then subside overnight and are expected to remain below Advisory conditions Friday into next week. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...Small Craft Advisory until 2 AM EDT Friday for LMZ845>848. && $$ DISCUSSION...Ceru AVIATION...Thomas MARINE...Ceru

NWS GRR Office Area Forecast Discussion