240 FXUS63 KGRR 050512 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 1212 AM EST Fri Dec 5 2025 .KEY MESSAGES... - Periods of light snow late Friday and again Sunday - Accumulating snow possible with systems mid to late week && .UPDATE... Issued at 951 PM EST Thu Dec 4 2025 While it will be a quiet overnight period there is the potential for record lows south of the I 96 corridor. Latest satellite shows clouds along the lake shore and through the north portion of the Lower Peninsula. However, clear skies, low dewpoints and winds that should be fairly light should allow for lows to drop near zero along and adjacent to the I-94 corridor. Clouds should move in from the west overnight, however those clouds are expected to infiltrate through the southern most portion of the lower peninsula. Forecast lows for tomorrow morning for Kalamazoo, Battle Creek and Holland are all at or below the record for December 5th. Grand Rapids and Muskegon would be within 5 degrees. For more information refer to the climate section below. && .DISCUSSION... Issued at 312 PM EST Thu Dec 4 2025 - Periods of light snow late Friday and again Sunday As noted previously, we are looking at a brief window of lake effect flurries by the lakeshore this afternoon thanks to a thin layer of convective cloudiness in the DGZ. Surface observations and satellite indicate a land breeze induced convergence band that is slowly pushing offshore between Little Sable Point and Holland, which will similarly displace the area of flurries offshore. No changes in expectations regarding the next system beginning later Friday and Friday night. The 04/12Z HRRR looks scary in terms of forecast reflectivity during this time, especially over Lake MI, but this is likely related to the HRRR`s Thompson microphysics scheme that has a penchant for creating water-coated crystals. This yields large simulated reflectivity, but not necessarily large precipitation rates. Best accumulations still look to be over the northwest forecast area. Lake Michigan, being substantially warmer than the surrounding coastal areas, will be able to induce a thermal pressure trough that could enhance convergence along the eastern lakeshore, but even with this in play, we are dealing with limited moisture, sub-optimal crystal growth, and therefore modest accumulations. Farther south, along and south of Grand Rapids, there is a signal for brief freezing drizzle Friday night towards midnight that, from a time of day/week perspective, may pose limited risks, but could still be sneaky in terms of causing slippery travel on overpasses and other exposed areas. Our next accumulating snow episode arrives Sunday morning. This will be associated with somewhat more phasing between the northern and southern streams. However, it appears that the best PV forcing manages to bifurcate our area, meaning limited snowfall accumulations for much of southwest Lower MI, albeit a better chance for some snow along and south of I-96 compared to Friday night. - Accumulating snow possible with systems mid to late week As noted previously, we expect at least one potentially impactful system towards mid-week with a seasonably deep surface low expected to cross Lower MI around Wednesday. Any time a surface low is forecasted to cross directly over the forecast area, this often sets the stage for a potentially diverse and complex precipitation type forecast that is also highly susceptible to change based on the track of the surface low. This system is no exception and will be a chief focus for concern in the coming days. There is a signal for yet another shortwave trough and round of winter precipitation towards the end of the work week - but all we can really say now is that the latter half of the week looks to be unsettled with perhaps a favoring of more lake effect by the weekend. && .AVIATION /00Z TAFS THROUGH 00Z SATURDAY/... Issued at 1213 PM EST Thu Dec 4 2025 VFR conditions will continue through Friday afternoon. Light and variable winds continue to shift southwest overnight and increase to near 10 knots especially along the lakeshore. Wind gusts near Lake Michigan over 20 knots are possible beginning late tonight. Areas of LLWS are possible across parts of western Lower Michigan late tonight into Friday morning. Stronger wind shear will move Friday night into Saturday. Snow showers should move in between 03Z and 06Z Saturday with lower cigs and vsbys. Expect MVFR possibly IFR cigs after 03Z for GRR, MKG, AZO and BTL. Vsbys will lower in snow showers after 00Z for MKG with MVFR periods, possibly IFR. && .MARINE... Issued at 312 PM EST Thu Dec 4 2025 Have maintained the Gale warning and added a Small Craft Advisory for all remaining marine zones to the south that will last well into Saturday. It still looks like the Whitehall to Pentwater region immediately south of the Gale warning could see 2-3 hours of gale conditions tonight, but this is a pretty borderline situation and have therefore elected to leave things as is for now. && .CLIMATE... Issued at 724 PM EST Thu Dec 4 2025 Overnight Min Temp Forecast and Record Lows for December 5th Forecast(F) Record(F)(Year) Grand Rapids 7 4 (1964) Kalamazoo 1 9 (2002) Battle Creek 1 3 (1991) Lansing 5 -11 (1886) Holland 10 12 (1926,1931,1991) Muskegon 15 10 (1926) && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...Small Craft Advisory until 7 PM EST Saturday for LMZ844>848. Gale Warning until 10 AM EST Friday for LMZ849. && $$ UPDATE...Ceru DISCUSSION...TJT AVIATION...Ostuno/Ceru MARINE...TJT CLIMATE...Ceru

NWS GRR Office Area Forecast Discussion