669 FXUS63 KGRR 072338 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 638 PM EST Wed Jan 7 2026 .KEY MESSAGES... - Unseasonable warmth and melting snow this week - Widespread rain Thursday Night and River Rises - Rain Changing to Snow on Saturday && .DISCUSSION... Issued at 304 PM EST Wed Jan 7 2026 - Unseasonable warmth and melting snow this week Our overall weather pattern across most of the country right now is actually fairly zonal, with a significant warm front nearly stationary south of the state of Michigan. This zonal pattern is starting to slowly amplify ahead of what will become a much more active weather pattern for the end of this week. With a weak subsidence inversion overhead, and lots of melting snow and moisture from recent rainfall stuck in the boundary layer, we`re in Day 2 of a very gloomy West Michigan weather pattern. While much of the fog dissipated after sunrise today, we stay vulnerable to areas of fog redeveloping through at least the first half of the night before boundary layer winds shift to southwesterly and start to increase in strength after midnight. This deepening southwest flow begins to develop in response to an amplification of the overall CONUS weather pattern. An upper disturbance currently in the base of the trough making landfall across the Baja Peninsula will sweep rapidly northeast tomorrow. As it does, a significant surface low will start to take shape on the east side of the Rockies and strengthen to near 994 mb over southern Wisconsin Thursday evening. As the wind fields respond to this strengthening low, the strong warm front to our south will roar into Lower Michigan tomorrow and stick around through Friday. High temperatures make a run at 50 degrees along/south of I-96 tomorrow and will probably be several degrees warmer on Friday (especially in the eastern areas). Meanwhile, moderate temperatures of the last few days have conditioned much of the remaining snowpack to melt quickly once temperatures jump into the 40s. By Friday afternoon, we`re expecting a complete loss of snowpack at most areas south of US-10, and up to half of the snowpack to melt north of US-10 up toward Cadillac. - Widespread rain Thursday Night and River Rises In addition to unseasonably warm temperatures, we are still on track for a widespread soaking rain for most of the area. A subtle trend has continued today among guidance for a slightly more northwesterly low track (which is consistent with a stronger system compared to a few days ago). This puts the heaviest rain north and west of us, but still produces about one-half inch of rain for most of our area - with slightly higher amounts near Ludington and slightly lower amounts near Jackson. A few hundred joules of CAPE also make their way into our southern counties Thursday night, so a rumble of thunder can`t be completely ruled out either. Combined with the snowmelt runoff, this should eventually get pretty good rises going on many of our rivers. Thankfully, we have enough room in the rivers right now such that significant flooding is not expected. However, any areas that do still have ice left on the rivers should monitor closely in case ice jams form, but we`re not currently expecting this to become a major issue. - Rain Changing to Snow on Saturday The forecast for this weekend remains a bit uncertain, as a wave moving north along the large baroclinic zone draped across the country merges with an approaching northern stream trough directly overhead the Great Lakes region. It`s likely we`ll get another round of relatively light precipitation on Saturday that starts as rain but changes to snow as cold air invades from the west. Accumulations look fairly tame, with 25th/75th percentile snowfall on the ECE on the order of 1-4 inches (at Grand Rapids). However, the timing of the cold air arrival and subsequent rain- to-snow transition will be key here, and if the cold air arrives sooner we could see snow totals move toward the higher end of that range. By Sunday, 850 mb temperatures will have dropped down to a more seasonable -11C which will begin to turn on the lake effect machine once again, potentially adding a few more inches along the lakeshore, but these details are still murky this far out. && .AVIATION /00Z TAFS THROUGH 00Z FRIDAY/... Issued at 637 PM EST Wed Jan 7 2026 Low clouds with ceilings in the range of 400 to 1200 feet AGL at the beginning of the forecast will start to break up this evening with conditions going from IFR to MVFR overnight. Expect VFR on Thursday morning into the afternoon then VFR returns as low clouds move back in from the southwest. LLWS is expected across western Lower Michigan tonight into Thursday. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ DISCUSSION...AMD AVIATION...Ostuno/Thomas

NWS GRR Office Area Forecast Discussion