168 FXUS63 KGRR 122316 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 616 PM EST Mon Jan 12 2026 .KEY MESSAGES... - Light Rain Tuesday Transitions To Snow Tuesday Night/Wednesday - Notably Colder Late Week With Periods of Lake Enhanced Snow && .DISCUSSION... Issued at 248 PM EST Mon Jan 12 2026 - Light Rain Tuesday Transitions To Snow Tuesday Night/Wednesday Satellite shows substantial clearing across the area this afternoon as the result of surface and upper level ridging crossing the area. This reprieve is brief as a mid-level wave approaches the area tonight. Warm air advection with 850 mb temps around 2C will keep precipitation as rain Tuesday morning, transitioning to drizzle in the afternoon as the DGZ becomes unsaturated. Given poor moisture depth/quality, am expecting meager precipitation totals across the area Tuesday. Northerly flow Tuesday night causes 850mb temps to fall into the negatives causing precipitation to mix with, and eventually transition over to, snow. Northerly flow behind the associated cold front will keep the best precipitation chances near the lakeshore early Wednesday - Notably Colder Late Week With Periods of Lake Enhanced Snow Early Wednesday marks the arrival of an arctic front with 850mb temps crashing well into the negative teens. Robust ridging across the western CONUS and deep troughing over the eastern CONUS will develop and persist into the weekend. A burst of snow along the initial arctic front is likely before the arrival of shortwave ridging late Wednesday into Thursday brings a lull in the snowfall. One thing we will have to watch is a trend in the last few runs of several deterministic models bringing the best convergence and associated snow a bit further east, which could bring a few inches of accumulation into western Mason/Oceana/Van Buren Cos. This is also reflected into the LREF constituent ensemble means. This is highly sensitive to wind direction so confidence is low, with chances of over 2 inches of snow 25-40% in western Mason/Oceana/Van Buren. While, as is normal at this range, the exact timing and placement of synoptic features is uncertain, there is a strong signal for several shortwaves to reinforce the cold air in the trough and send a few clippers through the area starting Friday. This is a very favorable pattern for lake effect snow given the robust cold pool and position in cyclonic flow. This will support lake effect snow chances Friday into early next week. The progression of the aforementioned clippers will add synoptic enhancement to the pattern. What this means for West Michigan is several days of lighter lake enhanced snow events that will pile up over time, in addition to an extended period of cold conditions. These rounds of snow may lead to slick travel at times, especially west of US131. && .AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/... Issued at 616 PM EST Mon Jan 12 2026 VFR conditions will continue overnight and into Tuesday afternoon. LLWS is expected beginning Tuesday morning with 40 knots around 2000 feet AGL. Clouds with ceilings decreasing from 3000 feet AGL to about 2000 feet AGL will move in during the afternoon and MVFR conditions could continue into the evening across central Lower Michigan. Conditions may remain VFR across southern Lower Michigan. && .MARINE... Issued at 248 PM EST Mon Jan 12 2026 Southwest flow keeps Small Craft Advisory level conditions going through this evening with a brief lull overnight. We then see winds and waves ramp up early Tuesday morning from the southwest. Given the lull across our southern zones is 6 hours or less, have elected to just extend the current advisory through 4am Wednesday morning at which point a Gale Watch goes into effect. In strong cold air advection behind an arctic front winds in excess of 40 knots in the mixed layer has growing confidence in a solid gale event from late Tuesday Night into late Wednesday Night. With some BUFKIT overviews showing 50 knots in the mixed layer a low (10% or less) chance of storm force gusts exists as well. In coordination with neighboring offices, will be issuing a Gale Watch for the entire nearshore from 4am Wednesday through 1am Thursday, Given how cold the airmass is arriving over the lake, freezing spray is also a concern. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...Small Craft Advisory until 4 AM EST Wednesday for LMZ844>849. Gale Watch from late Tuesday night through late Wednesday night for LMZ844>849. && $$ DISCUSSION...Thomas AVIATION...Ostuno MARINE...Thomas

NWS GRR Office Area Forecast Discussion