937 FXUS63 KGRR 202336 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 636 PM EST Tue Jan 20 2026 .KEY MESSAGES... - Moderate to Heavy Snow Tonight into Wednesday Morning - Light Snow Continues with Periods of Moderate Snow - Bitter Cold Friday into Sunday && .DISCUSSION... Issued at 325 PM EST Tue Jan 20 2026 - Moderate to Heavy Snow Tonight into Wednesday Morning A round of moderate to heavy snow is expected tonight into Wednesday morning bringing hazardous travel conditions for the morning commute across much of the area. Light lake effect snow will continue due to the low level moisture off of Lake Michigan, 850mb-lake surface temperature differences, and the wind flow off of Lake Michigan. Any accumulations will be light until we see southwest flow and warm air advection ramp up ahead of a low pressure system that will move in tonight. Within the southwest flow expect Ottawa, Muskegon, and Oceana counties to be hit the hardest due to the convergence from the orientation off of Lake Michigan. This is highlighted in various ensembles with up to 8 inches likely and a 30-40 percent chance of 8 or more inches. Mason, Lake, and Newaygo counties will be on the edge of higher amounts with generally 3-6 inches expected across the area but isolated higher amounts are possible mainly for western portions of these counties. Along the I-94 corridor and along and south of I-96 generally 3-6 inches expected with 1-3 inches elsewhere. Snowfall rates of 0.2-0.7"/hr are expected as snow starts with areas in the Winter Storm Warning looking at 1-2"/hr rates at times. This will quickly reduce visibilities and accumulate on roads creating hazardous travel conditions. As the low pressure system departs snowfall rates drop off late Wednesday morning, but expect light lake effect snow to linger through the day. - Light Snow Continues with Periods of Moderate Snow A series of shortwave troughs will bring additional rounds of accumulation snow outside of the continuous light lake effect snow. The next round moves in Wednesday night into Thursday with another low pressure system. The probability of 2 or more inches of snow is focused along and west of a Big Rapids to Battle Creek line with probabilities 40 to 70 percent with the higher values to the west. The probability of 4 inches or more however drops peaks at 20 percent in the Grand Rapids area. Expect another day of impacts to the morning commute Thursday morning. Thereafter additional disturbances in the upper level pattern will bring more rounds of snow Friday and through the weekend into next week. - Bitter Cold Friday into Sunday Arctic air moves in for the end of the week with highs in the single digits and lows below zero. Wind Chill values will be in the teens below zero Friday. Wind chills are not expected to be as cold Saturday and Sunday however they are still expected to be below zero until Sunday afternoon. && .AVIATION /00Z TAFS THROUGH 00Z THURSDAY/... Issued at 632 PM EST Tue Jan 20 2026 Radar shows light snow diminishing across the region. However, more snow was noted over southeast MN/northeast IA moving this way. Light snow will develop around/shortly after midnight and visibilities will fall to 1-1.5sm. Snowfall rates around 0.2 in/hr are expected before the snow diminishes during the afternoon. Another low will move in quickly Wednesday evening and mainly affect MKG in this TAF period. The other terminals will see snow redevelop after 00z Thursday. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...Winter Weather Advisory from 1 AM to 10 AM EST Wednesday for MIZ037-038-044>046-051-052-057>059-064>067-071>074. Winter Storm Warning from midnight tonight to 10 AM EST Wednesday for MIZ043-050-056. MARINE...Small Craft Advisory until 7 AM EST Wednesday for LMZ844>849. && $$ DISCUSSION...TJT/RAH AVIATION...04

NWS GRR Office Area Forecast Discussion