242 FXUS63 KGRR 182025 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 325 PM EST Sun Jan 18 2026 .KEY MESSAGES... - Snow, Blowing Snow, and Whiteouts Tonight into Monday Night - Multiple Snow Events Possible Mid to Late Week; More Cold Coming && .DISCUSSION... Issued at 325 PM EST Sun Jan 18 2026 - Snow, Blowing Snow, and Whiteouts Tonight into Monday Night Forecast remains on track for impactful and hazardous winter weather tonight through Monday. SW flow lake effect snow is ongoing near and west of Grand Rapids, and will increase markedly between 4 PM and 8 PM as inversion heights rise and the midlevels above the lake effect saturate with the arrival of a Clipper system. HREF mean suggests 3 to 6 inches of snow falling by 7 AM Monday in a fair portion of the Winter Storm Warning area from the first phase of this event. Arctic cold front reaches West Michigan prior to daybreak Mon, and winds becoming west-northwest during the morning will spread snow farther inland, to also include areas east of Kalamazoo- Ionia. Temperatures 10-15 degrees and winds gusting 30-40 mph along with broken banded lake effect snow bursts will create whiteout conditions at times, most frequently near/west of US-131 but also occasionally toward US-127. Additional QPF 0.10 to 0.25 inches during the day Mon is possible in the warning area, so even with potentially smaller flake size, impacts will remain fairly high given the falling and blowing snow. Totals around 6 to 8 inches by Mon night is a fair bet in much of the lakeshore counties, with about a 10 percent chance for a given location reaching 10 to 12 inches (not factoring in drifting). In central to south-central Michigan, the advisory is expanded to include Mount Pleasant, Lansing, Battle Creek, and Jackson for 1 to 3 inches of snow Monday but relatively greater-than-usual impacts due to blowing snow, variable visibility, and slick road conditions from the cold temperatures. Highway pileup crashes can just as easily (if not more easily) occur in low-accumulation areas when patchy whiteouts and changing road conditions occur. Accumulating lake effect snow should persist through Monday night but will trend a little lighter as broader synoptic support for lift weakens. Temperatures will fall into the single digits with wind chills around -5 to -15 F Tue morning. - Multiple Snow Events Possible Mid to Late Week; More Cold Coming A few inches of accumulating snow is likely on Wednesday as a low traverses the Midwest along a baroclinic zone (north/south temperature gradient). Temperatures could climb all the way back into the 20s on the front end of this low on Wed before the next surge of Arctic air moves in for late in the week. A majority of the Euro ensemble members advertise daytime temperatures in the lower single digits Fri and Sat as truly cold 850 mb air around -30 C swings through the Great Lakes. The GFS and Canadian ensembles are mostly not on board with air that extreme, but are nonetheless in the ballpark of lower 10s to upper single digits. Low temperatures Saturday morning could be well below zero, perhaps -10 to -20 F in inland areas, under high pressure and a radiational cooling setup (i.e. clear and no wind). && .AVIATION /18Z TAFS THROUGH 18Z MONDAY/... Issued at 1230 PM EST Sun Jan 18 2026 Bottom line up front... significant impacts to aviation are expected over the next 24 hours as a winter storm crosses the area, with the worst conditions at MKG and GRR. Light snow showers continue through the afternoon with intermittent drops to IFR possible over the next few hours at MKG/GRR. Deteriorating conditions begin after 21z at MKG/GRR with light snow expected and moderate to heavy snow possible as lake enhanced snow increases in coverage and intensity. After 00z snow expands across the rest of the terminals with moderate to heavy snow at MKG/GRR and light to moderate snow at the other terminals. An arctic front crossing the terminals after 11z will result in further deterioration as winds increase and BLSN develops. Visibilities could be significantly impacted, with widespread LIFR conditions. Periods of near blizzard conditions are likely at MKG after 11z, and potentially at the other terminals as well (with GRR having the best chance of the other terminals). Expect southwest winds today to become westerly Monday with gusts of 30-35 knots during the day on Monday. && .MARINE... Issued at 325 PM EST Sun Jan 18 2026 Hazardous conditions for small craft with SW winds this evening will trend toward WNW winds with gales late tonight and through the day Monday. Heavy freezing spray is likely Monday into Monday night. Hazardous conditions for small craft are expected through much of the rest of the week. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...Winter Storm Warning until 7 AM EST Tuesday for MIZ037-038-043- 044-050-056-057-064-071. Winter Weather Advisory until 7 AM EST Tuesday for MIZ039-040- 045-051-058-065-072. Winter Weather Advisory from 10 PM this evening to 7 AM EST Tuesday for MIZ046-052-059-066-067-073-074. MARINE...Small Craft Advisory until 1 AM EST Monday for LMZ844>849. Gale Warning from 1 AM to 7 PM EST Monday for LMZ844>849. Heavy Freezing Spray Warning from 1 AM Monday to 7 AM EST Tuesday for LMZ844>849. && $$ DISCUSSION...CAS AVIATION...Thomas MARINE...CAS

NWS GRR Office Area Forecast Discussion