242 FXUS63 KGRR 181150 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 650 AM EST Sun Jan 18 2026 .KEY MESSAGES... - Snow, Blowing Snow, and Whiteouts Tonight into Monday - Multiple Snow Events Possible Mid to Late Week && .DISCUSSION... Issued at 345 AM EST Sun Jan 18 2026 - Snow, Blowing Snow, and Whiteouts Tonight into Monday A hazardous travel period sets up later this evening and lasts into Monday as lake enhanced snow and some significant blowing and drifting snow develops particularly near and west of US 131. Prior to this, we still have some leftover snow showers and localized accums to deal with early this morning mainly from Muskegon to the north. This activity will gradually subside. Not much has changed with previous forecast reasoning regarding the setup this evening into Monday. An Arctic front arrives tonight as upper heights fall and lake aggregate troughing and surface low development occurs across Lakes Superior and Huron. As the Arctic front approaches, SW flow lake enhancement develops in the 21z-00z time frame this evening. Nam12 is showing strong omegas in the DGZ from BIV to GRR and MKG and points northward this evening and early tonight. The SW flow shifts westerly 03z-09z and then WNW to NW after that. Expect lake effect bands to orient themselves accordingly. The worst travel conditions look to occur from very early Monday morning through Monday afternoon as boundary layer winds increase and surface gusts reach 30-40 mph with some gusts of 40-50 mph along the immediate lakeshore. This occurs with fairly prolific lake effect snow coverage across the region. 00z WPC guidance gives areas near and west of US 131 0.25"-0.50" through Monday evening with snow ratios of 17:1 to 20:1. This will yield 4"-8" of snow during the bulk of the event with some additional light accums Monday night into Tuesday. Combine this with gusty winds and blowing/drifting snow will be problematic. Particularly hazardous conditions are expected to develop along N/S roads like US 31 and US 131 where whiteouts are expected at times with potentially disorienting travel conditions with loss of visibility. 00z HREF guidance is indicating a 50% probability for blizzard conditions to develop along and west of US 131. While this certainly could be true at times in open areas, we historically have a very difficult time sustaining true blizzard conditions solely from a lake effect event. As such, we are not considering a Blizzard Warning at this point but will go ahead with an upgrade to a Winter Storm Warning for the existing Watch area plus some additional counties based on a combination of accumulating snow, strong winds with blowing/drifting snow, and hazardous travel. A Winter Weather Advisory will be issued further inland as amounts will be lower but travel impacts will still occur. Further eastward expansion of headlines may occur with future forecast updates. Snow intensity is expected to decrease late Monday into Monday night as inversion heights decrease, though light accumulations and poor visibility are still likely to occur with snow production continuing above the DGZ (at temps colder than -18C). The wind factor does drop off, though some travel impacts are likely to continue into Tuesday morning. As such, have extended headlines into early Tuesday to cover this threat. As for wind chills, still looking likely that most areas will get into the -5 to -15 range Monday into Tuesday with a possibility that areas inland may dip colder than -15. - Multiple Snow Events Possible Mid to Late Week; More Cold Coming A very active winter pattern continues mid to late week with potentially multiple impactful snow events with hazardous travel conditions possible at times. The Wednesday through Friday period may feature a couple of lake enhanced snow events with some gusty winds as well given a few pronounced deep troughs that swing through providing some synoptic lift over the lake. It`s not impossible that lake effect snow showers may be nearly continuous during this period. ECE guidance for multiple cycles has been showing even colder air arriving next weekend compared to what`s coming Monday into Tuesday. Highs may not even get out of the single digits potentially. This may be a reflection of the increasingly negative Arctic Oscillation developing. && .AVIATION /12Z TAFS THROUGH 12Z MONDAY/... Issued at 642 AM EST Sun Jan 18 2026 Light snow showers may persist at MKG this morning into the afternoon before increasing this evening. Expect a flare up in lake enhanced snow to impact MKG and GRR starting in the 21z-00z time frame. This occurs as southwest flow ahead of an Arctic front will lead to snow development off the lake. Sometimes these events overperform on visibility reductions, so moderate to heavy snow is a possibility even within the 21z-00z window. After this, moderate to heavy snow is expected in the 03z-12z time frame at MKG and GRR with light snow elsewhere with potentially periods of moderate snow. BLSN will develop toward the end of this TAF period (MKG and GRR) which could markedly reduce visibilities, especially heading into the 12z to 18z Monday time frame with near blizzard conditions at times especially at MKG. && .MARINE... Issued at 345 AM EST Sun Jan 18 2026 Gales are expected along with freezing spray Monday into Tuesday. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...Winter Weather Advisory until 7 AM EST this morning for MIZ037- 038-043-044-050. Winter Storm Warning from 4 PM this afternoon to 7 AM EST Tuesday for MIZ037-038-043-044-050-056-057-064-071. Winter Weather Advisory from 4 PM this afternoon to 7 AM EST Tuesday for MIZ039-040-045-051-058-065-072. 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...Hoving AVIATION...Hoving MARINE...Hoving

NWS GRR Office Area Forecast Discussion