289 FXUS63 KGRR 171053 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 653 AM EDT Tue Mar 17 2026 .KEY MESSAGES... - Snow winding down today - Light burst of Snow Wednesday morning && .DISCUSSION... Issued at 303 AM EDT Tue Mar 17 2026 - Snow winding down today 17/00Z HREF guidance suggests a secondary lower tropospheric trough best resolved around 700 mb is swinging across western Lower MI at this time. This feature is well corroborated by regional VWPs. We have seen a slight decrease in lake effect snow intensity and coverage in the last hour indicating that inversion heights (currently around 7 kft AGL deep per the KGRR VWP) are in the process of decreasing in response to subsidence behind the trough. Water vapor imagery supports this notion with mid-level subsidence just beginning to pivot across Lower MI in the wake of the trough. We will see a continued decrease in snow today, probably wrapping up by afternoon when near surface pressure ridging takes hold. - Light burst of Snow Wednesday morning We will have to watch for the possibility of minor travel impacts Wednesday morning as an area of WAA/isentropic ascent could bring a quick burst of snow. Accumulations at this time expected to be less than an inch for roughly the western half of the forecast area but temperatures will be below freezing and untreated roads may be slippery. && .AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/... Issued at 653 AM EDT Tue Mar 17 2026 No significant changes to the previous package in terms of general expectations for restrictions. We are seeing occasional IFR visibility restrictions early this morning chiefly at MKG and LAN, but these have been rather transient and should be less common as we move into late morning. Latest model guidance does now suggest scattered snow showers being possible well into the afternoon after 18Z, so have added this. Any snow showers this afternoon should cause brief MVFR restrictions above fuel alternate thresholds. && .MARINE... Issued at 303 AM EDT Tue Mar 17 2026 Coastal marine stations now reporting peak gusts below 35 knots, so this is the cue to cancel our Gale warning and replace it with a Small Craft Advisory (SCA) valid through this evening. For now, kept the heavy freezing spray warning going until noon, but this almost certainly can be cancelled prior to that. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...Winter Weather Advisory until 11 AM EDT this morning for MIZ037>039-043-044-050-056-064-071-072. MARINE...Small Craft Advisory until 8 PM EDT this evening for LMZ844>849. Heavy Freezing Spray Warning until noon EDT today for LMZ844>849. && $$ DISCUSSION...Ostuno/TJT AVIATION...TJT MARINE...TJT

NWS GRR Office Area Forecast Discussion