288 FXUS63 KGRR 172319 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 619 PM EST Tue Feb 17 2026 .KEY MESSAGES... - Central Michigan Freezing Rain Late Tonight - Chance of a Thunderstorm Wednesday Morning - Mixed precipitation with thunderstorms possible again late week - Low chances for accumulating snow this weekend && .DISCUSSION... Issued at 251 PM EST Tue Feb 17 2026 - Central Michigan Freezing Rain Late Tonight No changes to previous thinking regarding expectations for ice accumulations with the Winter Weather Advisory for Clare and Osceola Counties. The latest HREF is quite consistent with the previous run in terms of ice accumulations in this location. Climatologically, there is significant sensitivity to elevation when it comes to accumulating freezing rain (FZRA). The greater elevations associated with Clare/Osceola drop off abruptly farther south across the northern reaches of Mecosta/Isabella Counties. We had pondered expanding the advisory southward into these counties, but given the elevation factors and what should be a substantial north-south thermal gradient in the vicinity of the warm front, we decided to stay the course with the original two counties. As mentioned previously, there is a lot of bust potential with this forecast as there will be much sensitivity to the warm front evolution overnight; consequently, there is a large spread in guidance solutions. This particular FZRA forecast is based largely on climatological and pattern recognition heuristics as well as strong consideration of the HREF. Observations at CAD and HTL right now would suggest we will stay way too warm for FZRA, but then we also have to consider notably colder air poised at OSC and APN that could change things rapidly over interior Lower MI early tonight. - Chance of a Thunderstorm Wednesday Morning HREF guidance still suggest thunder potential, albeit more around 12Z Wednesday and closer to the lakeshore. The deterministic ECMWF Lightning Flash Density product also hints at less coverage compared to before. The SPC day 1 and 2 thunderstorm outlooks continue to advertise general thunder across much of Lower MI with severe hail and wind probabilities staying below 5 percent. As noted before, there is a non-zero chance for gravity wave associated convection (GWAC) with this activity tomorrow, especially if a wavetrain is able to set up west of the area in the MN/WI/IA vicinity. One of the characteristics of GWAC is its ability to produce significant surface wind gusts even while the convection is elevated, so any nocturnal or marine boundary layer induced inversion that sets up south of the warm front Wednesday morning would not prevent GWAC; rather, it would create a more favorable environment for it to occur. - Mixed precipitation with thunderstorms possible again late week There is now somewhat better consensus among the model solutions regarding the track of the surface low Thursday night and Friday. The majority report tracks the low center from northern IL through WI and towards northern Lake MI. This places the forecast area in the warm sector for a rather long time, presumably with a longer duration of rain before the transition to rain/snow, then finally snow by late Friday night. - Low chances for accumulating snow this weekend Impacts are expected to be limited this weekend. Snow eventually becomes the most likely precipitation type with little to no accumulations expected. Temperatures at 850mb won`t be particularly cold; medium range ensemble guidance shows only a 40 percent chance of less than -10C, which is marginally favorable for lake effect. Highs should climb into the lower/mid 30s both days. && .AVIATION /00Z TAFS THROUGH 00Z THURSDAY/... Issued at 615 PM EST Tue Feb 17 2026 No significant changes to the going forecast. Still expecting some fog this evening and then showers and potentially thunderstorms after midnight. Ceilings will gradually improve during the morning and skies will clear during the afternoon. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...Winter Weather Advisory from midnight tonight to 9 AM EST Wednesday for MIZ039-040. MARINE...None. && $$ DISCUSSION...TJT AVIATION...04

NWS GRR Office Area Forecast Discussion