670 FXUS63 KGRR 281147 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 647 AM EST Sat Feb 28 2026 .KEY MESSAGES... - Snow accumulations likely tonight, heaviest axis still uncertain - Impactful wintry mix looking likely Tuesday - Warmer late week with rain chances && .DISCUSSION... Issued at 245 AM EST Sat Feb 28 2026 - Snow accumulations likely tonight, heaviest axis still uncertain Being within 24 hours of our next snow event, normally we would have this pinned down fairly well. However, this system remains a bit elusive regards to specific snow amounts for each location and location of the heaviest axis. Quite a bit of uncertainty remains regarding the specific details amongst the deterministic and ensemble members. Ensemble means such as the HREF are fairly smeared out with their snow amounts. This is due to a wide range of solutions spread out, with their individual members showing the better snow occurring anywhere from near I-94 to north of I-96. As has been mentioned repeatedly over the past few days, this uncertainty is tied to the mid level fgen and where exactly the best forcing just south of the fgen is able to trigger the atmospheric response with the stability present. Taking a step back to look at the bigger picture, there is a slightly elevated chance compared to the rest of the area that the best axis of accumulating snow will be near the I-96 corridor. Extrapolating the track of the forecast snow out to our west would support this, as would the overall mean of all the various solutions. One thing to note too is that the upper level divergence with the upper jet coupling and the resulting mid level fgen will be weakening as it moves overhead, compared to areas further west. So, a forecast of 1 to 2 inches for most of the area is a responsible way to go at this point considering the circumstances. Chances are this is overdone a bit for some areas on the northern and southern peripheries, and underdone for some other areas where the heaviest axis ends up. We do have areas near the I-96 corridor with a tad higher amounts (1-3 inches). The good news with this is that given the timing of the snow being mainly evening into the early overnight hours, impacts will not be as high as if this came through during a weekday rush hour. - Impactful wintry mix looking likely Tuesday We have seen a noticeable acceleration of the next system coming into the area, going from Tuesday night, to now Tuesday over the past couple of days. This is due to the slower southern stream energy coming out of the desert SW, and a northern stream short wave able to come in quicker not being phased. The deep cold air will remain well north of the area with the polar jet staying well over Canada. The short wave coming through will be able to act on Gulf moisture coming northward with the srn branch of the jet. We will have shallow colder air near the sfc undercutting the warmer air aloft and moisture coming in. This means that we have a better chance for more of the forecast area to see a wintry mix of precipitation types during the daylight hours on Tuesday. There is fairly good agreement with the synoptic models and ensemble members showing that the southern portion of the forecast area near I-94 will see mainly rain. The uncertainty is where temps can be above freezing vs. below freezing that brings rain or freezing rain. This area of uncertainty is really centered on the I-96 corridor. Still a few days to figure that out, but it is encouraging to see the decent amount of agreement. - Warmer late week with rain chances We should see a break now on Wednesday, with warmer air coming in on the wake of the Tuesday system. This is due to rising heights in the long wave pattern in response to lowering heights across the Western U.S.. Another wave will move in for Thursday, bringing another good chance for precipitation. The difference for the Thursday system is the higher heights and warmer sfc temps. We still may have a little freezing rain up north Thursday with marginally cold enough temps early. Overall though the warmer temps will support mostly rain for most of the area. The Thursday system will mark the change taking place from the more zonal flow and cooler temperatures, to more of a flow from the SW bringing in more warm air and rain. && .AVIATION /12Z TAFS THROUGH 12Z SUNDAY/... Issued at 647 AM EST Sat Feb 28 2026 VFR conditions dominate this morning at all of the terminals, in the wake of a weak cold front that has passed through the area. High clouds remain over much of the area this morning. Clouds will lower as the next area of snow moves toward the area later this afternoon. Some uncertainty remains as the band of snow will be somewhat narrow as it moves in. The various sets of data continue to differ on the track, even as we ware within 24 hours. The thought is the I-96 corridor has a slight bit better of a chance of seeing the heavier snow. We have gone with lower conditions along the I-96 corridor terminals, and less impact for the I-94 terminals. The snow will move out later this evening and overnight. Conditions will improve a bit to MVFR, before more improvement on Sunday morning. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ DISCUSSION...NJJ AVIATION...NJJ

NWS GRR Office Area Forecast Discussion