954 FXUS63 KGRR 101825 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 125 PM EST Sat Jan 10 2026 .KEY MESSAGES... - Widespread precipitation today, lake effect snow showers tonight - Periodic rain/snow chances much of the coming week - Stronger system with colder air arrives late in the week && .DISCUSSION... Issued at 337 AM EST Sat Jan 10 2026 - Widespread precipitation today, lake effect snow showers tonight No changes needed to the going Winter Weather Advisory with this forecast package. Latest set of data continues to support the advisory well over the NW corner of the forecast area with amounts tapering off to the south and east. This event today is being driven largely by a strengthening upper jet core, with the left front exit region passing over the NW counties early this afternoon. This jet streak is strengthening as the next strong wave comes in and strengthens the gradient a bit. Up over the favored NW area, it is cold enough for all snow and snow to liquid ratios (SLR) will be the highest there. The orientation of the heaviest snow gives the impression there is a lake enhancement to it, but it is not with the low level flow offshore through much of the event. Further south, we will see lighter precipitation rates being further removed from the best forcing mentioned above. In addition, sfc temps above freezing, and a melting layer around 1500 ft will allow some of the precipitation to fall as rain toward I-94. Even if snow falls there, it will be associated with low SLRs, so amounts will be minimal through today down there. We will see a lull in the precipitation very late this afternoon and evening, before another batch of snow showers develops/moves in. We will lose the forcing with the upper jet by this evening. We see a period of slight ridging aloft in the upper air pattern out ahead of the main upper low and another short wave rotating around it and into the region. As the energy moves in later this evening and overnight, snow showers will then spread southward through the area. Some lake enhancement is expected to occur as 850 mb temps drop into the negative mid teens, and the flow becomes onshore. Heavy amounts of snow are not expected tonight. That is due to the progressive nature of the main low and short wave. The flow will be constantly changing, until the entire low complex moves out Sunday morning. The cyclonic flow aloft moves out, and lake effect will taper off through Sunday. - Periodic rain/snow chances much of the coming week We will see a return to the upper flow coming in from the WNW, after the break in dominant pattern this winter so far with the warmer SW flow. The western ridge will rebuild, and set the flow from the WNW once again. We will be on the southern edge of this flow, so we will not be under the influence of the cyclonic flow or cold pool aloft. We will be close enough however to see the periodic chances for precipitation. This is evident in the short wave coming through on Tuesday. Much of the area is likely to see more rain than snow with this system as 850 mb temps are above 0C and a sufficient southerly low level flow ahead of the system will keep sfc temps above freezing. We will see cooler air filter in on Wednesday behind the Tuesday system. Another short wave will arrive for Wednesday, and support light snow chances across much of the area at that time. No significant amounts of snow are expected with the speed of the system, and limited moisture associated with it. We will see temperatures continue to get progressively cooler then behind the Wednesday system as the upper flow will become more northerly ahead of the building ridge over the western half of the country. Temperatures at 850 mb in the negative teens would be sufficient for lake effect. However, ridging at the sfc and aloft will squash snow chances on Thursday. - Stronger system with colder air arrives late in the week The more amplified flow developing across the country through the week will eventually allow a stronger upper low to be carved out over the Great Lake region by Friday. We see a stronger clipper bring some temporary warmer in briefly, but then drops the temps quickly behind it next Friday night. This will increase the threat of lake effect with colder temps. && .AVIATION /18Z TAFS THROUGH 18Z SUNDAY/... Issued at 125 PM EST Sat Jan 10 2026 This TAF period we begin with widespread IFR and lower cigs and vsbys at MKG, GRR, AZO, and BTL. MKG and GRR are both LIFR vsbys with LIFR cigs at times. Latest radar shows the heaviest snow bands continue to move through the region through 20Z. Expect Periods of mixed precipitation at the southern TAF sites, especially AZO and BTL. Temperatures will drop throughout the day and will switch over to snow eventually. There is some disparity on when that will happen. Rain to snow at AZO, BTL will be between 21Z and 01Z. Snow through the northern TAF sites will lighten after 20Z as the back edge of the front moves through. There will be some improvement in vsbys this evening before lake effect flow takes over. Expect MVFR to VFR vsbys after 00Z at MKG and GRR before they drop back down around 09Z as lake effect flow increases. Those showers will then bring vsbys and cigs back to MVFR with periods of IFR possible between 11Z and 15Z. && .MARINE... Issued at 337 AM EST Sat Jan 10 2026 Not much of a reprieve in the winds/waves after Friday`s event, and the next event beginning this afternoon and continuing through Sunday morning. High pressure and a weak gradient is overhead right now, but will move out quickly this morning. This will allow winds to come up this afternoon, and max out very late tonight/early Sunday morning as Gales with the arrival of the colder air. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...Winter Weather Advisory until 1 PM EST Sunday for MIZ037>039- 043>045-050. MARINE...Small Craft Advisory until 4 AM EST Sunday for LMZ844>849. Gale Warning from 4 AM to 1 PM EST Sunday for LMZ844>849. && $$ DISCUSSION...NJJ AVIATION...Ceru MARINE...NJJ

NWS GRR Office Area Forecast Discussion