857 FXUS63 KGRR 141715 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 115 PM EDT Wed Oct 14 2026 .KEY MESSAGES... - Wet and windy system Thursday through Friday - Cool and dry weekend with moderating temperatures next week && .DISCUSSION... Issued at 302 AM EDT Wed Oct 14 2026 - Wet and windy system Thursday through Friday A few showers will remain possible early this morning before ending/moving south of the forecast area by daybreak. The vast majority of the convection is already south of the area closer to the sfc boundary where the better instability is found. The short wave that is helping to fuel these showers and storms will be shifting east of the area by 12z this morning. We are expecting a considerable amount of cloud cover to hold much of the day as plenty of low level moisture will advect south from Canada behind the short wave. Holes in the clouds should develop as the clouds lift with diurnal mixing helping a bit. Our attention then turns to the phasing system that has generally been handled well quite consistently by the models for days now. The southern stream part of this system will push showers and a few storms over the area beginning mid to late Thursday. This will be associated with a sfc low that is forecast to ride through our forecast area Thursday evening. Thu evening will be the best chance for better rain and the best chance of storms. This is when we see the best instability approach the area via the best moisture push associated with the nose of a 50 knot low level jet clipping the far southern portion of the area. Instability progs show that we likely do not see sfc based instability this far north, but we do see sufficient elevated instability. This setup should keep most, if not all of the severe potential south. We may see a brief break in the rain as the southern feature moves out by Friday morning, and the northern stream trough is still to our NW. The upper jet core crosses the forecast area Friday afternoon, bringing the cyclonic flow overhead at that time. This is delayed a bit compared to earlier runs, and is likely to hold rain/showers over the area longer on Friday. The showers will be the result of the deep cold pool aloft with diurnal instability, and lake effect. The best chance of showers will be Friday afternoon into Friday evening until the upper jet core on the backside passes east. We are looking at a legit chance of lake effect thunderstorms Friday afternoon and evening. Forecast soundings modified for lake effect show lifted parcels way above the ice generation layer, allowing for lightning to be generated. The thunder chance will be limited to mainly the lakeshore. All of this will be accompanied by winds of 35 to 45 mph bringing in the much colder air. - Cool and dry weekend with moderating temperatures next week By Saturday morning, sfc ridging will be over the area already as the upper trough moves by and we are downstream of the next long wave ridge. This ridge will become a familiar feature as it is expected to hold over the area through early next week. It gets held up with the strongly amplified pattern with strong lows near both coasts of the CONUS. We start off quite cool in the wake of Friday`s system for the weekend. Temperatures may end up in the 50s only once again on Saturday. We will see a gradual warming trend then through early next week with dry weather. A better push of warmer air comes around Tuesday as return flow brings a warm front toward the area. This could bring a small chance of some rain. && .AVIATION /18Z TAFS THROUGH 18Z THURSDAY/... Issued at 112 PM EDT Wed Oct 14 2026 Satellite and observational trends show MVFR cigs are lifting to VFR, however intermittent MVFR is likely through late afternoon. VFR is expected then this evening into the first part of the night, before clouds increase around 3500 ft tonight, potentially falling to 2500 ft with boundary layer cooling. Best signal for MVFR potential is LAN/JXN, with weaker low-level moisture further west so have gone with SCT 2.5kft cigs at other terminals for now. At these sites, MVFR is forecast to set in near or shortly after 18z. && .MARINE... Issued at 302 AM EDT Wed Oct 14 2026 We will be hoisting a Gale Watch from late Thursday night through Friday evening. There is good agreement amongst the various model suites, and there has been good run to run consistency with this system with regards to winds on the lakes. This also is a solid Gale event, versus being a borderline event. We should see winds and waves come down significantly for Friday night and early Saturday. Winds will come up again later Saturday and persist at least through the weekend. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...Gale Watch from late Thursday night through late Friday night for LMZ844>849. && $$ DISCUSSION...NJJ AVIATION...Thomas MARINE...NJJ

NWS GRR Office Area Forecast Discussion