235 FXUS63 KGRR 092302 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 702 PM EDT Thu Jul 9 2026 .KEY MESSAGES... - Scattered Thunderstorms Tonight - Upper High builds in Next Week && .DISCUSSION... Issued at 258 PM EDT Thu Jul 9 2026 - Scattered Thunderstorms Tonight Storms have remained below severe limits so far this afternoon. There is still a threat for hail and damaging winds this evening across the southeast zones where instability is greatest. A cold front slowly sinks south overnight then slows and stalls on Friday just south of Lower Michigan with a low chance of lingering showers across the far south. - Upper High builds in Next Week Heights rise early next week with an upper high centered across the upper Mid-west and Northern Plains extending into Michigan early in the week, bringing hot and dry weather. The details are still to be determined, but height falls are expected mid-week as upper troughing develops across eastern Canada. This could result in a cooling trend by mid to late week and possibly some much needed rainfall if MCS activity forms along the top of the ridge and advects into Michigan. && .AVIATION /00Z TAFS THROUGH 00Z SATURDAY/... Issued at 702 PM EDT Thu Jul 9 2026 Lingering thunderstorms north of the terminals should remain north of the TAF sites until they dissipate with sunset. Light northeast flow off of Lake Huron overnight will support fog development, with a period of low stratus possible near daybreak. Generally MVFR conditions favored but IFR is possible, best chance at LAN. Any fog/low stratus should mix to VFR after sunrise. Low chance (20%) of showers or thunderstorms developing near I-94 after 16z Friday. Will not include in TAFs given low confidence but this will need to be monitored in subsequent forecasts. Winds become light and variable overnight before increasing to 5-10 kts out of the northwest on Friday. && .MARINE... Issued at 258 PM EDT Thu Jul 9 2026 Scattered thunderstorms will be ending from north to south this evening with a low chance for gusty winds and small hail. Then high pressure builds in for the weekend and into next week. North winds could gust over 20 knots Friday evening as the high builds in then winds should be blo 15 knots for most of the weekend. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ DISCUSSION... AVIATION...Thomas MARINE...Ostuno

NWS GRR Office Area Forecast Discussion