161 FXUS63 KGRR 280642 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 242 AM EDT Fri Aug 28 2026 .KEY MESSAGES... - Warming Up Into Next Week - On and Off Chances for Showers and Thunderstorms Saturday into Next Week && .DISCUSSION... Issued at 242 AM EDT Fri Aug 28 2026 - Warming Up Into Next Week Pressure heights will gradually rise today with southwest flow moving in for Saturday and continuing into next week. Within the southwest flow warmer temperatures and higher dew points will advect into the region. Highs today are expected to be around 80, but high temperatures have a 30 to 60 percent chance to hit 90 Monday through Thursday with the best chances on Tuesday across south central Michigan. Dew points in the 60s to near 70 paired with these hotter temperatures will cause heat index values to be in the low to mid 90s with upper 90s possible toward south central Michigan on Tuesday. - On and Off Chances for Showers and Thunderstorms Saturday into Next Week Low chance (10 percent) for another stray shower this afternoon, otherwise rain chances hold off until Saturday night and continue off an on into next week. Deep lift is lacking, but with moisture advection within the southwest flow near the surface it won`t take much to spark off showers and thunderstorms. The main driving force for our chances will be the low level jet as it moves into the area Sunday. The convergence from the low level jet will provide lift, but there is the potential for storms to train over the same area which would pose a risk for flooding. Confidence for any one location is not high enough to pinpoint but the best chances (40 to 60 percent) look to be each night as the low level jet ramps up with lower chances during the day as the low level jet weakens. && .AVIATION /06Z TAFS THROUGH 06Z SATURDAY/... Issued at 140 AM EDT Fri Aug 28 2026 VFR conditions are expected over the next 24 hours. A brief period of MVFR visibilities is possible between 10-12Z. Added a TEMPO group for GRR, BTL, LAN, and JXN. Otherwise winds are expected to become more westerly with the lake breeze this afternoon with FEW to SCT cumulus around 6000 feet. && .MARINE... Issued at 242 AM EDT Fri Aug 28 2026 The lake breeze will develop this afternoon with winds becoming more onshore. Southerly winds then develop for Saturday and continue through most of next week. Winds will be strongest Sunday into Monday with gusts around 25 knots possible. With warmer air over the open waters it may keep winds from hitting Small Craft Advisory Criteria until right along the lakeshore. We`ll continue to monitor these trends as this could impact wave heights and the need for headlines Sunday night into Monday. Thunderstorms will be possible on and off Sunday into next week with the best chances (40 to 60 percent) during the overnight hours. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ DISCUSSION...RAH AVIATION...RAH MARINE...RAH

NWS GRR Office Area Forecast Discussion