372 FXUS63 KGRR 040005 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 805 PM EDT Sun May 3 2026 .KEY MESSAGES... - Marginal Risk Severe on Monday - Cool with Frost/Freeze Potential This Week && .DISCUSSION... Issued at 250 PM EDT Sun May 3 2026 - Marginal Risk Severe on Monday Southwest flow with modest moisture return and elevated instability ahead of an advancing cold front is expected to touch off scattered showers and thunderstorms late Monday afternoon and evening. Deep layer shear of 35 knots will aid the cause. Any sustained updrafts could produce hail and strong winds are also a threat given DCAPE resulting from evaporation of precip in a dry adiabatic sub cloud layer. The threat diminishes after midnight as the cold front moves through. - Cool with Frost/Freeze Potential This Week The front stalls across the Ohio Valley with a surface low tracking northeast along the front. At this point it looks like the precip shield stays east of Lower Michigan. Frost/Freeze conditions will return for Tuesday and Wednesday nights Showers are possible on Thursday afternoon and evening as a shortwave trough and vorticity maximum moves though and model soundings show wet-bulb zero heights not far off the surface across the northern zones, so graupel or wet snow is possible there. Frost/Freeze potential lingers into next weekend and beyond as a cold northwest flow regime continues. && .AVIATION /00Z TAFS THROUGH 00Z TUESDAY/... Issued at 805 PM EDT Sun May 3 2026 VFR is expected tonight into much of Monday with patches of clouds at or above 6,000 feet scattering out this evening. Gusty winds will diminish tonight as temperatures near the ground cool off, though about 20 to 30 knots of LLWS will be present in its place until 06 or 08 Z. Gusty winds are again expected with daytime heating on Monday. Scattered showers or thunderstorms may develop late in the day and will pose a microburst / surface gust / wind shear threat given how well mixed and dry the lower atmosphere will be beneath the cloud bases. && .MARINE... Issued at 250 PM EDT Sun May 3 2026 No changes to the SCA. There will be a brief lull tonight then another SCA will be needed for Monday into Monday night. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...Small Craft Advisory until midnight EDT tonight for LMZ844>849. && $$ DISCUSSION...Ostuno AVIATION...CAS MARINE...Ostuno

NWS GRR Office Area Forecast Discussion