430 FXUS63 KGRR 041758 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 158 PM EDT Mon May 4 2026 .KEY MESSAGES... - Warm and Windy Today, Rain and Thunderstorms Tonight - Cooler with Frost/Freeze Potential This Week && .DISCUSSION... Issued at 310 AM EDT Mon May 4 2026 - Warm and Windy Today, Rain and Thunderstorms Tonight Southwest flow and warm air advection ramp up today with highs in the mid 70s across much of the area. It won`t be as windy as yesterday, but gusts 25 to 35 mph are expected to develop this morning into the afternoon. With the warm temperatures and gusty winds there is an elevated fire risk today. Check the FIRE WEATHER section below for more information. Our next shortwave trough that will help spark off shower and thunderstorm development moves in this evening from the Northern Plains. Upper level divergence picks up with the approaching trough with some low level convergence with the low level jet across southern Michigan. This convergence could spark off showers and storms near the I-94 corridor around 6PM. Shear around 30 to 40 knots and MUCAPE values around 1000 J/kg along with decent mid level lapse rates and a deep dry layer at the surface will pose a risk for severe storms. Damaging winds and large hail are possible, with the best risk south of I-96. An approaching cold front will spark off additional showers and thunderstorms further north and shift slowly southeast overnight into Tuesday. - Cooler with Frost/Freeze Potential This Week The cold front will still be moving through southeast portions of the area Tuesday with some lingering rain showers before dry conditions return Tuesday night into Wednesday. Behind the cold front colder air will be advecting in. Depending on winds and cloud cover frost/freeze conditions will be possible each night into the weekend. The upper level low will remain over the Hudson Bay area and continue to rotate shortwave troughs through the region. Chances for rain will depend on the timing and moisture with each shortwave. At this time slight chances (20 percent) for rain exist each day into the weekend. && .AVIATION /18Z TAFS THROUGH 18Z TUESDAY/... Issued at 158 PM EDT Mon May 4 2026 Prevailing VFR expected over the next several hours with few to scattered cumulus bases around 6,000 feet. Winds will be gusty from the southwest. Scattered showers and thunderstorms may develop between AZO and JXN after 22 Z, followed by a 2 or 3 hour period of showers and some embedded thunderstorm cells in the vicinity of a cold front sweeping through the whole area from west to east between 00 and 06 Z. Any thunderstorms will be capable of microbursts and outflow resulting in gusty winds up to 40 or 50 knots and LLWS. && .MARINE... Issued at 310 AM EDT Mon May 4 2026 A lull in Small Craft Advisory conditions will be short lived as southwest winds build once more this morning into Monday afternoon. The highest waves will be north of Holland of 3 to 6 feet. Some isolated gales are possible toward Big Sable this afternoon before winds fall below Small Craft Advisory levels this evening. High waves will linger a few hours longer before dropping below 4 feet prior to midnight. Thunderstorms are expected this evening along a cold front with winds shifting to the northwest behind the front. Winds and waves are expected to remain below Small Craft Advisory levels through the rest of the week. && .FIRE WEATHER... Issued at 310 AM EDT Mon May 4 2026 A warm, windy, and dry airmass over the region will bring elevated fire weather conditions for today. Wind gusts around 35 mph with isolated gust toward 40 mph could cause fires to quickly spread. Minimum relative humidity values this afternoon are expected to drop into the mid 20s across much of the area. There is a 20 percent chance for minimum relative humidity values to drop below 25 percent east of US-131 and north of I-96. Avoid activities with open flames or sparks and avoid power equipment that create sparks. Check for any burn bans in your local area. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...Small Craft Advisory until 11 PM EDT this evening for LMZ844>849. && $$ DISCUSSION...RAH AVIATION...CAS MARINE...RAH FIRE WEATHER...RAH

NWS GRR Office Area Forecast Discussion