848 FXUS63 KGRR 242257 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 657 PM EDT Fri Jul 24 2026 .KEY MESSAGES... - Thunderstorms Possible Late Saturday into Monday. Severe storms possible, but confidence in where/when/if storms impact West Michigan is low at this time. - Northwest Flow Continues Into Late Next Week && .DISCUSSION... Issued at 212 PM EDT Fri Jul 24 2026 - Thunderstorms Possible Late Saturday into Monday. Severe storms possible, but confidence in where/when/if storms impact West Michigan is low at this time. Surface ridging and poor moisture quality keeps conditions dry over the next day or two, with precipitation chances holding off until Saturday Night. Saturday night a weak shortwave crosses the area. However, poor moisture quality keeps precipitation chances low (20- 25%) across the area with most seeing a few hundredths of an inch of rain or less. Attention then turns to the Sunday/Monday timeframe where we transition into a Ring of Fire setup on the eastern periphery of an upper-level ridge. Long range CAMs and other NWP guidance suggest that one or more clusters form on this ridge and track through Great Lakes region. Sunday Evening/Night and Monday Evening/Night are the favored windows at this time. However, these setups are well known for being very difficult to nail down the timing and placement of any thunderstorms. Some solutions suggest development near peak heating Sunday as well, and some suggest the storms miss the region all together. This whole timeframe has at least some potential for thunderstorms. Forecast soundings show a conditional severe weather threat in this timeframe , meaning that if the storms track through West Michigan, the environment will be favorable for severe weather. Sunday will feature MUCAPE values near or above 2000 J/kg with 40+ knots of deep layer shear, definitely sufficient for severe thunderstorms. The same environment may exist into Monday/Monday Night as well, with a more favorable mid-level jet placement across the area. Bottom line is environment is favorable for one or more rounds of severe thunderstorms early next week. However, confidence in where and when those storms would occur (including whether they affect West Michigan) is low given the synoptic pattern and dependence on boundaries from previous convection. Will continue to monitor and refine the forecast in the coming days. - Northwest Flow Continues Into Late Next Week Post the cold front later Monday into early Tuesday the northwest flow pattern continues. Surface ridging returns and low-level moisture diminishes for the mid-week period. This keeps conditons dry until Friday when a shortwave may trigger showers. && .AVIATION /00Z TAFS THROUGH 00Z SUNDAY/... Issued at 644 PM EDT Fri Jul 24 2026 VFR conditions will continue to dominate through the forecast period. Winds are expected to go light/variable between 00Z to 01Z this evening. Winds will mix out of the southwest between 13Z to 17Z. That mixing will increase with wind gusts upwards of 20kts likely at MKG and GRR at 18Z and 20Z respectively. Winds will remain gusty at times into the early evening. && .MARINE... Issued at 212 PM EDT Fri Jul 24 2026 Conditons remain below hazardous levels until Saturday afternoon. Strengthening southwest flow of 15-18 knots may result in a marginal High Swim Risk/Beach Hazards event north of Pentwater. Right now moderate swim risk is favored but slightly stronger winds/more onshore flow may nudge that to high. Dangerous winds and waves are also possible Tuesday in northwest winds behind a cold front. One or more rounds of thunderstorms are possible between Sunday and Monday night. Confidence in if/when storms impact the waters is low, however any storms may be capable of gusts over 34 knots. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ DISCUSSION...Thomas AVIATION...Ceru MARINE...Thomas

NWS GRR Office Area Forecast Discussion