020 FXUS63 KGRR 291845 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 245 PM EDT Mon Jun 29 2026 .KEY MESSAGES... - Extreme Heat Today Through At Least Thursday - Chances for Storms Later in the Week && .DISCUSSION... Issued at 243 PM EDT Mon Jun 29 2026 - Extreme Heat Today Through At Least Thursday Temperatures climbing into the low to mid 90s with dew points in the low to mid 70s is expected to bring heat indexes to around 100 to 110 for four days in a row, which is a fairly impressive heat wave and one with a major heat risk to people acclimated to normal Michigan weather. Temperatures will naturally be cooler along the Lake Michigan shore especially north of Holland. 850 mb temperatures 19 to 23 C are expected today through Thursday as southwesterly flow transports hot air around a 596 dekameter 500 mb high centered over Kentucky. A few locations may come close to record daily highs, particularly Lansing on Wed and Thu. More likely will be challenging record warm nighttime lows Wed morning and Thu morning. Temperatures by Friday may trend slightly cooler as the ridge flattens a little and waves of convection have a greater chance of occurring father south than earlier in the week. 75 percent of ECE members give highs below 90 on Friday. - Chances for Storms Later in the Week Elevated thunderstorms this morning stayed in northern Lower Michigan and will not be a factor in our weather to the south. A strong convective cap forming from subsiding air within the ridge will limit our thunderstorm potential today and likely Tuesday. Only a few experimental models, including some runs of the RRFS and some MPAS-based models, develop storms in Nebraska this evening and bring the resulting atmospheric wave as far south as west-central Lower, near US-10, by late Tue morning. All of the models within the HREF are keeping that threat farther north. As the upper-level ridge flattens slightly later in the week and successive shortwaves with associated thunderstorms around the "ring of fire" continue marching through, generally a little more south with time, the chance of an MCS or two in Southern Lower MI will increase, particularly between late in the day Thursday and Friday night, as indicated by most global model ensemble members. && .AVIATION /18Z TAFS THROUGH 18Z TUESDAY/... Issued at 138 PM EDT Mon Jun 29 2026 VFR conditions are expected through the period. South winds will become breezy during the afternoon but diminish a bit after sunset. && .MARINE... Issued at 243 PM EDT Mon Jun 29 2026 Small Craft Advisory and Beach Hazards Statement continues through Tuesday, for areas north of Holland toward Ludington/Manistee, as south winds will be present. These winds are expected to be fairly breezy over the land, but over the water, should be limited by a sharp marine temperature inversion layer. Air temperatures flowing in from the south are expected to stay much warmer than the water even through the overnight, limiting the amount of winds aloft that will mix down to impart momentum onto the water. It is quite possible that our advisory busts too high today and Tuesday, given that at noon today, wind and wave values at the Port Sheldon, South Midlake, and Central Midlake buoys are meaningfully lower than the NBM winds and the resulting WW3 model waves. This matches a similar bust scenario that occurred at a couple times last summer, with breezy south-southwest winds occurring at the onset of extreme heat. Nonetheless, at least moderate swim risk should still be planned for and extra care taken south of south piers. && .CLIMATE... Issued at 245 PM EDT Mon Jun 29 2026 Records for June 28 - July 2 Record High Temperatures for June 28 Grand Rapids 97 (1913) Lansing 96 (1964) Muskegon 93 (1964) Kalamazoo 100 (1934) Battle Creek 99 (1934) Holland 96 (1906) Record High Temperatures for June 29 Grand Rapids 99 (1931) Lansing 98 (1913) Muskegon 92 (2020) Kalamazoo 98 (1934) Battle Creek 100 (1913) Holland 95 (1921) Record High Temperatures for July 1 Grand Rapids 101 (1931) Lansing 97 (1913) Muskegon 93 (2018) Kalamazoo 101 (1931) Battle Creek 100 (1931) Holland 96 (1949) Record High Temperatures for July 2 Grand Rapids 97 (1913) Lansing 98 (1966) Muskegon 95 (1966) Kalamazoo 100 (1911) Battle Creek 98 (1949) Holland 96 (2012) Record Warm Low Temperatures for June 28 Grand Rapids 76 (1931) Lansing 73 (1996) Muskegon 76 (1931) Kalamazoo 78 (1901) Battle Creek 74 (1920) Holland 76 (1931) Record Warm Low Temperatures for June 29 Grand Rapids 76 (1931) Lansing 77 (2018) Muskegon 78 (1913) Kalamazoo 76 (2018) Battle Creek 76 (2018) Holland 72 (2002) Record Warm Low Temperatures for July 1 Grand Rapids 78 (1931) Lansing 74 (1931) Muskegon 74 (2018) Kalamazoo 77 (1931) Battle Creek 74 (1970) Holland 77 (1934) Record Warm Low Temperatures for July 2 Grand Rapids 74 (1911) Lansing 74 (1931) Muskegon 73 (2002) Kalamazoo 75 (1931) Battle Creek 75 (1931) Holland 72 (2002) && .GRR WATCHES/WARNINGS/ADVISORIES... MI...Beach Hazards Statement through Tuesday evening for MIZ037-043- 050-056. Extreme Heat Warning until 8 PM EDT Thursday for MIZ037>040- 043>046-050>052-056>059-064>067-071>074. Air Quality Alert from midnight tonight to midnight EDT Tuesday night for MIZ050-056-057-064-071. MARINE...Small Craft Advisory until 8 PM EDT Tuesday for LMZ846>849. && $$ DISCUSSION...CAS AVIATION...04 MARINE...CAS CLIMATE...Thomas

NWS GRR Office Area Forecast Discussion