850 FXUS63 KGRR 291739 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 139 PM EDT Mon Jun 29 2026 .KEY MESSAGES... - Non-zero chance for storms this morning - Extreme heat starts to set in today && .DISCUSSION... Issued at 257 AM EDT Mon Jun 29 2026 - Non-zero chance for storms this morning Still the potential for a few lightning strikes from the showers currently over the area. The showers currently over Michigan give our southern and eastern zones their best shot for rain/thunder this morning. The northern zones best chance comes from whether or not showers/storms currently developing over Wisconsin make a southerly/southeasterly turn and make it across Lake Michigan. Still enough instability to keep us in the marginal risk for severe weather - with greatest risk for hail and damaging winds. Models have all backed off somewhat on bringing anything into the area at all...keeping decaying storms in northern Lower...so this morning could also be a complete bust. It certainly a wait and see what the next few hours brings kind of a morning. Window for any storms today seems to close around or shortly after noon. - Extreme heat starts to set in today The well advertised heat and humidity starts to build in today and remains through at least the end of the week. High temperatures should reach the upper 80s to lower 90s today across West Michigan...making Monday the coolest day of the week. 90s to near 100 for highs Tuesday through Thursday are still expected with heat index values of 105+. Lack of overnight relief from the heat and humidity still expected with lows in the 70s for at least the next 4 nights. Its possible we might see a few record highs this week...but we may be more likely to break a couple of record warm low temperatures. && .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 257 AM EDT Mon Jun 29 2026 Waves and winds will increase through the day with hazardous swimming and boating conditions on Lake Michigan expected through Tuesday. && .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...Maczko AVIATION...04 MARINE...Maczko