645 FXUS63 KIWX 292210 AFDIWX Area Forecast Discussion National Weather Service Northern Indiana 610 PM EDT Mon Jun 29 2026 .KEY MESSAGES... - Extreme Heat Warning is in effect through Thursday evening for an extended period of high heat indices and limited nighttime cooling. - Heat may remain a concern Friday, but chances for showers and thunderstorms begin to increase resulting in lower confidence on the amount of impacts. && .DISCUSSION... Issued at 140 PM EDT Mon Jun 29 2026 Forecast generally on track with the main focus into Thursday remaining on the extended period of heat and humidity. Dewpoints continue to climb and are somewhat concerning as hints of some of the model blends are appearing as pockets of 76 to 78 degree values are being noted even back into IL. Always a fine balance on how warm air temps can get as the very high dewpoints arrive, but low to mid 90s still seem reasonable over the next several days. A strong mid level cap, depicted by 700 mb temps of +12 to +15 C, should keep any convective chances nearly non existent through at least Wednesday. Starting Thursday the upper level ridge begins to weak ever so slightly and may allow for some widely scattered shower/storm development mainly in the west or northwest. The ridge slowly gives way over the weekend, especially Sunday into next week as it flattens out somewhat. Chances for convection will generally be diurnal, but will need to monitor for upstream complexes each day and possible impacts. As for heat concerns, the warning continues into Thursday with some potential for extension into Friday. && .AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/... Issued at 610 PM EDT Mon Jun 29 2026 VFR/dry conditions are expected to persist through the TAF on the northern periphery of a ~595 dm 5H ridge. Low level south-southwest flow will diminish to mainly less than 10 knots tonight, then pick up a bit again late Tuesday morning into Tuesday afternoon with gusts up to near 20 knots at times. Atmosphere likely remains mixed well enough otherwise to keep widespread haze and potential vis restrictions from developing under the building heat dome. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...Extreme Heat Warning until 8 PM EDT /7 PM CDT/ Thursday for INZ005>009-012>015-017-018-020-022>027-032>034-103-104- 116-203-204-216. OH...Extreme Heat Warning until 8 PM EDT Thursday for OHZ001-002- 004-005-015-016-024-025. MI...Extreme Heat Warning until 8 PM EDT Thursday for MIZ078>081- 177-277. Air Quality Alert from midnight tonight to midnight EDT Tuesday night for MIZ177-277. MARINE...None. && $$ DISCUSSION...Fisher AVIATION...Steinwedel