411 FXUS63 KIND 290645 AFDIND Area Forecast Discussion National Weather Service Indianapolis IN 245 AM EDT Mon Jun 29 2026 .KEY MESSAGES... - Hot and humid condition expected for much of this week with multiple days in the 90s and heat indices over 100 degrees - Heat Advisory in effect this afternoon through Thursday - Thunderstorm chances will increase late week into the holiday weekend && .DISCUSSION (Today through Sunday)... Issued at 245 AM EDT Mon Jun 29 2026 Steamy early this morning as with leftover convective cloud debris drifting southeast across the region on the eastern flank of the upper ridge. 06Z temperatures were in the mid and upper 70s. The ridge will amplify across much of the eastern part of the country over the next several days with an extended stretch of hot and humid conditions lasting into the upcoming weekend. This will be easily the hottest weather of the summer to date through Thursday with dangerous heat indices becoming a primary concern throughout the forecast period. The ridge will flatten by the end of the week as the jet stream drifts back south into the area. Scattered convection largely prevalent on any waves ripping through the flow will increase for the holiday weekend as a result. The remnants of convection from Sunday afternoon continue to track southeast out of lower Michigan early this morning on the east side of the upper ridge. There remains just enough low level moisture that a few stray showers are not entirely out of the question across the northeast half of the forecast area through daybreak. After that...the ridge axis will pivot across the Ohio Valley shifting any threat of rain well to the east of central Indiana. Despite scattered diurnal cu development today...the onset of the dangerous heat and humidity that has been discussed for several days now arrives over the Ohio Valley today. Today will mark the first in an extended stretch of days with highs 90 degrees or warmer and heat indices above 100 as the heat ridge becomes the dominant influence for much of the next week. The Heat Advisory will go into effect at 16Z this afternoon and continue through Thursday. The hottest days will be Tuesday and Wednesday as the core of the ridge parks over the region with heights at 596-597dam. Highs both days will peak in the mid 90s in some locations with limited clouds. Daytime dewpoints remaining well into the 70s will ensure max heat indices at 105 to 109 degrees and provide an oppressive airmass that will only exacerbate the hot temperatures. The ridge will slowly flatten heading into the weekend as waves aloft drift further south into the lower Great Lakes and Ohio Valley. Moisture lifting around the back side of the ridge may be enough to generate more cu and perhaps isolated late afternoon and evening convection by Thursday. Convective coverage should steadily increase Friday into the weekend as the mid level heights begin to fall back. Locally intense slow moving storms will be a possibility within the moist and highly unstable airmass. Very warm and humid conditions will linger into the holiday weekend with highs slipping back into the upper 80s by Sunday. && .AVIATION (06Z TAF Issuance)... Issued at 1202 AM EDT Mon Jun 29 2026 Impacts: - Patchy MVFR fog possible overnight, periods of IFR possible at KBMG Discussion: High level convective cloud debris will continue to drift southeast across the region over the next few hours. Still feel LAMP guidance is underforecasting fog potential...and NBM probabilities tend to hint at somewhat more possibility for visibility restrictions predawn and through daybreak. Greatest potential will be at outlying terminals and will continue with a period of tempo MVFR. At KBMG which is both climatologically vulnerable and in one of the wetter regions of the area in recent days...IFR visibilities will be possible later in the overnight. VFR conditions are expected once any fog dissipates in typical diurnal fashion by mid morning. Diurnal cu is possible for this afternoon before diminishing as skies clear this evening. S/SW winds up to 10kts are possible later today. && .IND WATCHES/WARNINGS/ADVISORIES... Heat Advisory from noon today to 8 PM EDT Thursday for INZ021- 028>031-035>049-051>057-060>065-067>072. && $$ AVIATION...Ryan DISCUSSION...Ryan