053 FXUS63 KLMK 291732 AFDLMK Area Forecast Discussion National Weather Service Louisville KY 132 PM EDT Mon Jun 29 2026 ...Forecast Update and Aviation Discussion... .KEY MESSAGES... * A few pockets of light rain (20% chance) will be possible across the Bluegrass Region this morning. Otherwise, hot and humid today with afternoon highs in the low to mid 90s. A Heat Advisory remains in effect today through Thursday. * A strong ridge of high pressure over the region will bring the hottest temperatures so far this year. The heat will peak Tuesday through Thursday, with afternoon highs in the mid 90s and peak index values of 105+. * Hot and humid for the Fourth of July holiday weekend, with isolated to scattered storms possible in the afternoon and evening. && .UPDATE... Issued at 130 PM EDT Mon Jun 29 2026 Went ahead and upgraded the existing Heat Advisory headline to an Extreme Heat Warning in coordination with surrounding offices. The prolonged nature of this week's heat combined with it being the first notable heat of the year and the holiday week, felt it would be more prudent to message this for potential impacts. We'll pockets of peak afternoon HI values over 110F, especially along or west of I- 65, however max HI values around 105 look pretty reasonable at least through Thursday. Could always get a thunderstorm complex to bust an afternoon temp forecast, but this doesn't really become a possibility until mid to late week anyway after several days of oppressive heat. So, decided this was the best route to take both for impacts and messaging simplicity. && .SHORT TERM /THROUGH TONIGHT/... Issued at 340 AM EDT Mon Jun 29 2026 A warm front stretches southeast through central Indiana and the Bluegrass Region early this morning. GOES-East Nighttime Microphysics RGB imagery shows a band of lower level clouds along this boundary. We even have a few tiny showers drifting through portions of Shelby, Anderson, and Mercer counties at the time of this writing. There is a notable Theta-E gradient across the warm frontal boundary. Despite increasing subsidence aloft, modest low- level convergence should lead to additional isolated showers in the Bluegrass Region. There is a slight chance (20%) for a brief shower through the morning hours, with the warm front lifting northeast of the area by 18Z today. Conditions will be hot and oppressively humid this afternoon and evening. An upper level ridge will continue to build over the region, with the center of the mid-level ridge moving over western TN/KY. Despite a scattered cumulus field, temperatures will have no trouble rising into the lower 90s in most places. A few spots west of I-65 and the Louisville Metro may briefly top out in the mid 90s. Sfc dewpoints are forecast to remain in the mid and upper 70s, yielding afternoon heat indices in the 100-109 range. No changes are planned to the Heat Advisory for today. The HREF's probability for an apparent temperature greater than 109 is only 10-20% in the far western CWA (Dubois, Perry, Hancock, Ohio counties). Tonight will be dry and quite warm, with lows only in the mid 70s. && .LONG TERM /TUESDAY THROUGH SUNDAY/... Issued at 340 AM EDT Mon Jun 29 2026 The upper level ridge overhead will peak in intensity Tuesday through Thursday, and this is when we will see the hottest temperatures of this heat wave. Afternoon highs in the mid 90s are likely each day. Peak afternoon and evening heat index values of 105- 110 are also likely Tuesday - Thursday. The probabilistic HeatRisk tool shows very high probabilities (90-100%) for major or higher heat-related impacts, affecting anyone without cooling/hydration as well as health systems and industries. Drink water, stay in the A/C if possible, stay out of the sun, and check up on family, friends, and neighbors. The mid and upper level ridge begins to break down heading into the holiday weekend, with multiple mid-level shortwave disturbances forecast to ride east across the Midwest and Great Lakes. With a hot and humid airmass still in place, a chance (30%) of scattered pulse convection returns for Friday - Sunday. A weaker ridge and afternoon pulse convection will allow highs to settle back into the lower 90s over the weekend. && .AVIATION /18Z TAFS THROUGH 00Z WEDNESDAY/... Issued at 130 PM EDT Mon Jun 29 2026 High pressure at the surface and aloft will control the region for this TAF cycle, and for the upcoming week. Look for Sct-Bkn cumulus clouds between 3500-4500 ft this afternoon. Light to steady SSW wind between 5 and 10 mph are expected during the afternoon, with light winds overnight. Can't rule out some patchy fog given the amount of low level moisture, however upper sky cover and some light winds keeping the low levels mixed may be just enough to mitigate the fog potential. Will leave it out for now with low confidence. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...Extreme Heat Warning until 9 PM EDT /8 PM CDT/ Thursday for KYZ023>043-045>049-053>057-061>067-070>078-081-082. IN...Extreme Heat Warning until 9 PM EDT /8 PM CDT/ Thursday for INZ076>079-083-084-089>092. && $$ UPDATE...BJS SHORT TERM...EBW LONG TERM...EBW AVIATION...BJS