861 FXUS63 KLMK 012324 AFDLMK Area Forecast Discussion National Weather Service Louisville KY 724 PM EDT Thu Aug 1 2024 ...Updated Aviation Discussion... .KEY MESSAGES... * Thunderstorm chances continue Friday into Saturday. Torrential rainfall could result in localized flash flooding, especially where the ground is already saturated. Gusty winds also possible in the stronger storms. * Dry weather Sunday into early next week, but hot temperatures will return, pushing the heat index near 100 at times. && .UPDATE... Issued at 529 PM EDT Thu Aug 1 2024 Dropped the Heat Advisory for a handful of counties where thunderstorms have dropped temperatures 20 degrees. Thanks to PAH for coord. Would like to hold on to the SVA a little longer and monitor trends before dropping counties. Yesterday afternoon widespread storms moved through the region, but SPS-level storms still managed to redevelop behind the storms mid-evening. Today we still have a few hours of sunshine left, and there has been some redevelopment, albeit relatively weak, between EVV and PAH. While we will still probably drop western counties from the SVA early, don't want to jump the gun. && .SHORT TERM /THROUGH FRIDAY/... Issued at 319 PM EDT Thu Aug 1 2024 The same overall pattern remains with upper ridging over the western US. Northwest flow continues to bring round after round of convection through southern Indiana and central Kentucky. We began the afternoon by issuing a Heat Advisory from a line from Perry County, Indiana to Monroe County, Kentucky and to the southwest for heat indices near 105 degrees. Based on observations, we could have added Dubois County as well, but approaching showers will cool them within the next hour. For the rest of the day, eyes will be on convection that has just entered southwest Indiana. While the storm developed over southern Illinois, it exploded, producing lots of lightning and severe winds over 50 knots, but now the overall strength of the storm has weakened as outflow has jumped ahead of all but the southern part of the line. As the system moves eastward along a MLCAPE gradient of 2- 3,000 J/kg, the system is expected to increase in size, and with DCAPE values around 1,000 to 1,100 J/kg gusty winds will be the primary concern along with lightning. Deep layer shear remains weak, but with storm to storm and outflow interaction, localized areas of enhancement will be possible. Flash flooding is also of concern as we head through the afternoon and evening hours. Precipitable water values are currently around 2" around current convection with 1.8-1.9" values over the CWA. These are close to the same values that have been over the CWA for the last few days, and with warm temperatures in place, most areas have been able to handle most of the rainfall as long as there are some breaks in the heavy rainfall. There could be so isolated issues if any heavy rainers sit stationary, but believe the expected progressive nature of the convection will limit widespread flooding issues. Tonight and tomorrow, as a closed upper low rides in on the northwest flow from the Midwest towards the Lower Ohio Valley, isolated to scattered showers remain possible. During the overnight, the added low level moisture could lead to patchy fogging and/or low stratus while other areas see more clearing. Low temperatures tonight are expected to drop into the low to mid 70s before mid to upper 80s return tomorrow. && .LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/... Issued at 319 PM EDT Thu Aug 1 2024 Showers and storms should start winding down in coverage Friday night with the loss of daytime heating and no appreciable lifting/forcing mechanism in place. Isolated to scattered activity could linger into the morning hours, and then increase in coverage some during the afternoon Saturday, but drier, more stable air working in behind an upper level trough should steadily end the rain threat from west to east. Dry weather should continue Sunday into early next week as warmer 850-700mb temps cap convective development. Temps will be on the warmer side of climo due to the lack of more widespread clouds and convective development (likely climbing into the low 90s), and dewpoints in the upper 60s to low 70s will certainly make it feel muggy. At this point, though, it appears we'll stay short of heat advisory criteria, with most spots hitting 95-100 degree peak heat indices through next week. Rain chances may begin to creep up by midweek depending on how the upper level flow evolves. Most models keep us on the southern fringes of the more active flow aloft, which in theory would result in most convective waves/MCSs passing just to our north. Current forecast carries small PoP chances to account for these waves as well as any potential diurnal pulse-convection that may develop on mesoscale boundaries. && .AVIATION /00Z TAFS THROUGH 06Z SUNDAY/... Issued at 723 PM EDT Thu Aug 1 2024 Earlier storms will have moved off to the east by the start of the TAF period other than a few lingering rumbles of thunder at RGA and possibly LEX/BWG. For the remainder of the night, skies should be partly cloudy with light winds. Can't rule out widely scattered thunderstorms overnight once again in the humid air mass, though low confidence restricted TAF mention to PROB30. Could see some light BR at HNB/RGA around dawn. Another day of scattered storms is expected tomorrow, so went with PROB30 for the afternoon hours. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...None. IN...None. && $$ UPDATE...13 SHORT TERM...KDW LONG TERM...DM AVIATION...13