855 FXUS63 KLMK 132333 AFDLMK Area Forecast Discussion National Weather Service Louisville KY 733 PM EDT Wed Aug 13 2025 ...Updated Aviation Discussion... .KEY MESSAGES... * Warm and humid with isolated to scattered showers and thunderstorms, tonight into tomorrow. The risk for severe weather is low, though some storms could produce locally heavy downpours and frequent lightning. * Hot and humid this weekend with highs in the low to mid 90s. Triple digit heat index values possible at times. && .SHORT TERM /THROUGH THURSDAY/... Issued at 332 PM EDT Wed Aug 13 2025 Positively tilted mid level trough stretching from the northeast US back into the Ohio Valley, along with a slow moving sfc boundary will keep the scattered showers/storms over the area this afternoon, tonight and into the day tomorrow. The main threat remains the same, heavy rainfall, thanks to PWAT values ranging between 1.50" to 2.00". Localized flooding, lightning and some gusty winds will remain the main threat with any storms we see develop over the next 24 hours. Shear remains light and weak over the area so there appears little to no threat of organized convection. Radar mosaic this afternoon shows scattered showers and isolated storms developing along both a weak sfc trough across southern and central KY and the weak sfc boundary across southern IN. As mentioned above, main threat this afternoon, remains locally heavy rainfall, lightning and gusty winds. While most of this activity is expected to diminish with the loss of daytime heating later this evening, like last night, some activity may linger overnight into the early morning hours. Patchy fog will once again be possible as we go overnight and into the early morning hours. Where and how dense the fog is will likely be determined on where it rains this afternoon and evening and how much clearing we can get overnight. Tomorrow looks like another wash, rinse and repeat kind of day but the PoPs as well as location of rain/storm looks to be lower (20- 30%) as well as further south with areas from Lexington to Louisville and points northward into southern IN look to remain mainly dry. It will remain warm and humid with overnight lows in the upper 60s/low 70s and highs tomorrow upper 80s to low 90s. && .LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/... Issued at 332 PM EDT Wed Aug 13 2025 For the end of the week and into the weekend, ridging will expand from the central Plains and over the Ohio Valley along with strong sfc high pressure will be positioned to our east and out into the Atlantic Ocean. Other than just a slight chance of an isolated shower or storm across the far southeastern corner of our CWA on Friday, the forecast looks dry but hot. Highs will climb from the low 90s on Friday and into the mid 90s by Sunday, we should see enough mixing to keep dewpoints in the upper 60s to near 70 producing heat index values into the upper 90s with a few locations seeing it feel like 100. Ridging over the central US will weaken some for the start of next week as a weak upper trough works over the top of the ridge and into the Great Lakes and Ohio Valley. This will push another sfc boundary southward towards southern IN and KY but how far south it reaches is still in question. Given the mid-level trough and proximity of sfc boundary, along with very warm temperatures in the low 90s. Diurnally driven convection is possible each afternoon. && .AVIATION /00Z TAFS THROUGH 06Z FRIDAY/... Issued at 733 PM EDT Wed Aug 13 2025 Weak surface front continues to sink slowly southward through the region this evening. A smattering of convective outflows were noted on the region 88-D`s and boundary collisions could still force a couple of showers/storms in the region through mid-evening. With the loss of heating, storms will end rather quickly. Overnight fog looks to develop across the region. Latest guidance remains similar to previous forecast, so not much change here with the forecast thinking overnight. Expect sites to drop into the IFR range due to fog, with the exception of SDF which looks to stay at MVFR levels for now. The outlook for Thursday calls for VFR conditions with light/variable winds. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...None. IN...None. && $$ SHORT TERM...BTN LONG TERM....BTN AVIATION.....MJ