FXUS63 KLMK 031921 AFDLMK Area Forecast Discussion National Weather Service Louisville KY 321 PM EDT Thu Jul 3 2025 .KEY MESSAGES... * Very warm temperatures with highs in the 90s for most, but reasonable humidity levels through Independence Day. * Higher humidity returns this weekend, with rain and thunderstorm chances increasing Sunday into next week. && .SHORT TERM /THROUGH FRIDAY/... Issued at 320 PM EDT Thu Jul 3 2025 Sfc high pressure over the Ozarks is maintaining a light northerly breeze across the Ohio Valley, which is keeping the humidity reasonable with dewpoints in the lower 60s. NW flow aloft still has some weak cyclonic curvature, so the Cu field is fairly extensive. Even with that, building heights have helped to push temps to around 90 degrees. Light winds and clearing skies tonight will favor radiational cooling, so expect at least patchy fog toward Friday morning, especially in valleys and other sheltered areas. For Friday the sfc high will consolidate over western New York, setting up a light east wind across the Ohio Valley. Heights will be rising, so temps look to run 2-3 degrees above today, with lower to mid 90s for most. Dewpoints remaining in the lower/mid 60s will keep the heat index out of triple digits. && .LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/... Issued at 320 PM EDT Thu Jul 3 2025 Humidity starts to ramp up this weekend as the sfc ridging slips east of the mid-Atlantic coast. Temps will easily reach the lower/mid 90s but dewpoints will rise slowly, not reaching 70 until fairly late Sunday afternoon as S/SW flow deepens. Not much concern yet about heat index values reaching advisory thresholds. but if dewpoints recover more quickly than advertised we could start to see the heat index reach 100+. Shower and thunderstorm chances also start to ramp up on Sunday, with scattered coverage expected for much of next week. Westerlies are fairly weak this far south, so no real shear to organize storms. However there is sufficient instability that if storms do develop, they could be strong with pulse severe hazards on the table. && .AVIATION /18Z TAFS THROUGH 00Z SATURDAY/... Issued at 105 PM EDT Thu Jul 3 2025 VFR conditions expected through the valid TAF period, with sct-bkn cu this afternoon. Light north winds this afternoon will decouple quickly at sunset. High pressure will then pass to our north, setting up light easterly winds by late morning Friday. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...None. IN...None. && $$ SHORT TERM...RAS LONG TERM...RAS AVIATION...RAS