textproduct: Louisville

KEY MESSAGES

* Dry weather for most today, though there is a chance for an isolated afternoon or evening storm mainly over southern Kentucky. Scattered afternoon thunderstorm chances (30-50%) return Thursday afternoon and evening.

* Rain and thunderstorm chances peak Friday into Saturday, especially during the afternoon and evening hours. Slow-moving storms will be capable of locally torrential rainfall, lightning, and gusty winds.

* Outside of storms, heat indices will peak in the 97-103 degree range each afternoon through at least Friday. Minor to moderate heat risk is possible, mainly affecting vulnerable populations sensitive to heat, especially those without cooling/hydration.

SHORT TERM /THROUGH THURSDAY NIGHT/

Issued at 245 PM EDT Wed Jul 15 2026

At 2pm EDT, temperatures across central Kentucky and southern Indiana were generally in the upper 80s degF, with a couple spots touching 90. Given dewpoints in the low 70s, heat indices (or "feels like" temperatures) were in the mid to upper 90s, making for another muggy day.

Mid-level water vapor imagery reveals a pronounced dry slot across the region associated with the subsidence of the ridge, and a cut- off low continues to meander across the southwest. Meanwhile, moisture streams from the eastern side of the low, keeping much of the region under a moist airmass. With just enough lift from the nearby low and strong diurnal heating, the highest convective chances remain confined mainly to southwest KY. Isolated showers are possible this afternoon and with elevated PWATs around 1.75-2", any shower that develops will have ample moisture to work with for a quick, heavy downpour. While model soundings indicate moderate instability is available across the region (SBCAPE values from 2500- 3000 J/kg), 0-6km bulk shear weakens through the afternoon, so showers will be slow-moving and efficient rain-producers.

By Thursday, the upper-level ridge begins to weaken, allowing more coverage for afternoon pop-ups. PoPs range from 30-50% in the western half of the region, and similarly to Wednesday, moderate instability and weak shear are expected to keep these pop-up showers' main threats contained to locally heavy downpours and gusty winds. Temperatures remain seasonably warm as we switch to a southwesterly flow, and with highs in the upper 80s to low 90s and dewpoints in the 70s, heat indices will likely approach 98-102 degF. Due to nocturnal cooling, showers and storms will diminish throughout the evening/overnight, and temperatures are expected to fall back into the lower 70s across the region.

LONG TERM /FRIDAY THROUGH TUESDAY/

Issued at 245 PM EDT Wed Jul 15 2026

===== Friday - Saturday =====

A subtle mid-level shortwave disturbance is forecast to begin the period over the Mid-Mississippi Valley. This feature will meander anticyclonically around the mid-level ridge axis and across the Lower OH Valley through Saturday. This feature will help draw deeper moisture into the region, with ensemble mean PW values increasing to 1.9-2.0 inches. By Saturday, we also see a much weaker ridge aloft (over our region) with the amplification of the upper level ridge over the Rockies and the downstream trough diving southeast over the Great Lakes. A sfc low is forecast to track east across portions of the Great Lakes, with an attendant cold front dropping south through the Upper Midwest.

Sfc dewpoints in the low to mid 70s look to be common both Friday and Saturday. At least moderate destabilization of the warm, moist airmass appears likely both days. Given weak forcing and much less subsidence aloft, scattered to numerous showers and storms are expected each afternoon and evening. Very weak deep-layer shear and low-level forcing will support a pulse convective mode. Outflow boundary interaction may locally enhance storm coverage and threats. The primary threats are locally torrential rainfall, strong wind gusts, and lightning. Very slow-moving cells capable of torrential rainfall may lead to isolated flash flooding. Outside of storms, afternoon temperatures will rise into the 85-90 degree range. Morning lows will reach the lower 70s.

===== Sunday - Next Week =====

By late Saturday night, low pressure is forecast to be deepening to the northeast across New England with a sfc cold front dipping south into the Lower OH Valley. A deeper upper level trough will continue to be carved out over the northeastern CONUS heading into Sunday. We'll start to see some drier air aloft advect into the region from the northwest. The cold front pushing through will keep a chance (30- 50%) for rain in the forecast for central and southern KY through Sunday.

Monday looks much drier overall in the wake of Sunday's cool front. Another digging upper level trough and deepening sfc wave across Ontario may then drag another cold front into the region by late Tuesday. This keeps a low chance (20-30%) of rain in the forecast for Tuesday, but confidence in the details is low at this time range.

AVIATION /18Z TAFS THROUGH 00Z FRIDAY/

Issued at 143 PM EDT Wed Jul 15 2026

High pressure will maintain light winds and dry weather throughout the forecast period. Diurnal cu around 4kft should dissipate this evening, which will result in a favorable environment for patchy fog by 08-12z; this remains in the forecast via a tempo group at the terminals with the highest confidence (20-30%), i.e., HNB, LEX, and RGA.

LMK WATCHES/WARNINGS/ADVISORIES

KY...None. IN...None.