textproduct: Louisville

KEY MESSAGES

* Scattered showers will continue through this evening, with patchy drizzle overnight. At least a low (15-30%) chance for afternoon showers will continue across south-central and eastern Kentucky through Wednesday.

* Rounds of showers and thunderstorms are expected to continue each afternoon and evening late week through the weekend as a moist and unstable airmass combines with a frontal boundary sinking southward toward the area.

SHORT TERM /THROUGH MONDAY NIGHT/

Issued at 148 PM EDT Sun Aug 2 2026

Through Monday night...

Early Sunday afternoon, a positively-tilted upper level trough extends from Quebec across the Ohio Valley and into the Deep South. At the surface, an occluded, nearly stationary area of low pressure is centered over Kentuckiana, providing convergence for scattered showers which will continue into the evening before waning with the loss of diurnally-driven instability. Like last night, another round of low stratus and patchy drizzle is expected, especially in areas near and east of the I-65 corridor where the latest RAP paints splotches of light QPF, depicts the highest 0-1km RH (>90%), and advertises weakly negative omega (rising motion). Overall, visibilities don't look particularly bad, with the High Resolution Ensemble Forecast (HREF) system and National Blend of Models (NBM) each advertising around 10-25% chances for visibilities under 2 miles (highest southeast of a Williamstown to Glasgow line) between roughly 3am and 8am EDT.

Temperatures, which are unlikely to climb much more from the mid 70s early Sunday afternoon, will run a little cooler than normal again tomorrow as clouds associated with the low take their time scattering out during the afternoon. Forecast highs (upper 70s to low 80s) are a little warmer across western portions of the area where shortwave ridging will attempt to nudge in behind the low, which will become cutoff and drift into the Deep South. We may still have a couple showers in the east tomorrow afternoon, but overall coverage will be lower at around 20-30% (vs 40-60% today).

LONG TERM /TUESDAY THROUGH SATURDAY/

Issued at 148 PM EDT Sun Aug 2 2026

Tuesday - Wednesday...

The pesky cutoff low will meander back to the NW on Tuesday, settling somewhere near the GA/TN/NC borders. As this occurs, expect the NW extent of the associated moisture plume to reach up into our SE CWA. This combined with diurnal heating should allow for some afternoon and evening showers and storms. The vertical shear profile will be very light, so any storm modes will be pulse in nature and of the general garden variety. Overall instability values will also be fairly modest for this time of year, likely peaking in the 700- 1200 J/KG range. Another factor suggesting strong storms are not likely.

The closed low finally begins to open up and will start to lift through the central Appalachians as an open wave Wednesday and Wednesday night. This will occur as broad and low amplitude baggy troughing settles into the Great Lakes region, and the slightly stronger westerlies associated with it finally pick up the meandering upper low. By this time, the bulk of the moisture plume will be along and south of the Ohio River, so expect this will be the best placement for renewed shower and storm development on Wednesday afternoon and evening. Much like Tuesday, only expect garden variety showers and a few storms as vertical wind shear remains non-existent and only modest instability values are able to develop. Strong storms not likely again on this day. Temps during this stretch will likely range in the mid 80s each day, with lows in the mid 60s to around 70.

Thursday - Sunday...

Fairly active weather will likely continue late week into the weekend as we sit between the western periphery of an upper ridge centered off the Mid-Atlantic coast, and the baggy trough mentioned above. A decent mix of Gulf and Atlantic moisture will likely be able to feed into our area around the upper ridge. In addition, a weak frontal boundary will slide southward toward the Ohio River with a bit of additional moisture, and the near-surface convergence necessary to trigger some diurnally driven showers and storms. It appears that the actual surface front may never quite make it into our region, but will likely get close enough to bring repeated rounds of showers and storms each day, especially across southern IN. Additional scattered coverage of airmass thunderstorms is also possible across KY moreso from the Gulf/Atlantic deeper moisture feed. Coverage would likely be less in KY, and higher up along the front where better triggering. The northern storms will also have a bit more deep layer shear to work with thanks to the upper troughing. Perhaps there will be enough shear at times to support some loosely organized updrafts capable of multicell cluster storm modes. It is possible that some rainfall totals will start to add up through the the weekend as the combination of a quasi-stationary frontal boundary, a plentiful deep moisture feed, and relatively slow storm movement combine to create some locally heavy rainfall potential. Will monitor trends to see if any potential flooding threats could develop. Highs should generally range in the 85 to 90 degree range for most spots through each day, although afternoon highs may be somewhat dependent on storm activity each day.

AVIATION /18Z TAFS THROUGH 00Z TUESDAY/

Issued at 148 PM EDT Sun Aug 2 2026

A mix of MVFR and VFR ceilings continue early Sunday afternoon as a low pressure system rotates overhead. Scattered showers (40-60% coverage), however, will bring occasional visibility reductions through around 00z when diurnal instability wanes. Low ceilings and drizzle should return tonight, especially at LEX and RGA where IFR ceilings are likely (60-80% chance) from 09-13z. Like today, ceilings will gradually rise tomorrow morning into early afternoon.

LMK WATCHES/WARNINGS/ADVISORIES

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