textproduct: Louisville

KEY MESSAGES

* Unsettled weather pattern to continue tonight and into Saturday with showers and thunderstorms expected across the region. Any storm will be capable of localized heavy rainfall. Most folks can expect 0.5-1" of rainfall, but some very isolated amounts of 2-3" are possible.

* Overall drier and hotter conditions arrive early next week while an upper level ridge builds in.

SHORT TERM /THROUGH SATURDAY NIGHT/

Issued at 255 PM EDT Fri Sep 11 2026

Early morning mid-level wave axis has pushed off to the northeast. In its wake, skies are starting to slowly clear across southern IN and the northern half of KY. This has led to a temperature gradient across the region with upper 70s to around 80 across southern IN and northern KY with mid-upper 80s down along the KY/TN border region.

For the remainder of the afternoon, we'll see cloud cover slowly mix out across southern IN and northern KY. While temperatures have been kept in the upper 70s, we should still have enough heating and evening daylight to push temps into the lower 80s prior to sunset. A few scattered showers/storms can't be ruled out across southern KY where a washed out frontal boundary resides. However, the lack of concentrated forcing for lift will likely keep PoP coverage at 20% or less for the evening. The best chances for any convection this evening will likely be out west of the I-165 corridor.

For tonight, the next mid-level shortwave trough axis is expected to slowly eject from the lower MS Valley. The latest CAM solutions show an uptick in convection across western TN and western KY by mid- late evening spreading east-northeast into central KY overnight. While the shortwave trough and associated height falls would be enough support for lift, overall coverage/intensity of convection is uncertain given that instability will be lost due to loss of daytime heating. However, model soundings do show a bit of elevated instability along with plenty of low-level moisture. So convection that fires overnight would be capable of producing locally heavy rainfall and lightning. Lows tonight will be mild with upper 60s and lower 70s expected. Have gone closer to the HREF for low temps tonight with this forecast issuance.

Moving on to Saturday, another in a series of shortwave troughs is expected to move across the region. Model soundings show plentiful low-level moisture in place along with some instability. Most soundings continue to show a tall/skinny CAPE profile across the region. Given the expected timing of the shortwave, the highest chances of convection look to be in areas mainly east of the I-65 corridor. Given the instability/shear profiles, the threat of severe weather here continues to look low. However, slow movement of convection given the forecast steering flow would result in locally heavy rainfall being the main threat. Highs for the day will likely be limited by ongoing cloud cover and expected precipitation. Have gone closer to the HREF guidance here with highs in the 82-87 degree range.

Shortwave trough axis will move northeast and away from the region Saturday night with the threat of convection diminishing from west to east. Lows will be in the upper 60s to around 70.

LONG TERM /SUNDAY THROUGH THURSDAY/

Issued at 255 PM EDT Fri Sep 11 2026

Sunday - Thursday Night...

An upper level ridge will begin to build into the region from the west, bringing higher surface pressure. This will bring drier and warmer temperatures into the forecast. Maximum temperatures for Sunday and Monday will be in the mid to upper 80s, however Tuesday will warm into the low 90s. LREF guidance shows these temperatures in the 90th percentile of climatology for this time of year.

PoPs are expected to stay minimal for the beginning of the week, with slight chances of scattered showers on Wednesday. As the upper ridge continues east, the flow aloft will shift more southwesterly bringing some moist back into the region. Confidence is fairly low with any developing rain due to the effect on the ridge from the upper level trough over Canada. A draping cold front will try to push into the Ohio Valley mid week, however some guidance is suggesting it will become nearly stationary near the Great Lakes. This will decrease the chances for rain as this would be the lifting mechanism for development. Otherwise, temperatures will remain near normal with highs in the high to mid 80s through late next week.

AVIATION /18Z TAFS THROUGH 00Z SUNDAY/

Issued at 124 PM EDT Fri Sep 11 2026

Mid-level disturbance responsible for the morning convection continues to move off to the north and east. For the afternoon hours, no additional widespread precipitation is expected with cigs increasing into the VFR range and winds starting off light/variable and generally shifting to the east/east-southeast during the afternoon.

A secondary mid-level wave will lift out of AR this evening and may bring scattered convection back to western KY (BWG terminal) this evening. Additional convection with this wave may affect HNB/SDF overnight. For now, confidence level is good enough to mention PROB30s here, but we may have to go more pessimistic with the forecast in later issuances as confidence increases. Winds tonight will be southeasterly and shift to the south/southwest towards dawn Saturday.

Outlook for Saturday will feature scattered showers/storms mainly along and east of the I-65 corridor. May start off with a low stratus deck which may be MVFR at times, but VFR conditions are expected during the day outside of any convection.

LMK WATCHES/WARNINGS/ADVISORIES

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