textproduct: Louisville

KEY MESSAGES

* Quiet weather is expected for tonight and tomorrow across the region, though patchy fog is possible tonight.

* Shower and storm chances (50-90%) return by late Thursday, and linger through at least Saturday. Any training storms could result in localized flooding, especially Thursday night and Friday.

* Summerlike heat and humidity is forecast to return next work week. There is a 35-50% chance heat indices surpass 100 degrees by Tuesday.

SHORT TERM /THROUGH WEDNESDAY/

Issued at 403 PM EDT Tue Jun 23 2026

It is a pleasant day across central Kentucky and southern Indiana as high pressure continues to build in over the area. A mid-level cu field will clear out after sunset tonight, allowing temperatures to drop into the mid-to-upper 50s. With calm winds expected tonight, there is the potential for patchy fog to develop across the CWA, with the highest chances of more widespread fog to occur for places along and east of I-75.

For Wednesday, high pressure will continue to prevail across the region, allowing for another nice weather day. Temperatures will remain slightly below average, with highs in the low 80s forecast. Winds will shift to the south during the late morning/afternoon hours, but continue to remain fairly calm.

LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/

Issued at 403 PM EDT Tue Jun 23 2026

Starting Wednesday night, the surface high pressure begins to shift off to the east as the upper-level pattern begins to become more zonal. A few showers are possible along and north of the Ohio River late Wednesday night as a weak wave moves through that part of the region. There is decent uncertainty in the models on the placement of this feature, so PoPs <30% were included in the forecast package during this time.

The early part of the day on Thursday appears to be fairly dry, but with building southerly flow temperatures will rise into the mid-to- upper 80s by the afternoon hours. This will all take place ahead of a mid-level shortwave that is slated to move over the Ohio Valley Thursday night. Additionally, the cold front of a surface low over Quebec will become nearly stationary over central Indiana and Ohio, acting as a pathway for this and subsequent shortwaves to move over. The southerly flow will also allow more Gulf moisture to return to the region, with LREF PW values over 1.8" covering most of the area by Thursday night. The nose of an enhancing LLJ will move into the region near the onset of the initial shortwave, and with near- parallel flow to the cold front this should help support back- building of showers and thunderstorms. The placement of the cold front will be important as areas just south of the boundary will most likely experience the most rainfall with this system and additional systems through Saturday night. LREF guidance currently has 40-50% probabilities of greater than 2" along and north of the Ohio River Thursday night-Saturday night, with 45-55% probabilities being outputted by the NBM during the same timeframe. The confidence in severe storms on Thursday/Thursday night remains low at this time, mainly due to the offsetting placement of areas of highest instability and higher wind shear. While modest wind shear will be present as the system moves thorugh with the presence of the LLJ, decreasing instability could limit the extent of stronger storm development, with the primary concern at this point in time being a damaging wind threat.

By the end of the weekend on Sunday, the pattern will begin to shift as upper-level ridging builds in over the eastern CONUS. This will allow any remaining precipitation to depart off to the east, setting up a stretch of mostly dry conditions to start the following workweek. Additionally, this pattern change will bring the return of really warm temperatures and higher dew points. LREF probabilities for highs greater than 90 increase each day from Sunday (15-35%)- Tuesday (55-75%), and with dew points in the 70s expected, there is the potential for triple digit heat indices. With the higher dew points in place, overnight temperatures will not cool much, with morning lows in the 70s forecast Sunday and Monday nights. While this is still just a little under a week out, recent model trends continue to suggest a hot and humid start to next week.

AVIATION /18Z TAFS THROUGH 00Z THURSDAY/

Issued at 218 PM EDT Tue Jun 23 2026

VFR conditions will continue across the terminals through at least 06z tonight. Patchy fog could develop near all sites except for HNB after 08z, quickly dissipating after sunrise. RGA has the highest likelihood of experiencing dense fog, so visibility was lowered to 2SM during the 08-12z timeframe. VFR conditions will prevail after the dissipation of any fog that develops through the rest of the TAF period.

LMK WATCHES/WARNINGS/ADVISORIES

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