textproduct: Louisville

KEY MESSAGES

* Hot and humid conditions on Sunday with highs in the low/mid 90s and heat indices up to 109 degrees. Heat Advisory is in effect through 9 PM EDT/8 PM CDT for a large portion of southern IN, central and southern KY.

* Another round of showers and storms are possible late Sunday ahead of a cold front moving through the region. Any storms that become severe would be capable of producing damaging winds.

* A reprieve from the hot and humid weather, as well as showers and storms, comes Monday evening once the cold front departs to the south. Showers and storms arrive again for the mid and late week time frame, however temperatures should be slightly below normal for this time of year.

SHORT TERM /THROUGH MONDAY/

Issued at 400 AM EDT Sun Aug 16 2026

Looking across the region this morning, multiple perturbations are passing by just off to our north in Illinois, Indiana, and Ohio, producing scattered showers and thunderstorms. While we are currently dry, an area of weaker showers over southern Illinois could clip southern Indiana and far northern Kentucky during the morning hours on Sunday. While a few rumbles of thunder cannot be ruled out, chances for precipitation this morning for those areas are fairly low (15-35%).

Through the middle part of the afternoon on Sunday, conditions across the region will again be hot and humid, with a Heat Advisory in place for the western 2/3 of the CWA that goes through 9 PM EDT/8 PM CDT. HREF probabilities for heat indices above 105 are greater than 70% for most places west of I-65, with greater than 60% chances for heat indices above 100 across the entire area. This will precede a west to east oriented cold front and associated surface low that will begin to slowly move over the region late Sunday. Ahead of the cold front, isolated to widely scattered showers and storms will begin to develop during the late afternoon and evening hours. Ample moisture will be present ahead of the front, with HREF outputting over 2" of PW. Additionally, plenty of instability will be available (HREF mean CAPE > 2500 J/kg) for these showers and storms. A limiting factor to how much development and how intense these storms could get is the fact that there is meager wind shear present (20-30 kt of deep-layer shear). The Storm Prediction Center does have a Slight Risk for severe weather for north central Kentucky and southern Indiana. The main concerns will be damaging winds, heavier downpours, and frequent lightning, though confidence remains low in more robust severe weather occurring.

For Sunday night through Monday, the cold front will slowly push southward across the region, allowing for chances of showers and storms to continue into the start of the workweek. This will be amplified by an additional shortwave moving through early Monday that develops over Nebraska and Kansas late Sunday. Chances for strong to severe storms associated with this shortwave are rather low, with limited instability and weak shear in place at that time.

LONG TERM /MONDAY NIGHT THROUGH SATURDAY/

Issued at 400 AM EDT Sun Aug 16 2026

On Monday night, the cold front will finally push southward out of the region. This will allow weak surface high pressure to fill in and bring a much-needed reprieve from the uncomfortable heat and humidity that's been felt over the past several days. Per the most recent LREF guidance, lows on Tuesday will be in the upper 60s north of the Parkways and around 70 for places south. Conditions will also be dry through early Wednesday as the surface high slowly drifts to the east. Afternoon highs on Tuesday will be in the upper 80s, but with dew points in the mid 60s it will feel very comfortable outside. For Tuesday night, expect lows in the mid-to-upper 60s across the region.

A broader pattern shift will begin to take place on Wednesday as the upper ridge over the western CONUS begins to amplify and an upper trough over the eastern CONUS digs southward. The southern periphery of the upper jet will be placed over southern Indiana and central Kentucky, acting as a pathway for multiple shortwaves to pass over the region through the start of the weekend. The first shortwave will move into the region Wednesday afternoon, bringing back chances for showers and thunderstorms for the remainder of the week. While temperatures Wednesday afternoon will be in the upper 80s/low 90s, the repeated rounds of convective activity afterwards will keep daytime highs in the low-to-mid 80s for the rest of the forecast period.

While there is some uncertainty in the timing and progression, a cold front is expected to move through the area near the end of the forecast period (late Friday-Saturday), with surface high pressure building in behind. This will provide an end to the repeated rounds of showers and storms, with the convective activity pushing off to the south and east. With northerly flow persisting behind the front, temperatures will continue to remain mild, potentially making for a rather comfortable weekend ahead.

AVIATION /12Z TAFS THROUGH 18Z MONDAY/

Issued at 647 AM EDT Sun Aug 16 2026

VFR conditions will prevail across the terminals through 00z this evening. WSW winds will steadily increase during the daytime hours Sunday, with gusts up to 17 kt possible in the afternoon for SDF and LEX. Chances for showers and storms will increase after 00z for all terminals except BWG, with Prob30 groups introduced in the TAF package. While ceilings will remain VFR, heavier downpours with any showers and storms that develop could cause brief reductions in visibility. Chances for showers will linger after 06z, with Prob30 groups included through 12z for all terminals except BWG.

LMK WATCHES/WARNINGS/ADVISORIES

KY...Heat Advisory until 9 PM EDT /8 PM CDT/ this evening for KYZ023>031-034-038-039-045-046-053-054-061>065-070>078- 081-082. IN...Heat Advisory until 9 PM EDT /8 PM CDT/ this evening for INZ076>078-083-084-089>092.