textproduct: Louisville

KEY MESSAGES

* Heat Advisory is in effect and has been extended through the day Thursday.

* Unseasonably hot temperatures will continue until the end of the week. Daily highs in the in the mid/upper 90s with heat index values above 100 to 105 degrees. Overnight lows only bottom out in the low/mid 70s.

* Mainly dry through the end of the week with low end (10% or less) chance of isolates showers or storms.

* Low (10-30%) rain chances return late in the week into the weekend, with a significant cooldown unlikely through Sunday.

SHORT TERM /THROUGH THURSDAY NIGHT/

Issued at 247 PM EDT Tue Sep 15 2026

Late season heat will be the main impact through the end of the week as we will remain under a very strong 600 dm upper ridge. Heat Advisory remains in effect and was extended through the day Thursday for most of central and western KY and all of southern IN. Locations inside the advisory will experience daily highs in the mid to upper 90s with heat index values ranging from 100-105 degrees. At night, temperatures will remain unseasonably warm with overnight lows in the low to mid 70s. Outside of the advisory, across the Bluegrass and along and east of the I-75 corridor, it will still be very warm but highs will be in the low 90s with heat index values in the upper 90s. Each day the wet bulb globe temperature (WBGT) will be around or above 85 and up to 88 degrees. The Heat Advisory may need to be extended into Friday but with a few counties trimmed to the north and east as the overall ridge starts to flatten out, retrogrades to the west and a cold front drops southward towards the Ohio River.

Cold front currently over the Upper Midwest will slowly work east- southeast into northern and central IN later tonight. With 850 temperatures around 20-22 degrees and the influence of the strong upper ridge and sfc high, and convection that gets fired should diminish as it moves southward towards the Ohio River. There is just a small chance (less than 10 percent) that any precipitation works into the region overnight. By tomorrow morning, the cold front should stall just to our north and then begin to lift northward as a warm front. Some of the hi-res models want to show isolated activity across the area tomorrow afternoon but current thinking is we stay mostly dry and confidence in this scenario remains low.

LONG TERM /FRIDAY THROUGH TUESDAY/

Issued at 247 PM EDT Tue Sep 15 2026

By the end of the week the warm front will sag south as a cold front and stall near the Ohio River once again, This will bring an increased chance of showers and storms (10-30 percent) mainly across southern IN and east of I-65. As of now activity looks relatively scattered to isolated with low QPF. This will bring slightly cooler temperatures with highs in the low/mid 90s and upper 80s across the Bluegrass. Heat advisory may need to remain in place for locations to the west and south for the end of the week.

The weekend looks to be split with temperatures still remaining unseasonably warm on Saturday as the aforementioned front lifts back north as a warm front allowing for high to get back to around the mid 90s and mostly dry but a weak shortwave trough working over the top of the retrograding upper ridge will push a stronger cold front through by the end of the weekend and into early next week. We will see an increased chance of showers and storms with this system and cooler temperatures into the 80s by the start of next week.

AVIATION /00Z TAFS THROUGH 06Z THURSDAY/

Issued at 714 PM EDT Tue Sep 15 2026

VFR conditions are expected to continue through the forecast period. Mostly clear skycover overnight with light winds from the south. For tomorrow, should see some diurnal cu develop again, but VFR will continue with winds from the SW.

LMK WATCHES/WARNINGS/ADVISORIES

KY...Heat Advisory until 8 PM EDT /7 PM CDT/ Thursday for KYZ023>034-038-045-046-053-054-061>065-070>077-081. IN...Heat Advisory until 8 PM EDT /7 PM CDT/ Thursday for INZ076>079-083-084-089>092.