textproduct: Louisville

KEY MESSAGES

* Heat Advisory remains in effect for all counties in the forecast area today and Thursday with it being extended until Friday evening.

* Daily afternoon temperatures in the mid to upper 90s with even some locations potentially reaching 100 by Thursday. Heat index values will be over 100 and up to 107.

* Major Heat Risk is likely across the area through the end of the week with urban locations along the I-65 corridor from Louisville to Bowling Green reaching the Extreme Risk. Practice heat safety by staying hydrated, limiting time outdoors and checking on those who may not have adequate cooling.

* A weak cold front could bring scattered showers and storms to the area late Friday and Saturday.

SHORT TERM /THROUGH THURSDAY NIGHT/

Issued at 316 AM EDT Wed Sep 2 2026

Peak heating for the ongoing heat wave is expected today into Thursday as the strong upper ridge is expected to be directly over the Ohio and Tennessee Valleys the next two days. After many places saw highs well into the 90s with BWG and SDF into the upper 90s, a run at 100 degrees is not entirely out of the question for some during this time frame, with the best shot of this occurring on Thursday. Heat Advisory remains in effect today into Thursday and extended into Friday. Given that the overall pattern has seen very little change the last few days it is expected that once again we will see the development of afternoon mid-level Cu along with dry air mixing during the afternoon into the evening. While we still had heat index values over 100 yesterday, the mixing brought dew points down into the mid/upper 60s keeping heat index values under 105.

Highs should be a few degrees warmer today than they were yesterday with many locations in the upper 90s to mid 90s into the Bluegrass. Overnight lows will remain warm in the mid/upper 70s both tonight and Thursday night.

The overall forecast continues to be mainly dry but some of the hi- res short range models do introduce the chance for an isolated shower or thunderstorm. Went ahead and increased PoPs across the southern half of the CWA.

The probability for Major HeatRisk across central KY and southern IN today and Thursday is 90% and above and we start introducing a higher than 50-60% chance of Extreme HeatRisk for Thursday. At the Extreme level, the ongoing heat becomes Very Dangerous to people without proper hydration and adequate cooling.

LONG TERM /FRIDAY THROUGH TUESDAY/

Issued at 316 AM EDT Wed Sep 2 2026

===== Friday through the Weekend =====

By the end of the week and into the weekend the upper ridge is expected to weaken and eventually start to retrograde westward as a closed upper low over eastern Canada deepens a trough over the CONUS northeast by Saturday and the weekend. A weak backdoor cold front is expected to drop south-southwest out of Ohio and Indiana late Friday into Saturday but trends in guidance continue to have this arriving more later than earlier. This is increasing the confidence that many locations across our CWA will still have to contend with the high heat and humidity for another day. With that said, the decision was made to extend the current Heat Advisory until Friday evening. Current probability for Major HeatRisk is above 90 percent on Friday as we will still be dealing with afternoon temperatures in the mid to upper 90s and heat index values above 100 to 107 with dew points in the upper 60s to low 70s if we don't get afternoon mixing. The main limiting factors to the heat on Friday would be a faster solution with the approaching sfc boundary, development of any scattered to isolated showers and thunderstorms as well as placement of any potential MCS coming out of the Great Lakes late Thursday into Friday and the path it takes along the edge of the upper ridge.

Backdoor cold front is expected to work through the area on Saturday increasing the chance for showers and thunderstorms Saturday afternoon and evening (30-40%). As was mentioned in the previous discussion, there will be ample instability along with steep low to mid-level lapse rates but overall shear remains weak (less than 20kts) decreasing the potential for any organized convection. Albeit "cooler" than the last several days, highs will still be in the low 90s to mid 90s with even a few upper 80s across the Bluegrass. with a more east to west temperatures gradient across central KY. Temperatures to end the weekend will be in the mid/upper 80s with low 90s across the west and southwest with just an lingering isolated chance of a shower or storm but looks mainly dry as the front will be further south and the upper ridge off to the west.

The Labor Day holiday looks mainly dry and seasonably hot with temperatures like Sunday into the upper 80s to low 90s across the CWA but deterministic models seem to agree that the ridging will begin to expand and build back over the Ohio Valley for the middle of the week but may not have the same staying power as they models also seem to generally agree on an upper level shortwave passing just north of the Great Lakes by the end of next week flattening the ridge once again.

AVIATION /06Z TAFS THROUGH 12Z THURSDAY/

Issued at 108 AM EDT Wed Sep 2 2026

Flight categories will remain VFR as our stagnant pattern continues thanks to the influence of strong ridging aloft over the Ohio and Tennessee Valleys and SFC high pressure over the region as well. This will continue for the next couple of days with mainly clear skies and the only impacts coming from increased winds to around 10 kts in the afternoon thanks to mixing. The potential challenge here as we saw on Tuesday will be the potential for variable winds over 7kts with winds going from the SW to more north at times then back as we lack sufficient forcing to maintain wind direction.

LMK WATCHES/WARNINGS/ADVISORIES

KY...Heat Advisory until 8 PM EDT /7 PM CDT/ Friday for KYZ023>043- 045>049-053>057-061>067-070>078-081-082. IN...Heat Advisory until 8 PM EDT /7 PM CDT/ Friday for INZ076>079- 083-084-089>092.