textproduct: Louisville

KEY MESSAGES

* Heat Advisory continues for all counties in the forecast area through Friday.

* 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.

* Warm overnight temps in the mid to upper 70s will provide little relief during the nighttime hours. Practice heat safety by remaining hydrated and limit time outdoors if possible.

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

SHORT TERM /THROUGH TONIGHT/

Issued at 439 AM EDT Thu Sep 3 2026

Heat Advisory continues through today and into Friday. The ongoing heatwave has seen several consecutive days in the 90s with each day warmer than the last. After nearly getting to 100 yesterday, many locations have a chance of seeing their high break into the century mark. Not only would this be the hottest day of the ongoing heatwave but also the hottest day of 2026. While we may see some mixing like previous afternoons, like yesterday I don't think it will be enough to mix dew points down from the upper 60s to low 70s. We should see heat index values over 100 to as high as 108.

We will also see another afternoon with scattered Cu develop but along with those clouds we could see an isolated shower or storm pop up. Best chance appears to be along or south of the parkways with a less than 20 percent chance. While we lack a real strong trigger and have weak flow, any activity that could develop will generally be short lived.

As we lose the daytime heating with the setting sun tonight, clouds will clear and winds will diminish. Temperatures will remain warm with lows in the upper 70s with even a few locations staying in the 80s for most of the overnight period. With all this warmth it is possible a few new record warm minimum temperatures could be set.

LONG TERM /FRIDAY THROUGH WEDNESDAY/

Issued at 439 AM EDT Thu Sep 3 2026

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

End of the week will start to signal the end of the ongoing dominance of the strong upper ridging that provided the hot temperatures this week. An upper low over eastern Canada will start to deepen southward into the northeast CONUS and Canadian Maritimes. This will allow the upper ridge to weaken slightly as it flattens and retrogrades back to the west.

As this takes place a weak backdoor sfc cold front is expected to drop south-south west out of Ohio and central IN. Along with this boundary we will see a shift in upper winds out of the northwest. This will allow for MCS that form along the edge of the departing ridge to move from the Great Lakes southeast into the Ohio Valley. SPC days 2 and 3 have parts of the area under a marginal risk for severe weather, this includes Friday and Saturday. While we will see an increase in moisture ahead of the approaching boundary on Friday with continued heating taking place across the area any activity we get will generally be more isolated with the better chance of showers and storms late Friday into Saturday. While we lack much in the way of deep layer sheer, we make up for it with steep lapse rates and high instability. Think the main threat with any potential storms that for Friday into Saturday will be strong gusty winds.

As for the heat, the Heat Advisory continues until Friday evening and a lot of how hot it gets will come down to the placement of the aforementioned backdoor cold front and how much convective development we may get in the afternoon. As of now, the current forecast still see the potential for highs to be in the mid to upper 90s on Friday with heat index values above 100 and a Major to Extreme HeatRisk across the area on Friday. It remains hot for Saturday with high ranging from the low/mid 90s from the Bluegrass over to I-65 with mid/upper 90s west of the I-65 corridor. The Heat advisory may need to be extended for parts of the area going into the weekend. By Saturday the front will be working across the Commonwealth and we could still be dealing with more scattered showers and storms with the threat of gusty winds. Things look more dry and more seasonable when it comes to the heat as we go into the rest of the long holiday weekend.

===== Next Week =====

Dry weather is expected for Labor Day and into the first half of next week as the upper ridge begins to shift east with time again. Temps are forecast to be in the lower 90s next week with dewpoints in the upper 60s.

AVIATION /12Z TAFS THROUGH 18Z FRIDAY/

Issued at 700 AM EDT Thu Sep 3 2026

We will remain under the influence of the strong upper ridge and sfc high pressure today into tonight. Once the sun rises we will quickly start to heat up and we expect very similar conditions to what we've seen over the past several days. A scattered Cu field developing with winds increasing and at times turning variable but mostly out of the west south-west. Some gusts of 15 to 20kts are possible. There is a chance that a few spots could see an isolated shower or storm but the odds are generally low. Once the sun sets and we lose direct daytime heating, skies will clear and winds will turn light.

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.