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 Friday. 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, ending our stretch of hotter conditions across the region.

UPDATE

Issued at 900 PM EDT Thu Sep 3 2026

At this hour, most of central Kentucky and southern Indiana is under mostly clear skies while continuing to cool down from sweltering afternoon temperatures in the mid-to-upper 90s and low 100s. I say most of the area is clear as we were able to get a few showers to develop mainly along and south of the Parkways this afternoon. A few showers continue at this hour across portions of Allen and Barren County, though given the weak forcing and decreasing sfc-based instability, these showers should dissipate over the next hour or two. There is also a band of showers and thunderstorms over southern Ohio at this time; however, these are not expected to make it into our northeast Bluegrass counties.

For the rest of this evening and tonight, temperatures should slowly drop through the 80s and into the mid-to-upper 70s by early Friday morning. May have to watch out for patchy fog in the few areas which have received rain this afternoon and evening, though most should remain fog free. Just tweaked PoPs over the next few hours with this forecast update; otherwise, the forecast remains on track at this time.

SHORT TERM /THROUGH SATURDAY NIGHT/

Issued at 340 PM EDT Thu Sep 3 2026

It's another hot day across central Kentucky and northern Indiana, as temperatures across the region are in the mid to upper 90s. With a few more hours of peak heating still to come, some places reaching 100 cannot be ruled out. This stretch of hot weather is thanks to an upper-level ridge overspreading the eastern 2/3 of the CONUS. A Heat Advisory is still in place through Friday evening with heat indices of 100-107 expected. A few very brief and isolated showers have developed this afternoon, but with very weak wind shear present (<15 kt of 0-6 km shear), convective activity will remain quite limited for the remainder of the afternoon. For tonight, the hot air mass will again limit our overnight temperature recovery, with lows in the mid 70s forecast.

For Friday, A surface frontal boundary currently over the upper Midwest will push southward towards central Indiana and Ohio by the evening hours. Slight (~20%) chances for showers and storms will be possible tomorrow afternoon, with the SPC placing the northern portions of the area under a Marginal Risk for severe weather. While SBCAPE will be near 2000 J/kg during the afternoon, weak wind shear (<20 kt) will again limit the potential for more robust development. The main concern with the strongest storms would be gusty winds, but confidence in severe weather occurring is low.

The frontal boundary will begin to move through the area on Saturday, with elevated chances for showers and scattered storms (30- 50%) mainly east of I-65. There is some model disagreement as to how much convection occurs ahead of the front, but this does present the highest chance for precipitation for the next several days. A Marginal Risk is again in place for most of the area for gusty winds, but the continued presence of weaker wind shear will again limit the severe potential on Saturday. Temperatures will still be on the hotter end, with highs in the low to mid 90s. While confidence was not high enough to extend the Heat Advisory into Saturday, further consideration may be needed in future forecast packages.

LONG TERM /SUNDAY THROUGH THURSDAY/

Issued at 340 PM EDT Thu Sep 3 2026

With the cold front departing off to our south by Sunday morning, surface high pressure and drier air will fill in over the region. Looking broadly at the upper-levels, an omega block tries to take shape as two upper-level lows flank both sides of a well-amplified ridge over the central CONUS. Central Kentucky and southern Indiana will be placed just to the east of the ridge, with northerly flow aloft persisting into the early portions of next week. Temperatures to close off the weekend and start the following workweek will be closer to normal for this time of year, with highs ranging from the mid 80s to around 90. The biggest benefit from this pattern change will be the increase in drier air, allowing dew points during the overnight hours to drop into the 60s. This will help with overnight temperature recovery, allowing for lows to also be in the 60s Sunday and Monday night.

As the workweek progresses, the previously mentioned omega blocking pattern quickly breaks down, causing the upper ridge to move eastward towards the Ohio Valley. While the upper-level flow will continue to be northerly over the region, lower-level and surface flow will shift to the south, allowing warmer air to fill back in. Widespread afternoon highs in the 90s will return Tuesday, lasting through the rest of the forecast period. A few weak perturbations passing over the region could allow for a few isolated diurnally- driven showers and storms to develop, but with limited moisture and weak wind shear in place, chances will remain rather low through Wednesday (<20% chance).

The end of the forecast period on Thursday becomes more uncertain as another pattern shift looks to take shape. Most deterministic and ensemble guidance picks up on a robust upper level low moving from central Canada towards the NE CONUS while a surface cold front passes over the Ohio Valley. The uncertainty lies in the timing and progression of these features, but it does appear that this could be the next chance for more appreciable precipitation across the region.

AVIATION /06Z TAFS THROUGH 12Z SATURDAY/

Issued at 110 AM EDT Fri Sep 4 2026

Ridging aloft and sfc high pressure continue to influence our forecast through the 06z TAF forecast period. Overall we remain VFR but here are the potential impacts during this forecast:

Through the rest of the overnight and morning we will remain quiet with light winds and clear skies. Some patchy fog is possible in spots but I think terminal sites remain unaffected.

As has been the trend the last couple of days, with the heat and humidity we have the chance of isolated showers or storms with a scattered Cu field in the afternoon. The chance of showers is under 20 percent so no mention of a Prob30 but it is possible an isolated storm could hit a site tomorrow afternoon/evening but confidence is generally low.

Mixing winds are again possible as we go late afternoon and evening with some isolated gusts of 10-15kts.

Once the sun sets, skies clear and winds become light but a sfc cold front to our northeast will start to track into the region late tomorrow and Saturday. Think this is slow to arrive but as it gets closer we could see more increased clouds and PoP chances late Friday into Saturday.

LMK WATCHES/WARNINGS/ADVISORIES

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