textproduct: Louisville

KEY MESSAGES

* Hot and humid conditions continue through the end of the week and into the Independence Day holiday. Afternoon temperatures warming the low-to-mid 90s and heat indices between 100-115 combined with limited nighttime cooling will lead to adverse heat-related impacts if precautions are not taken.

* We will see the increase of afternoon storm chances as we head into the holiday weekend bringing localized flash flooding and gusty winds in some areas.

* Humidity remains high into next week with slight heat relief from a weakening ridge and afternoon rain through midweek.

SHORT TERM /THROUGH THURSDAY NIGHT/

Issued at 227 PM EDT Wed Jul 1 2026

We remain locked in under a strong upper level ridge through the short term period with very hot and humid conditions continuing into tomorrow. Temperatures this afternoon are a few degrees warmer than they were at the same time yesterday. Dew points are in the mid/upper 70s and the heat index values were between 100-105. Excessive Heat Warning remains in effect through tomorrow and into the end of the week. The forecast will remains relatively unchanged as we go into tomorrow. The only noticeable change to the forecast grids was to remove the chance of isolated convection tomorrow afternoon keeping us dry and hot.

LONG TERM /FRIDAY THROUGH WEDNESDAY/

Issued at 227 PM EDT Wed Jul 1 2026

===== Friday - Mid Week =====

The overall synoptic pattern slowly shifts by the end of the week as the upper level ridge begins to break down moving east over the Mid- Atlantic. As this happens, the positioning along the west side of the departing high will allow a surge of PWATs ranging 1.7-1.9" to move in from SW flow. This will also allow any discrete small waves or disturbance to move over KY, bringing in the chance for diurnally driven storms to return.

Confidence remains low with storm chances in the afternoon, keeping PoPs low. However, any sort of lift is all that is needed to initiate storms in such a convective environment. HREF ensemble mean SBCAPE values range well above 3,500 J/kg, though shear values are expected to remain weak in the afternoon with the lack of any large scale disturbances nearby. That being said, if anything causes parcels to break the already weakening cap as the ridge axis moves east, precipitation will likely come in the form of heavy, slow- moving downpours from storms. This remains an isolated risk of flash flooding and gusty winds, though with the latest flooding event KY has went through, this is a trend to monitor. It is worth noting that 50th percentile of rainfall from now until Saturday morning remains <0.1", though other ensemble solutions are right-skewed towards more than 0.5" in our far S/SW communities.

With high humidity in the air and elevated temperatures in the mid 90s, the Excessive Heat Warning will remain at least through Saturday morning, though may be extended dependent on rain chances for Saturday. Heat indices remain high on Friday in the 100-110 range still.

By Friday night, any lingering storms would likely rain themselves out and most communities begin dry by Saturday morning ahead of an incoming trough. Lows in the morning are still warm in the low to mid 70s. To our north, the jet stream will be moving quick bursts of disturbances over the Great Lakes. The greatest deal of uncertainty with this weekend's forecast, especially for Independence Day, is determining when it may rain. Should the ridge clear sooner and the jet stream sink a little further south, then KY will be closer to these fast moving shortwaves and multiple rounds of showers and storms are possible. The opposite is true if the jet trends further north. For now, scattered storms during the afternoon are possible, bringing lightning, general gusty winds, and heavy downpours. A Marginal Risk for excessive rainfall has been issued for our whole area, indicating the risk of flash flooding should repeated rounds of scattered storms occur. This set up does not support repeated training storms as what occurred last weekend, though PWATs will remain high so any downpour still poses a risk for flash flooding.

Highs on Saturday will depend on the coverage of afternoon storms but will be in the low to mid 90 with heat index temperatures in the afternoon in the upper 90s to mid 100s.

Heading into Sunday, we move into a more zonal pattern, which allows for continued subtle shortwaves to move over the KY/southern IN area. Daily rain chances from storms will linger through Tuesday as our hot and muggy air mass won't change significantly. In fact, synoptic winds will remain rather weak over central/southern CONUS. Long range guidance is suggesting a cut off low at the surface will meander its way across the Plains, keeping a weak moist southerly flow in place. Daily rain chances will continue as long as the location of the low nearby. Temperatures remain warm albeit with a slight cooling trend by midweek.

AVIATION /00Z TAFS THROUGH 06Z FRIDAY/

Issued at 748 PM EDT Wed Jul 1 2026

High pressure will foster continued light winds and predominantly VFR conditions throughout the forecast period. The one exception will be during the 08-12z timeframe when there is a low chance for fog at BWG, LEX, and HNB; a tempo group has been added to account for this.

LMK WATCHES/WARNINGS/ADVISORIES

KY...Extreme Heat Warning until 9 PM EDT /8 PM CDT/ Friday for KYZ023>043-045>049-053>057-061>067-070>078-081-082. IN...Extreme Heat Warning until 9 PM EDT /8 PM CDT/ Friday for INZ076>079-083-084-089>092.