textproduct: Louisville

KEY MESSAGES

* Scattered showers and storms will move southeast over west-central and south-central KY this morning. These storms could produce locally excessive rainfall and flash flooding in areas that see repeated rounds of torrential rainfall.

* Strong upper ridge over the region will result in the hottest temperatures of the summer for all of next week. Highs around the mid 90s, dew points in the mid/upper 70s will result in heat index values above 100 to near and even above 105. Heat related headlines will likely be needed.

* High heat and humidity will continue into the Independence Day Holiday with the potential for isolated to scattered thunderstorm during the afternoon and evening.

SHORT TERM /THROUGH TONIGHT/

Issued at 333 AM EDT Sun Jun 28 2026

One last convectively-induced mid-level impulse is swinging over the Lower OH Vally early this morning. A subtle sfc boundary and low- level moisture gradient stretches from St. Louis southeast into south-central KY. Scattered showers and storms are already developing along this axis, where PWATs remain 2.1-2.2 inches. Moderate 25-30 kt WSW low-level flow and moisture transport will feed this convective axis through the remainder of the morning hours. This setup is likely to lead to additional convective training across portions of west-central and south-central KY, where a Flood Watch is now in effect through Noon EDT / 11 AM CDT. The Flood Watch remains in effect through 8 AM EDT for portions of SW Indiana, where scattered convection remains possible early this morning. The Flood Watch for the rest of southern IN and areas north of I-64 in KY (our northeastern CWA) has been cancelled, as convection is likely to remain southwest of these areas.

A swath of 1 to 3 inches of rainfall (fairly narrow) is expected from NW to SE through portions of central and southern KY, centered on a Owensboro to Columbia axis. Localized totals of 4+ inches cannot be ruled out due to training storms, which may lead to considerable flash flooding in isolated areas.

These showers and storms are expected to sink south of the TN border by 15-16Z today. A few rogue cells will be possible through the afternoon and evening, but the second half of the day will trend drier due to increasing subsidence aloft. Mid and upper level ridging will amplify considerably over the MS Valley and Lower OH Valley later today into tonight.

As low clouds gradually scatter and lift into the afternoon hours, temperatures will have an opportunity to rebound quite a bit. Afternoon highs are forecast to top out in the mid 80s (Bluegrass Region) to around 90 (Bowling Green and surrounding areas). With a very humid airmass still in place (mid 70s dewpoints), afternoon heat index values will range from the lower 90s (Bluegrass Region) to the low 100s west of I-65. Temperatures will drop back into the low to mid 70s early Monday morning.

LONG TERM /MONDAY THROUGH SATURDAY/

Issued at 333 AM EDT Sun Jun 28 2026

As we start a new week, end the month of June, start July and head into the 4th of July Holiday, the main weather story will be the hottest temperatures so far this summer.

A strong sprawling 594-597 ridge will build in over the Ohio Valley and be centered over the Commonwealth for a good portion of the week. This will allow for daily high temperatures to climb into the low/mid 90s through the first half and potentially the upper 90s by the end of the week. Along with the heat will be the oppressive dew point values into the mid to upper 70s and even near 80. The combination of the high heat and oppressive humidity will result in heat index values approaching Heat Advisory criteria around 105 and potentially Excessive Heat Warning criteria by late in the week around 110. While forecast confidence is high that the week ahead will feature our first heatwave of the season (three or more consecutive days above 90) and that we will likely issue heat related headlines as early as Monday there are some potential limiting forecast factors that lower confidence for highs into the upper 90. The first is model bias towards towards a much warmer solution. The NBM continues to show a heat bias and that is showing up in the extended. The second is the saturated ground currently over central KY and southern IN. As the heat builds in over the area it will start to evaporate the moisture in the ground, this takes energy out of the atmosphere and cools temperatures through the evaporation process.

By the end of the week and into the weekend an upper level shortwave will work along the northern peripheral of the ridge weakening it slightly. Forecast models hint that this could be enough to introduce isolated to scattered convection to form in the afternoon heading into the 4th of July Holiday. While this could bring some slight relief, the forecast remains hot and humid through the long term.

This is potentially dangerous heat and warrants those working outside to take longer breaks, drink plenty of water and find ways to cool down when possible. This week is a good time to check on those who may not have AC in their home and check on your neighbors during the day when you can.

AVIATION /06Z TAFS THROUGH 12Z MONDAY/

Issued at 209 AM EDT Sun Jun 28 2026

SCT thunderstorms are drifting east across southern KY early this morning, near BWG. LEX will see showers nearby at the start of this TAF period. However, the main aviation impact for most terminals will be the development of IFR and low-end MVFR clouds early this morning. These clouds will expand and lower between 06-09Z, with most terminals returning to VFR by 17-18Z.

The other concern will be a band of SHRA/TSRA that is forecast to set up from NW to SE centered on an axis from roughly OWB/KY8 to EKQ. This band will train southeast over south-central KY between 08- 16Z this morning. BWG has the highest chance (80%) at seeing TSRA impacts, including lightning and torrential rainfall. HNB should be on the northern fringe of this activity, with a 30-40% chance for a storm between 08-12Z. Much of this convection should remain southwest of SDF and RGA, but there is a lower-end chance (20-30%) for a brief shower or storm.

LMK WATCHES/WARNINGS/ADVISORIES

KY...Flood Watch until noon EDT /11 AM CDT/ today for KYZ023>029- 045>048-053>057-061>067-070>078-081-082. IN...Flood Watch until 8 AM EDT /7 AM CDT/ this morning for INZ083- 084-089-090.