textproduct: Louisville

KEY MESSAGES

* Strong to severe thunderstorms are expected Monday evening and Monday night. A relatively higher risk for severe weather exists west of I-65, but isolated damaging winds will still be possible east to the I-75 corridor.

* Another round of strong to severe storms is expected Tuesday evening and into the overnight. Damaging winds and large hail are the main severe threats.

* Temperatures cool Wednesday afternoon and will run below average through next weekend for late April/early May. Mostly dry weather is expected after Wednesday, with a slight chance for light rain on Friday.

SHORT TERM /THROUGH TUESDAY/

Issued at 412 PM EDT Mon Apr 27 2026

A small cluster of thunderstorms is lifting northeast across southern IN this afternoon. One severe thunderstorm dropped quarter to golf ball size hail through portions of Warrick and Dubois counties. This activity formed in an area of robust mid-level warm advection and on the eastern fringe of a 45-50 kt SSW low-level jet. These storms have begun to diminish in intensity as they push east of the richer low-level moisture and the stronger plume of instability.

Current satellite imagery and SPC mesoanalysis data reveal a plume of moderate to strong instability extending north into the Mid-MS River Valley. While the core of this instability plume will stay to our west over MO/IL/western KY, the 40-50 kt SW LLJ will propagate eastward over the Lower OH Valley through the evening and early overnight hours. The robust low level flow should bring mid to upper 60s sfc dewpoints as far west as the I-65 corridor. Despite early day clouds and scattered convection, MLCAPE of 1000-1500 J/kg should be realized west of I-65 through 00Z this evening. This could be important if the convective complex over southeastern IL can dive southeast a bit faster into portions of SW Indiana and west-central KY. Think we may see thunderstorms push into our NW CWA a bit faster between 5-8 PM this evening. Heavy rainfall, gusty winds, lightning, and hail would all be possible with this activity, and isolated severe gusts/hail are also possible.

After 00Z this evening, convective evolution is messy and lower confidence. Multiple discrete cells and convective clusters should tend to evolve eastward across portions of central KY ahead of a primary convective line. This activity should tend to grow upscale before being absorbed by a QLCS late tonight. But expect rain and thunderstorm chances to ramp up from west to east across central KY between 00-06Z this evening. Isolated to widely scattered instances of 60-70+ mph damaging straight-line winds are the primary severe threat. As instability wanes overnight, storms may tend to become more elevated in nature (resulting in a much lower hail and tornado risk). The robust low-level flow and curvature will maintain at least a low-end tornado risk through the late evening hours.

Showers and storms will exit the region from NW to SE early Tue morning. Tuesday looks relatively dry overall; spotty light showers will be possible as the sfc cold front stalls over the region. However, much of the day looks mostly dry with any additional widespread rain holding off until after 8 PM EDT Tue.

LONG TERM /TUESDAY NIGHT THROUGH MONDAY/

Issued at 412 PM EDT Mon Apr 27 2026

===Another Round of Storms Tuesday Evening into Tuesday Night===

Another fast-moving mid/upper level shortwave trough is forecast to swing east across the stalled sfc boundary Tuesday into Tuesday night. Storms are expected to initiate upstream over the Ozarks during the afternoon hours. It appears at least a portion of this activity could grow upscale into an MCS, which then races east along the remnant sfc boundary/instability gradient draped through central KY. The most likely arrival time in our western/southwestern forecast area is around 7-8 PM CDT. Large hail and damaging winds would both be on the table at this time, especially across south- central KY. The southern portion of the CWA (south of the stalled boundary) will see stronger destabilization Tue afternoon and evening ahead of any approaching MCS.

Shower and thunderstorm chances peak overnight, with the chance for severe weather waning after 06Z Wednesday due to the loss of instability. A deepening sfc wave is forecast to lift northeast across the eastern half of KY early Wednesday morning as the primary mid-level wave swings over the Midwest. Expect widespread showers to linger through Wednesday morning before tapering off from NW to SE Wednesday afternoon.

===Drier and Cooler Weather to End the Week===

Cooler, drier air filters into the region Wednesday and Wednesday night behind the departing weather system. Clearing skies will allow temperatures to drop into the low to mid 40s Thursday morning. Modifying high pressure builds into the region for Thursday, with fair weather and highs in the 60s.

A small chance (20%) for rain returns by Friday as a weak cold front dips in from the north. A separate southern stream low pressure system is expected to spread rainfall across the Southeast Friday into Saturday. At this time, it looks like central KY and southern IN is mostly likely to stay dry through the weekend with weak high pressure once again building in from the northwest.

AVIATION /18Z TAFS THROUGH 00Z WEDNESDAY/

Issued at 156 PM EDT Mon Apr 27 2026

A small line of TSRA will lift NE across southern IN at the start of this TAF period, impacting HNB in the first hour of this TAF period. HNB can expect MVFR and possibly brief IFR conditions in heavy TSRA. Lightning, gusty winds, and small hail will all be possible at the terminal.

Otherwise, mainly dry conditions will continue through the afternoon hours in central KY. TSRA chances will mostly hold off until 00Z Tue and beyond tonight. SCT TSRA chances will increase from the northwest this evening ahead of a main convective line. This main convective line will push southeast through southern IN and central KY between 03-09Z Tue. Heavy rainfall, lightning, and strong gusty winds will all be possible within this line. There is also a low-end risk for a brief tornado. Low-end MVFR and borderline IFR ceilings will develop in the wake of the storms early Tuesday. Low clouds will slowly lift back to VFR Tue afternoon.

LMK WATCHES/WARNINGS/ADVISORIES

KY...None. IN...None.