textproduct: Louisville

KEY MESSAGES

* Unsettled weather with localized area of heavy rainfall and flash flooding are possible across KY and southern IN now through Wednesday morning. While basin average rainfall of 0.75-2 inches are expected, localized amounts of 3-6 inches will be possible in heavier swaths, mainly across central KY.

* Despite some morning showers and weak storms on Wednesday, hot temperatures and mugginess are expected Wednesday and Thursday, with peak afternoon heat index values between 90-100.

* An approaching cold front later in the week provide more opportunity for rain and some storms Thursday evening through Friday, though timing is still uncertain.

SHORT TERM /THROUGH WEDNESDAY/

Issued at 401 AM EDT Tue Jun 9 2026

A complex of showers and storms continues overnight along our western CWA gradually moving NE. Though daytime heating has waned, there is plenty of moisture in the vertical throughout our CWA, which has produced some torrential downpours along our western border counties. Some of these areas have already picked up 1-1.5" of rain in the past few hours and will continue to see on and off moderate rain showers through the morning. This type of periods of heavy rain will be the theme for the short term, at least through Wednesday morning. The synoptic setup features very weak low to mid level flow over the next 24 hours. As a result, as waves of rain and storms roll through, localized heavier rainfall totals creating flooding concerns will continue through this afternoon and into overnight Wednesday. The current rounds of rain was part of a series of shortwaves moving through the Plains, and as the first of a couple moves off to our north, it leaves behind moisture-rich air, high dewpoints and warm temperatures for the morning. Another shortwave moving NE through the central plains will maintain surface SW flow for the remainder of Tuesday - Wednesday.

From general lift induced by the central plains shortwave, additional rounds of MCVs will move in along an axis of enhanced PWATs oriented along a NW-SE line from roughly the Kansas City area towards Richmond, KY. The initial MCV moving SE from Kansas City will generally break up as it approaches, though rainfall rates will remain high within embedded storms from what will likely become a messy scattered complex of convection. Short range model guidance has a general drying trend later in the evening on Tuesday, before more storms and/or additional MCVs fire off again within a pool of increased PWATs that will linger right over KY overnight through Wednesday morning.

This general pool of increased stationary PWATs of 1.8-2.0" lingering through the overnight is the cause of greatest concern for flooding. Latest 00Z HREF guidance suggests a series of back- building and training storms over far southern IN moving SE through the heart of KY towards the Somerset-Richmond, KY area. HREF 6hr LPMM data through overnight Wednesday features some areas of receiving 4-6". Other signals of significant rainfall within short bursts of time exist in HREF guidance, with 3hr QPF probability of exceeding 1" is above 50% early Wednesday morning, with a 10% hatched area of exceeding 3" in 3hr QPF. Altogether, there is a strong signal of localized flooding, mainly through central KY going through a lull of flooding probability Tuesday afternoon and increasing in action from training storms overnight Tuesday into Wednesday. As a result, the current Flood Watch will be extended through 12Z Wednesday morning, and will be monitored for any further expansion or time extensions.

With regard to any severe risk, as storms approach from the WNW, there may be enough mid-level shear to sustain a severe wind threat over our western CWA. The severe risk is low and is only for gusty winds and this will be monitored throughout the day. The main concern is for localized flooding concerns that ramp up later in the night on Tuesday. Area wide rainfall totals through Wednesday morning should range 0.75 - 2", though localized areas of 3-6" are still possible in training storms in central KY.

Despite the rounds of rain today, muggy conditions with dew points in the low to mid 70s will make the air feel thick and oppressive between showers. Highs will be in the low to mid 80s with breaks in cloud cover later on Tuesday.

By Wednesday morning, the main concern will be continued training showers and storms. Surface moisture will remain high giving plenty of moisture for storms to work with despite the lack of daytime heating. As the day progresses, an axis of high pressure to our SW will build into the lower Ohio Valley, expected to act as a lid for any continued convection and generally sweep storms out towards the east by lunchtime. Latest HREF guidance wants to slow this process down with continued convection. For now, we are forecasted skies to gradually clear SW to NE during the day. Without a significant change in air masses though, dew points will remain high in the low to mid 70s. A heat advisory may need to be issued for Wednesday as highs will reach the low 90s by afternoon, with heat indices maxing out in the low 100s at times.

LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/

Issued at 401 AM EDT Tue Jun 9 2026

Wednesday - Sunday ...

Heading into Thursday, the surface to mid level ridge will remain overhead locking in hot temperatures and high dew points. Heat indices will raise into the upper 90s and isolated low 100s again, meaning another heat advisory may be needed. One note of difference is a building LLJ from the SW in response to a tightening pressure gradient on Thursday. A larger mid to upper level trough will be swinging through the Northern Plains meaning gusty winds on Thursday afternoon from daytime mixing is possible, gusting 20-25 MPH. This could serve as a way to cool off during the day if nothing else.

This trough over the northern plains will kick off a trailing cold front that should sweep through the Ohio Valley. The timing of this cold front is key to any severe weather potential Thursday evening- Friday morning. Current trend is to sweep through during the overnight limiting the severe potential and serving as another rain chance with some gusty winds. Beyond this, relief from the heat at least temporarily is expected. Temperatures will remain near or just above normal as a return of warm moist air looks to return beyond Saturday.

AVIATION /06Z TAFS THROUGH 12Z WEDNESDAY/

Issued at 149 AM EDT Tue Jun 9 2026

VFR to MVFR conditions will continue through the night, transitioning to low end MVFR from lowered ceilings in the early morning. A complex of weakening storms will continue moving NE towards HNB/SDF/LEX overnight which may bring TSRA conditions temporarily. Southerly flow will continue though the whole TAF period, becoming gusty and variable in times of passing thunderstorms. Otherwise, -SHRA between dry periods are expected through Tuesday morning. By midday, slowly improving ceilings will keep VFR-high end MVFR around with a continued S-SW flow, gusting near 20 kts. We will monitor rounds of training storms for our airports midday through the evening on Tuesday, though the exact timing remains uncertain. VFR-MVFR will end the TAF period with passing showers.

LMK WATCHES/WARNINGS/ADVISORIES

KY...Flood Watch through this evening for KYZ023>031-034-038-045- 046-053-054-061>065-070>078-081-082. IN...Flood Watch through this evening for INZ076>078-083-084- 089>092.