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.

UPDATE

Issued at 1117 AM EDT Tue Jun 9 2026

Early morning MCS has pushed eastward into eastern KY. Secondary MCV now evident just northeast of Owensboro and working eastward. Band of showers and thunderstorms with intense rainfall will move across Meade/Breckinridge/Hardin and Harrison IN/Jefferson counties over the next 60-90 min. Atmosphere is pretty worked over in the I- 65 corridor and points east, so while this may temper the intensity of the ongoing convection, intense rainfall is likely to skim along and south of the I-64 corridor in Kentucky through the late morning and into the early afternoon hours.

Issued at 1004 AM EDT Tue Jun 9 2026

Early morning MCS continues to roll eastward into the Bluegrass region. This area has missed out on earlier rainfall so rainfall amounts of 1-2 inches will be possible with this activity this morning which could cause some minor issues here and there.

Next band of precipitation continues to move toward the I-65 corridor. Heavy rainfall will likely slide east along and just south of the I-64 corridor. This will likely impact areas from the Metro southward and eventually down into east-central KY and the Bluegrass region. After this band moves through, we may see a bit of a break in the action as convection will likely become more scattered in nature.

Have gone ahead and expanded the Flood Watch in area to include the Bluegrass region of central KY and to extend the watch out through Noon EDT Wednesday. Early 12Z data suggests a break in the rainfall this evening, but another MCS is likely to drop into the region overnight. Will be evaluating the 12Z data suite and the 12Z HREF to better define convective expectations for the afternoon package. However, given ongoing rain in the Bluegrass which will just prime the soil, felt it was the best option to go ahead and expand the watch rather than wait.

Will make some adjustments to the forecast grids and get a full update of products out in the next hour. Also, we'll be updating our briefing packets with the latest data and a new packet will be released in a little bit.

Updated 911 AM EDT Tue Jan 9 2026

Ongoing MCS continues to push into east-central KY this morning. Widespread 1-1.5 inch rain amounts are occurring with this rainfall. However, there are smaller streaks where intense rainfall has produced rainfall values of 4-5 inches.

Low-level jet appears to be driving the next round of convection that is oriented from NW-SE across portions of Breckinridge southeast into Hardin/LaRue/Green/Taylor counties. This activity will pivot eastward, but the storms here are moving at 20-25 mph, so the residence time of heavy rain at any one location may be a bit more limited that what we've seen this morning. We do have some tall/skinny CAPE profiles in the morning proximity soundings. With MLCAPE around 1000 J/kg or less and shear through the column remains below 20kts. PWAT values are solidly in the 2-2.1 inch category and freezing heights are up near 13-14kft. So, the overall threat here will be storms with very efficient rainfall and localized flash flooding.

Secondary band of convection out north of Evansville will continue to slide southeast this morning. This may clip the southern end of the Louisville metro area, with the bulk of it going through north- central Kentucky. Once this passes, a break in the action looks possible through the late afternoon and evening before the next wave of precipitation arrives.

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 /18Z TAFS THROUGH 00Z THURSDAY/

Issued at 126 PM EDT Tue Jun 9 2026

A mix of VFR/MVFR conditions are expected across the region this afternoon. Early morning MCS continues to move off to the east- southeast into southeastern Kentucky. Upstream convective development has been noted over southern IL and into southwest IN. This could result in some additional chances of convection at KHNB later this afternoon. Additional scattered convection looks likely to develop down across western KY that could affect BWG this afternoon. Later tonight, there is a signal for another MCS to develop to our northwest and drop southeastward into southern IN and central KY after midnight eastern. Surface winds this afternoon will be out of the SW at 5-10kts and will drop off slightly after sunset.

LMK WATCHES/WARNINGS/ADVISORIES

KY...Flood Watch through Wednesday morning for KYZ023>043-045>049- 053>057-061>067-070>078-081-082. IN...Flood Watch through Wednesday morning for INZ076>079-083-084- 089>092.