textproduct: Louisville

KEY MESSAGES

* A Flood Watch is in effect for repeating rounds of showers and storms through tonight. Rainfall amounts between 1-2 inches possible, but could see streaks of higher amounts across southern Indiana.

* Another round of isolated to scattered thunderstorms will be possible this evening and into the overnight period. Any stronger storm could produce gusty winds and some marginally severe hail.

* A lull in precipitation is expected on Friday where temperatures will be well above normal and could break high temperatures records Friday afternoon. A frontal boundary will move through the region on Saturday bringing another round of showers/storms.

* Rainfall amounts through Saturday will average between 1-2 inches in southern Indiana with 0.5-1 inches between the Ohio River and the WK/BG Parkway region. South of the Parkways, up to a half inch of rainfall will be possible. Some minor hydro issues may be seen through the period.

UPDATE

Issued at 818 PM EST Wed Mar 4 2026

The tail end of an MCV is working through southern IN with a small supercell working through Washington County into Scott County in southern Indiana. The environment is more stable as it is north of the boundary where temperatures are cooler. As this small cell continues to work through southern IN, the main threat appears to be small hail.

As of 01z SDF was reporting 68 degrees while LOU was 64 and across the river into Clark county IN it was around 60 and reports of localized dense fog. Expect the fog to mix out as this waves works through.

As for the forecast grids overnight, went ahead and adjusted PoPs to account for this break in precipitation as well as take out PoPs south of the Ohio through the rest of the overnight. Also adjusted temperatures slightly but it will still be a bit of a challenge right along the meandering boundary from Tell City IN, to Louisville, to around Lexington and toward Jackson, KY.

SHORT TERM /THROUGH THURSDAY NIGHT/

Issued at 344 PM EST Wed Mar 4 2026

Showers and storms have been observed across the northern half of the CWA this afternoon, driven by a mid-level disturbance moving over the region, and a stationary boundary stalled along the I-64 corridor. Cloud cover has split the forecast area, with better clearing to our south resulting in temps warming into the mid-70s. However, closer to the sfc boundary, temps have remained in the low to mid-60s. Storms have mostly moved along a east-west oriented instability gradient nearly parallel to the Ohio River, and have not be able to realize the stronger instability to the south. Beginning to see a break in convective activity working in from the west, with only some thunderstorms generally east of I-65 at this time.

Later this afternoon or early evening, the boundary is expected to lift just north of the area as a warm front as a sfc low moves across Missouri and into central Illinois. We'll see low-level jetting strengthen tonight ahead of the sfc low, maintaining our WAA and moisture transport into the area. PWATs are around 1.3" this afternoon, and are expected to remain around the same or slightly higher. Based off sounding climatology, PWATs of this magnitude are among the max for this time period.

There remains a conditional severe threat for this evening, with uncertainty on just how much instability could be left after the afternoon convective. GOES satellite imagery shows a bit more thinning of the overcast deck for portions of southern IN and north- central KY, which will lead to a short window for at least some recharging of the atmosphere. Additionally, model soundings continue to indicate rather steep mid-level lapse rates this evening, with effective bulk shear values around 50kts supportive for organized convection. In addition to ELs near 12km, and some dry air entrainment at the mid-levels, large hail and/or damaging winds will be the primary hazard with any discrete convection through this evening, with the best chances mainly west of I-65. There is a low end chance for a tornado with any discrete cells across southern IN, with model soundings suggesting some backed sfc winds as a possibility. Scattered storms may congeal into a cluster as they move east of I-65 this evening, with less favorable instability to the east and waning severe chances as they move east.

Aside from the marginal severe threat this evening, there is growing concern for training convection through the overnight, especially across southern Indiana. QPF for this evening through tomorrow afternoon is mainly between 1-2 inches, though with the convective nature of precip, streaks of higher amounts certainly will be possible, leading to some potential for minor flooding issues into tomorrow. Given the possibility of training over grounds already somewhat saturated, collaborated with other WFOs on a Flood Watch for this evening and into tomorrow.

Additional isolated to scattered showers and storms will be possible throughout the day tomorrow. Temperatures climb to the low to mid-70 across the region.

LONG TERM /FRIDAY THROUGH WEDNESDAY/

Issued at 344 PM EST Wed Mar 4 2026

Friday through Wednesday...

As the system from Thursday/Thursday night lifts off to the north, Friday should be quieter with the frontal boundary also to the north. Afternoon highs will get into the upper 70s, with some places getting above 80. As a result, some of our climate sites could have their record highs broken. A stray shower or two is possible during the afternoon hours, and a stray rumble of thunder cannot be ruled out either.

Beginning on Friday and continuing into Saturday, an amplified upper flow pattern will rapidly develop, with a trough digging southward over the western CONUS and an upper ridge building over the southeast CONUS. A shortwave trough will develop over the Great Plains on Friday before shifting eastward towards the Midwest and Great Lakes. In addition, its cold front will move east/southeast, passing over the CWA on Saturday. Good southwesterly flow will allow for ample moisture as the front moves through, allowing for another round of showers and storms. Marginal mid-level lapse rates, in addition to models showing 25-30 kts of wind shear will limit the extent of strong/severe storms for Saturday. The threat will be conditional, depending on how much surface instability can develop prior to the frontal passage. Another 0.5 - 1.0" of rainfall is currently expected with this system, which may result in some localized flooding concerns across the region.

As the cold front retreating to the south and east by Sunday, broad zonal flow aloft will develop over the Ohio River Valley. This will help result in a much calmer pattern over the area for the remainder of the day Sunday and most of the day on Monday. Sunday highs will be in the low-to-mid 60s, rebounding into the low-to-mid 70s for Monday.

The flow aloft will begin to shift more southwesterly late Monday, allowing for moisture to fill back in over the region. Showers and a few storms are possible Monday night, with more widespread rain showers and a few storms possible on Tuesday as a few waves pass through. A surface trough axis extending from Texas to the Great Lakes will develop Tuesday night through Wednesday, with the frontal boundary setting up just north of the region over central Indiana. Southwesterly flow for the CWA will help result in more rain showers for the remainder of the forecast period, with afternoon highs in the upper 60s/low 70s.

AVIATION /00Z TAFS THROUGH 06Z FRIDAY/

Issued at 626 PM EST Wed Mar 4 2026

Scattered showers and thunderstorms are currently moving into SDF/HNB from the southwest. Another round of showers and embedded thunderstorms are possible tonight, mainly impacting the northern TAF sites. Sites could experience brief lower vis with heavier rainfall. A MVFR cloud deck will move into the area from the northwest with ceiling around 1500ft mainly for HNB/SDF. LLWS is possible for BWG/LEX/RGA tonight from 05-09z at 20kft. SSW winds will become gusty overnight as a weak LLJ moves through the area with the shortwave disturbance.

LMK WATCHES/WARNINGS/ADVISORIES

KY...Flood Watch through Thursday afternoon for KYZ023-032. IN...Flood Watch through Thursday afternoon for INZ076>079-083-084- 089>092.