textproduct: Louisville

KEY MESSAGES

* Mild temperatures overnight with showers/storms working back into southern IN/north central KY by early tomorrow morning.

* A few strong to severe storms are possible along a stalled warm front later Wednesday, possibly into Thursday.

* Rainfall amounts between 1.00 to 2.00 inches are possible across north central KY into southern IN by Friday morning.

* Well above normal temperatures will persist all week, growing increasingly warmer by Thursday/Friday.

* After another fairly strong system on Saturday that could bring more rounds of strong storms, rainfall totals may begin to cause a few minor flood concerns across southern IN.

UPDATE

Issued at 909 PM EST Tue Mar 3 2026

Across central KY and southern IN at this hour, it is dry, with broken high clouds streaming across the region south of I-64, while lower level clouds are observed along and north of I-64. The sfc warm front is analyzed roughly along the US 50 corridor at this hour, in other words, just north of our border with WFO IND. To the north of the front, rounds have convection have persisted this afternoon and evening, with many areas in central IN receiving between 1 and 3 inches of rain so far.

Over the next few hours, a secondary LLJ is expected to strengthen near the confluence of the Ohio and Mississippi Rivers, with 35-40 kt of 850 mb SW flow extending into the lower Wabash Valley. As MCSs like the one ongoing to our north will tend to propagate in the opposite direction of the LLJ, it makes sense that hi-res models show this area of convection sagging into southern IN and north central KY between midnight tonight and sunrise Wednesday. The pool of 500-1000 J/kg MUCAPE over southern IL is expected to re-orient itself more east-west along the I-64 corridor later tonight, so it's likely that we'll continue to see embedded thunderstorms as convection sags south. Given cool air undercutting convection, would expect things to remain elevated, but we could see some small hail with any stronger cores late tonight into Wednesday morning.

As far as the flooding threat is concerned late tonight into tomorrow morning, WPC did extend the Day 1 (through 7 AM Wed) Marginal Risk for Excessive Rainfall down to just south of the I-64 corridor. The air mass feeding into convection will have good saturation, with PWAT values rising to 1.25-1.40" just south of the area of convection. On top of that, slab-like lifting over the llvl boundary and modest (not too much) instability could allow for efficient rain rates, though it's still likely that some inefficiencies due to ice generation will be experienced. HREF and REFS 6-hr LPMM progs do show some swaths of 1-2" of rain between now and midday tomorrow, mainly north of the WK/BG Parkways. While there certainly may be a need for a few flood advisories and possibly even a flash flood warning tomorrow morning, the expected rainfall amounts (even in the heaviest cores) are largely below flash flood guidance, so we'll continue to hold off on any Flood Watches. Most hi-res guidance shows enough southward propagation of the convective line to limit the amount of training of heavier cells. If the southward propagation is less robust, that would increase the potential for localized flash flooding, mainly across southern IN and north central KY, Wednesday morning.

SHORT TERM /THROUGH FRIDAY/

Issued at 356 PM EST Tue Mar 3 2026

The main focus through the short term will be shower and convective activity associated with a meandering warm front across the Ohio Valley. This will bring waves of showers and storms, with some storms potentially being strong to severe late Wednesday afternoon and evening. Heavy rainfall with the increasing potential for localized flash flooding, most notably across our southern Indiana counties Wednesday into Thursday.

Warm front has lifted into southern Indiana this afternoon, this is evident by 19z sfc observations with temperatures into the low 70s in DuBois county in Indiana along with mid/upper 60s. The core of the LLJ was positioned over southern IN into central KY, and with some partial clearing this afternoon, mixing has allowed the southerly flow to gust between 20-25 mph. The warm front is expected to continue to lift northward and then stall over central IN along the I-70 corridor this evening and overnight. While there could be a few isolated to scattered showers/thunderstorm this evening across southern IN, the bulk of the activity looks to take place north of the CWA across central IN.

Shortwave trough passing through the Great Lakes late this evening and overnight will help to shift the warm front along with any ongoing shower/storm activity southward through southern IN and along the Ohio River by the start of the day tomorrow. Lows will be mild overnight dropping into low/mid 50s across southern IN, north central KY and the upper 50s across south central KY.

Elevated convection is expected for the northern half of the CWA through the first half of the day tomorrow. Given that at least half of the evening and overnight look to remain mostly dry across our southern IN counties, with the rainfall not expected until the early predawn hours. Forecast rainfall totals overnight until 18z tomorrow across southern IN ranges from one half an inch to an inch this is well below the 6 hour flash flood guidance which is currently over two inches. After collaboration with our WFO neighbors to the north, where there is a Flood Watch in effect for tonight into tomorrow morning, decided no to issue one given the forecast QPF and current FFG. With that said, if the rain were to drop south sooner increasing the duration of rainfall over our southern IN counties, then we may have to monitor for the possibility of flooding concerns.

Convective activity should taper off briefly around midday or early afternoon before picking back up towards the late afternoon and early evening. A vort max ahead of an approaching shortwave trough ejecting out of the central plains tomorrow will bring another round of showers and storms to southern IN/central KY late tomorrow afternoon and evening. Most of the CAMs show steep mid-level lapse of 7-7.5 C/km, with MUCAPE between 500-1000 J/kg, the one limiting factor could be the widespread cloud cover, limiting the instability. SPC has continues to have southern IN/north-central KY in a Marginal Risk (1/5) for severe weather with large severe hail as the main threat with possible gusty winds.

Shortwave trough works into the Ohio Valley Thursday morning with a sfc low working into the Great Lakes. Sfc cold front will swing through with another round of showers/storms ahead of the approaching boundary. As was mentioned in the previous discussion, there remains uncertainty on timing of this system. Current SPC outlook has the area in a general thunder as model soundings do not look very impressive. The main impacts from this along with the convective activity Wednesday night could be the potential concerns and flooding as we continue to put water over increasingly more saturated ground. An additional 1-2" is possible with locally higher amounts in strong storms from 18z Wednesday to 12z Friday.

Friday may be our break from all the active weather as the front lifts back northward as a warm front. Strong warm air advection with strong southerly flow will help to push afternoon temperatures to above record values across the CWA. Highs in the low 80s to upper 70s are likely.

LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/

Issued at 356 PM EST Tue Mar 3 2026

Saturday through Tuesday...

On Saturday, a robust low in the lee of the Rockies ejects eastward across the Plains towards the Midwest. In addition, its cold front will move over the Ohio River Valley early Saturday through Saturday afternoon. Steady southwest flow will allow for more than enough moisture to be present for convective development to take place. Given the current morning/midday timing of the frontal passage, as well as model guidance depicting marginal mid-level lapse rates and 0-6 km wind shear, the potential for strong-to-severe weather is limited, but not completely ruled out. Temperatures will remain warm during the day, with highs in the low 70s across the area. With 0.5- 1.00" of QPF currently forecast for this frontal system, there is the potential for a few minor flooding concerns across southern Indiana with soils already being saturated from the previous storms occurring earlier in the forecast period.

As the cold front passes to the southeast Saturday night, temperatures will not cool substantially. Overnight lows will range from the upper 40s to mid 50s, with highs on Sunday getting into the upper 60s. A few showers and storms are possible during the day on Sunday as the front lingers just to the south of the area. With a broad upper-low retrograding off the Baja, zonal flow aloft sets up over most of the CONUS. This will help result in a mostly quieter pattern for the CWA through the remainder of the forecast period. Low-level southeasterly flow will carry some Gulf moisture over the region, and with a few weak perturbations passing through the region on Monday and Tuesday, a few showers could develop. Temperatures will slowly continue to rebound from the weekend frontal passage, with highs in the low 70s on Monday and in the upper 70s on Tuesday.

AVIATION /00Z TAFS THROUGH 06Z THURSDAY/

Issued at 654 PM EST Tue Mar 3 2026

For the first six hours of the current TAF period, there is fairly high confidence in VFR conditions with the warm front and rain remaining north of the region. Expect a fairly steady south wind around 6-10 kt this evening. While there will be a 35-40 kt S/SW jet around 2 kft AGL tonight, LLWS should be marginal, so we'll leave it out of this TAF package. Between 06-12Z tonight, the warm front will sag to the south, with rain, and possibly a few embedded storms, sinking toward HNB/SDF/LEX during the pre-dawn hours Wednesday. Forecast confidence in TSRA isn't super high right now, but mention may need to be added in subsequent forecasts. As the front and rain sinks south tomorrow morning, winds will back toward the east to the north of the front. The main impacts during the current forecast period appear to be reduced VIS from SHRA tomorrow morning, as well as lower CIGs through the day on Wednesday. BWG/RGA would be favored to be the least impacted, as the front may not sink far enough south to reach those terminals.

LMK WATCHES/WARNINGS/ADVISORIES

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