textproduct: Louisville

KEY MESSAGES

* Unseasonably warm temperatures continue this weekend, with highs in the 70s and 80s expected.

* Increasing threat of strong to potentially severe storms ahead of a cold front Sunday evening and overnight. A Slight Risk (Level 2/5) has been issued for northern portions of the CWA. Large hail and damaging winds are the main severe hazards.

* Cooler and mainly dry conditions are expected early next week.

SHORT TERM /THROUGH SATURDAY NIGHT/

Issued at 400 PM EDT Fri Mar 20 2026

Surface low pressure is analyzed over southern Ontario this afternoon, with a cold front extending to the west-southwest across the lower Great Lakes region. A relatively strong pressure gradient is present over the Ohio Valley between this sfc low and high pressure over the Gulf states, resulting in breezy southwest winds. Warm advection ahead of the front has allowed temperatures to warm into the 70s this afternoon, with a few locations in southern KY approaching 80 degrees.

As we head through the afternoon and evening hours, the above- mentioned cold front will drop south across Ohio/Indiana, approaching the Ohio River after sunset. Moisture will continue to increase along and immediately ahead of the front, with dewpoints rising into the low-to-mid 50s. This should be sufficient for around 300-500 J/kg of CAPE to develop, with higher amounts to the east. As the low-level winds converge along the front, there may be just enough lift to support a narrow band of clouds and showers for areas along and east of I-75, but the probability of showers is less than 20%. The front will begin to dissipate as it attempts to continue to push south late tonight, which should leave a pool of greater low- level moisture across south central KY for the day on Saturday. As winds become much lighter behind the front, can't rule out some patchy fog late tonight, but this will be dependent on how much clearing/cooling can take place.

Residual clouds associated with the front tonight should dissipate during the morning hours tomorrow as the cold front completely washes out. With a rather weak pressure gradient in place across the region, light and variable winds are expected, with mostly sunny skies in the afternoon helping temperatures again climb into the mid- to-upper 70s and low 80s. The leftover moisture across southern KY may be sufficient for isolated showers and thunderstorms to develop during the evening hours, and a weak mid-level shortwave passing through the region may provide modest forcing for ascent. As a result, we'll carry a slight chance for showers and storms late tomorrow afternoon and into the early evening for areas along and south of the Cumberland Parkway.

Outside of any isolated showers/storms in the southern CWA, Saturday evening into Saturday night should be dry across the area with mostly clear skies expected. A broad frontal zone/low pressure developing to the northwest of the area Saturday night should lead to increasing southerly flow during the overnight hours. This should keep temperatures mild, with lows only expected to drop into the upper 50s and lower 60s.

LONG TERM /SUNDAY THROUGH FRIDAY/

Issued at 400 PM EDT Fri Mar 20 2026

Sunday and Sunday Night...

Sunday morning, an elongated frontal zone will stretch from the Red River Valley across the mid-Mississippi Valley and into the northeast US. S/SW flow across the Ohio Valley along with some sunshine should send temperatures surging into the 80s across the area Sunday afternoon, with some daily high temperature records potentially being threatened. While winds will be breezy during the day on Sunday, this area of low pressure will not be nearly as strong as the one which impacted the region last weekend, and maximum wind gusts are favored (>50% probability) to remain below 30 mph outside of our typically gusty locations.

Sunday evening into Sunday night, an upper-level jet will move across the lower Great Lakes and into the northeast US, digging slightly southward as it does so. This upper-level forcing should nudge a cold front down across southern IN and central KY during the late evening and overnight hours Sunday night. Initially, model soundings show a pretty stout warm layer aloft between 850-700 mb which should cap convection during the afternoon on Sunday. However, as the front begins to work into the area Sunday evening, we expect the cap to erode somewhat, allowing a band of showers and thunderstorms to develop along the leading edge of the front.

With sfc dewpoints rising into the low 60s ahead of the front, MLCAPE on the order of 500-1000 J/kg should develop across the Ohio Valley. With 500 mb flow expected to be around 60-65 kt, effective bulk shear values should be around 50 kt, which will be more than sufficient for organized convection. There are a couple aspects of this setup which are unique in comparison to recent severe weather events. First, the aforementioned capping inversion may initially help to keep convection more discrete, especially the farther south and west you go. Second, above the cap, model soundings show a reasonably impressive EML with mid-level lapse rates on the order of 7.5-8 deg C/km. Also, while the deep-layer shear will be fairly strong, the low-level shear is expected to be less than recent events, with relatively unidirectional W/SW to W flow expected. Given this combination of factors, think we'll have a relatively higher threat for large hail, especially initially if we can get any discrete/supercellular structures across southern/central IN. If/when storms begin to line out along the front, the primary threat would then transition to straight-line winds. Overall, the tornado threat looks to be pretty low, but we can't rule out a spin-up or two. The severe threat is expected to be greatest across southern IN and northern KY where SPC has continued the Day 3 Slight (Level 2/5) Risk, with the severe threat diminishing as instability wanes later Sunday night across the southern half of the area.

Monday - Thursday...

Behind the cold front, a couple days of dry and cooler weather are expected for Monday and Tuesday as temperatures fall back into the 50s and 60s. NW flow aloft will continue into the middle of next week, at which point weak perturbations within the upper wave pattern may be able to support light rain chances. As we get later into next week, ensembles tend to support a warm up for Thursday before another cold front passes through the region before next weekend. Timing and intensity of the late week system varies between models, so confidence in specifics is fairly low at this time.

AVIATION /18Z TAFS THROUGH 00Z SUNDAY/

Issued at 132 PM EDT Fri Mar 20 2026

For the rest of this afternoon, VFR conditions are expected to continue along with breezy SW winds as a cold front approaches the region from the north. The cold front is expected to dissipate as it attempts to cross area terminals tonight; however, marginal LLWS will be possible just ahead of the front. Additionally, there could be a few showers near LEX/RGA, but since confidence is low and coverage is not expected to be all that great, will continue with a dry forecast for now. Early tomorrow morning, low-level moisture behind the cold front could result in some patchy fog and low stratus at LEX/RGA; however, this is low confidence, so will just mention the potential here. VFR conditions should return Saturday morning with light winds expected.

LMK WATCHES/WARNINGS/ADVISORIES

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