textproduct: Louisville

KEY MESSAGES

* Dry and mild weather is expected for tonight and Monday. Monday will feature breezy conditions with wind gusts of 25-30 mph.

* Strong/severe thunderstorms are expected Monday night and into Tuesday morning. The highest risk of severe weather is in areas west of I-65 and decreases as you head east of the I-65 corridor.

* A conditional threat of severe storms exists for Tuesday afternoon and evening. Damaging winds and large hail are the main severe threats.

* Temperatures cool Wednesday afternoon and will run below average through next weekend for late April/early May. Mostly dry weather is expected after Wednesday, with a slight chance for light rain on Friday.

UPDATE

Issued at 922 PM EDT Sun Apr 26 2026

Several storm clusters are producing a nice blob of colder cloud tops covering most of Missouri this hour. New storms are behind that developing along a boundary in eastern KS and OK. GOES Sounder data shows these storms should weaken as they head eastward into a much drier airmass. Model precipitable waters will start to increase rapidly Monday, as easterly low-level winds veer to the south and southwest ahead of a potent surface low. That should set the stage for the well-advertised storms/hopeful rainfall we get Monday evening into midweek.

Updated the gridded forecast for the latest trends, but we look to be pretty much on track.

SHORT TERM /THROUGH MONDAY NIGHT/

Issued at 316 PM EDT Sun Apr 26 2026

Earlier low stratus has finally mixed out and has left skies partly to mostly sunny. The earlier cloud cover has led to a gradient of temperature across the region. Where skies have been cleared out for much of the day, temperatures were in the middle-upper 70s. Along/north of the I-64 corridor in KY, the clouds hung around a bit longer and temperatures were in the mid-upper 60s. With higher sun angles and plenty of daylight left, temperatures in the previously cloud covered area will gradually recover. No significant weather is expected through the afternoon and evening. Highs on the day will likely be in the 70-75 degree range across southeast Indiana and into the Bluegrass region of central Kentucky. Across the I-65 corridor and points south, highs in the upper 70s to around 80 are expected.

For tonight, upper level ridging will continue across the region with winds beginning the night out of the northeast. As surface high pressure moves off to the east, winds will gradually shift to the east and southeast overnight. Overnight lows will be in the lower 50s in SE Indiana and into the Bluegrass region. Some of the traditional cooler/radiational cooling spots may get into the upper 40s. Across the central and western sections of the forecast area, lows in the mid-upper 50s are expected.

For Monday, surface winds will veer around to the south by morning and then shift to the southwest by mid-late morning. The pressure gradient will gradually increase through the day with winds becoming gusty in the mid-late morning through the afternoon. Wind gusts of 25-30 mph will be possible. To our west, and MCS is forecast to be in progress across MO. High cirrus/convective debris will spread eastward yielding a high veil of clouds across the region for much of the day. Despite the anticipated cloud cover, the warm advection pattern will boost temperatures into the 79-84 degree range for highs.

For Monday night, somewhat complicated forecast as convective evolution for the daytime hours on Monday remains in question. Majority of the short-range guidance suggests that extensive convection will develop across MO/IL during the afternoon with discrete supercells being possible ahead of a cold frontal boundary. As this boundary moves eastward, discrete convection is likely to grow upscale into one or more lines and then push eastward into the lower Ohio Valley by late evening. Current guidance does show some variability in the overall convective evolution with some models showing some isolated/discrete convection developing out ahead of the main line and moving northeast affecting our southern IN counties. Should this occur, the overall environment would support supercells with all hazards being possible. However, the majority of the short-range guidance suggests that a line of convection will push through the region during the overnight period. The atmosphere will undergo nocturnal stabilization after sunset, though the low- level jet will remain overhead. With this setup in mind, a strongly forced line of convection (though likely weakening with eastward extent) will result in a damaging wind risk across our region. Given the ample shear in place, QLCS spin-up tornadoes within the line will be possible. The highest risk of severe weather continues to be focused in areas west of I-65 with a decreasing risk of severe as one heads east of I-65. This band of storms will quickly move across the region exiting the LMK CWA before sunrise Tuesday. Moderate to heavy rainfall is expected with this line with rainfall amounts of one half to one inch amounts being possible.

LONG TERM /TUESDAY THROUGH SUNDAY/

Issued at 316 PM EDT Sun Apr 26 2026

A Second Chance for Storms Tuesday into Tuesday Night...

At the beginning of the extended forecast period Tuesday morning, the first wave of strong storms should be clearing into the TN Valley and Appalachia, with a lull in shower/storm activity expected through a good chunk of the day on Tuesday. Behind this first wave, some clearing is expected, which should help temperatures warm into the upper 70s and low 80s Tuesday afternoon. With the trough that forced Monday night's line of storms lifting into Ontario by Tuesday morning, the sfc cold front will lose its upper-level support, causing it to become quasi-stationary over the Ohio Valley during the day on Tuesday. This boundary should also become more west-east oriented, with higher sfc dewpoints pooling along and south of this boundary.

By Tuesday afternoon and evening, a 60-65 kt mid-level jet streak and shortwave will cross from KS into MO, with sfc low pressure beginning to develop over the Ozarks in association with this wave. This forcing, along with a strongly unstable environment over the lower and mid-Miss. Valley, should lead to the development of showers and storms Tuesday afternoon and evening to the west of the area. As the storms approach the lower Ohio Valley, aforementioned moisture pooling with sfc dewpoints in the mid-to-upper 60s along the remnant front should increase instability. With that being said, there is a fair amount of spread in guidance in the exact amounts of instability, likely due to uncertainty in how much clearing and upstream convection evolution. With some of the more aggressive progs, 2000-3000 J/kg of MLCAPE would be available Tuesday evening across portions of the area, which is certainly supportive for strong storms. While mid- and upper-level flow will remain strong, low-level winds and shear will be limited, with the strongest LLJ expected to remain to the south of the region. This should result in more linear hodographs with relatively modest amounts of curvature/SRH in the lowest 1-2 km.

All of this points to a second chance for strong to severe storms across much of the area Tuesday evening into Tuesday night. The extent/level of the threat is still quite uncertain, and we'll need to see how things evolve Monday night into Tuesday morning to get a better handle on the second severe threat. In general, there will be a greater risk the farther south and west you go where the greatest instability is expected. As previous forecasts have mentioned, the deep-layer shear and amount of potential instability both support an elevated threat for damaging winds and hail, while the tornado potential is more uncertain given the limited low-level shear.

The sfc low is expected to deepen and track across the Ohio Valley late Tuesday night into Wednesday morning, with a trailing cold front sweeping across the region during the day on Wednesday. Falling dewpoints behind the front should bring an end to the shower/storm chances, although if the front is slower, we could see another chance for storms Wednesday afternoon east of I-65. Temperatures will begin to trend downward on Wednesday, with highs ranging from the upper 60s across southern IN/northern KY to the mid 70s across southern KY. Clearing skies are expected Wednesday night as CAA helps temperatures to fall into the 40s.

Thursday - Next Weekend...

In the wake of the mid-week disturbance, quieter weather is expected for the end of the week into next weekend. Zonal mid- and upper- level flow should setup beneath troughing across the eastern half of North America during this period, helping to shove the storm track into the Gulf states by the end of the week.

Thursday continues to trend drier as the region sits between the departing shortwave and a meandering closed low off the California coast. Temperatures should be slightly below normal, with low temperatures in the 40s bringing a refreshing change after recent warmth.

The next chance for precipitation we'll have to watch for is late Thursday night into the day on Friday as a wave in the northern branch of the jet stream drops from NW to SE across the region. This disturbance won't be carrying much moisture with it, so while there are 20-30% chances for rain at this time, the chance for significant rains (>0.10") is only about 5-10% across the area, so Friday should by no means be a washout.

For the weekend, the vast majority (~95%) of model guidance keeps the region dry with slightly below normal temperatures. The above- referenced cutoff low will is expected to slowly drift to the E/NE during this period; however, the current expected position of the upper trough over the eastern US is such that any moisture return/precipitation chances are expected to remain along the Gulf. At this time, temperatures in the early morning Saturday and Sunday may be cool enough that frost comes into play, with below normal temperatures likely through the first weekend in May.

AVIATION /00Z TAFS THROUGH 06Z TUESDAY/

Issued at 711 PM EDT Sun Apr 26 2026

Winds will veer around to easterly and then southerly through Monday morning as a low pressure system deepens over the central Plains. Gusts will pick as the morning goes on. Storm chances should hold off until late in the TAF period for both HNB and SDF...with chance for gusty winds and IFR conditions as storms move through Monday late afternoon/evening.

LMK WATCHES/WARNINGS/ADVISORIES

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