textproduct: Louisville

KEY MESSAGES

* Cold front approaching from the northwest could fire off scattered showers/storms later this afternoon and evening. Mainly along and north of I-64 and along and east of I-65. Main impact could be strong gusty winds, heavy downpours and lightning.

* Weekend will be mainly dry and warm with highs around 80 degrees. Low end chance of scattered to isolated showers/storms on Saturday across southern and eastern KY.

* Severe Weather potential for Monday afternoon and evening as a low pressure system moves through the region. The setup is favorable for severe storms, though confidence in details remain low at this time.

SHORT TERM /THROUGH TONIGHT/

Issued at 358 AM EDT Fri Apr 24 2026

===== Today - Tonight =====

This morning begins calm with light southerly winds and clear skies. Conditions slowly change after sunrise as clouds move in from the west along with increasing SW winds. A shortwave will be approaching from the west ushering in increasing dewpoints and wind gusts of 15- 25 MPH.

Despite these changes, a weakening cold front from a shortwave will approach from the west. The trough responsible for the shortwave will be lifting well to our north, taking dynamical support with it. Combined with ridging ahead of this shortwave, weakening frontogenesis, and rather unimpressive mid-level lapse rates Friday morning/afternoon, storms and showers along this front will begin collapsing, at least in western communities west of I-65. So by late Friday morning, what seems to be an impressive line of storms will weaken to rain showers, with a stray rumble of thunder in western areas. However, the front will slowly continue to press eastward throughout the day and will initiate a few more storms in the early afternoon pushing east of I-65 through the evening.

By early afternoon, a second broken line of storms will reform along and north of the Bluegrass, most favored in our eastern Indiana counties. Surface instability may increase up to 1300 J/kg at the 90th percentile, depending on daytime heating and raising dewpoints in the low 60s. As a resul, this second line of storms east of I-65 and north of I-64 has a low-end chance of producing strong wind gusts (<20%). Otherwise, this second line will progress eastward and initiate more storms south of the Bluegrass. Highs today will be their warmest right before the front sweeps through, ranging in the upper 70s to low 80s area wide.

Eventually, the front will slow its eastward progression, keeping a boundary draped over our southeastern communities from Bowling Green curving towards Lexington, KY. Some lingering showers will stick around as a result from this boundary in these areas overnight Friday night heading into Saturday. Altogether, rainfall totals have trended down in the past 24 hours, with 0.1-0.25" possible (75%) for everyone, though there is still a left-skewed distribution in HREF ensemble data, meaning some people may dodge any rainfall and remain dry. Despite the low-end severe threat in our northern border counties, tomorrow should eventually become overcast in the afternoon with gusty winds and scattered showers and storms.

LONG TERM /SATURDAY THROUGH THURSDAY/

Issued at 358 AM EDT Fri Apr 24 2026

***Saturday and Sunday***

Cold front will push through early Saturday morning with a weak mid- level impulse following behind. That should be enough lift for a few isolated to scattered showers and storms (20-40%) mainly south of the parkways into the Lake Cumberland region. Sfc high pressure is expected to build in from the north as upper ridging builds back in over the Ohio Valley late Saturday into Sunday. We will remain above normal each day with highs in the upper 70s to low 80s.

***Potential Severe Weather Threat Monday***

--Synoptic Setup--

Deterministic model guidance continues to show a favorable mesoscale setup for potential severe weather across parts of the Mid- Mississippi Valley and the western Ohio Valley on Monday. A shortwave trough coming onshore off the central CA coast will track across the Desert Southwest and into Central Plains by Monday morning. Strong surface cyclogenesis will develop a deepening sfc low over the Central Plains Sunday Night. The negatively tilted mid- level shortwave trough and sfc low will then work northeast into the Upper Midwest and Great Lakes Monday night into Tuesday. This will lift a warm front across the Ohio Valley during the day Monday as Gulf moisture is drawn northward into the region. Aloft, a strong mid-level jet core will setup over the mid/upper Mississippi Valley providing strong upper-level divergence over the region, mainly across the western Ohio Valley. There will also be a strong LLJ ahead setting up over the Ohio Valley late Monday resulting in ample shear supporting organized storm structures before becoming more linear along and ahead of an approaching sfc cold front Monday night into Tuesday morning.

--Confidence in Severe Threat--

Given that we are still 4-days out from this event, will continue to hold on to a low end Medium confidence for severe weather potential but the latest 00z deterministic guidance has significantly backed off on overall severe threat for central KY and southern IN. Both the GFS and ECMWF are trending slower and have backed off on the amount of available instability. While the GFS continues to be the more aggressive of the two models with higher SBCAPE (1000-1500J/kg) both models now hold off until Monday night to bring in the convection with a strong capping inversion in the afternoon. While the current guidance trend is backing off on the threat, CIPS Analog, CSU Machine Learning probabilities, and NCAR AI NWP have actually shifted a little more east. While the SPC Day-5 outlook expanded the Slight Risk (level 2/5) towards I-65 and added an Enhanced Risk (level 3/5) across the Mid-Mississippi Valley. We will see what happens later this morning when SPC released their day-4 outlook, but it is the opinion of this forecaster that we will likely see little overall change with this update.

--Impacts--

While confidence is high that far western KY across the Mid- Mississippi Valley has the highest probability of experiencing severe weather on Monday, with all threats on table from damaging winds, large hail and tornadoes possible, there are still a lot of unknowns as we go into the weekend and fine details that need to be worked out. As you work eastward from western KY towards I-65 and into eastern KY the confidence drops but it isn't zero. As we get more detail the fuzzy image that is the current forecast starts to come into focus and increases confidence. This is a great time to start planning as we close out the week and head into the weekend and create a plan for Monday just in case.

***Tuesday through Friday***

Cold front from Monday pushes through Tuesday morning and stalls out across the Tennessee Valley as the upper pattern become more zonal through the end of the week. Currently our forecast keeps a chance of precipitation every day through the end of the week but I anticipate there to be more dry than wet. We will also see cooler temperatures. Highs will go from the mid/upper 70s on Tuesday and keep getting cooler each day with potentially highs in the 60s by the end of the week.

AVIATION /12Z TAFS THROUGH 18Z SATURDAY/

Issued at 642 AM EDT Fri Apr 24 2026

VFR conditions are ongoing now but will gradually deteriorate to MVFR ceilings, especially in southern and eastern areas later this evening. A cold front is approaching from the northwest, bringing in overcast skies gradually dropping to 5,000 ft this afternoon. Western areas will see scattered showers and storms, with PROB30s for thunderstorms at HNB and SDF this afternoon. Otherwise, plain scattered showers will move in from this front with very light rainfall totals. SW wind gusts peak in during the day for everyone ranging 20-25 kts before dying down in the evening. Southern and eastern airports may not see scattered showers until later this afternoon/evening, with -SHRA for BWG-LEX-RGA at some point in time. The front will slow down later Friday night, meaning BWG may get socked into deeper moisture, lowering cloud decks to IFR ceilings towards the end of the TAF period. Otherwise, high-end MVFR to VFR conditions will stick around through Saturday morning.

LMK WATCHES/WARNINGS/ADVISORIES

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