textproduct: Louisville

KEY MESSAGES

* Isolated to scattered showers and thunderstorms will be possible for the reminder of the afternoon and the evening today. Locally heavy rainfall, gusty winds, and frequent lightning will be the primary weather hazards.

* The late weekend and into early next week will feature dry, hot, and humid conditions with highs warming into the lower 90s, and heat indices approaching 100.

* An active stretch of weather looks increasingly likely during mid to late next week. Multiple clusters of thunderstorms could move through the region, with strong to severe storms at times and heavy rainfall.

SHORT TERM /THROUGH SUNDAY NIGHT/

Issued at 407 PM EDT Sat Aug 8 2026

While it has been a dry day for most of southern Indiana and central Kentucky, a few showers and storms have developed this afternoon, especially in southern Kentucky. This trend will continue into the evening hours before the loss of diurnal heating eliminates the main source of energy for these showers and storms.

Our region is currently stuck in the middle of a few different synoptic scale patterns, including upper trough over the Great Lakes and southern Canada, an upper ridge over the central and western CONUS, both of which are deamplifying, and a western Atlantic/SE CONUS ridge. This has resulted in a weaker area of surface high pressure, with generally light surface, mid, and upper-level flow. After any showers and storms dissipate this evening, conditions will be dry and mild, with overnight temperatures in the low 70s forecast.

For tomorrow, the pattern will begin to shift some as a more robust shortwave trough swings from the northern Plains towards the Midwest/Ohio Valley. Guidance is picking op on an MCS developing early Sunday, tracking southeastward towards Indiana and Ohio by the evening hours. The influence of the SE CONUS ridge appears to be enough to keep the track of the MCS off to our north and east. As a result, while over 2000 J/kg of SBCAPE will be present over the area tomorrow, limited wind shear and forcing aloft will only provide a very slight chance (10-20%) for showers and a couple storms tomorrow afternoon, primarily south of the Parkways. Afternoon highs will be in the low 90s, and with dew points in the 70s heat indices reaching 100 cannot be ruled out. For Sunday night, again expect dry and mild conditions with temperatures in the low 70s.

LONG TERM /MONDAY THROUGH SATURDAY/

Issued at 407 PM EDT Sat Aug 8 2026

Going into the start of the upcoming workweek, the upper-level pattern will be fairly zonal, with surface high pressure lingering over the area. While ample amounts of instability will be present (>2500 J/kg of mean SBCAPE per latest LREF), weak forcing and shear will again be a limiting factor in the production of showers and storms. Southerly near-surface flow will allow for very warm and humid air to linger over the region towards the middle of the workweek. Highs in the low 90s with dew points in the low-to-mid 70s are forecast, allowing afternoon heat indices to peak in the upper 90s/reaching 100. While this is currently expected to remain below advisory criteria, conditions will be quite muggy regardless over this stretch. Overnight relief will be limited, with temperatures only dropping down to the low-to-mid 70s.

With the zonal pattern overhead and the main jet remaining off to the north for the early part of the week, most of the shortwaves and perturbations that pass by that could produce showers and storms will also stay off to the north. This won't last for long though as the pattern begins to shift on Tuesday. The upper-level pattern will amplify some, with the western CONUS ridge building and troughing over the eastern CONUS digging. This will allow the flow over our region to shift to a northwesterly regime, as well as the southern periphery of the jet to move towards the region as well. With numerous shortwaves expected to trek towards the Midwest and Ohio Valley, chances for showers and storms will increase starting Tuesday night. The coverage initially will be in north central Kentucky and southern Indiana, slowly shifting southward as the trough continues to dig southward. With model soundings continuing to show elevated instability and a modest wind shear profile, strong to severe storms cannot be completely ruled out with each passing wave. The potential for excessive rainfall is also possible as any stronger storms that do develop could produce heavier downpours.

A cold front will move over the area by late week, proving a well- needed reprieve from the hot and humid conditions over the region. The progression and placement of the front by the end of the forecast period is uncertain based off the most recent ensemble guidance, resulting in additional uncertainty in precip chances during that portion of the forecast period.

AVIATION /00Z TAFS THROUGH 06Z MONDAY/

Issued at 734 PM EDT Sat Aug 8 2026

VFR conditions are expected to continue through the forecast period. Isolated showers and storms are currently moving over south central KY, and are expected to continue for the next couple hours. TEMPO groups were added to all TAF sites (except SDF) for a brief period of fog in the morning. Skies will start to clear NW to SE in the early morning hours with FEW/SCT 250 for the day tomorrow. Sites are expected to stay dry during the day tomorrow.

LMK WATCHES/WARNINGS/ADVISORIES

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