textproduct: Jackson

KEY MESSAGES

- Mainly dry and cooler weather through Wednesday, though locally dense river valley fog is expected late tonight.

- A cold front brings scattered to widespread thunderstorms Wednesday night and Thursday, with a few strong wind gusts and localized heavy rain and flooding possible.

- Noticeably cooler and less humid air arrives this weekend and continues into early next week.

UPDATE

Issued at 1115 PM EDT TUE AUG 18 2026

No significant changes were made to the forecast with mainly just the inclusion of the latest obs and trends for the T/Td/Sky grids. Still anticipated areas of dense fog developing in the valleys later this night. The forecast adjustments have been sent to the NDFD and web servers along with a freshening of the zones.

UPDATE Issued at 740 PM EDT TUE AUG 18 2026

23Z sfc analysis shows weak high pressure currently in control of the weather over eastern Kentucky. This is working to settle the winds and keep skies mostly clear. Currently, temperatures are running in the low to mid 70s in the sheltered valleys to the upper 70s on the ridges. Meanwhile, amid light north winds at 5 mph or less, dewpoints generally range from the lower 60s north to near 70 in the far south. Have updated the forecast mainly to add in the latest obs and trends for the T/Td/Sky grids. These minor adjustments have been sent to the NDFD and web servers along with a freshening of the SAFs and zones.

LONG TERM

(Thursday through Tuesday) Issued at 330 PM EDT TUE AUG 18 2026

At the onset of the extended forecast period, large-scale 500 mb troughing remains anchored across much of the eastern CONUS. In the pre-dawn hours Thursday, a nocturnal 40-50 kt low-level jet (LLJ) oriented across western and central Kentucky will coincide with a shortwave passing through the Ohio Valley. While the LLJ weakens to 30-40 kts as it shifts into eastern Kentucky, rounds of showers and thunderstorms are expected through Thursday. The first round will move through during the morning hours, favoring areas across the Cumberland, Southern Licking, and Big Sandy River basins near the TN, VA, and WV borders. A brief lull in activity is expected before redevelopment occurs early Thursday afternoon along the I-64 corridor, propagating south through the remainder of the day. Models indicate drier air working in aloft by late afternoon, which could suppress rain chances. However, the environment will support PWAT values near 1.75 inches (80th to 85th percentile of climatology). Given saturated soils from recent rainfall, isolated instances of minor flooding remain possible Thursday through Thursday night, supporting WPCs Marginal Risk (Level 1 of 4) for excessive rainfall. Adequate storm motion should keep activity progressive, limiting widespread flash flooding potential.

As the frontal boundary associated with Thursdays convection lingers near the area on Friday, shower and thunderstorm chances will persist, with the highest probabilities during the afternoon along and south of the Hal Rogers Parkway / KY Highway 80 corridor. Beyond Friday, models and ensemble guidance remain in broad agreement on a continued upper-level pattern featuring a ridge over the western CONUS and troughing across the east, though amplitude differences remain. Another shortwave embedded within the longwave trough is projected to dig out of the Upper Midwest into the Great Lakes and Ohio Valley Saturday into Sunday. Multiple 00Z AI-based guidance suites from August 18th show conditional severe potential on Saturday, primarily centered over SW Pennsylvania, with lower probabilities (5-15 percent) extending southwest into eastern Kentucky. At present, PoPs support isolated to scattered coverage across the Licking and Big Sandy basins on Saturday. Isolated shower or storm activity may linger across the Big Sandy early Sunday morning; otherwise, dry weather is expected to return through Monday morning. By Monday afternoon, guidance depicts another upper level low which a few models attempt to close off digging southeast from the Upper Midwest into the Northern Great Lakes. This feature could bring another round of shower and thunderstorm chances to the area on Tuesday.

AVIATION

(For the 06Z TAFS through 06Z Wednesday night) ISSUED AT 157 AM EDT WED AUG 19 2026

High pressure is cresting over eastern Kentucky early this morning and is bringing favorable conditions for extensive fog formation in the valleys. The fog is likely to impact adjacent ridges by daybreak, especially south of I-64. Reductions to at least MVFR are forecast at JKL, LOZ, SME, and SJS, but could be briefly worse. Confidence in fog formation was too low at IOB and SYM to include in this TAF cycle. The fog will lift after sunrise, allowing conditions to improve in all areas between 12 and 14Z. Light winds will continue through daybreak. West winds at less than 10 kts then return by midday Wednesday with high clouds and a few cumulus arriving after ~14Z.

JKL WATCHES/WARNINGS/ADVISORIES

None.