textproduct: Jackson

KEY MESSAGES

- Mainly dry and cooler weather returns 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 flooding possible.

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

UPDATE

Issued at 1122 AM EDT TUE AUG 18 2026

Hourly grids have been freshened up for recent observations and trends. Some drizzle or sprinkles in upslope flow may linger from the stratocu and cumulus as those this should be fleeting as daytime heating and mixing progress into the afternoon.

LONG TERM

(Wednesday night through Monday) Issued at 435 AM EDT TUE AUG 18 2026

By Wednesday night, the cold frontal boundary will sag closer to the area and shortwaves riding through the broader upper level troughing will aid in forcing convection. This will lead to an increasing threat of showers and thunderstorms Wednesday night, with chances peaking in the 50 to 60 percent range near/north of I-64 and lesser chances (20 to 30 percent range) toward the Virginia border. The chance of showers and thunderstorms then increases further Thursday (50 to 70 percent range), as the frontal boundary sags deeper into Kentucky and a more pronounced shortwave arrives. There is a decent surge of moisture noted with the boundary, with PWAT values generally peaking in the 1.7 to 1.9 inch range, but the overall movement of this activity is expected to be rather progressive. Even so, locations that experience multiple rounds of convection could be at risk of minor flooding issues, and WPC does have all of eastern Kentucky in a Marginal Risk (1 out of 5) for Thursday into Thursday night. There is at least some question on the potential for a few stronger storms, with MUCAPE in the 1000-2000 J/kg range and effective shear in the 30-40 kt range. This is a reasonable enough parameter space to aid in organizing convection, with the main risk being strong wind gusts. This comes as DCAPE values increase toward 900 J/kg Thursday afternoon.

By the end of the week, the cold front is expected to slowly sink southward. There is some uncertainty as to how far, but enough to keep rain chances lower for Friday and Saturday, generally in the slight chance/chance range. Then by the late weekend into early next week there remains at least some model uncertainty with regard to the depth of the eastern CONUS trough as stronger shortwave drops out of the Northwest Canadian Arctic. Some guidance shows a closed upper low developing across the northern Ohio Valley/Eastern Great Lakes while 500 hPA ridging pumps back up over the Western CONUS. This could set the stage for a Canadian cold front to cross eastern Kentucky late Saturday or early Sunday with a subsequent early fall-like high pressure system to start the last full week of August.

AVIATION

(For the 18Z TAFS through 18Z Wednesday afternoon) ISSUED AT 155 PM EDT TUE AUG 18 2026

Cumulus was present across the region at issuance time with all areas in or climbing into the VFR range with these as high pressure builds into the OH Valley and ushers drier air. More widespread fog is probable tonight compared to last night as that high pressure system crests over eastern Kentucky. This fog should bring reductions to MVFR initially as early as 04Z in some areas, with some reductions to IFR or lower in many locations between 07Z and 08Z and 12Z, before fog begins to lift and categories improve in all areas by 13Z to 14Z. West northwest to northwest winds at 10KT or less are expected to begin the period, before becoming light and variable by around 00Z. West to northwest winds at less than 10KT should return to end the period along with the potential for a few cumulus as well after about 15Z.

JKL WATCHES/WARNINGS/ADVISORIES

None.