textproduct: Jackson

KEY MESSAGES

- Above normal heat and humidity will persist to start the new week. - A cold front will eventually make its way through the region, with an increasing potential for showers/thunderstorms through mid week.

- Cooler and drier air will arrive behind the cold front for late week.

UPDATE

Issued at 836 PM EDT SAT SEP 19 2026

Precip has died out with loss of surface based instability. A 20% POP was already in the forecast for a while into the evening. Will leave it alone for the time being to avoid flip-flopping just in case something develops yet. However, if the 20% POP were not already in place, it would not be getting added. Have made adjustments to the sky cover for tonight into Sunday based on the latest obs and model trends, but the changes are minimal.

LONG TERM

(Monday through Saturday) Issued at 409 PM EDT SAT SEP 19 2026

At the start of the long term period, eastern Kentucky will find itself in a region of largely zonal flow aloft, with a broad trough over the northeastern CONUS and a closed upper level low to the northwest in the Northern Plains. At the surface, a cold front will push through the forecast area before losing momentum near the TN line. Although the timing of this front remains in question, a temperature gradient looks to set up across the forecast area; north of the boundary, northerly winds will keep weather cooler, with high temperatures remaining seasonable (upper 70s to low 80s), while south of the boundary, southerly to southwesterly flow will dominate. This will keep weather feeling more like summer, with highs in the upper 80s or perhaps low 90s in areas unaffected by convection. That being said, the aforementioned boundary, in addition to a shortwave trough embedded within flow aloft, will keep PoPs elevated, with at least scattered convection possible as early as Monday afternoon.

The pattern looks to be quite active from Monday evening onwards as the previously mentioned closed low progresses eastward and eastern Kentucky finds itself under the influence of amplifying troughing centered over the western Great Lakes. Each day, the environment will be moist (LREF mean PW values generally in the 70th percentile or higher compared to climatology). There will be ample forcing for convection as multiple embedded shortwaves traverse the base of this trough, and with a surface low and associated boundary lingering in the vicinity of the forecast area through at least Wednesday, rain chances should remain high through at least midweek. Ensemble guidance suggests moderate instability remains favored to build each afternoon, and with high freezing levels and a very saturated profile, any convection could yield efficient rainfall rates. Flow will remain fairly weak aloft, and thus minimal shear should preclude an organized severe weather risk; however, this unimpressive upper level flow will also keep storm motion quite slow (generally in the 10-15 kt range). Altogether, these factors indicate that the environment will be favorable for flash flooding, particularly in areas that receive multiple rounds of heavy rain. Given this, WPC has maintained Day 3, 4, and 5 Marginal Risks (Level 1/4) for Excessive Rainfall across most of eastern Kentucky, with the caveat that model spread remains high and a categorical upgrade could be needed if/when confidence in these details increases. On a positive note, this pattern should also provide some relief from the heat; highs will generally be in the 70s across the forecast area, near to below average for this time of year.

In the latter half of the week, ridging will build over the central CONUS, with troughing now displaced east of our area. With this more stagnant pattern in place, the trend will be towards less active weather, with only slight chance PoPs from Friday onwards. It will also feel more like fall; northerly flow should maintain cooler temperatures, with highs in the low to mid 70s!

AVIATION

(For the 00Z TAFS through 00Z Sunday evening) ISSUED AT 754 PM EDT SAT SEP 19 2026

A small thunderstorm was affecting the northern end of the JKL forecast area at TAF issuance, northwest of KSYM, probably resulting in very isolated sub-VFR conditions. Otherwise, conditions were VFR across the area. Won't rule out some additional showers or thunderstorms affecting northern and eastern portions of the forecast area this evening, but they would likely be very isolated if they occurred, and have not been addressed in TAFs. Away from any precip, VFR conditions should persist until late tonight. Valley fog is forecast to develop overnight, especially in extreme eastern and southeastern KY, resulting in localized IFR or worse conditions. The fog will dissipate on Sunday morning, leaving VFR conditions area wide through the afternoon.

JKL WATCHES/WARNINGS/ADVISORIES

None.