textproduct: Jackson

KEY MESSAGES

- Well-above normal temperatures persist into the weekend, with near-record heat possible over the Cumberland River Basin today. - The heat, humidity, and a nearby frontal boundary could foster isolated to scattered thunderstorms across the area at various times over the next several days.

- Rain chances increase early next week as the persistent upper level ridging breaks down.

LONG TERM

(Saturday night through Thursday) Issued at 239 AM EDT FRI SEP 18 2026

Upper level ridging over the southeast CONUS will continue weaken as we move into the the long term period. Largely zonal flow aloft will be positioned just to our north at the start of the period. Multiple weak impulses moving through the flow will help to drive it very slowly southward as the upper high breaks down. By midweek, some semblance of an upper low is forecast to evolve near the Great Lakes, pushing faster flow aloft even further south for late week.

At the surface, this will eventually drive a significant cold front southward. This boundary should start the long term period to our north, near the Ohio River or further north, with its true position possibly somewhat muddled by prior convection. There is potential for some of this convection to feed off of our heat and humidity on this side of the front and make it south into our area in the Saturday night through Monday time frame, but confidence in details is very low due to mesoscale influences which would be in play. The greatest POP looks to be as the front pushes through. Models have not come into agreement yet, with cold fropa timing likely to be in the Tue-Wed time frame.

Noticeably cooler air should arrive behind the front as sprawling surface high pressure sets up in the vicinity of the Great Lakes and southeast Canada for late week. Our POP drops off with the change in air mass, but some light precip won't be completely ruled out, depending on the evolution of the persistent upper low/trough and any impulses rotating around it.

AVIATION

(For the 06Z TAFS through 06Z Friday night) ISSUED AT 153 AM EDT FRI SEP 18 2026

VFR conditions were observed over the TAF sites at the 06Z issuance. Valley fog is likely overnight but impacts at the TAF sites outside of KSME appear unlikely. Any fog should dissipate rapidly after sunrise. Showers are then possible as early as 12-15Z across northeastern TAF sites such as KSYM, KIOB, and KSJS ahead of a weakening cold front pushing south out of the Ohio Valley. Thunderstorm chances pick up around 18Z at all terminals except KLOZ and KSME, where chances begin more toward 20-22Z, later tapering off after sunset. Showers and storms could lead to MVFR or lower reductions and PROB30s have been included in the TAF sites during the periods of greatest concern. Winds will remain light and variable through daybreak before increasing to around 5 kts from the northwest to northeast. Locally stronger and erratic winds are possible near convection.

JKL WATCHES/WARNINGS/ADVISORIES

None.