textproduct: Jackson

KEY MESSAGES

- Heat indices will again reach the 100 to 105 degree range in some locations on Saturday, mainly near Lake Cumberland and possibly a few other locations near the TN border.

- Although a shower or thunderstorm cannot be ruled out tonight, chances peak Saturday afternoon and evening.

- The strongest storms on Saturday afternoon and evening could produce damaging, torrential downpours, and perhaps hail.

UPDATE

Issued at 750 PM EDT FRI SEP 4 2026

Over the past hour, convection has waned while outflows and the convection as well as the approach of sunset has led to temperatures cooling and relief from the daytime heat. This heat advisory as cancelled early around 7 PM EDT as a result. For now, no changes were made to pops although some of the recent CAM runs have overnight convection with the approach of a cold front and perhaps some upstream convection moving in from the northwest and into northern and/or eastern sections. Overall, chances increase during the day on Saturday.

LONG TERM

(Sunday through Friday) Issued at 452 PM EDT FRI SEP 4 2026

An amplified upper air pattern will be in place to start the long term period, with high pressure over the southern plains ridging north to Canada and closed lows near the NW and NE corners of the CONUS. At the surface, High pressure near the Great Lakes will be dropping southeast under northwest flow aloft and supplying us with relatively cooler and drier air compared to recent days. Enough lingering low level moisture could be left in southeast KY for a few showers on Sunday before the change in air mass fully takes hold. Dew points look like they`ll dip low enough to allow for the coolest valleys to radiate below 60 by Monday morning.

The upper lows are expected to weaken drift east by Midweek, with the sprawling (but flatter) upper high shifting east to the Tennessee Valley. Our low level flow will turn to the south and southwest as the surface high shifts to our east. The low level flow and building geopotential heights will give us warmer temperatures and climbing dew points.

There is model agreement that the upper low initially near the northwest CONUS will eventually merge with another low traversing southeast Canada late in the week. This leads to more troughing over the eastern CONUS, suppressing the high southwestward. This would allow another cold front to push through. Models show some variation in timing, with the general idea in the latest runs of the GFS and ECMWF being for fropa in the Wed night-Thu time frame (perhaps a bit faster than what the required NBM forecast currently shows). Should it come to fruition, at least modest cooling and drying would arrive to end the week.

AVIATION

(For the 00Z TAFS through 00Z Saturday evening) ISSUED AT 800 PM EDT FRI SEP 4 2026

Convection has waned across the region and although a shower or storm cannot be ruled out overnight, chances do not peak until the last 6 hours of the TAF period. Outside of non TAF location valley areas affect by fog and MVFR or lower reductions in the 04Z to 14Z timeframe or brief reductions in any isolated storms, VFR should prevail at all TAF sites through 18Z. Thereafter, PROB30 was used for convective chance to end the period. Winds are expected to be strong and erratic near storms, but should generally light and variable otherwise.

JKL WATCHES/WARNINGS/ADVISORIES

None.