textproduct: Jackson

KEY MESSAGES

- The expectation of showers and thunderstorms will persist through the weekend and into the middle of next week, with the greatest coverage for the area, as a whole, today and Saturday as well as from Tuesday through Thursday. - Isolated heavy to excessive rainfall may occur where storms are most persistent.

UPDATE

Issued at 725 AM EDT FRI AUG 7 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. These minor adjustments have been sent to the NDFD and web servers along with a freshening of the zones.

LONG TERM

(Saturday night through Thursday) Issued at 500 AM EDT FRI AUG 7 2026

The latest model data indicate that the pattern aloft mostly remains the same through the period with a broad ridge parked over the bulk of the southwestern half of the nation well into next week. They also keep Kentucky on the southwest fringe of a large trough over all of northeast Canada yielding persistent northwest mid-level flow with periodic impulses passing by mainly north of the JKL forecast area. These should be close enough, though, to keep shower and thunderstorm chances in the forecast each day with diurnal trends still dominant. Excessive rains will probably be isolated at best and due mainly to very site specific training.

The previous long term discussion follows:

Scattered to numerous showers and thunderstorms are still expected across Eastern Kentucky on Saturday, when broad mid/upper level troughing will remain in place over the Greater Ohio River Valley. A shortwave disturbance is still progged to propagate around the base of that trough during the initial stages of the forecast period, although it is notably quicker and less amplified than it was in previous model runs. The effects of those changes are twofold. First, there will probably be ongoing isolated to scattered convection when the period opens on Saturday morning. This introduces the potential for leftover cloud debris to decrease the magnitude of diurnal warming/destabilization, which, in turn, could limit the intensity of any activity that tries to develop later that afternoon/evening. Saturday morning has entered the temporal range of the 12z CAM runs, and many of those higher-resolution, convection- allowing models support the idea that the PM convection will be weaker. A few models still try and develop afternoon/evening activity in SE KY, which is notably where the blended baseline guidance resolves the highest PoPs (55-75%). However, the convective parameter spacing appears marginal at best, with poor CAPE/shear balance and poor lapse rates. This is the second effect of the less- amplified shortwave; storms are less likely to get organized and sustain themselves for longer periods of time. Severe storms appear unlikely on Saturday if these changes persist into future model runs.

Model soundings do resolve between 1.7 and 1.9 inches of precipitable water in the atmospheric column over the forecast area on Saturday afternoon, along with freezing levels around 15kft and cloud-layer winds below 10 knots. If sufficient destabilization is realized and additional showers/storms develop across Eastern Kentucky on Saturday afternoon/evening, they will likely be efficient rainmakers and slow movers. Given the potential for localized pockets of already-wet soils from the activity described in the short term forecast period, Saturday's rainfall could once again prove excessive. The related flash flood risk is shrouded in the uncertainty though. The residual impacts of any AM activity and the evolution of the parent shortwave will determine whether or not such a risk actually materializes. WPC has maintained a broad- brushed Marginal (Level 1/4) Excessive Rainfall Outlook for the entire JKL CWA on Saturday, but widespread flash flooding is not currently anticipated. Isolated instances cannot be ruled out in any locales that experience particularly persistent downpours or multiple rounds of torrential rainfall, as is typical during late summer in Eastern Kentucky. Interests in flood-prone places are encouraged to remain weather aware on Saturday, just in case.

Another change in this morning's forecast guidance suite is the potential for yet another round of summertime showers/storms in Eastern Kentucky on Sunday. Both the GFS and the ECMWF had a QPF signal across portions of the CWA on Sunday afternoon in this morning's 12z data. It is intriguing that both deterministic models and their respective ensemble counterparts still resolve midlevel height rises in this same time frame. The troughing responsible for the early-weekend activity is progged to lift further to the northeast throughout the day on Sunday while ridging strengthens over the south-central CONUS. Those synoptic shifts place eastern KY within a regime of quasi-zonal flow aloft early next week. The related subsidence and midlevel dry air advection would reprieve our area from the recent repetitive marginal excessive rainfall risks. Thus, any convective activity that does occur in the Sunday-Monday time frame will likely be of the garden variety (sub-severe). It is plausible for future NBM baseline data to introduce isolated to scattered type PoPs to Sunday's forecast grids, so that will be a period to monitor for future adjustments.

The attention then turns towards a series of ridge-riding shortwave impulses approaching the forecast area between Tuesday and Thursday. The presence of these disturbances in the coarse long term guidance causes scattered to numerous PoPs to reenter the forecast by midweek, and pattern recognition suggests that next week's convection could take the form of MCSes moving through the Ohio River Valley. While SPC notes that predictability is low in such a setup, the available medium-range machine learning models and analog- based convective guidance both suggest that a damaging wind gust could materialize within any MCS that moves through the forecast area during peak diurnal heating next week. The arrival time of those disturbances will play a role in determining the intensity of next week's storms, but increasing model spread makes it impossible to pinpoint those details at the current temporal range. Nevertheless, the long term forecast period looks to end on an active note, and interests are encouraged to monitor for updates in the coming days.

AVIATION

(For the 12Z TAFS through 12Z Saturday morning) ISSUED AT 755 AM EDT FRI AUG 7 2026

Another round of showers and storms is still on track to develop later today, initially across the I-64 corridor in the morning, likely followed by additional areas along the KY/TN and KY/VA borders as the afternoon progresses. These should fade out late this evening and quiet weather follows, though fog will be found in the valleys during the late night hours - not expected to impact and TAF terminals. Storms along and near the I-64 corridor today carry a greater potential for producing gusty and erratic winds. Otherwise, winds will be light and variable through the rest of the period.

JKL WATCHES/WARNINGS/ADVISORIES

None.