textproduct: Jackson

KEY MESSAGES

- Above normal temperatures return for today through Saturday.

- Near-record heat is possible Thursday with high temperatures expected around 90 degrees in many locations.

- Isolated to scattered showers and storms re-enter the forecast on Thursday afternoon, then persist through the weekend. Most of this activity will be limited to the afternoon/evening hours.

UPDATE

Issued at 720 AM EDT TUE SEP 15 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

(Wednesday night through Monday) Issued at 400 AM EDT TUE SEP 15 2026

The extended portion of the forecast remains on track with the idea of a large 5h ridge weakening and drifting southwest a bit through the rest of the week and into next weekend. This could perhaps include the eastern Gulf or coastal southeast region becoming more active late in the period - not necessarily a recipe for helping to clear a 5h ridge to the north. The net result will continue to mean temperatures staying unseasonable warm and a limiting factor to the potential for widespread rain for much of the time.

The previous long term discussion follows:

Ridging remains the dominant synoptic-scale weather feature across the Eastern Kentucky for the duration of the long term forecast period. When the period opens on Wednesday morning, a nearly 600 decameter ridge will be centered over the Tennessee River Valley, or just to the south of the forecast area. The strength of this ridge is quite impressive. These modeled geopotential heights rank among the upper echelon of model climatology for this time of year. In fact, mean LREF heights of 600 dm sit at the 100th percentile of the dataset. This signal has been present in the data for multiple runs in a row, which bolsters forecast confidence. The proximity of this anomalously strong mid/upper atmospheric ridging should accordingly yield mostly dry and unseasonably warm sensible weather conditions across Eastern Kentucky. On Wednesday, expect high temperatures in the lower 90s, mostly sunny skies, efficient diurnal mixing processes, and overnight ridge-valley temperature splits. Valley lows in the mid/upper 60s should be sufficient for patchy fog formation near sources of water, while ridgetops and the more exposed western locales could stay closer to the 70 degree mark.

Confidence in these dry/hot conditions is highest on Wednesday, as the parent ridging will be closest to the JKL CWA in this time frame. Large-scale subsidence and antecedent dry air throughout the column will largely limit the potential for meaningful convection in the initial stages of the period. The dry air (and mixed afternoon dewpoints) should also prevent Eastern Kentucky from reaching heat advisory criteria. Apparent temperatures peak in the upper 90s, but remain largely below the triple digit mark. The heat continues into Thursday, with similar forecast highs in the lower 90s and heat indices in the upper 90s. While this may be enough to break the record high at the Jackson climate site, this is only because the previous record is a "weak" 90 degrees. The pattern actually looks to shift a little bit on Thursday, and that shift will eventually culminate in relief from the heat.

As the ridge retrogrades west a little bit, return flow around its northern periphery will advect a plume of modified Gulf moisture towards the CWA on Thursday. The presence of this moisture will likely make it feel a couple of degrees warmer outside in the western third of the CWA. Those western counties will remain closer to the center of the ridge and thus under more of its influence. Locales situated in the Bluegrass and near Lake Cumberland could flirt with triple digit heat indices on Thursday, but this is unlikely in counties further to the east. Isolated to scattered general thunderstorm chances re-enter the forecast on Thursday afternoon for locations along and east of the Pottsville Escarpment. Similar, sub-50% PoPs remain in the grids through the weekend, largely modulated by the diurnal instability cycle. These could provide some localized pockets of relief from the heat before a more robust pattern shift emerges early next week. The forecast guidance suite continues to disagree on how exactly that pattern change unfolds, but there is a notable increase in the spread between the 25th and 75th NBM temperature quartiles on Sunday and Monday. This affirms the notion that the increased rain chances correspond with increased forecast uncertainty surrounding the heat in the latter stages of the period. However, there is a better-defined downward trend in the temperatures early next week, with more compact model spread and median values back in the upper 70s/near 80 degrees.

AVIATION

(For the 12Z TAFS through 12Z Wednesday morning) ISSUED AT 740 AM EDT TUE SEP 15 2026

VFR conditions are expected at the terminals through the period. Fog is found in the typical river valley locations but will dissipate shortly. Daytime cumulus development will be suppressed at most locations due to the presence of dry air and strong mid- level ridging, but will be more prevalent along and south of the KY-80 corridor, mainly showing up in the LOZ and SME obs. Southwest winds at 5 kts or less can be anticipated from late morning through the afternoon.

JKL WATCHES/WARNINGS/ADVISORIES

None.