Area Forecast Discussion

KEY MESSAGES

- Above normal temperatures return for today through Saturday.

- Near-record heat is possible Thursday with high temperatures within a few degrees of 90F.

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

UPDATE

Issued at 125 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 SAFs and zones.

UPDATE Issued at 1031 PM EDT MON SEP 14 2026

The forecast is on track, with no significant changes needed.

SHORT TERM

(This evening through Tuesday night) Issued at 415 PM EDT MON SEP 14 2026

Current analysis shows a surface ridge passing over the Great Lakes in the wake of a cold front that is stalled over the Tennessee Valley/Southern Appalachians. Behind this front, cold, dry air advection continues over Eastern KY. Satellite imagery shows that the low cloud cover from this morning has thinned out and been replaced by a few fair-weather cumulus and high, wispy cirrus. Expect mostly clear conditions this evening and tonight with temperatures dropping into the 50s for most areas. Fog development is expected in the sheltered river valley areas given efficient radiational cooling and dry air overhead.

Model guidance shows strong upper-level ridging building over the Ohio Valley heading into mid-week. As this occurs, low-level winds will turn more southerly on Tuesday, advecting warmer air back across Eastern KY. By 18Z Tuesday, the LREF supports impressive 500mb heights rising to near climatological maxima for this time of year. With this anomalous ridging, temperatures will peak in the upper 80s and low 90s on Tuesday afternoon with dew points in the 60s. In spite of the heat, the moderate dew points should keep heat indices below Heat Advisory criteria, although areas west of I-75 could see values in the mid to upper 90s. Fog remains possible in the valley locations again on Tuesday night.

LONG TERM

(Wednesday through Monday) Issued at 530 PM EDT Mon Sep 14 2026

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 06Z TAFS through 06Z Tuesday night) ISSUED AT 145 AM EDT TUE SEP 15 2026

VFR conditions are expected at the terminals with light and variable winds through the rest of the night. Fog is developing in the typical river valley locations. 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 impacting LOZ and SME. Southwest winds at 5 kts or less can be anticipated from late morning through the afternoon.

JKL WATCHES / WARNINGS / ADVISORIES

None.