textproduct: Jackson

KEY MESSAGES

- Hot conditions are expected through Friday. Afternoon heat indices are forecast to top 100 degrees in many locations through Friday.

- Wednesday and Thursday will most likely be the hottest days.

- Showers and thunderstorms are possible at times from Friday through the weekend.

UPDATE

Issued at 1007 PM EDT TUE SEP 1 2026

Refreshed the grids by incorporating the most recent observational and model data across the region. The forecast remains on track, as valleys continue to cool faster than surrounding ridge locations. Current valley temperatures in the lower to middle 70s are expected to fall into the upper 60s later tonight. Areas of valley fog are expected to develop late tonight before mixing out tomorrow morning. Cumulus clouds are expected to redevelop heading into tomorrow afternoon under high pressure, resulting in hot and muggy conditions.

LONG TERM

(Thursday through Tuesday) Issued at 350 PM EDT TUE SEP 1 2026

As the long term period opens, an anomalously strong 500 mb ridge will still be located over the forecast area. By Friday, a trough over the Great Lakes region associated with a closed upper level low over Quebec will begin to dig farther south, with this ridge becoming temporarily less amplified as the ridge axis retrogrades westward. Weather on Thursday and Friday will still be hot, owing to continued influence from this ridge; however, Friday will be noticeably cooler than Thursday as the forecast area finds itself on the periphery of this ridging rather than being directly beneath it. In terms of sensible weather impacts, there is high confidence that temperatures will be firmly above average; thus, the main forecast question during this period is just how hot it will get. Deterministic guidance is generally split into two camps in this regard: either dew points are lower with a higher air temperature, or dewpoints are higher with a lower air temperature. These drier solutions have proven unrepresentative in this pattern thus far, largely because of unrealistically deep mixing; given this bias, it seems more likely that a cooler and higher dewpoint solution would come to fruition on Thursday and Friday. In support of this, surface high pressure just south of the forecast area in Tennessee should promote westerly to southwesterly winds across the forecast area, maintaining these higher dewpoints. Accordingly, MaxTs were nudged down Thursday and Friday, with highs in the low to mid 90s on Thursday and a few degrees cooler on Friday. Meanwhile, dewpoints were largely maintained, expected to be generally in the upper 60s to lower 70s across the region. This will keep apparent temperatures just below heat advisory criteria, but triple digit heat indices are still expected. Overnight Thursday, relief will be relatively limited; clear skies and high pressure will allow for a modest ridge-valley split, but low temperatures will still generally fall into the low 70s on ridges and the upper 60s in valleys (where typical fog formation is expected).

By the weekend, the base of the upper level trough will be to our southeast, with amplifying ridging west of the forecast area over the Great Plains. This pattern will place eastern Kentucky in a northwest flow regime aloft. More appreciable PoPs look to return to the forecast as early as Friday as ridging breaks down and a weak cold front approaches. At least a slight chance of showers and storms is in the forecast through Saturday evening, in conjunction with this front and the potential for multiple shortwaves embedded within this northwesterly flow. As is typical in these patterns, model spread and uncertainty are high, particularly in regard to the timing of these features; accordingly, NBM PoPs are quite broad brushed for now, representing the averaging of numerous different timing solutions. Thus, these PoPs will bear some refining later. Thankfully, this pattern will also allow temperatures to return closer to normal, with highs in the mid to upper 80s expected in the forecast area by Sunday afternoon. Ridging also looks to build back toward our area near the end of the period, which should mark an end to this wetter pattern.

AVIATION

(For the 06Z TAFS through 06Z Thursday) ISSUED AT 125 AM EDT WED SEP 2 2026

VFR conditions will largely prevail during the the TAF period, though areas of valley fog are forecast through ~13z. Fog should develop in the vicinity of LOZ, SME, and SJS TAF sites and could lift into those areas around or after 08z this morning. This could temporarily reduce visibilities into MVFR or IFR conditions, but for now given the uncertainties will keep a TEMPO group with VFR conditions. Winds will remain light and variable, before becoming southwesterly Wednesday morning while remaining under 10 KT. Tomorrow, expect cu fields to redevelop ~15z with diurnal heating and a moist airmass.

JKL WATCHES/WARNINGS/ADVISORIES

None.