textproduct: Jackson

KEY MESSAGES

- Hot conditions are expected through Friday. A Heat Advisory has been issued for today and Thursday where confidence is highest in reaching Major HeatRisk criteria. Afternoon heat indices are forecast to top 100 degrees in many locations through Friday.

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

LONG TERM

(Thursday night through Tuesday) Issued at 353 AM EDT WED SEP 2 2026

As the long term period opens, the axis of an anomalously strong 500 mb ridge will have shifted south and extend from the Carolinas to western KY, centered over the vicinity of the Southern Appalachians. By Friday, a 500 mb trough is expected to extend across eastern sections of the Great Lakes to the mid Atlantic states from a closed upper level low over Quebec. Multiple shortwaves are progged to be moving in northwest flow across the Great Lakes to Mid Atlantic at that time. The upper ridge should be at least temporarily less amplified at that point, with the ridge becoming centered further west in the mid MS Valley vicinity and Plains by Friday into Friday night. This will all occur downstream of an upper low in the vicinity of the Pacific Northwest and trough in the western Conus.

Temperatures on Friday should still be hot, owing to continued influence from this ridge; however, highs should trend cooler compared to midweek as the forecast area finds itself more 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 by around 10 degrees or so; thus, the main forecast question during this period is just how hot it will get on Friday before potential convective development. Deterministic guidance is generally split into two camps in this regard: either dew points are lower with a higher air temperature (GFS and MEX), or dewpoints are higher with a lower air temperature (ECMWF and ECX). The drier solutions have proven unrepresentative in this pattern thus far and too warm by several degrees, largely because of unrealistically deep mixing. Given this bias, it seems more likely that a cooler and higher dewpoint solution would continue from the near term into the day on Friday, with the NBM deterministic highs offering a reasonable middle ground. In support of this, the flow between the ridge of surface high pressure just south of the forecast area and a cold front associated with the upper low in Canada and troughing into the eastern Great Lakes sagging toward the Lower OH Valley region and mid Atlantic should promote southwesterly to westerly winds across the forecast area, maintaining these higher dewpoints. Meanwhile, dewpoints were largely maintained, expected to be generally in the upper 60s to lower 70s across the region. This will keep apparent temperatures generally just below heat advisory criteria, but triple digit heat indices are still anticipated at least briefly though convective development on Friday should provide relief at least in some areas. Preceding the day on Friday, 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 axis and base of the upper level trough will be to our east and 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. At least a slight chance of showers and storms remain for Friday night as the cold front sags into the area. Chances for convection likely peak on Saturday, mainly in the scattered range, in conjunction with cold front continuing to sag south and southwest and the potential for multiple shortwaves embedded within this northwesterly flow. As is typical in these patterns, model spread and uncertainty remain quite high, particularly in regard to the timing of these features for Friday night to Saturday; accordingly, NBM PoPs remain quite broad brushed for now, with small chances lingering into Sunday, representing the averaging of numerous different timing solutions.

Thus, as timing and presence of individual waves becomes more certain, PoPs will bear some refining later to end the week. This northwest flow pattern will allow temperatures to return closer to normal, with highs mainly in the mid to upper 80s expected for Sunday and continuing into Tuesday. Ridging also looks to build back toward our area early next week, which results in diminishing pops by Monday and Tuesday and potentially more confined to the VA border.

AVIATION

(For the 12Z TAFS through 12Z Thursday morning) ISSUED AT 708 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 this morning, with redevelopment tonight generally beginning between 03z-06z and continuing through the end of the TAF period. Confidence in fog reaching any TAF site is too low to include at this time, however. Winds will remain light and variable, before becoming southwesterly this morning while remaining under 10 kts. Expect cu fields to develop ~15z with diurnal heating and a moist airmass.

JKL WATCHES/WARNINGS/ADVISORIES

Heat Advisory from 11 AM this morning to 8 PM EDT Thursday for KYZ044-050>052-058>060-068-069-079-080-083>085-104.