textproduct: Jackson

KEY MESSAGES

- Hot conditions will persist into Saturday. The hottest conditions are expected on Thursday and Friday with widespread maximum heat indices in the lower to middle 100s.

- Showers and thunderstorms are possible at times from Friday through early next week.

LONG TERM

(After midnight Friday night through Wednesday) Issued at 6:45 AM EDT THU SEP 3 2026

At the start of the long term period on Friday evening, upper level ridging is expected to extend from the Carolinas across the Southern Appalachians to the mid MS Valley and north to the Upper MS Valley as well as southwest into west TX. Meanwhile, troughing associated with an upper low over the St Lawrence Valley/Quebec should extend into the Northeast Conus to mid Atlantic states. This will all be in place downstream of an upper low over the Pacific northwest and associated trough over portions of the western Conus. Over the Commonwealth and OH Valley, northwest flow should be in place at the start of the period as the upper trough extending into parts of the eastern Conus digs farther south and ridging retrogrades/becomes established further westward in the Plains by late Friday night. Chances for convection should linger into late Friday evening/night Rain chances return to the area as early as Friday afternoon/evening as a shortwave approaches ahead of a weak cold front. Isolated to scattered thunderstorms will be possible with this feature, particularly in the northern and eastern portions of the forecast area where height falls will be the most robust. Given the hot and moist weather leading into Friday evening, any storms during the late evening will have some instability to work with, a strong to perhaps severe thunderstorm are not off the table to begin the period. Atmospheric moisture will also be rather high, with LREF mean PW values in the 1.5-1.7 in range (80th percentile or higher compared to climatology). As such, torrential downpours will also be possible within thunderstorms.

By late Friday night into Saturday morning, the aforementioned cold front will sag south through much or all of eastern Kentucky, providing another focus for showers and storms. There is still significant model disagreement regarding the timing and extent of convective coverage associated with this frontal passage, resulting in NBM PoPs likely being a bit underdone at least at times compared to true rain chances, although uncertainty remains too high to refine these PoPs at this time. Adding to this uncertainty, some deterministic guidance depicts MCS activity or its remnants diving southeast out of the Midwest during the day on Saturday, following the periphery of the ridge. Thus, although rain appears likely at some point on Saturday, the details continue to remain unclear at this time. For now, the NBM keeps PoPs generally low, maximized mainly in the 20-50% range, to account for this. Meanwhile, northerly postfrontal winds will keep highs in the upper 80s on Saturday afternoon, with low 90s near the KY/TN line.

Rain chances look lower from Sunday onward as the upper level ridge begins to expand to the east. With surface high pressure building to the northeast of the forecast area, northeasterly winds will keep Sundays temperatures cooler than at the start of the period (but still quite warm). Dewpoints look to be modestly lower as well (in the 60s rather than the 70s), and this drier pattern will continue through the end of the period. Even so, Labor Day looks to be quite warm, with above average temperatures in the upper 80s expected across the area. Other than this, the weather will be quite pleasant and sunny, with the exception of an isolated diurnally driven thunderstorm in south or southeast.

AVIATION

(For the 12Z TAFS through 12Z Friday morning) ISSUED AT 6:45 AM EDT THU SEP 3 2026

VFR conditions will largely prevail during the the TAF period with high pressure dominating, except for fog development in the river valleys this morning and then again tonight, mainly after 04z. Confidence in fog reaching any TAF site is too low to include any mention at this time. The fog will lift and dissipate by 13z to 14z, with the return of a cumulus field around 16Z and after. Winds will remain light and variable.

JKL WATCHES/WARNINGS/ADVISORIES

Heat Advisory until 8 PM EDT Friday for KYZ044-050>052-058>060- 068-069-079-080-083>085-104.

Heat Advisory from 11 AM this morning to 8 PM EDT Friday for KYZ086>088-106>120.