textproduct: Jackson

KEY MESSAGES

- Mainly dry weather is expected through mid week, along with a strong warming trend. Afternoon heat indices will top 100 degrees in many locations from Tuesday through Friday with Wednesday and Thursday likely the hottest days.

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

LONG TERM

(Tuesday night through Sunday) Issued at 400 AM EDT MON AUG 31 2026

Again the most current model data supports the forecast of an unseasonably hot period into the latter part of the week with mid 90s expected for highs at its peak on Wednesday and Thursday. In the earlier model runs disagreement it seems trends are favoring the drier and somewhat warmer ECMWF through Thursday. We still see the potential for convection in a good number of the model solutions across forecast area later Thursday and into the weekend. This occurs as the 5h ridge weakens a bit and the mid level northwest flow pattern to the northeast starts to get increasingly active - perhaps close enough to brush into eastern Kentucky with its periodic impulses as they pass through the central Appalachians. Heat headlines may yet be warranted for at least the western parts of the area at midweek - still dependent on how effectively higher dewpoints can move east into this part of the state.

The previous long term discussion follows:

The main story of the long term period will be heat. On Tuesday morning, there is high confidence that an anomalously strong upper level ridge will sit directly over Kentucky. LREF mean 500-mb heights reach 595 dam across the forecast area, representing the 99th percentile when compared to climatology, with minimal spread among ensemble solutions. Subsidence associated with this ridge should suppress convection, keeping weather dry and PoPs near zero through at least midweek. Meanwhile, at the surface, high pressure over the Southern Appalachians will keep winds out of the southwest across the forecast area, maintaining a moist air mass across eastern Kentucky. There is still some uncertainty regarding how high dewpoints will climb, owing to model disagreement regarding the exact positioning of the surface high (and associated wind pattern); however, ensemble guidance indicates dewpoints in the mid to upper 60s are likely, with raw NBM output even suggesting widespread dewpoints in the 70s (with the highest dewpoints in our southwestern counties). Given that both ensemble and deterministic guidance favor a drier solution, these NBM dewpoints are likely overdone, and forecast dewpoints were nudged down a few degrees to better match model consensus at this time. Should this hold, we will narrowly avoid hitting heat advisory criteria, though apparent temperatures could reach the triple digits. Regardless, expect hot and humid weather on Tuesday and Wednesday. High temperatures will generally range from the mid to upper 90s, with the hottest temperatures closer to the I-64 corridor. Overnight, limited relief is expected; lows on Tuesday and Wednesday nights will range from the upper 60s in sheltered valley locations to the low 70s on ridges, with typical valley fog formation likely.

A pattern change is expected on Thursday as upper level troughing over the Northeast digs southward, flattening and weakening the ridge over Kentucky. There is still some disagreement over how quickly this ridging will break down over us; however, high temperatures should cool from Thursday onward, and rain chances look to increase through the end of the period. With a trend toward northwesterly flow, pattern recognition suggests that this setup could open the door for multiple shortwave impulses to ride the periphery of the ridge. In fact, deterministic guidance shows a signal for MCS type activity to develop in the Midwest and progress southeastward with time, potentially into our area. That being said, the track of any convective complexes would depend on the position and strength of upper level ridging. Unfortunately, models disagree significantly on these details on Thursday and Friday; the ECMWF favors a more quasi-zonal pattern aloft during this time, while the GFS keeps flow more northwesterly, with a much more amplified ridge to the west over the Mississippi Valley. In both scenarios, some scattered showers and storms would be possible on Friday, but confidence in any further forecast details remains very low at this time.

By the weekend, models come into better agreement regarding a more robust northwest flow pattern aloft as ridging continues to amplify over the Plains. Meanwhile, at the surface, a weak cold front will sag south into the forecast area, providing additional forcing for more focused shower and storm chances, although details again remain quite uncertain at this stage in the forecast. Thankfully, temperatures will fall closer to normal around this time, bringing an end to any heat concerns.

AVIATION

(For the 06Z TAFS through 06Z Monday night) ISSUED AT 145 AM EDT MON AUG 31 2026

High pressure in place across the region will result in valley fog through 13Z. This is not expected to affect any of the TAF sites and VFR should return to all locations by 14Z. Thereafter, diurnally driven cumulus clouds in the 3 to 5 kft agl range are expected to develop by the 16Z to 18Z timeframe though these should remain in the VFR range and a few spotty sprinkles or light showers cannot be completely ruled out from these. Winds will be light through the period.

JKL WATCHES/WARNINGS/ADVISORIES

None.