textproduct: Jackson

KEY MESSAGES

- Fair weather with more comfortable humidity is here for Labor Day, followed by temperatures and humidity creeping higher at mid week.

- A cold front looks to arrive on Thursday, bringing our next decent shot of showers and thunderstorms.

UPDATE

Issued at 125 AM EDT MON SEP 7 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.

LONG TERM

(Tuesday through Sunday) Issued at 427 PM EDT SUN SEP 6 2026

When the long term period opens, eastern Kentucky will again find itself on the eastern fringe of an upper level ridge centered over the Mississippi Valley. To the northwest, a closed upper level low will be located over southern Saskatchewan. With time, the low and its associated trough will translate east, helping to flatten the ridge until the forecast area finds itself at the base of a broad upper level trough late Wednesday into Thursday. Prior to this, weather will be relatively quiet, with surface high pressure located to the east of the forecast area on Tuesday. Dewpoints should remain largely in the 60s except perhaps in our westernmost counties; thus, although Tuesday will be unseasonably hot, with high temperatures in the mid to upper 80s, it will not feel as muggy. Overnight, clear skies and a weak pressure gradient will allow a very modest ridge valley split to develop (on the order of a few degrees), with typical valley fog development. Moisture will return again Wednesday as the surface high sinks south and winds become increasingly southwesterly, bringing dewpoints back into the upper 60s or perhaps low 70s in our westernmost counties. Highs will again climb into the upper 80s to perhaps 90 in a few locations. Other than the lingering heat, no impactful weather is expected.

The pattern begins to change by Wednesday night as upper level troughing digs into the area. A surface cold front extending from the now vertically stacked low over Canada will progress toward Kentucky through the overnight hours, with rain chances increasing in northeastern Kentucky as early as Thursday morning. There is still some uncertainty regarding the exact timing of this front, although ensemble guidance is hinting that rain would most likely begin in the late morning or early afternoon for most of the forecast area. There is high confidence that this front will interact with an anomalously moist air mass; LREF mean PW values are in the 1.6-1.8 range, generally representing at least the 80th percentile compared to climatology. This, plus deterministic model soundings showing a deep warm cloud layer, indicates that any storms that form could be efficient rain producers capable of unleashing torrential downpours. Given this environment, WPC has introduced a Day 5 Marginal Risk for Excessive Rainfall for the entire forecast area. Thankfully, the progressive nature of this system, relatively dry antecedent conditions, and expected fast storm motions should work to mitigate the flash flood threat somewhat. Additionally, some machine learning guidance has also picked up on a low end risk for severe thunderstorms on Thursday, and given many deterministic models depict a belt of stronger mid level flow just north of the forecast area, it is not inconceivable that moderate shear (~30 kts) could support a more organized storm mode as the front moves through. Even so, any severe risk will remain heavily dependent on frontal timing, and with the best shear along and north of the Ohio River, widespread severe weather appears implausible at this time.

Model spread increases significantly following the passage of the cold front. Some deterministic guidance is hinting that an additional shortwave trough could spark additional rain chances Friday afternoon into Friday night, particularly near the TN and VA lines, while other model guidance suggests shortwave ridging will build in, keeping the forecast area dry. Similar uncertainty exists on Saturday. For now, NBM output has averaged these two solutions, resulting in chance PoPs in the southern half of the forecast area on Friday and Saturday afternoons, although this will bear refining in the future. Ridging looks to build back in by the end of the period, marking a return to a drier pattern.

AVIATION

(For the 06Z TAFS through 06Z Monday night) ISSUED AT 150 AM EDT MON SEP 7 2026

VFR conditions were present across the area at the 06Z TAF issuance. Fog will develop in the river valleys early this morning, especially across southeast Kentucky. However, the extent of it outside of sheltered valleys is likely to be minimal due to a decent 15 to 30 kts of northeast to easterly flow between the surface a few thousand feet AGL. Any of the valley fog could bring localized IFR or worse conditions, but concern for impacts at any TAF site was too low to include. Any fog will dissipate on just after sunrise this morning and leave VFR conditions around under an extensive cumulus field. A stray shower will be possible through the day with minimal impacts on any of the TAF terminals. Expect light and variable winds through the period.

JKL WATCHES/WARNINGS/ADVISORIES

None.