textproduct: Jackson

KEY MESSAGES

- Generally dry weather with mild days and cool nights holds through late tonight. - Breezy and rainy conditions expected this weekend as a strong system, including the remnants of Hurricane Isaias (currently in the Gulf), moves northeast across the region.

- There is still considerable uncertainty with this system and potential impacts, and forecasts will become better refined as the event nears.

UPDATE

Issued at 725 AM EDT FRI OCT 9 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 zones.

LONG TERM

(Saturday night through Thursday) Issued at 500 AM EDT FRI OCT 9 2026

The extended portion of the forecast looks to be on track with the idea of the remains of Isaias exiting to the east Sunday and early Monday followed by drying in its wake as ridging aloft builds into the state from the southwest. A nearby front, initially to the north of Kentucky, could become a factor in our weather by the middle of next week.

The previous long term discussion follows:

At the start of the extended period, all eyes will shift towards the remnants of Hurricane Isaias. Model and ensemble guidance continue to meander west and east with the storm track as Isaias approaches the Gulf coastline. Previous guidance has generally continued shifting the expected path west; however, some of the latest 12Z guidance has trended back east a bit. As Hurricane Isaias makes landfall and starts its trek north towards the Tennessee Valley, it will be greeted by the subtropical jet and enter a highly sheared environment. This will help weaken the storm as it gets closer to eastern Kentucky. This will occur as an amplified upper-level ridge across the Eastern US, with 500 mb heights over the Commonwealth near 584-588 dam early on Saturday, slowly departs northeast.

Showers and a few thunderstorms will spread initially across the area from south to north on Saturday (then southeast to northwest at times) under downsloping easterly or southeasterly winds. Winds should gradually increase through the afternoon, peaking between midnight and 8 AM Sunday. These easterly gusts could generally range from 20-30 mph away from the high terrain bordering Tennessee and Virginia. For those high terrain areas near the state border with Tennessee and Virginia, wind gusts of 35-45 mph are becoming more probable, with the NBM, LREF, and REFS ensembles all showing at least a 55% chance of exposed mountain tops near Cumberland, such as Black Mountain, seeing wind gusts around or north of 40 mph. The peak gust timing in these areas ranges from 8 PM Saturday through 8 AM Sunday. Looking at model soundings near Bell, Harlan, and Letcher counties, winds aloft were as strong as 50-55 mph just below the the top of the inversion, with stable lower levels and conditionally unstable layers with weaker winds further above the inversion. Mountain waves could be a possibility, which will be something that bears watching as higher-resolution model runs become more readily available.

With downslope flow expected, lower sfc dew points than NBM deterministic are probable. To account for this on both Saturday and Sunday, forecasted dew points were lowered below the deterministic NBM using raw model guidance. Low temperatures will generally remain in the upper 50s to low 60s both Saturday and Sunday nights. Previously, high temperatures Saturday were wide- ranging as the ensembles had upper 60s to mid-80s as possibilities. This was largely due to variability in timing for the storms arrival to the area. A sooner arrival meant more clouds and lower temperatures, whereas a delayed arrival led to more sunshine and ample heating into the mid-80s. However, the latest guidance has started to come into better agreement, narrowing the spread into the upper 60s to low 70s. Keep in mind the above scenarios can still drive high temperatures up or down based on when the remnants of Isaias work in here. Latest data has trended toward a quicker arrival and thus a cloudier start to Saturday. For this reason, high temperatures were lowered from the upper 70s in yesterdays forecast to the low-to-mid 70s for this package. The low 70s are around the 75th percentile of model and ensemble guidance.

As low-level flow turns southerly around the departing high, deep moisture associated with Isaias will begin creeping northward. PWATs will climb toward 1.0-1.3 inches near the Tennessee border by Saturday morning, bringing shower and thunderstorm chances to the area from the south. The timing of rain arrival will be earliest along the state line with Tennessee and Virginia, potentially starting as early as 6-8 AM Saturday. Shower and thunderstorm chances will increase through the day Saturday, overnight, and into Sunday. By the time the system reaches the Tennessee Valley to Lower OH Valley on Sunday, it becomes post- tropical and follows the upper-level westerly and southwesterly flow east into the Mid-Atlantic region by Monday. Rain is likely across eastern Kentucky through much of Sunday, accompanied by isolated to scattered thunderstorm chances.

Broad southwesterly flow aloft between the Atlantic ridge and western troughing will help channel the tropical moisture plume from the Gulf low into the Ohio Valley. This will surge PWAT values across the JKL CWA Sunday morning into early Sunday afternoon, with forecasted PWATs falling within the 90th percentile. Current guidance shows the heaviest rain falling Saturday evening through Sunday morning. The WPC has a Day 3 Marginal Risk for Excessive Rainfall for all of eastern Kentucky for the 8 AM Saturday through 8 AM Sunday timeframe. Currently, much of the heavier rain should remain in the Bluegrass, including the I-64 corridor and along/west of I-75. As the system pushes east of the area, wrap around flow may produce lingering showers into Monday morning across portions of eastern Kentucky near the West Virginia and Virginia borders.

Monday through Wednesday, high pressure builds into the area in the wake of the departing system for Monday afternoon into early Tuesday. Clouds will decrease heading into Monday evening, with fair conditions lasting through Tuesday. A cold front does drop southeast into and perhaps south the Ohio Valley region around midweek, but current guidance keeps the area dry as upper ridging builds across the Southeast. Another system could approach the area by the tail end of next week as models show another surface low transiting portions of the Central Conus. Temperatures Monday through Thursday will generally range from the 70s to low 80s during the day, with lows in the upper 50s to low 60s.

AVIATION

(For the 12Z TAFS through 12Z Saturday morning) ISSUED AT 745 AM EDT FRI OCT 9 2026

At 12Z issuance time, VFR conditions were in place across eastern Kentucky and are expected to persist throughout the period at the TAF sites. Any valley fog will clear out by 14Z. Light and variable winds will persist through around 14Z, before they become easterly at less than 10 kts through the rest of the period.

JKL WATCHES/WARNINGS/ADVISORIES

None.