textproduct: Jackson

KEY MESSAGES

- Dry weather with mild days and cool nights holds through the end of the work week.

- Breezy and rainy conditions are possible this weekend as a strong system, including the remnants of Tropical Storm 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.

LONG TERM

(Friday night through Wednesday) Issued at 250 AM EDT THU OCT 8 2026

The long term period will open with broad mid-level troughing over the northeastern CONUS and ridging off the Atlantic Coast; this subtropical ridge will expand westward during the day on Friday, keeping weather quiet, although with high temperatures running above average (ranging from the upper 70s to mid 80s). To the south of the forecast area, however, Hurricane Isaias will continue to progress northward towards the Gulf Coast, with this system being our primary focus this weekend. The current NHC forecast suggests that the storm will make landfall as a hurricane in this region overnight. In a strongly sheared environment, Isaias should be rather asymmetric, with the most impactful weather on the eastern side of the storm. Then, the storm will quickly weaken as it becomes post-tropical.

By Saturday, what remains of Isaias will ride north, owing to deep southerly flow along the periphery of the ridge. This track will set the remnant low on a collision course with a weaker cut off low initially near the TX/LA border. Although this system will have lost its tropical characteristics by this point, its associated surface low should still remain well defined, with a large precipitation shield primarily on the eastern side of the storm. Increasingly southerly flow aloft should work to increase PWs throughout the day, with LREF mean PW values rising to the 1.2-1.3 inch range by Saturday evening (roughly 70th to 80th percentile compared to climatology). LREF guidance indicates that the most likely time of rain onset would be late Saturday into very early Sunday morning, with the earliest rain chances near the TN line. However, there is still uncertainty regarding the exact track and timing of the original system, and it is worth noting that even the 25th percentile LREF suggests rain could easily begin as early as Saturday evening. Then, the system looks to take an eastward turn as it is pushed out by a trough arriving from the west, with rain chances finally diminishing gradually Monday morning.

A primary hazard with this system will be rainfall, potentially heavy at times. WPC has introduced a Marginal Risk (Level 1/4) for Excessive Rainfall near the I-75 corridor from Saturday morning through Sunday morning, corresponding with the highest confidence in higher rainfall totals.

A second hazard will be the potential for gusty winds. Saturday evening and overnight, southeasterly winds could become breezy to gusty, with strong winds aloft associated with Isaias impacting the higher terrain along the TN, VA, and WV borders. Both the GFS and ECMWF indicate 50-60 kt winds at 850 mb. 01Z NBM ensemble guidance indicates a 30-75% probability of surface wind gusts meeting or exceeding 40 mph overnight Saturday into Sunday. Ensemble probabilities have increased over the last several model runs in both the NBM and LREF ensembles. This trend will continue to be closely monitored in subsequent model runs.

Consequently, low level shear will be quite dramatic, with even LREF mean 0-1 km SRH in the range of 300-400 m2/s2 as the disturbance arrives. Individual deterministic model soundings display even higher parameters; however, any tornado risk would depend on the timing of the lows arrival and the structure of the system itself, particularly with respect to the nature and location of any dry air entrainment within the parent low. Thus, this remains a very low confidence scenario at present. A significant mitigating factor will be the cross-barrier mid- and low-level flow upstream and any drying/stabilizing effects from downsloping off of the Cumberland Mountains. Global models typically underestimate this effect at these lead times, with high-resolution CAMS likely providing a better handle on any mitigating impacts on this risk.

The system exits east from the area Sunday night into Monday, but upslope west to southwesterly low-level flow and stronger northwesterly flow aloft will mean a continued Q-G warm advection scenario persists into the daytime hours, and thus forcing for ascent and sufficient remaining moisture should be able to produce some light rain lingering into Monday, at least toward the Cumberland Mountains.

After a brief drying/clearing trend later Monday into early Tuesday, a cold front will drop southeast through the Ohio Valley and bring the next low chance for rain, mainly east of Interstate 75. High pressure then brings mild weather for Wednesday along with cool nights Tuesday and Wednesday nights.

$$

AVIATION

(For the 06Z TAFS through 06Z Thursday night) ISSUED AT 116 AM EDT THU OCT 8 2026

High pressure centered over the Southern Appalachians was leading to VFR and light winds at issuance time. A weak cold front will cross the area from the north and northwest now through 15z. At least patchy fog is anticipated for valleys near and south/ southeast of a KSJS to KJKL to KLOZ line. This fog is still not expected to impact the TAF sites and the passing front may lead to a shorter period of valley fog than what has occurred the past couple of nights. Winds will be light and variable or south to west through 08Z in all areas, before becoming northwest to north through 15Z as the front passes. Northwest to north winds at less than 10 kts should then prevail for most of the rest of the period, with winds slackening toward sunset/23Z.

JKL WATCHES/WARNINGS/ADVISORIES

None.