textproduct: Jackson

KEY MESSAGES

- A major pattern change begins tonight, with a much colder air mass gradually working its way into Eastern Kentucky. - Showery weather returns this evening, then lingers through Saturday morning as the cold air advection regime persists.

- The first snowflakes of the season could fall on Friday/Friday night, with only minor accumulations confined to the higher terrain locales along the Virginia state line.

- Drier and cooler weather expected next week.

LONG TERM

(Thursday night through Tuesday) Issued at 518 AM EST Wed Nov 11 2026

Confidence is high that a robust troughing pattern will be in place over the Eastern CONUS at the beginning of the long term forecast period. The model guidance suite collectively resolves the parent longwave feature digging deeper into the Ohio River Valley between Thursday night and Saturday morning, with a series of embedded shortwave disturbances rotating through the forecast area as it does so. These impulses will keep Eastern Kentucky's weather active in this time frame, as the related precipitation chances will overlap with a persistent cold air advection regime and upsloped low-level winds. This combination should yield the first snowflakes of the season on Friday, but widespread, meaningful winter weather impacts are not anticipated. Rather, this system will act as an appetizer for the upcoming winter weather season, with sensible weather impacts largely limited to noticeably colder temperatures for the rest of the forecast period.

When the period opens on Thursday night, rain showers will likely be ongoing across the forecast area. Northwesterly surface flow in the wake of the previous day's frontal passage will allow temperatures to cool into the mid 30s overnight, but the attendant cloud coverage will inhibit radiational cooling and mute the diurnal cooling curve. So, the baseline deterministic NBM low temperature guidance appears too cold, despite the near-surface CAA. This event recently entered the temporal range of higher-resolution ensemble guidance, which confines >20% probabilities for freezing temperatures on Friday morning to the mountains along the Virginia state line. Minimum and hourly temperature grids were blended towards CONS guidance to account for this, but the colder temperatures were retained at the mountaintops. The freezing probabilities atop Big Black Mountain are actually above 75%, which suggests that those higher terrain locales will be the first to experience a changeover to wintery precipitation. Expect a cool rain to dominate elsewhere at first, although colder air is expected to move in aloft on Friday morning.

As the additional shortwave disturbances rotate around the base of the digging parent trough on Friday, they will provide sufficient dynamic lift for continued precipitation chances across the Ohio River Valley. The passage of each disturbance will be marked by shifts towards northwesterly flow aloft and thus a deeper cold air advection regime. Modeled critical thickness values drop below the 540 decameter threshold area-wide by dawn, when model soundings depict subfreezing temperatures at 950mb and above. The lack of a warm nose/melting layer in those soundings effectively (and thankfully) rules out any sleet and freezing rain potential in this setup, but the growing influence of the cold aloft should allow snow to mix with the rain outside of the mountain locales on Friday morning. The longevity of those snow chances is uncertain, as filtered diurnal heating should keep surface temperatures above- freezing through the daytime hours. Rain should remain the dominant precipitation type through the afternoon hours, but temperatures will struggle to warm much higher than the low/mid 40s amidst the deepening CAA regime. These below-normal highs will set the stage for temperatures to easily drop below freezing-area wide on Friday night, when a full changeover to snow is possible in the higher terrain locales of Southeast Kentucky. The greatest and longest- duration PoPs on Friday and Friday night will come in places with northwest-facing slopes. There, orographic lift will combine with the aforementioned dynamic components and a fetch of moisture off Lake Michigan to squeeze out the most precipitation. Accumulation potential is limited by the lack of an antecedent cold spell, but a dusting/trace cannot be ruled out in places along and east of the Pottsville Escarpment. The LREF resolves a >20% chance of at least 0.01 inches of snow in the SE half of the JKL CWA through Saturday morning, with the greatest chances for measurable snow atop Pine and Black Mountains. There, those probabilities jump to between 50 and 70%. If the accumulation threshold is raised to an inch, chances drop to less than 25%, with contours confined entirely to the tops of the Mountains.

The current storm total snow grids mirror these accumulation probabilities, with only a few tenths forecast in the higher-terrain locales of Bell, Harlan, Letcher, and Pike Counties. A dusting cannot be ruled out further to the northwest, and neither can an over-performance atop Black Mountain. Pattern recognition and past experience suggest that cloud coverage and upslope PoPs will be slower to clear than most model guidance on Saturday, when the forecast area will remain under the influence of the deeper CAA regime. The performance of the latest NBM configuration in such patterns is yet to be determined this season, but antecedent local knowledge and collaboration with neighboring WFOs called for retaining slight chance PoPs for longer than the baseline NBM grids. It would not be surprising if cloud cover and some flurries stick around into Saturday morning, and that cloud cover could limit the amount of diurnal warming realized on Saturday afternoon. Highs may struggle to surpass the 45 degree mark, as LREF MaxT probabilities above 50% percent values are confined to areas west of I-75 in central Kentucky. So, Saturday looks to be the coldest day of the season thus far.

A drier and calmer weather pattern returns to the region by Sunday, when the previous troughing is progged to open up and propagate east into the NE CONUS. A broad surface high pressure system looks to build into Kentucky early next week as a split flow pattern sets up aloft. Hysplit back trajectories suggest that a modified polar airmass will remain in place over the CWA early next week, with synoptic scale subsidence keeping conditions dry and skies fair. Expect efficient diurnal processes for Sunday and beyond, with near- normal to just-below-normal temperatures. Ample afternoon sunshine should yield a gradual warming trend through the 50s, but radiational cooling will yield valley lows in the 20s each night. Both these highs and these lows are a seasonably chilly departure from the above-normal temperatures that our area has experienced so far this fall. So, once again, the most tangible impacts from Friday's system are likely to stem from the the related (and quite potent) cold air advection regime.

AVIATION

(For the 12Z TAFS through 12Z Thursday morning) ISSUED AT 638 AM EST WED NOV 11 2026

After river valley fog burns off this morning, clear skies will remain through this morning before high and then mid-level clouds begin to move into the area this afternoon and this evening. A round of showers, and possibly a thunderstorm or two, moves through the area this evening, mainly after 03z, ahead of a disturbance and cold front. Lowering ceilings and a transition from southwest to westerly and then northwesterly winds is expected over the last 6 hours of the TAF period as the front crosses the area. Reductions to MVFR or briefly lower conditions are probable during the last 6 hours of the period. Winds will average 10 kts or less generally from the south to southwest through early this evening, with winds likely trending more westerly after 00z and then northwesterly by 12z. A few gusts of 20 kts or more cannot be completely ruled out this evening and overnight. Though thunder is possible this evening into the overnight, probabilities were too lower to put in any particular TAF.

JKL WATCHES/WARNINGS/ADVISORIES

None.