Bailey Switch, Kentucky Weather Forecast Discussion

055
FXUS63 KJKL 292318
AFDJKL
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
718 PM EDT Mon Sep 29 2025
.KEY MESSAGES...
- Increasing moisture around the outskirts of Tropical Storm
  Imelda`s circulation could produce a few rain showers in
  Southeastern Kentucky tomorrow.
- Dry and seasonably warm conditions return on Wednesday and then
  persist into early next week.
- Valley fog is likely to develop each night this week in the
  deeper river valleys of Eastern Kentucky.
&&
.SHORT TERM...(This evening through Tuesday night)
Issued at 305 PM EDT MON SEP 29 2025
Shallow, fair-weather cumulus are developing across eastern
Kentucky this afternoon, with temperatures in the low to mid-80s.
High clouds are streaming northward into far eastern Kentucky,
associated with a weak upper low over the Southern Appalachians
and tropical moisture. The surface analysis shows an ~1024 mb
high centered over Lower Ontario, while a sub-998 mb low (Imelda)
is circulating north of the Bahamas. Aloft, 500 hPa ridging
predominates over the Ohio Valley and Great Lakes.
Through the short-term period, Imelda will accelerate northeast
toward Bermuda while 500 hPa ridging weakens slightly, allowing
some upper-level energy and tropical moisture to seep westward
across the Central Appalachians tonight and especially on Tuesday.
This increased moisture will manifest over eastern Kentucky as
slowly increasing cloud cover from the east tonight. The moisture
and some meager destabilization on Tuesday could yield a few
showers, primarily in the first and second tier of counties
adjacent to the Virginia-Kentucky border. This activity should be
of the nuisance variety with most of the area being dry and even
where rainfall does occur, substantial dry time is likely.
In terms of sensible weather, outside of typical diurnal cumulus,
high clouds will gradually increase from the east through at
least midday Tuesday. While a rogue shower cannot be entirely
ruled out tonight in the far east, the best chance for any showers
(20 to 30 percent) will come on Tuesday afternoon and evening. As
is typical for this time of year, fog is favored each night in
the usual river valleys. Temperatures will remain mild with lows
mainly in the 50s at night, recovering into the lower to middle
80s on Tuesday.
.LONG TERM...(Wednesday through Monday)
Issued at 436 PM EDT Mon Sep 29 2025
The forecast guidance suite collectively resolves a mid/upper-level
ridge nudging into the Ohio River Valley on Wednesday as the
aforementioned upper level low and tropical cyclones eject further
east-northeast into the Atlantic. That ridging feature is then
forecast to strengthen, leading to mid-level height rises and the
development of a surface high pressure system over much of the
Eastern CONUS. The persistence of these two ridging features into
the weekend will keep skies mostly clear, foster efficient diurnal
warming/mixing processes, and allow temperatures to remain above
climatological norms through next Monday.
In sensible weather terms, expect seasonably pleasant conditions
throughout the period. Afternoon highs in the mid 70s to near 80 are
forecast each day, with ridge-valley splits likely to emerge at
night. While ridgetops will see lows in the upper 50s, the cooler
valleys will experience MinTs closer to 50. A few pockets of diurnal
minimums in the upper 40s cannot be ruled out, especially in the
more sheltered valleys of far-east Kentucky. Overnight river
valley fog has been added throughout the long term forecast period
given the synoptic pattern at hand, but the fog will likely
decrease in spatial coverage each night as the ground
progressively dries out. In fact, there are no mentionable PoPs in
the forecast from Wednesday through Monday. That dryness will
likely maintain or even worsen the D0/D1 drought conditions
currently delineated across most of the commonwealth.
There are some hints of moisture return from the Gulf just beyond
the end of the forecast period. However, models disagree on both the
timing and strength of its parent feature, leading to limited
extended-range precipitation forecast confidence. The CPC`s 6-10 and
8-14 day extended period outlooks mirror this sentiment; they show a
strong (60-80% chance) for above-normal temperatures, but no strong
signal towards wetness/dryness on the precipitation side. Autumn is
climatologically the dry season in KY, but surges of moisture
related to Gulf disturbances can interrupt this and dampen the
potential for fall fire weather concerns. Thus, the evolution of
that feature could become a focal point of future long term forecast
packages. With that being said, the main idea of today`s long term
forecast is the continuation of seasonably warm and dry conditions
into early October.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
ISSUED AT 718 PM EDT MON SEP 29 2025
Tonight`s river valley fog is unlikely to affect the terminals
given the persistent low-level dry air advection, so it is also
not mentioned in the TAFs. Localized vsby reductions in the deeper
valleys remain likely between 04z and 13z. Mid/high-level clouds
streaming off tropical moisture in the Carolinas will reach
eastern terminals (such as KSJS) by tomorrow morning. The
proximity of the parent upper-level disturbance could trigger
some rain showers tomorrow at these eastern sites, so this may be
mentioned in a future TAF issuance. Otherwise, VFR conditions are
forecast to prevail at the TAF sites through tomorrow.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...GEERTSON
LONG TERM...MARCUS
AVIATION...CMC

NWS JKL Office Area Forecast Discussion