Letcher Kentucky Weather Forecast Discussion

298
FXUS63 KJKL 130535 AAA
AFDJKL
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
135 AM EDT Mon Oct 13 2025
.KEY MESSAGES...
- Dry, seasonably pleasant weather continues across eastern
  Kentucky through the upcoming work week.
- Temperatures will remain near or just above climatological
  averages for the duration of the forecast period.
- While confidence in specific details remains low, the next
  chance of showers/storms will come next weekend.
&&
.UPDATE...
Issued at 125 AM EDT MON OCT 13 2025
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.
UPDATE Issued at 1106 PM EDT SUN OCT 12 2025
The extreme eastern portion of the JKL forecast area (near WV)
continues mostly cloudy, while areas west of KJKL are mainly
clear, and the area in between sees westward moving clouds
eroding. This has resulted in the coolest late evening
temperatures being in valleys and low lying places in the western
portion of the forecast area. The general scenario should continue
overnight. Late evening conditions have been blended into the
forecast, and the amount of clouds forecast to be left at dawn
has been reduced slightly.
UPDATE Issued at 834 PM EDT SUN OCT 12 2025
Clouds are eroding as they try to progress further west over the
the forecast area. However, where they are prevalent, they are
greatly slowing the normally quick evening drop for valley temps
in our eastern counties. Have modified forecast lows to keep
eastern valleys a bit milder than what was earlier forecast.
UPDATE Issued at 712 PM EDT SUN OCT 12 2025
Low clouds are arriving from the east, on the back side of the
coastal storm, more aggressively than was forecast. The forecast
has been updated to account for this, but confidence is not high
for how well they hold together and how far west they make it.
Models don`t seem to be handling them particularly well. Where
clouds are prevalent, they will also impede temperatures from
falling and subsequent fog development. These parameters may need
to be subsequently looked at for updating as well in a little
while.
&&
.SHORT TERM...(This evening through Monday night)
Issued at 343 PM EDT Sun Oct 12 2025
Eastern Kentucky is currently positioned in between a deepening non-
tropical low centered over coastal North Carolina and a building
ridge of high pressure over the Greater Ohio River Valley. In
sensible weather terms, this translates to mostly clear skies, with
a few fair weather diurnal cumulus clouds noted in the Bluegrass
region and low/mid level clouds draped over WV and VA. The previous
short term forecast for the remainder of this afternoon and evening
remains on track. Temperatures are on track to warm into the low to
mid 70s before sunset, and light/variable winds will adopt a more
northeasterly component to them overnight as the aforementioned
coastal low shifts closer.
Tonight, these northeasterly winds are expected to advect some low-
level moisture into the region around the far northwestern periphery
of the coastal low. This could lead to the development of a low
stratus deck into tomorrow morning, and forecast guidance has
trended towards this solution as the day has progresses. The
baseline NBM data used to populate the forecast grids picked up on
this trend, and the forecast depicts increasing cloud cover over
northeastern portions of the area after sunset. Synoptically, this
can be attributed to both the wraparound moisture and a subtle
inverted surface trough/convergence zone between the two
aforementioned dominant synoptic features. The signal for cloudy
skies is strongest in the HREF between 2am and 9am, and confidence
in clouds is highest northeast of the I-75 corridor. Before this
time frame, antecedent dryness and clear skies should favor ridge-
valley temperature decoupling. The more sheltered valleys should
quickly cool off into the 50s after sunset, and this may lead to
overnight valley fog formation, especially in our SW counties. The
signal for increasing cloud cover is intriguing from a fog/ridge-
valley split forecast lens. If a widespread low stratus deck comes
to fruition earlier than anticipated or if the spatial coverage of
these clouds is greater than what is currently forecast, low
temperatures could be more insulated and fog formation would be less
likely. If the stratus deck under-performs, the fog could be more
widespread and more radiational cooling could be realized. Thus,
confidence in tonight`s forecast is lower than usual, and the
sensible weather will be highly dependent upon observed trends in
sky cover after dark.
The effects of tonight`s convoluted sky forecast cascade into
tomorrow`s temperature forecast. While models are in generally good
agreement that dry air advection via northerly winds and efficient
diurnal warming under otherwise clear skies will prevail eventually,
a lingering stratus deck could dampen the amount of mid-day warming
realized. That could relegate forecast highs to the upper 60s/near
70 in NE portions of the forecast area, but otherwise, temperatures
are expected to climb towards the the low/mid 70s by tomorrow
afternoon. The persistence of a surface high pressure system and
rising midlevel heights from a building ridge aloft support this
notion. Mostly clear skies will favor efficient diurnal processes
tomorrow afternoon and into tomorrow night. In accordance with the
expected degree of boundary layer mixing, dewpoints were slightly
lowered from baseline guidance and winds were bumped up during the
afternoon hours. After sunset tomorrow night, valley MinTs were
lowered into the 40s, ridgetop MaxTs temperatures were raised into
the 50s, and winds were adjusted for localized terrain effects.
Collectively, these edits support the addition of overnight river
valley fog to the end of the short term forecast grids. Overall,
tommorow`s forecast looks like a typical, pleasant Mid-October day
in the commonwealth. However, those with early morning travel plans
tomorrow should prepare for potential visibility reductions, whether
they come in the form of ridgetop-hugging low level stratus or the
classic Eastern Kentucky morning river valley fog.
.LONG TERM...(Tuesday through Sunday)
Issued at 306 PM EDT SUN OCT 12 2025
Ridging prevails through the end of the week, with the exception of
a brief period of northwesterly flow aloft allowing for a backdoor
cold front to move south and then southwesterly across eastern
Kentucky during the day Wednesday. This will bring a cooldown,
especially for overnight lows Thursday night, as cold advection
diminishes and excellent radiational cooling develops. This will
allow for lows in some of our more sheltered valleys to drop into
the mid to upper 30s, which will also mean the chance for some
patchy frost, particularly in our northeastern counties.
Warm advection increases Friday into the weekend ahead of another
potentially stronger disturbance that looks to impact the area next
weekend. This system looks to have pretty good jet support, with the
operational GFS and ECMWF models depicting different solutions
though still roughly in line with the global model ensemble
consensus. Possible impacts include strong to severe storms upstream
over the Mississippi and/or Lower Ohio Valleys at some point,
with more local downstream impacts still to be determined.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
ISSUED AT 135 AM EDT MON OCT 13 2025
A ceiling of about 4-5K ft AGL is attempting to move westward
into the JKL forecast area. Confidence is not very high
concerning the progress of the clouds and how well they will hold
together during the rest of the night. If/where they remain
dominant, they will tend to inhibit valley fog development.
Elsewhere, valley fog is developing and becoming locally dense.
The TAF sites with the greatest potential to be affected by IFR or
worse conditions from fog by dawn are KSME, KLOZ, and KSYM. Any
fog will dissipate on Monday morning, leaving VFR conditions to
finish the period. Winds will be light and variable through the
period.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...GREIF
SHORT TERM...MARCUS
LONG TERM...CMC
AVIATION...HAL/GREIF

NWS JKL Office Area Forecast Discussion