682
FXUS63 KJKL 170502
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
1202 AM EST Wed Dec 17 2025

.KEY MESSAGES...

- Near normal, to above normal, temperatures will be the rule
  through the end of the week. The exception will be Friday being
  colder than normal in the wake of a cold front.

- Multiple weather systems are on track to bring mainly rain
  chances to the area from Thursday through early Friday, and
  again Saturday night into early next week.

&&

.UPDATE...
Issued at 1202 AM EST WED DEC 17 2025

Quick update was made to raise overnight low temperatures several
degrees to account for greater overall cloud cover overnight.
Expect lows mainly in the 30s. Otherwise, the near-term forecast
remains on track.

UPDATE Issued at 745 PM EST TUE DEC 16 2025

Low cloud deck has hung on longer than expected, which is
tempering the nocturnal temperature drop off so far. Have
accordingly increased cloud cover and slowed the hourly decrease
in temperature through midnight. Dew points have also been running
a bit drier than forecast. Otherwise, all seems to be on track
through the overnight.

&&

.SHORT TERM...(This evening through Wednesday night)
Issued at 359 PM EST TUE DEC 16 2025

For once, it`s a bit of a benign forecast. Still under the influence
of high pressure to our southeast, with mild upper level ridging
across the Commonwealth and locations southward. Return flow in the
low levels is actually quite decent, however, and the influx of
moisture has led to an area of llvl clouds which moved across the
Commonwealth and eastern Kentucky throughout the day today. The mass
was a little larger than the state, and did have some impact on the
temperatures. As of the 3pm hour, it continues to show signs of
erosion, and do expect it to completely dissipate through the
evening.

As we head into the overnight, skies should initially clear, which
will lead to quick decoupling of the valleys and temperature falls.
However, models are all in agreement that another round of clouds
will begin to roll in overnight, generally high in nature, connected
to a shortwave that will begin impacting the state. If we do see bkn
to ovc skies, this will also affect temperatures, not only stopping
the decoupling in the valleys, but also moderating them with the
rest of the elevations. Tried to show this in the diurnal trends.
While things will be calm at the surface, it looks like a mile
nocturnal llvl jet will set up around 850mb. This could lead to some
pretty good llvl wind shear potential across much of eastern KY,
which was also reflected in the aviation forecast.

Heading into Wednesday, clouds will likely persist, finally
dissipating late in the day as the weakening shortwave exits to the
east. Pops do increase a bit across the south as the shortwave moves
through, but not enough to warrant any precipitation mention (all
10% and below). Even if pops did increase for some reason,
temperatures are well into the mid 40s and low 50s with the SW flow
in place during the day, so anything that occurs will be in the form
of light rain.

Wednesday night will be a similar set up to tonight, where initial
clearing during the first part of the overnight will give way to
more clouds moving in from the west ahead of the next system, which
will begin to impact us as we head into the extended portion of the
forecast on Thursday. Did not show as much decoupling of the valleys
during the first part of Wednesday night like I did tonight,
however, as there is still some time for the timing of the cloud
cover to change - and moisture will also be higher, which could
limit any elevation influences. Temperatures should generally settle
in the 30s.

.LONG TERM...(Thursday through Tuesday)
Issued at 525 PM EST Tue Dec 16 2025

When the long term forecast period opens on Thursday morning, a
robust trough will be digging into the Upper Midwest. As this trough
propagates east-northeast throughout the day, it will adopt more of
a negative orientation. This feature, coupled with the approach of a
strong related cold front, will lead to a windy and wet Thursday.
Colder weather briefly returns on Friday, when NW flow briefly
returns behind the trough axis. Quasi-zonal flow looks to dominate
the rest of the forecast period, with strong ridging building into
the Central CONUS and a few shortwave disturbances passing around
its northern periphery. This favors seasonably mild conditions and
periodic rain chances for the first half of the next week, albeit
with greater uncertainty than at the beginning of the forecast
period.

The surface low pressure system associated with Thursday`s trough is
poised to deepen upon approach, yielding a tightening low-level
pressure gradient. As southerly winds strengthen in response to
this, warm air advection and moisture return will prime the
atmosphere for widespread rain showers. Expect highs to climb into
the upper 50s/near 60, with PWATs peaking above 1 inch. Both of
these values are much above climatological averages for mid
December in Eastern Kentucky, but severe weather or flooding
appears unlikely. Modeled instability continues to look
unimpressive with this set-up, although frontal forcing, a stout low
level jet, and decent shear parameters could combine to yield a few
thunderstorms west of Interstate 75 on Thursday evening. PotThunder
trended upwards with this forecast package, but remained just below
the 15% mentionable threshold in the grids. Given the kinematic
environment, SPC has maintained a Level 1/5 Marginal risk for strong
wind gusts across the western third of our forecast are in this time
frame. The evolution of upstream activity will need to be monitored
closely on Thursday afternoon, as will the data from higher-
resolution forecast models once this system enters their temporal
range. Most of the area should expect general rain showers with
embedded wind gusts of 30-35 mph before the cold front sweeps
through overnight.

After the cold frontal passage on Thursday night, a changeover to
snow showers is possible on Friday morning. Northwesterly flow aloft
will set up a brief, but potent cold air advection regime to end
the work week. Temperatures will quickly drop to near or below
freezing by Friday morning, and may struggle to warm up much higher
than that in locations north of the Mountain Parkway. There, pattern
recognition suggests that cloud coverage is likely to stick around
for longer, and after coordinating with neighboring WFOs, a slight
chance of snow showers/flurries was added for the northeastern third
of the forecast area. Any accumulations would likely be light, but
wet grounds from Thursday`s rain may combine with the cold to create
isolated slick spots on Friday morning. A potential limiting factor
for both the snow chances and the black ice potential is the
advection of drier air into the lower levels of the column via
westerly post-frontal winds. This wraparound dry air will allow
skies to clear from SW to NE as the trough ejects on Friday night.

Temperatures are forecast to rebound this weekend as the midlevel
flow pattern becomes quasi-zonal. Saturday looks clearer and warmer,
with highs in the 50s and overnight lows in the mid 30s. A clipper
type system passing to the north will drag a weaker cold front into
the region on Sunday, resulting in slightly cooler highs in the
upper 40s/lower 50s, a chance of rain, and overnight lows near
freezing. Next week, return flow around the backside of a post-
frontal high will keep warm/moist air advection processes in place
as a series of shortwave disturbances navigate around the periphery
of the broad ridging over the south-central CONUS. These
disturbances yield periodic precipitation chances, but their exact
timing gets smoothed out in the blended data used to populate the
long term forecast grids. Despite the timing uncertainty, any
precipitation leading into Christmas is most likely to fall as a
plain, liquid rain. There is a 60-70% chance that next week`s
temperatures will be above climatological norms, with forecast highs
in the 50s and lows in the upper 30s/near 40.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
ISSUED AT 1202 AM EST WED DEC 17 2025

An area of low-mid cloud cover is still over the area at TAF
issuance. This has not been modeled well but is generally bringing
low VFR ceilings. Expect this lower ceiling to gradually
dissipate over the next several hours, leaving behind mid and
high level clouds. Meanwhile, a llvl jet is already ramping up,
leading to some llvl wind shear issues early this morning. With
weak southerly winds at the surface and winds at 850mb between 30
and 40 kts, the TAF sites can expect a decent period of llvl wind
shear into the morning hours, before mixing takes hold once more
during the day on Wednesday.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

UPDATE...GEERTSON
SHORT TERM...JMW
LONG TERM...MARCUS
AVIATION...GEERTSON