318
FXUS63 KJKL 081308 CCA
AFDJKL

AREA FORECAST DISCUSSION...CORRECTED
National Weather Service Jackson KY
808 AM EST Mon Dec 8 2025

.KEY MESSAGES...

- Snow accumulations are forecast on Monday, primarily north of
  the Cumberland River Basin.

- A Winter Weather Advisory is in effect for locations northeast
  of a line from Harlan to Estill County, including the I-64 and
  Mountain Parkway corridors.

- Gusty southwesterly winds between 30 and 40 mph are likely on
  Wednesday.

- The pattern remains active through the end of the work week,
  although confidence remains low in each passing system`s
  precipitation type forecast.

- A much colder airmass is forecast to move into the region for
  the weekend, with widespread low temperatures in the teens
  likely.

&&

.UPDATE...
Issued at 808 AM EST MON DEC 8 2025

Light precipitation is gradually transitioning to snow from
northwest to southeast and from higher elevation to lower
elevation. Latest observations would suggest that the transition
has occurred for most locations north of the Hal Rogers
Parkway/KY-80 corridor. A full changeover to all snow is expected
for the remainder of the area reaching the Middlesboro area last,
perhaps as late a noon. Still anticipate amounts averaging 1 inch
of snowfall in most of the Winter Weather Advisory. However, the
latest hi-res guidance continues to highlight a potential for
heavier 1 to 2 inch snowfall totals over Pike and adjacent
counties. (Higher elevations of Pike County could pick up 3
inches). A narrow swath or two of higher 1 to 2 inch snowfall
amounts remain possible near/north of the Mountain Parkway as
well.

&&

.SHORT TERM...(Today through Tuesday)
Issued at 412 AM EST MON DEC 8 2025

Radar echoes are increasing in coverage across eastern Kentucky
early this morning as a cold front sags southeast of the area and
a potent upper level disturbance and shortwave trough (embedded
within broadly cyclonic 500 hPa flow) approach from the Mid-Mississippi
Valley. As the precipitation is developing, temperatures range
from near freezing north of I-64 and over the highest southeastern
mountains to the lower 40s near Lake Cumberland and in the deeper
mainstem Coalfield river valleys. The precipitation has been
primarily in liquid form thus far; however, that will change
heading through the remainder of the morning.

As precipitation increases over the next several hours, northerly
low-level flow will feed colder air into the forecast area
causing the precipitation to transition to all snow from north to
south and higher elevations to lower elevations. The transition
will occur latest, perhaps around noon in the deeper valleys along
the KY/TN border. By that time, the strongest forcing associated
with the 500 hPa disturbance and trough will begin its departure.
Thus, the longest period of snowfall can be expected over the
northeastern half of the forecast area and most notably in and
adjacent to Pike County. In that area, the greatest snowfall
amounts can be expected, ranging from perhaps an inch in the
warmest valleys to as much as 2 or 3 inches in the cooler high
elevation locales. Farther west, from Harlan to Estill counties
and northward, amounts will be generally up to an inch, though
isolated higher amounts cannot be ruled out. In fact, RAP13
soundings do show a very small amount of elevated instability
extending into at least the middle of the DGZ. If any instability
is fully realized, counties along and adjacent to the US-460
Corridor would be favored for briefly moderate to heavy snowfall
rates capable of producing locally higher 1 to 2 inch snowfall
tallies. The snow will taper off through the afternoon, exiting
through Pike County around 00Z as the 500 hPa shortwave trough
axis and trailing vort lobe depart. Low-level moisture gradually
diminishes tonight into Tuesday morning amidst overall weak
height rises as a surface high pressure center scoots eastward
along the Gulf Coast and brushes the JKL CWA. This will bring us a
drier, sunnier, and milder day for Tuesday.

In sensible weather terms, look for a cold light rain to develop
area-wide over the next few hours, gradually transitioning from
north to south through noon. That snow will then taper from west
to east between noon and 7 PM. It will be a cooler day with high
temperatures ranging from the lower to mid 30s in the north to the
lower 40s in the deepest valleys along the TN-KY border. High
temperatures will largely be established this morning. For
tonight, clouds gradually break up across portions of the area
while temperatures sink back into the upper teens north to mid 20s
south. A cool but nicer Tuesday follows with partly to mostly
sunny skies and afternoon highs in the lower to middle 40s.

.LONG TERM...(Tuesday night through Sunday)
Issued at 420 AM EST MON DEC 8 2025

The long term forecast period continues look quite active here in
Eastern Kentucky. A series of quick-moving, clipper-type systems are
forecast to move across the Greater Ohio River Valley between
Wednesday and Friday. Confidence is increasing that the primary
impacts from the first system on Wednesday will come from gusty
winds, but forecast guidance continues to disagree upon the exact
track/timing/evolution of the ones later in the work week. This
model spread leads to uncertainty in the late week precipitation
type and accumulation forecasts, but guidance collectively points
towards much colder and drier air advecting into the region behind
these systems.

The first clipper system is expected to deepen and dig into the
Southern Great Lakes at the beginning of the period on Tuesday
night. As it does so, an intensifying low level jet will yield
southwesterly winds of 40-50 knots at 925mb by daybreak over the
forecast area on Wednesday morning. BUFKIT momentum transfer model
soundings indicate that these winds are likely to mix down to the
surface after daybreak on Wednesday, but it remains uncertain if
these winds will reach traditional advisory criteria (gusts in
excess of 40mph). The more aggressive GFS soundings yield gusts
between 35 and 40 mph across western portions of the forecast area,
whereas the NAM continues to resolve values closer to the 30 mph
mark. While the EPS Ensemble probabilities for advisory-crtieria
gusts greater than 40mph have continued their recent downward trend,
30-40% probabilities remain in locations along/west of the I-75
corridor and in locations along/north of the I-64 corridor. In
collaboration with neighboring WFOs, forecast wind gusts were
accordingly blended towards the 90th percentile NBM data on
Wednesday, yielding widespread gusts between 30 and 35 knots in
these aforementioned corridors and in high-terrain locations closer
to the Virginia state line. Elsewhere, winds are still forecast to
be breezy, with peak gusts closer to 25 knots. Regardless of exact
magnitude, Wednesday`s winds will likely produce nuisance-level
impacts across the region. Outdoor holiday decorations and temporary
structures like tents could be blown around/away, and interests are
encouraged to take advantage of the drier and milder conditions on
Tuesday night to secure loose objects ahead of time.

The persistence and strength of this southwesterly low-level flow
will yield the warmest MinTs and MaxTs of the forecast period on
Tuesday night and Wednesday afternoon, respectively. Increasing
cloud cover will combine with warm air advection to keep
temperatures well above freezing on Tuesday night. Most of the area
will see overnight lows in the mid 30s, giving Wednesday`s highs
(upper 40s/lower 50s) a head start. With temperatures solidly above
freezing, the prefrontal precipitation associated with this first
system will fall as a plain, liquid rain. Once the system`s cold
front passes through, a shift to west-northwesterly winds will
facilitate cold air advection overnight. A changeover/mix with light
snow cannot be ruled out, but the antecedent warmth should keep
precipitation impacts at a minimum.

Additional disturbances are forecast to pass through the mean NW
flow aloft in the latter stages of the work week, and depending upon
their track/evolution, they could produce more substantial winter
precipitation chances. Model spread increases substantially in this
time frame though. The Euro Ensemble`s temperature guidance goes
from 2 degrees of standard deviation on Wednesday night to 7 degrees
on Friday afternoon. Given the uncertainty in the thermal profiles
and individual system evolution, p-types were limited to a rain/snow
mix in this forecast package. The passage of these additional
disturbances will likely culminate in the arrival of a much colder
airmass on Saturday, although there is less of a signal for extreme
cold than there was at this time yesterday. The 00z forecast
guidance suite now relegates the coldest air to north of the Ohio
River on Saturday morning, although 850mb temperatures should still
fall well below freezing on Friday night. This favors snow with any
lingering precip before a drier continental polar airmass settles
into the region for the weekend. Drier conditions are forecast on
Saturday and Sunday as a Canadian high pressure system builds into
the area. Forecast lows are currently in the teens on Saturday,
Sunday, and Monday mornings, with daytime highs struggling to warm
above freezing amidst persistent cold air advection. The CPC
continues to outline a 40-60% chance for much below normal
temperatures in Kentucky on December 15th, but the compounding
forecast uncertainty and aforementioned northward trend with the
coldest air aloft reduces confidence in the idea that temperatures
could dip into the single digits. The average temperatures for mid-
December in Eastern Kentucky are highs in the mid 40s and lows near
freezing. Thus, it will still be noticeably colder than usual at the
end of the long term forecast period.

&&

.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
ISSUED AT 745 AM EST MON DEC 8 2025

Conditions are deteriorating to IFR from northwest to southeast
this morning as light rain transitions to mainly light snow.
Gradual improvement back to low-end MVFR is expected at SME and
SYM by 18Z as the snow begins to taper. The improvement can be
expected further south and east through the remainder of the
afternoon and evening. A return to VFR is anticipated near/north
of the Mountain Parkway for much of the overnight period while
MVFR or worse ceilings will be more persistent further south.
Winds will be northeast to north at under 10KT through the day.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 5 PM EST this afternoon for KYZ044-
050>052-058>060-088-104-106>109-111>113.

Winter Weather Advisory until 7 PM EST this evening for KYZ110-
118>120.


&&

$$

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