900
FXUS63 KJKL 071350
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
850 AM EST Sun Dec 7 2025

.KEY MESSAGES...

- Light snow accumulations are anticipated behind a cold frontal
  passage late tonight/Monday, primarily north of the Cumberland
  River Basin. The highest totals are forecast east of US-23.

- Southwesterly winds will become gusty on Tuesday and Wednesday
  ahead of a stronger mid-week system.

- 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 next
  week, with widespread low temperatures in the teens likely.

&&

.UPDATE...
Issued at 850 AM EST SUN DEC 7 2025

No substantive changes on this update. Clouds are thickening
across the area as fog lifts/dissipate.

&&

.SHORT TERM...(Today through Monday)
Issued at 505 AM EST SUN DEC 7 2025

A mixture of high clouds and patchy fog, especially in valleys,
is noted across eastern Kentucky this morning. Temperatures range
from the mid 20s in the coldest southern valleys to the lower 30s
on the warmest thermal belt ridgetops. At the surface, high
pressure is centered over Virginia and the Carolinas while a wavy
frontal boundary extends from New England across the Southern
Great Lakes and then southwest to a very weak wave of low pressure
along the northern fringe of the Ozarks. Looking aloft, broad 500
hPa troughing remains in place over the CONUS east of the Rockies.
An embedded low-amplitude trough axis is noted from Northern
Ontario to the Southern Plains.

That 500 hPa trough axis will translate eastward through the
short-term to a location east of the Central and Southern
Appalachians by the end of the period. At the surface, the
aforementioned wave of low pressure will ride toward the southern
shores of the Great Lakes today and dissipate. However, the
associated frontal boundary will still sag southeastward and into
the Commonwealth this evening with relatively little fanfare. A
vort max riding through the base of the approaching trough axis
will eject northeast toward the Southern Appalachians, inducing
cyclogenesis off the Carolinas. Synoptic lifting with this vort
max and subsequent trough passage, along with cold air advection,
near to total saturation up to around 700 hPa, and a northerly
upslope flow component, will support some upslope precipitation
enhancement. Additionally, a relatively stable layer between 925
and 850 hPa may further enhance precipitation in some areas due to
blocking effects; however, the flow is not ideally aligned for
maximal orographic effects. Once precipitation redevelops,
primarily after midnight tonight, it will gradually change from
rain to all snow from north-to-south. Through the event, the
saturated layer will be mostly warmer than -12C; thus, flakes are
more likely to be heavily rimed with fewer overall dendrites,
supporting a denser snow overall. The most persistent and heaviest
snowfall appears to be likely over Pike and adjacent counties
where forcing and blocking effects will be most effective for
enhancement and snowfall duration, yielding 0.5 to 2.0 inches of
accumulation. Lower accumulations, generally under an inch, can
be expected in the remaining counties from Harlan to Rockcastle
and northward. Temperatures will turn noticeably colder, with 850
hPa temperatures starting the period at 1 to 3C today but falling
to between -7 and -9C by Monday evening. While roads will be
warm going into this event, some eventual slick spots cannot be
ruled out in the typical shaded spots as well as on bridges and
overpasses that cool most quickly.

In sensible weather terms, look for increasing clouds today once
any morning fog dissipates. It will be milder with highs in the
mid 40s north to lower 50s south. For tonight, rain develops after
midnight and transitions over to snow from north-to-south between
3 AM and noon, then gradually diminishes from northwest to
southeast. The slowest transition and least wintry impacts, if
any, can be expected near Lake Cumberland and in those counties
adjacent to the KY-TN border. Most other locations will pick up at
least a solid dusting to a half inch, except east of the US-23
corridor and over Big Black Mountain where there could be some
tallies pushing 1 or 2 inches in spots. Temperatures will dip into
the mid 20s north of I-64 to the mid 30s along the Tennessee
border by sunrise Monday. During the day on Monday, look for
chilly temperatures area-wide only recovering into the low to mid
30s for most locations, though some upper 30s are possible in the
Cumberland River Basin where there should be little, if any,
measurable snowfall.

.LONG TERM...(Monday night through Saturday)
Issued at 509 AM EST SUN DEC 7 2025

Ridging builds back into the commonwealth at the beginning of the
long term forecast period, but the resultant reprieve from active
weather looks quite brief. A series of systems will move through the
Greater Ohio River Valley in quick succession during the latter half
of the work week. A tightening pressure gradient ahead of the first
systems will lead to strengthening southwesterly winds on Tuesday
and Wednesday. Winds could flirt with advisory criteria on
Wednesday, and the resultant warm air advection will position
Eastern Kentucky in the first system`s warm sector. This makes rain
the favored precipitation type with the initial midweek wave,
although the cold air advection behind it could set the stage for
potential winter precipitation during the late-week systems. Models
signal that a much deeper trough will dig into the region by the
weekend, and it is becoming increasingly likely that this period of
active weather will culminate in the coldest temperatures of the
season thus far.

When the period opens on Monday night, a post-frontal surface high
pressure system will be positioned directly over the forecast area.
This favors clear, calm, and seasonably cool sensible weather
conditions. Modest ridge/valley temperature splits appear possible,
but most of the forecast area is poised to see lows in the 20s.
Expect ridgetop MinTs closer to 25 while the conventional cold spots
(the sheltered and shaded valleys of NE KY) dip down into the upper
20s. These temperatures could trend a little bit cooler if the snow
from the short-term forecast period lingers around for one more
night. By Tuesday morning, the aforementioned surface high will have
propagated eastward into the Appalachians. This will shift winds to
the southwest, and winds are forecast to progressively strengthen
throughout the day as an Alberta Clipper deepens and dives into the
Upper Midwest. The strengthening winds will kick-start warm air
advection processes, and temperatures should quickly moderate into
the 40s by Tuesday afternoon. Increasing cloud cover and the
persistence of these winds will keep temperatures relatively warmer
on Tuesday night. Expect widespread lows in the mid to upper 30s,
with only the top of Big Black Mountain left below freezing.

That clipper system will approach the forecast area on Wednesday,
allowing the southwesterly low-level winds to both persist and
further strengthen. Confidence in wind gusts of at least 30 knots is
increasing, but winds may not make it all the way to advisory
criteria (gusts of at least 40 mph). The latest BUFKIT momentum
transfer model soundings continue to depict wind gusts around 30
knots out ahead of Wednesday afternoon`s frontal passage. This is a
slight decrease from the BUFKIT guidance at this time yesterday,
when a few sites had readings closer to 35 knots. Along these lines,
the latest EPS probabilities for wind gusts in excessive of advisory
criteria have actually decreased relative to the previous run. While
there is still a 20 to 40% chance of seeing an isolated 40 mph gust,
this particularly data source tends to have a high bias.
Nevertheless, Wednesday`s winds will likely cause nuisance-type
impacts to outdoor holiday decorations and temporary structures like
tents. Continued WAA will allow temperatures to climb into the 50s
across much of the area by Wednesday afternoon, and these warm
temperatures point towards liquid precipitation as PoPs increase
ahead of the system`s cold frontal passage on Wednesday night.

A second clipper-type system will approach the forecast area at some
point on Thursday. This disturbance generally looks weaker than the
first one, although it will need to be monitored closely for winter
precipitation potential given the antecedent cold air advection on
Wednesday night. Some thermal recovery is possible on Thursday
afternoon if a more northerly track is realized, but the exact
evolution of this system is highly uncertain. If it takes a
southerly track and/or its arrival aligns with colder temperatures
on Thursday night, winter weather would be more likely. Thus, the
late week precipitation type forecast is difficult to pinpoint at
this temporal range.

Models resolve a third low pressure system moving through the Great
Lakes States on Friday into Saturday, with much deeper troughing
digging into the Ohio River Valley aloft during this time frame.
Such a pattern favors the advection of a much colder, but drier
continental polar airmass into the region for the end of the
forecast period. Guidance collectively depicts 850mb temperatures
falling below freezing (0 degrees Celsius) on Friday and then below
negative 10 degrees Celsius on Saturday. This supports snow chances
in the grids on Friday, but the more noticeable impacts will come
from the cold temperatures in the forecast for next weekend. Lows
are poised to drop into the teens area-wide on Friday night, and
blustery NW flow will allow cold air advection to persist into
Saturday. Saturday looks just plain cold as the Canadian-sourced air
settles into the region. Expect highs to only reach the the 20s on
Saturday afternoon before temperatures potentially drop into the
single digits on Sunday morning. Ensemble probabilities reinforce
the notion that the coldest air of the season will arrive behind
these three late-week systems. The CPC has outlined most of Kentucky
in its Days 8-14 Hazards Outlook for "Much Below Normal
Temperatures" on December 14th and 15th, and the first sub zero
wind chills of the season cannot be ruled out in this time frame.
Brr.

&&

.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
ISSUED AT 715 AM EST SUN DEC 7 2025

Any fog will dissipate this morning, leaving VFR conditions
areawide. Clouds will increase gradually today ahead an
approaching cold front but should remain mid to high level.
Deteriorating conditions follow tonight as rain develops behind
the cold front and then changes over to snow from north-to-south.
This will yield widespread MVFR to IFR conditions by late tonight
with locally worse conditions possible. Light and variable winds
should prevail through 14Z, with winds becoming southwest to west
at less than 10KT for the afternoon veering northerly for tonight.

&&

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

&&

$$

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