766
FXUS63 KJKL 050059
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
759 PM EST Wed Dec 4 2024

.KEY MESSAGES...

- Another arctic cold front will push through tonight and send
  temperatures plummeting.

- The front will bring snow showers to many locations late tonight
  and early Thursday morning, with light accumulations of
  generally less than half of an inch.

- Temperatures will warm over the weekend, with above normal
  readings expected early next week, along with wet weather.

&&

.UPDATE...
Issued at 758 PM EST WED DEC 4 2024

The early evening update is out. The forecast is on track with the
exception of temperatures rising a little more than predicted just
ahead of the polar cold front crossing the area currently. The
remedy to this was to update the temperatures and use the latest
observations as the starting point for the updated forecast.

Though the radar shows returns moving through southeastern
Kentucky, very little of this activity is reaching the ground due
to a well-mixed lower atmosphere resulting in significant dew
point depressions. However, some locations will receive trace
amounts of rain. Better chances for rain and a brief round of snow
showers will come overnight as the arctic front crosses the area
between midnight and dawn.

&&

.SHORT TERM...(This evening through Thursday night)
Issued at 420 PM EST WED DEC 4 2024

Late this afternoon, an upper level low was centered over the
vicinity of Lake Superior and associated shortwave trough south
toward the mid MS Valley region within a trough that extended
from eastern sections of Canada into the eastern Conus. Another
upper level low was centered over the desert southwest with
ridging from the eastern Pacific into the northwest Conus and BC.
At the surface, an area of low pressure was centered in Ontario
with a trailing initial cold front/trough south to the mid MS
Valley to Southern Plains. A stronger arctic cold front trailed
from the low to northern Lake MI to IA to the Dakotas to MT.
Following a chilly start this morning, ahead of the cold fronts,
temperatures have warmed into the 40s to low 50s except for
locations above 2500 feet. Upstream, radar returns were noted from
portions of WV southwest to northern and central KY to portions
of western KY with a few stations noting rain or sprinkles
reaching the ground.

This evening through Thursday, the upper level low should move to
the eastern Great Lakes/southeast Ontario through tonight with the
associated shortwave trough sweeping across the central Great
Lakes, Lower OH Valley and into the mid Atlantic states. The first
cold front should work into eastern KY late this evening and cross
the area within a couple of hours after midnight followed quickly
by the arctic front. Rain showers or are expected ahead of and
near the first boundary except for locations above 2500 feet.
Colder air will move in quickly behind the second boundary that
will pass a couple of hours after the initial weaker boundary.
This boundary should also more readily transfer down higher
momentum form aloft especially within any showers or potential
snow squalls near the boundary. Outside of snow squalls, gusts of
25 to 35 mph are anticipated, but gusts of 40 mph or stronger are
possible near the boundary and especially with any snow squalls.
850 mb temperatures are expected to fall below 0C behind the first
boundary and then quickly to the -8C to -16C range from near the
VA border to Fleming County by around dawn. Moisture is progged
to increase ahead of the shortwave trough and as the fronts pass.
More significant lower level moisture is expected with the second
front and before the steadier showers end, the precipitation
should transition to all snow at least briefly areawide. Following
mild temperatures today, ground and road temperatures will be
mild and could limit accumulation or result in melting. QPF is not
all that high for the event only around 0.05 inches expect for
higher terrain near the VA border where it will be closer to an
inch. A good portion of this may fall as rain or just melt and not
accumulate. However, as the cooling is occurring aloft, surface
temperatures should plummet overnight from readings in the lower
40s for most at midnight to the mid to upper 20s southeast and
near 20 if not the upper teens northwest of I-64. A further drop
in temperatures of a couple more degrees is expected through
about 10 AM, before only a modest rise the remainder of the day.

On Thursday morning, saturation near 850 mb will linger for a few
hours after sunrise especially in the southeast and as late as
midday to early afternoon near the VA border. Some fluffy
flurries may fall from the remaining clouds. The potential for
black ice or freezing temperatures is the main concern after
generally minor accumulations of less than a half of an inch late
tonight.

High pressure will gradually build in behind the front from the
Plains and clearing skies and slackening winds should set the
stage for lows on average a couple of degrees colder than what was
observed this morning for valley locations and several degrees
colder for the coalfield ridges. Lows should mainly range form 10
to 16, but an 8 or 9 in a normally cold spot cannot be completely
ruled out.

.LONG TERM...(Friday through Wednesday)
Issued at 249 PM EST WED DEC 4 2024

By early Friday, a ridge resides in the west, reaching as far north
as British Columbia. Additionally, there`s a subtropical low
stationed just east of Baja, CA. The strong upper level low that
previously gave the state a shot of Arctic air, will begin to depart
to the north and east, towards Nova Scotia.

For eastern Kentucky, expect quiet weather Friday and Saturday, as
the state is under weak high pressure. Winds will be light out of
the west on Friday, becoming southwesterly on Saturday. The cold
weather is slow to move out on Friday, with highs only reaching into
the low 30s during the afternoon. Fairly clear skies will help
Friday night in lows reaching the teens in the valleys, scratching
low 20s across ridgetops.

By Saturday, the ridge in the west begins to flatten out, as an
upstream low further west begins to progress southeast out of the
Pacific Northwest. Additionally, the subtropical low over Mexico
begins to progress eastward, picking up moisture from the Gulf of
Mexico. As far as weather for eastern Kentucky, expect dry conditions
with warmer highs in the low to mid 40s. Lows Saturday night are
forecasted in the upper 20s to low 30s.

Sunday, increasing clouds are expected with the incoming system
nearing the state. Highs are expected to rise into the low to mid
50s ahead of the next system. Heading into the evening and overnight
hours, rain chances will gradually increase. Current thinking is
rain will likely be falling by midnight, spreading southwest to
northeast in time. Lows Sunday night will generally remain in the
low 40s. Rain will continue into Monday, with breezy southerly
winds. Highs will rise into the upper 50s, possibly reaching 60 in
few spots. As this frontal system is unfolding over eastern
Kentucky, a shortwave spills out of the Pacific northwest into the
deepening as an upper level low as it approaches the desert
southwest by Tuesday. Because of cloudy skies and ongoing rain, lows
will drop into the upper 40s. Models have some discrepancy on band
placement of another system at this current time, however chances
remain for rain showers to continue in varying degrees through mid-
week. Tuesday, forecasted highs are expected to be in the upper 50s,
near 60, with cooler highs Wednesday in the upper 40s. Lows will
generally remain in the upper 20s to mid 30s.

&&

.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
ISSUED AT 630 PM EST WED DEC 4 2024

Polar cold front is crossing the area currently bringing gusty
southwest winds with gusts as high as 25 kts. A lowering VFR
cloud deck is also accompanying this front, along with primarily
virga aloft but with a few raindrops possibly reaching the ground
here and there. Confidence in -RA at any one TAF site to warrant
inclusion in the TAF, however.

An arctic cold front will pass quickly through the area tonight.
Showers, initially falling as rain, develop after 03Z, with
ceilings expected to drop to MVFR in the showers during the 03Z to
06Z timeframe for most. Rain showers should then change over to
mainly snow showers before gradually taper to flurries through
12Z with a return to VFR ceilings. Winds will also continue to be
gusty and after a potential lull in wind gusts during the evening
and even the threat of LLWS, a few gusts to around or perhaps
exceeding 30KT may occur between 05Z and 11Z with the frontal
passage.

Clouds will diminish between 12z and 18z Thursday, with mostly
clear to partly cloudy skies consisting of shallow cumulus
thereafter. Winds will remain gusty out of the northwest through
the day Thursday, generally sustained winds of around 10 kts and
gusts to around 20 kts, though gradually diminishing through the
late afternoon into the early evening.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...CMC
SHORT TERM...JP
LONG TERM...GINNICK
AVIATION...CMC