JKL issues Area Forecast Discussion (AFD) at Dec 13, 7:15 AM EST
930
FXUS63 KJKL 131215 AAA
AFDJKL
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
715 AM EST Sat Dec 13 2025
.KEY MESSAGES...
- Areas of dense freezing fog will affect mainly the mid to high
terrain of much of eastern Kentucky south of the Mountain
Parkway for another hour or two this morning.
- Another light, to possibly moderate, snowfall is on its way for
this evening into early on Sunday, mainly north and east of a
Stanton to Jackson to Whitesburg line.
- An arctic airmass moves into our region for late tonight and
Sunday with significantly below normal temperatures and bitterly
cold wind chills on tap.
- Nearer to, if not above normal, temperatures can then be
expected from Tuesday through the end of next week.
&&
.UPDATE...
Issued at 650 AM EST SAT DEC 13 2025
Watching the area web and traffic cams there appears to be signs
of improvement to the dense freezing fog situation. Will keep
monitoring for a possible temporal extension to the current advisory.
Otherwise, have included the latest obs and trends for the
T/Td/Sky grids with this update. These minor adjustments have been
sent to the NDFD and web servers along with a freshening of the
zones and SAFs.
&&
.SHORT TERM...(Today through Sunday)
Issued at 515 AM EST SAT DEC 13 2025
09Z sfc analysis shows an area of deep low pressure to the north
of Kentucky with an approaching cold/Arctic front off to the
northwest of the state. Ahead of this impactful boundary, earlier
clear skies and the recent snow allowed areas of dense fog and a
low stratus to develop through much of eastern Kentucky generally
along and south of the Mountain Parkway nearly to the Tennessee
border. With temperatures for much of that area at 32 degrees or
less this has resulted in dense freezing fog. Accordingly, a
Dense Freezing Fog Advisory is in effect until 13Z. Otherwise,
temperatures are running in the upper 20s to lower 30s across the
JKL CWA. Meanwhile, amid mostly light westerly winds, dewpoints
are running in the upper 20s to lower 30s, as well, with most
places reporting near 100 percent RH on account of the fog -
though a little bit of a dewpoint depression shows up north of
the Mountain Parkway.
The models, and their individual ensemble suites, are still in
pretty good agreement aloft through the short term portion of the
forecast. They all depict a large eastern trough at 5h centered
north of the eastern Great Lakes. This feature amplifies greatly
through the next 24 hours with a sharp pivot southeast that sends
an impressive node of mid-level energy through the lower Ohio
Valley and much of Kentucky by 12Z Sunday. This wave and its
height falls sweep over eastern Kentucky later tonight through
Sunday morning before departing to the east. This process will be
enhanced by the right rear entrance of a 3h jet streak passing
just north of the Ohio River between 00 and 06Z tonight. This
extra enhancement will contribute to the lift available for the
sfc system and its snow as it passes through. The still pretty
small spread among the models generally supported using the NBM as
the starting point of the forecast grids with minimal adjustments
needed - mainly to include more of the CAMs details in PoPs along
with some terrain enhancement late this afternoon through Sunday
morning.
Sensible weather features a very active 24 to 36 hour period for
eastern Kentucky with what appears to be the grand finale of this
recent bout of colder than normal start to the cool season. We
start off this morning with the potential trouble caused by the
dense freezing fog for most of the area south of the Mountain
Parkway - perhaps lingering into the mid morning hours in some
places. Earlier the SPS for this concern was upgraded to a Dense
Freezing Fog Advisory as the threat lingered. Next up, the Arctic
front will blow in here starting late this afternoon in the north
and then dropping southeast through the night with its enhanced
lift from upper level dynamics likely able to give the northeast
quarter of the JKL CWA some 1 to 2 inches of snow - perhaps as
much as 3 inches in northern Fleming County. Falling temperatures
through the column will lead to climbing SLRs making for fluffier
snow that should maximize its fairly meager QPF. Accordingly, a
Winter Weather Advisory is in place for that portion of eastern
Kentucky from late this afternoon (in the northwest) through this
evening and into the morning on Sunday. The blustery northwest
winds behind the front will bring in easily the coldest air of the
season so far with single digits expected towards dawn west and
wind chills sub zero for those parts of the area. This prompted
the issuance of a Cold Weather Advisory based on the different
climatological regions of eastern Kentucky with the southernmost
tier having slightly milder criteria for an advisory. The CW
Advisory starts at 1 am tonight for the western and southern
counties running through 1 pm on Sunday. Should the cold air come
in a bit quicker or winds stay up enough post frontal this may
need to be extending areal-ly through the rest of the CWA. Either
way, Sunday will be a bitterly cold day in that Arctic air mass
with afternoon temperatures only in the mid teens northwest and
low 20s in the southeast. This is a very complicated situation
into Sunday morning with overlapping advisories in effect.
Definitely a day to stay weather aware and prepare for the snow
and cold to come tonight.
The changes to the NBM starting point were primarily focused on
adding in more details for the PoPs from the latest CAMs guidance
and some terrain enhancement to the snow later tonight.
.LONG TERM...(Sunday night through Friday)
Issued at 530 AM EST SAT DEC 13 2025
While one more night of bitterly cold weather is expected at the
beginning of the long term forecast period, a prominent pattern
shift is poised to produce much milder conditions for the upcoming
work week. The northwesterly flow responsible for the advection of
an arctic airmass into the forecast area at the end of the short
term forecast is expected to back towards the west and then the
southwest as the week progresses. The resultant return of ridging
and midlevel height rises favor a warming trend before two late-
period storm systems approach. Warmer antecedent temperatures will
limit the potential for widespread winter weather with these two
systems, a welcome relief from the snowy and cold start to December.
When the period opens on Sunday evening, the ground will likely be
covered in a dry, powdery snow. Northwesterly mid-/upper-level flow
will remain in place for one more night around the backside of an
eastward-propagating trough. At the surface, a high pressure system
will be passing directly overhead. Together, these features favor
efficient radiational cooling, and MinTs are accordingly forecast to
drop in the single digits area-wide by Monday morning. However, the
surface high's proximity will keep winds light and variable and
reduce the wind chill effect. Models collectively depict 850mb
temperatures warming above the -10 degrees Celsius threshold in this
time frame. Therefore, confidence in reaching Cold Weather Advisory
criteria is lower on Sunday night than it is on Saturday
night/Sunday morning. Higher-terrain locations near the Virginia
state line are most likely to do so, but decided hold off on
issuance for now. Interests are still encouraged to bundle up for
the Monday morning commute though, as these low temperatures are 20-
25 degrees cooler than climatological averages for mid-December in
Eastern Kentucky.
Surface flow becomes southwesterly on Monday as the high pressure
system settles into the Southeastern CONUS. The winds aloft will
weaken and adopt more of a westerly component, and 850mb
temperatures should finally climb above freezing on Monday
afternoon. Under mostly clear skies, surface temperatures in the
southern half of the forecast area should recover into the mid 30s.
The cold air will hang on for the longest in areas north of the
Mountain Parkway, where the snowpack is highest and where there
could be some cloud cover. Thus, one more day of freezing high
temperatures appears likely in our northern counties. There is some
model disagreement on the magnitude of potential ridge-valley MinT
splits on Monday night into Tuesday. Some of the available
deterministic MOS guidance drops valley locations into the single
digits again, but the ensemble probabilities for temperatures less
than 10 degrees Fahrenheit are less than 20 percent. The coarser-
resolution long term forecast guidance doesn't necessarily pick up
on small-scale local geographic effects, but the bias-corrected
baseline NBM guidance populated widespread MinTs in the lower half
of the 20s. For this forecast package, temperatures were bumped into
the upper teens in the typically colder shaded/sheltered valley
locales as a middle-ground solution. If higher-resolution guidance
reinforces confidence in the more dramatic splits, future forecast
packages may require further edits.
Quasi-zonal flow aloft and the southern surface high will keep the
sensible weather quiet on Tuesday and during the daytime hours
Wednesday. Southwesterly winds will become breezy in response to a
system passing well to the north of the forecast area. This
displaced disturbance looks rather weak and moisture starved, but it
should still foster a noticeable mid-week warming trend. The entire
forecast area should warm up above freezing and perhaps into the 40s
on Tuesday afternoon, allowing any remaining snow to melt off.
Increasing cloud cover could limit the amount of radiational cooling
on Tuesday night, and ridge-valley temperature splits look less
likely then. Pre-midnight lows near freezing are possible, but the
persistence of warm air advection should result in temperatures in
the mid 30s by the time the run rises on Wednesday morning. Expect
afternoon highs to warm further into the upper 40s/lower 50s.
A second, stronger disturbance will dig into the Great Plains on
Wednesday night into Thursday, leading to renewed precipitation
chances in the forecast area. With surface temperatures well above
freezing, any overrunning precipitation with this system's warm
frontal passage will fall as rain. The warm air advection regime is
expected to strengthen behind that boundary. The flow aloft will
become southwesterly ahead of the approaching trough axis, and
southerly to southwesterly surface winds will strengthen amidst a
tightening pressure gradient. Southwesterly wind gusts of 25-30mph
are possible out ahead of the system's cold front. High temperatures
in the mid/upper 50s will yield widespread rain showers, and some
convective activity cannot be ruled out. The negative tilt of the
parent troughing aloft and a strengthening 850mb jet points towards
potentially favorable shear parameters, but modeled instability
remains meager due to slower dewpoint recovery. Model trends will
need to be monitored closely with this late-week system, but for
now, the set-up favors generic gusty rain showers amidst seasonably
warm highs in the upper 50s/near 60. Once the cold front sweeps
through the area on Thursday night, temperatures should quickly drop
into the 30s. The colder airmass will also be drier though, and a
widespread changeover to snow on Friday is not anticipated.
&&
.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
ISSUED AT 715 AM EST SAT DEC 13 2025
Dense fog and freezing fog, due to stratus build down and/or
where there has been some snowmelt will impact TAF locations such
as KJKL, KLOZ, KSJS, and KSME through 13 or 14Z. Low clouds, at
IFR or lower, will also hold on at all sites and nearby ridgetop
locations into dawn. Some small improvement can be expected into
the afternoon, even as a cold front nears and moves across eastern
Kentucky. With this, some MVFR and IFR reductions linger in the
northeast portions of the area through the end of the period.
Snow is also forecast to develop in the more northern locations
before the end of the day, and this will probably affect KSYM
after about 22Z shifting southeast through the night with a 2 to 4
hour of impact on VIS at any terminal. Generally, light and
variable winds are expected through the bulk of the period
becoming northwest at 5 to 10 kts late.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 3 PM this afternoon to 10 AM EST
Sunday for KYZ044-050>052-059-060-104.
Cold Weather Advisory from 1 AM to 1 PM EST Sunday for KYZ044-
050>052-058>060-068-069-079-080-083>087-104-106-108-111.
Freezing Fog Advisory until 8 AM EST this morning for KYZ058-059-
068-069-079-080-108>118-120.
Winter Weather Advisory from 7 PM this evening to 1 PM EST
Sunday for KYZ106>110-112-113-115-118>120.
&&
$$
UPDATE...GREIF
SHORT TERM...GREIF
LONG TERM...MARCUS
AVIATION...GREIF
Source: JKL issues Area Forecast Discussion (AFD) at Dec 13, 7:15 AM EST (https://mesonet.agron.iastate.edu/p.php?pid=202512131215-KJKL-FXUS63-AFDJKL-AAA)
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