JKL issues Area Forecast Discussion (AFD) at Jan 20, 12:36 AM EST
001
FXUS63 KJKL 200536
AFDJKL
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
1236 AM EST Mon Jan 20 2025
.KEY MESSAGES...
- Accumulating snow will end by daybreak Monday in most locations.
- Apparent temperatures will fall to below zero for much of the
area this morning, and again Tuesday night into Wednesday
morning.
- Temperatures will gradually begin to moderate back toward
normal during the latter half of the week into next weekend.
&&
.UPDATE...
Issued at 1202 AM EST MON JAN 20 2025
Extended the Winter Weather Advisory for a few counties a couple
of hours to 07z where snow bands are still occurring, and dropped
the outer periphery of counties from the Winter Weather Advisory
where snow has ended or become extremely isolated.
UPDATE Issued at 1005 PM EST SUN JAN 19 2025
Persistent bands of snow showers have developed in line with what
some of the high resolution guidance had been suggesting with
these extending west of the original Winter Storm Warning area
back to Perry and Breathitt Counties as well as west near the Mtn
Pkwy corridor. With several reports of snowfall between 3 to 4
inch range across this area already received and the potential for
another inch or so under these bands if not locally 2 inches
should bring totals into Winter Storm Warning Criteria. Thus, a
few counties to west and northwest were upgraded to a Winter Storm
Warning from the Winter Weather Advisory that had been in effect.
These bands of snow showers should gradually wind down from west
and northwest to southeast over the next 2 to 4 hours.
UPDATE Issued at 758 PM EST SUN
JAN 19 2025
Hourly grids have been updated based on recent observations and
trends. Snow showers and some embedded squalls continue to move
across the area with the squalls generally across the central
portion of the CWA at this time. SPS products have been used for
these as these have been reducing visibility and putting down a
coating to a half of an inch. Lighter snow showers and flurries
linger to the west and northwest over central and northern KY. For
now will continue to let the winter headlines ride as they are,
but will evaluate through the remainder of the evening for
potential cancellations for some locations later in the evening
pending trends of snow showers and squalls.
&&
.SHORT TERM...(This evening through Monday night)
Issued at 430 PM EST SUN JAN 19 2025
20Z sfc analysis shows a fairly deep area of low pressure well
east of Kentucky now. This is encouraging an arctic front to push
deeper into the area along with persistent northwest to north flow
over the terrain of eastern Kentucky. This means upslope flow
continues late this afternoon - likely enhanced to some extent
from a fetch off of Lake Michigan - as the steadier snow has
transitioned to showers and a potential for snow squalls. The
radar returns have become more cellular this afternoon with that
transition. Outside of the better returns, flurries and light snow
continues most places. The chill of the day will get worse as
temperatures peaked near freezing early and have fallen to the mid
and upper 20s with northwest winds of around 10 mph and gusts to
near 20 mph
- cruelly adding to the chill. Meanwhile, dewpoints are falling
and now range from the mid teens north to the low 20s south. The
Winter Weather Advisories and Winter Storm Warnings will continue
at least past sunset when the snow squall potential starts to drop
off from west to east. One caveat is that the current wet treated
and untreated roads will be prone to icing up again as
temperatures drop into the teens and lower tonight.
The models, and their individual ensemble suites, are still in
excellent agreement aloft through the short term portion of the
forecast. They all depict the initial southern extent of a very
large trough swinging through eastern Kentucky this afternoon with
its 5h axis and the largest height falls passing currently. Fast
west to northwest flow follows with most of the energy staying
north of the Ohio River into Monday. However, the main trough axis
and better energy with it does gear up Monday night to the
northwest of the area setting up for a run at the area on Tuesday.
The still quite small model spread aloft made the NBM a reasonable
starting point for the forecast grids, though with some
adjustments per the latest radar trends, CAMs guidance, and
typical snow climatology for PoPs and Snow Amounts through
tonight.
Sensible weather features our coldest night of the year even with
clouds and snow/flurries lingering through the area for much of
it. As a result, we are continuing with the Cold Weather Advisory
through noon Monday with -5 to -10 wind chills likely for much of
the area for a time tonight. The snow winds down this evening for
most of the area with lingering accumulations in the higher
terrain and for any squalls/bands that continue after dark.
Flurries will linger until the clouds basically break up late
tonight from northwest to southeast. Plenty of sunshine on Monday
will be ineffectual at raising temperatures much in the parked
arctic air mass and high pressure keeping readings from climbing
out of the teens for most of the area. Normally, we would then be
looking at bitter cold temperatures that night into Tuesday
morning, but thankfully it appears that clouds will swoop in from
the southwest in fast flow aloft to keep the radiational cooling
to a minimum and it may turn out to be the milder of these nights
to start the new work week. In fact, would not be shocked to see
some flurries sneak out of the lower deck of these clouds around
dawn, Tuesday.
The changes to the NBM starting point consisted primarily of
tweaking the PoPs and QPF/Snow Amounts per the latest radar trends
and CAMs guidance but also with hand adjustments on account of
the climatological upslope snow norms. Temperatures were kept on
the cool side of the NBM PDF through the period, except Monday
night.
.LONG TERM...(Tuesday through Sunday)
Issued at 500 PM EST SUN JAN 19 2025
There remains very good model agreement regarding a mostly
amplified long wave pattern to control through Thursday, with deep
troughing remaining in place across the middle of the CONUS.
Thereafter, the models start to diverge, particularly by this
weekend, as the long wave pattern transitions to more of a split-
flow. The GFS has more influence from the southern stream across
the Ohio and Tennessee valleys, while the ECMWF brings another
reinforcing shot of northern stream influence. As such, have not
strayed far from the blended approach to the forecast, with low
confidence in precipitation chances by the end of the week, given
the model spread.
Mostly cloudy skies and perhaps a few flurries will be seen across
the area through Tuesday evening, as a short wave trough moves in
from the west. Models, especially the GFS, have backed off on the
intensity of the wave and associated depth of moisture compared
to yesterday. Temperatures will struggle into the teens and 20s
for highs. As clouds clear out late Tuesday evening, some sub-
zero valley temperatures will likely occur, as winds go calm over
the existing snowpack. Temperatures will gradually modify, but
will still range from 10 to 20 degrees below normal through
Friday, with another chance of flurries returning by that time.
Have continued to stay well below blended guidance in the valleys
during the overnight periods, with at least single digits still a
good bet Wednesday night, and then modifying to the 10 to 15
degree range by Thursday night. Near normal temperatures actually
look to return by the second half of this weekend, with the next
better chance of precipitation threatening by Sunday, with plenty
of uncertainty surrounding the details.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
ISSUED AT 1235 AM EST MON JAN 20 2025
Several snow bands exist across eastern Kentucky to the east of
Interstate 75 to begin the TAF period. These bands will primarily
impact KSJS and KJKL before diminishing before 12z this morning.
Within these bands, IFR and lower conditions are occurring with
locally intense snow. Outside of the snow bands and snow showers,
cigs are either low-VFR or high-MVFR, and a general improving
trend toward clearing skies from west to east and south to north
is expected through the daytime hours today.
West to northwest winds will remain quite gusty at 7 to 10 KT
sustained with gusts nearing 20 kts at times, especially within
any snow bands. These winds will gradually begin slackening to
around 5 KT from the same direction toward 12Z. Winds should
trend more westerly at about 5 KT to end the period.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
Cold Weather Advisory until noon EST today for KYZ044-050>052-
058>060-068-069-079-080-083>088-104-106>120.
Winter Storm Warning until 2 AM EST early this morning for
KYZ060-107>109-111-112-115.
Winter Weather Advisory until 2 AM EST early this morning for
KYZ086-087-106-114-116.
Winter Storm Warning until 3 AM EST early this morning for
KYZ088-110-113-118>120.
Winter Weather Advisory until 3 AM EST early this morning for
KYZ117.
&&
$$
UPDATE...CMC
SHORT TERM...GREIF
LONG TERM...JKL
AVIATION...CMC
Source: JKL issues Area Forecast Discussion (AFD) at Jan 20, 12:36 AM EST (https://mesonet.agron.iastate.edu/p.php?pid=202501200536-KJKL-FXUS63-AFDJKL)
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