JKL issues Area Forecast Discussion (AFD) at Dec 11, 11:00 PM EST419
FXUS63 KJKL 120400 AAB
AFDJKL
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
1100 PM EST Wed Dec 11 2024
.KEY MESSAGES...
- Below normal temperatures continue into Thu night, before
warming to above normal this weekend into early next week.
&&
.UPDATE...
Issued at 1100 PM EST WED DEC 11 2024
Hourly grids were updated based on recent observations and radar
trends. A few low clouds linger across the region with few
flurries or light snow showers falling from them. Overall, sky
cover has been decreasing over the past couple of hours and if
trends continue, flurries may be able to removed from the weather
grids by midnight.
UPDATE Issued at 710 PM EST WED DEC 11 2024
Some adjustments were made to hourly pops and temperatures based
on recent observations and radar trends. Overall, this led to no
substantial changes. The SPS for snow showers and some embedded
squalls was extended for a couple of more hours over the more
southeastern counties.
&&
.SHORT TERM...(This evening through Thursday night)
Issued at 335 PM EST WED DEC 11 2024
The system responsible for the steady snow earlier to day has
departed to our east and northeast leaving eastern Kentucky under
partly to mostly cloudy skies. Temperatures range from the upper 20s
on the ridges in the far eastern counties up to the upper 30s and
lower 40s west of I-75 where there clouds have broken for some
sun. A few colder readings are noted at the highest elevations.
Regional radar imagery shows rain and snow showers over Central
Kentucky along a surface trough and 700 mb vort max. A secondary
cold front follows, extending from roughly Lake Superior southward
into the Ozarks.
The surface trough will be responsible for the next round of snow
showers across the Coalfields this evening. Model soundings are
supportive of convective showers with this activity. Surface
temperatures appear warm enough for a mix of rain and snow initially
in the vicinity of Lake Cumberland before wet-bulbing occurs.
Thermal profiles should support primarily snow elsewhere. Modeled
equilibrium levels are generally warmer than -20C but cannot rule
out a stray lightning strike if the most robust cells are able to
push sufficiently above the equilibrium level. The high-resolution
guidance shows this activity reaching the I-75 corridor around 5 to
6 PM and rapidly spread toward the US-23 corridor by around 8 PM
EST. For most locations, the activity should last for only an hour
or two. While the heaviest activity could be squally, other than
rapid changes in visibility and perhaps a few briefly slushy spots,
warm pavement temperatures should preclude impacts to highways
outside of the higher elevations near the Virginia border. BUFKIT
mixed-layer momentum transfer supports wind gusts up to 30 mph in
the strongest activity. Due to the convective nature of this
activity, snowfall amounts could vary over short distances but in
most cases should be a trace to one half inch. A few spots under
the heaviest snow showers could pick up closer to an inch. Expect
the snow showers to exit through Pike County by 10 PM EST. The
moisture-starved and decaying secondary cold front sweeps through
thereafter, but is not expected to produce much more than some
flurries, primarily over northeast Kentucky and also in the higher
mountains near the Virginia-Kentucky border. Temperatures will
drop into the 20s overnight at lower elevations. Fortunately, the
combination of sharply dropping dew points and continued
northwesterly winds of 5 to 10 mph (with higher gusts) should
evaporate most of the lingering moisture on roadways before it has
an opportunity to freeze. That being stated, still cannot rule
out a few slick spots where water is able to puddle or seep
through the night.
The remainder of the short-term period will feature quiet weather as
chilly high pressure ridging builds in and crests over the Ohio
Valley on Thursday afternoon/evening. The surface pressure gradient
begins to tighten as clouds increase again on Thursday night. In
sensible terms, this will set the stage for below normal
temperatures on Thursday and Thursday night with highs in the mid
30s to low 40s and lows in the upper 10s to upper 20s, respectively.
.LONG TERM...(Friday through Wednesday)
Issued at 450 PM EST Wed Dec 11 2024
The long term forecast period is defined by a progressive pattern
aloft, which will result in a noticeable warming trend and the
return of rain chances in the sensible weather forecast for Eastern
Kentucky. At the surface, this pattern is first reflected by a
staunch high pressure system to our Northeast in the Mid Atlantic
states. This high should keep things dry on Friday, although the
flow throughout the column will begin to adopt more southerly
components as the day progresses. As winds shift towards the south,
moisture return magnifies, and thicker cloud coverage increases
significantly headed into Saturday. Before then, the proximity of
the high should allow for efficient radiational cooling on Friday
night into Saturday morning. Expect highs in the mid to upper 40s on
Friday afternoon before ridge-valley temperature splits emerge
overnight. Ridgetops will likely rise to above freezing, but the
more sheltered valleys and the Bluegrass region is poised for one
more night below freezing.
Headed into the weekend, warm and moist air advection will allow
afternoon highs to rise into the Mid 50s. The attention at the
surface will shift from the aforementioned high pressure to a wave
cyclone ejecting into the Great Lakes region. A warm front
associated with it is expected to lift north across the Ohio River
Valley, firmly situating the commonwealth in the warm sector. Thus,
any precipitation that falls will be rain, and a soaking stratiform-
type rain appears likely from Saturday night into Sunday. Forecast
guidance is not particularly enthusiastic about instability with this
system, so impacts will be limited to wet roads.
A brief lull in the precipitation is possible as precipitation
tapers off into Monday morning, but the progressive nature of the
overarching pattern means that the next system will be on our
doorstep by Monday evening. The passage of another warm front will
situate us in the warm sector of another wave cyclone passing to the
NW, and widespread rain chances are in the forecast once again on
Monday evening into Tuesday. Given the persistence of SW flow, high
temperatures on Monday may rise to near 60 degrees. This second wave
cyclone will likely drag a more potent cold front into the area than
the first one, and their associated cloud cover will limit the
amount of diurnal cooling that occurs overnight. Lows on Saturday,
Sunday, and Monday night will be well above freezing and in the 40s.
Temperatures will not drop below freezing again until Tuesday night
and after the precipitation ends. Therefore, this long term forecast
package exclusively features liquid precipitation, a welcome relief
from the repetitive shots of cold air and snow chances that Eastern
Kentucky has seen in the last few weeks.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
ISSUED AT 718 PM EST WED DEC 11 2024
An are of snow showers and some embedded squalls associated with
a passing disturbance and cold front is crossing eastern KY at
this time. As these pass, these have been reducing ceilings into
the MVFR range and visibility down to IFR along with gusts as high
as 20 to 25KT for as much as an hour or two. These have largely
passed areas near KSYM, KLOZ, and KSME while short tempo groups
were used to handle these ceiling and visibility reductions and
accompanying gusty winds at KJKL and KSJS. The heavier snow shower
activity should exit into WV by 3Z, though spotty flurries are
forecast to linger for a few more hours though VFR should prevail
within this and continue to end the period. Winds will average
south to southwest at 5 to 10KT ahead of the snow showers and then
pick up to as high as 10 to 15KT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...GEERTSON
LONG TERM...MARCUS
AVIATION...JP
Source:
JKL issues Area Forecast Discussion (AFD) at Dec 11, 11:00 PM EST---------------
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