JKL issues Area Forecast Discussion (AFD) at Apr 15, 6:01 AM EDT109
FXUS63 KJKL 151001
AFDJKL
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
601 AM EDT Tue Apr 15 2025
.KEY MESSAGES...
- After a cool-down for today and Wednesday, warmer temperatures
will return and carry through the weekend.
- Frost development is possible in some locations tonight and
again Wednesday night.
- Shower and thunderstorm chances return to the forecast on
Saturday and linger through Monday.
&&
.SHORT TERM...(Today through Wednesday)
Issued at 505 AM EDT TUE APR 15 2025
08Z sfc analysis shows the cold front responsible for the severe
weather last night has cleared out of eastern Kentucky. High
pressure is now working into the area from the west attempting to
clear the clouds and end the lingering showers. It is also
bringing in a chillier and drier air mass on west to northwest
winds of 5 to 10 mph. Currently temperatures are running in the
low to mid 50s across the area. Meanwhile, dewpoints range from
the mid 30s northwest to the low 50s in the southeast.
The models, and their individual ensemble suites, are in good
agreement aloft through the short term period. They all depict the
slow rebound from a deep 5h troughing bottoming out through the
eastern Ohio Valley this morning. This system's trough axis
passes by 18Z along with its stream of mid level energy settling
through far southeast Kentucky this morning. 5h heights will then
start to rebound and gradually climb for eastern parts of the
state, though northwest mid level flow will be the rule aloft
through mid week. This process is briefly held up tonight when a
reinforcing node of the main 5h trough swings through the eastern
portion of the Ohio Valley - its own weaker mid level energy
stream brushing by to the northeast of the state into Wednesday
morning. 5h heights climb quicker in its wake through the day
Wednesday. The rather small model spread supported using the NBM
as the starting point with minimal adjustments through the period
- mainly to include more of a terrain distinction to the
temperatures tonight and drier afternoon RH today and Wednesday.
Sensible weather features cooler and drier conditions through the
period as lingering showers this morning taper to sprinkles and
end after sunrise. The clouds also break up to allow for a fair
amount of sunshine by afternoon, but the secondary troughing
aloft will likely mean more clouds around tonight. These clouds
will keep temperatures from bottoming out and should limit frost
production to just a few valleys in the western parts of the area.
After a cooler start to the day, look for Wednesday to be a
slightly milder one with lighter winds and more sunshine as a
weak area of high pressure works through eastern Kentucky.
The changes to the NBM starting point consisted primarily of
including more terrain distinction to the temperatures tonight and
tamping down the dewpoints/RH each afternoon though Wednesday.
PoPs were minimum from the model guidance and kept that way
though some sprinkles will be possible through tonight - mainly
just for our northeast counties as a secondary cold front works
through the area.
.LONG TERM...(Wednesday night through Monday)
Issued at 558 AM EDT Tue Apr 15 2025
The long term forecast period will be defined by a warming trend and
a shift towards a more active weather pattern. After one more night
of frost potential at the very beginning of the period, rising
midlevel heights and warm air advection will combine to yield
seasonably warm temperatures by the weekend. However, a series of
atmospheric disturbances will approach the region from the Plains in
this time frame, resulting in renewed rain chances. There remains
some uncertainty in the exact timing and positioning of the surface
frontal boundaries associated with these disturbances, which leads
to increasing model spread in the forecast guidance for Saturday and
beyond. However, the synoptic features governing this new weather
pattern generally favor above-average temperatures and multiple
rounds of showers and storms over the next seven days.
On Wednesday night, a surface high pressure system is forecast to
move out of the Tennessee Valley and towards Eastern Kentucky. The
overhead influence of this feature will yield mostly clear skies and
prime the atmosphere for efficient diurnal processes. In other
words, ridge-valley temperature splits are likely to develop on
Wednesday night into Thursday morning. Forecast MinTs atop the
ridges are expected to hover around the 40 degree mark, whereas
valley locations are likely to cool off into the 30s. Areas of frost
are expected to develop in the valleys as a result, likely with
greater spatial coverage than the night before.
Temperatures are expected to recover into at least the upper 60s on
Thursday afternoon under initially clear skies. As Wednesday night's
sfc high continues to propagate east in response to a building
midlevel ridge, surface flow should gradually veer towards a more
southerly orientation. The resultant warm/moist air advection will
push a warm front northeast through the commonwealth, leading to
increasing cloud cover on Thursday evening. The best precipitation
chances with this first frontal passage will remain displaced to the
west of the forecast area, largely due to the antecedent dry air in
Eastern Kentucky. However, the isentropically-induced increase in
cloud coverage will combine with persistent WAA to yield a milder
night with lows near 50 degrees area-wide.
With the warm front positioned north of the Ohio River and the
midlevel ridge axis directly overhead, Friday afternoon is poised to
be quite warm. Flow throughout the entire atmospheric column is
expected to strengthen and shift towards the southwest, leading to
increasingly effective warm air advection and more meaningful
moisture return. High temperatures are forecast to reach the upper
70s/near 80 on Friday afternoon under partly cloudy skies. This
means that Eastern Kentucky will be situated firmly within the warm
sector as a storm system ejects out of the Great Plains and into the
Greater Midwest overnight.
This system will drag a surface cold front into the Ohio River
Valley on Saturday. Precipitation chances accordingly spread from NW
to SE across the forecast area as the day progresses. Persistent
southwesterly surface flow favors another warm day with highs in the
70s, but increasingly cloudy skies could limit the amount of diurnal
heating that is realized. The area's positioning in the warm sector
and the increasing amounts of frontal lift could result in
thunderstorm development by Saturday evening. DESI joint
probabilistic ensemble guidance resolves a broad corridor of
favorable MUCAPE, CIN, and Shear parameters south of the cold front
on Saturday afternoon. The Storm Prediction Center has delineated
much of Kentucky in its Day 5 severe weather outlook, but it is
important to note that this is a conditional risk. The strength of
these storms will be dependent upon the evolution and lingering
effects of upstream activity on Saturday morning. Needless to say,
there is too much uncertainty to discuss specific hazard types or
timing at this moment in time. This is just something to monitor for
now, especially for those with outdoor activities or travel planned
this weekend.
The cold front responsible for Saturday's activity is likely to
stall out somewhere in the Ohio River Valley overnight as it loses
its upper level dynamic support. The exact positioning of this stall
is yet to be determined, and precipitation chances will remain in
the forecast on Sunday as a result. The stalled front will
eventually lift back to the north as a more potent, negatively-
tilted upper level trough ejects out of the Ozarks and into the
Midwest early next week. Eastern KY will once again be positioned
within the warm sector out ahead of this system, and the return to
SW flow throughout the column on Monday will set the stage for
additional shower and storms. The strength and orientation of this
second system's mid/upper level synoptics look more conventionally
supportive for organized convection than with Saturday's system, and
some of the long-range AI model guidance suggests that there could
be severe weather potential in Eastern KY on Monday. Because
Monday's set-up is partially dependent on the evolution of
Saturday's event, compounding degrees of uncertainty once again
preclude the discussion of specific details.
For now, expect multiple rounds of showers and thunderstorms in
Eastern Kentucky towards the end of the long term forecast period.
Temperatures should remain seasonably warm, but depending on where
the first boundary stalls, there could be significant north-south
gradients in the forecast. Expect afternoon highs in (at least) the
70s and overnight lows in the 50s/lower 60s through next Monday.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
ISSUED AT 155 AM EDT TUE APR 15 2025
As a cold front drops south across the area early this morning
showers and a few thunderstorms will be possible before the
boundary reaches the Virginia border by 08Z. MVFR or lower
conditions will be possible in the heavier convection until then.
Any lower CIGs will clear out shortly thereafter and then VFR
prevails for all areas through the end the period.
As the front sags south, winds will become more west to northwest
at generally 5 to 10 kts across the remainder of the area through
around 08Z. However, after sunrise, winds should increase into
the 10 to 15 KT range, on average, from the west to northwest by
14Z onward, with gusts into the 20 to 25 KT range. Winds then
begin to diminish by sunset.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GREIF
LONG TERM...MARCUS
AVIATION...JP/GREIF
Source:
JKL issues Area Forecast Discussion (AFD) at Apr 15, 6:01 AM EDT---------------
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