JKL issues Area Forecast Discussion (AFD) at May 13, 1:12 AM EDT558
FXUS63 KJKL 130512
AFDJKL
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
112 AM EDT Tue May 13 2025
.KEY MESSAGES...
- Shower/storm chances linger for much of this week, especially
each afternoon and evening.
- Temperatures are forecast to be near normal through Wed, then
moderate to about 10 degrees above normal on Thu and Fri - back
closer to normal from Sat through Mon.
&&
.UPDATE...
Issued at 112 AM EDT TUE MAY 13 2025
Anticipate isolated to scattered showers through the remainder of
the overnight as a weak surface trough, emanating from the nearby
upper low, pivots through eastern Kentucky. Model soundings do
indicate some weak instability overnight, so a rumble of thunder
cannot be ruled out in the strongest cells. Rainfall could also be
briefly heavy with any thunderstorms. Fog and low clouds will
linger through the early morning at many locales.
UPDATE Issued at 1000 PM EDT MON MAY 12 2025
Shower coverage is diminishing late this evening. Once the ongoing
activity tapers, expect a mainly rain-free overnight outside a
few isolated to widely scattered showers. Fog has already
developed at many locations over eastern Kentucky as the rain has
diminished and anticipate that fog coverage will increase
overnight, especially where skies partially clear. Fog mention was
added to the forecast in most areas through the remainder of the
night.
&&
.SHORT TERM...(This evening through Tuesday night)
Issued at 255 PM EDT MON MAY 12 2025
A large, slow moving, closed, upper low is centered over the
lower Mississippi Valley this afternoon. Its long, spiraled inflow
of subtropical moisture is flowing over east KY, resulting in
showers and thunderstorms for our area. Somewhat drier mid/upper
level air is wrapping north northwestward into the system, and
this has been enough to cut off the widespread precip, with this
drying trend now entering the JKL forecast area from the west
southwest.
Models are in relative agreement for the big picture through the
short term. Where smaller scale differences exist, a model blend
will be used to hedge the uncertainties. The upper low center
will crawl northeast to the vicinity of OH by the end of Tuesday
night. As this happens, its diminishing dry slot will progress
across the JKL forecast area tonight and allow most of the precip
to taper off, especially as whatever weak instability there is
gets weaker with loss of daytime insolation.
The mid/upper level drying will mostly be refilled in with
moisture again on Tuesday, and with diurnal warming
destabilization beneath the upper low, showers/thunderstorms are
again expected to develop. This is followed by another diminishing
trend with loss of heating on Tuesday night.
.LONG TERM...(Wednesday through Monday)
Issued at 435 PM EDT MON MAY 12 2025
The models, and their individual ensemble suites, are in pretty
good agreement aloft through the bulk of the long term portion of
the forecast. They all depict the opening of a broad trough
over the Ohio Valley on Wednesday while the system progresses to
the northeast through the rest of the week. This is upstream of
ridging sliding east and expanding over the central Gulf Coast
through Thursday. Meanwhile, a sharp trough will pivot through the
Upper Midwest encompassing the majority of model differences for
this period. The GFS suite is quicker, stronger, and further north
with the core of this trough than the ECMWF's operational and
ensemble runs. As this large wave passes it will bring 5h height
falls to Kentucky along with a brush by of its mid level energy
late Thursday into Friday. For the weekend, broad troughing will
hold forth over the Upper Midwest, northern Great Lakes, and south
central Canada while ridging is parked over the Gulf of America.
Between these dominant features, mid-level zonal flow will work
west to east through Kentucky while carrying periodic impulses.
Toward the end of the weekend, the Gulf ridge will reassert its
presence in the Deep South and push toward Kentucky. This brings
rising 5h heights to the JKL CWA along with northwest mid level
flow and just some weak impulses until perhaps later Monday. The
model spread supported using the NBM as the starting point with
minimal adjustments needed through the period - mainly to include
some radiational cooling based terrain distinction in temperatures
at night over the weekend.
Sensible weather features a damp start to the long term portion of
the forecast as a stacked and weakening sfc low will be lifting
into the Ohio Valley at mid week. Limited drying will follow that
night into Thursday, though a stronger system will be approaching
from the northwest and may send a band of showers and storms into
the state late in the day. A concern will be for more organized
convection that night and on Friday night as the best upper
support pass by to the northwest. Unfortunately the system's cold
front will stall nearby on Friday night with a potential for
additional storm clusters keeping the PoPs fairly high through
Saturday morning. Weak high pressure and more distinct drying
does follow for late that day and at night. This will allow for
more of a ridge to valley temperature split that night and again
Sunday night before a better chance of showers and storms arrive
on Monday. Given the uncertainty with the pattern have carried a
chance for showers and/or storms each afternoon through the
weekend - but lowest threat and best chances for a dry afternoon
will be on Sunday. Likewise, temperatures will have a larger
potential spread through the weekend with the drier scenario
favoring the higher highs.
The changes to the NBM starting point consisted primarily of
adding terrain distinction to the temperatures for Saturday and
Sunday nights. As for PoPs - did not deviate from the NBM
solution given the fairly similar model clusters and net results
for this part of the area.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
ISSUED AT 112 AM EDT TUE MAY 13 2025
Widely varying flying conditions can be expected overnight as areas
of low stratus and fog develop. A passing weak surface trough,
associated with the nearby upper level low, will keep the the
threat of isolated to scattered showers in the forecast overnight,
which could cause brief variation from the prevailing conditions.
After any fog/low stratus dissipates on Tuesday morning, ceilings
should improve to VFR. However, shower and thunderstorm activity
is likely to increase again with diurnal heating, producing MVFR
conditions or worse at times. Winds will be light through the
period.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...GEERTSON
SHORT TERM...HAL
LONG TERM...GREIF
AVIATION...GEERTSON
Source:
JKL issues Area Forecast Discussion (AFD) at May 13, 1:12 AM EDT---------------
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