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000
FXUS63 KJKL 170900
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
500 AM EDT Wed Apr 17 2024

.KEY MESSAGES...

- Chances for showers and a few storms are in the forecast through
  tonight, and also Thursday night into Friday evening. Chances
  peak today and this evening when the strongest storms are
  possible.

- Well above normal temperatures will be in place over the area
  through Thursday, with readings peaking in the upper 70s to low
  80s each day, or about 10 degrees above normal. Cooler weather
  follows for the weekend.

&&

.SHORT TERM...(Today through Thursday)
Issued at 500 AM EDT WED APR 17 2024

08Z sfc analysis shows Kentucky between a deep area of low
pressure to the northwest while high pressure is well off to the
southeast. This is keeping a somewhat tight pressure gradient
through the area making for a well mixed boundary layer and winds
from the south to southwest at around 10 mph with occasional gusts
to 20 mph. The result is a very mild night with temperatures
holding in the low to mid 70s most places though a couple of the
most sheltered spots in the east have decoupled into the lower
60s. Meanwhile, under mostly cloudy skies with a few patches of
light showers around, dewpoints have managed to dry out down to
the mid and upper 40s for the majority of the obs sites. We will
see mainly light showers work into the area from the west through
the first part of the morning likely weakening and dissipating as
they arrive. The more robust of these showers may also bring down
some stronger wind gusts in the 30 to 35 mph range.

The models, and their individual ensemble suites, remain in very
good agreement aloft through the short term portion of the
forecast. They all depict a weakening closed low trough lifting
northeast through the northern Great Lakes and brushing by
Kentucky today. This has already led to 5h heights falling this
morning and continuing into the afternoon as the core energy with
the trough moves by to the north - beefiest this afternoon
cutting east through Ohio. The mid level flow then flattens out
this evening before influence from ridging over the Gulf pushes
heights back up over the area into Thursday - also out ahead of a
very large trough grinding through the Northern Plains and into
the Upper Midwest by that evening. This will have the effect of
tilting the flow more southwesterly for eastern parts of the
state by late day, Thursday. Due to the continued rather small
model spread, the NBM was used as the starting point for the
grids, though along the addition of CAMs guidance for the PoPs
through tonight.

Sensible weather features another breezy and warm day - but a
touch cooler than the past few on account of extra cloudiness and
a period or two of showers. Most of the CAMs suggests that the
morning activity will fade out by afternoon hindering the column`s
destabilization and recovery. So that, despite a promising set up
for storms, the question of initialization remains the biggest
issue for our late day convection chances. As such, eastern
Kentucky will have a conditional threat of severe storms should
instability build enough with daytime heating and a trigger
mechanism develops. The most likely severe scenario is for a few
storms to redevelop late in the day for northern parts of the area
either along a sagging cold front or on any thunderstorm outflow
boundaries that may push in from the north later this evening.
Given the limited model support the specifics of the forecast
remain uncertain but the potential is there for a more stormy
evening than currently depicted. Once any activity fades out
later tonight we will likely be in a dry lull through most of
Thursday ahead of the next system approaching from the Plains.
This will also mean more sunshine and a rebound in high
temperatures - back into the low to mid 80s.

The main adjustments to the NBM starting point were centered
around incorporating the consensus CAMs ideas for PoPs and pcpn
timing today through tonight and accounting for the conditional
threat of storms this evening. Again only made some minor
adjustments to temperatures based on terrain tonight as well as
taking highs up a notch today.

.LONG TERM...(Thursday through Tuesday)
Issued at 417 PM EDT TUE APR 16 2024

The period begins with the mid-level short wave toward the
Midwest and a surface low developing and moving northeast along
the cold front toward the Midwest. Meanwhile, in the Ohio Valley
ensembles and deterministic guidance show good indication of mid-
level height rises and warm front lifts northward as the
previously mentioned low tracks northeast. Given the rising
heights and mostly sunny skies we will see afternoon high
temperatures soar into the upper 70s to lower 80s on Thursday,
with ensembles showing about a 30 to 40 percent chance of greater
than 80 degrees for highs. The 80s don`t seem to hard to achieve
given the ensemble and deterministic forecast soundings showing
dry lower level. Then unsettled weather moves east, as guidance is
in good agreement on the front advancing eastward Thursday night
into Friday. This will lead to a 70 to 80 percent chance of rain
Thursday night, with about a 20 to 40 percent chance of
thunderstorms. There is some question as to how much instability
we can maintain through the evening and overnight that leads to a
fair amount of uncertainty on if we could see a stronger storm.
The shear isn`t the best, but effective shear is still around 30
to 35 knots which could lead to some organization. SPC does have a
portion of the CWA in the marginal risk and that seems reasonable
given the fair amount of uncertainty.

Friday, the cold front will advance eastward across eastern
Kentucky by Friday afternoon, as a high pressure noses eastward
from the Plains. The winds will veer from the southwest to
northwest through the day. The chances of rain through the
afternoon will be around the 60 to 80 percent range. This cold air
advection, clouds, and rain early in the day will lead to highs
in the upper 60s to lower 70s. The showers and perhaps
thunderstorm could extend into the evening, but this should tapper
off quickly into the 20 percent range. This as high pressure
continues to nose east into the Ohio Valley and will lead to dry
weather through Saturday night. The question in terms of frost
would be if we can clear out enough or long enough Saturday night.
Given this opted to keep out of the grids for now.

The ensembles and deterministic begin to diverge a bit on a
southern stream system by Sunday. The NBM keeps a small chance of
PoPs in the far southeast, but some guidance suggest it will be
dry Sunday and even if most of the CWA will remain dry. Then high
pressure finally builds east across the Ohio Valley and a
shortwave advances southeast into the Lower Ohio Valley where
guidance seems to have better agreement. Once again, we could see
a few 30s in the more sheltered valleys, but uncertainty remains
on if we could see cloud cover. Then yet another mid-level wave
advances east By Tuesday, but once again ensembles and
deterministic diverge, so stuck with slight chance values from
the NBM generally in northeast Kentucky.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
ISSUED AT 200 AM EDT WED APR 17 2024

For the most part VFR conditions will prevail through the TAF
period. There will be a small chance for a showers and perhaps a
few storms early this morning, with this initial batch of
activity weakening and dissipating as it moves across the aviation
forecast area. Additional storms will be possible later this
afternoon and evening but confidence in timing and location is
low. Winds will be southerly in nature, generally around 10 kts
with occasional higher gusts to near 20 kts, particularly during
the morning and through the afternoon. Some LLWS will also be
around into dawn - generally from the south to southwest at 40 to
45 kts.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...GREIF
LONG TERM...DJ
AVIATION...CMC/GREIF