-- Discussion containing changed information from previous version are highlighted. --
289
FXUS63 KJKL 230746
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
346 AM EDT Sun Jun 23 2024

.KEY MESSAGES...

- The upper level ridge responsible for our current heat wave will
  move away from the region through Monday, allowing more
  unsettled weather to take hold across the state.

- An approaching cold front brings some much needed rain to
  eastern Kentucky Sunday afternoon and night. A few storms may
  approach severe limits on Sunday with damaging winds being the
  primary threat.

- Another round of showers and thunderstorms is expected from late
  Tuesday through Thursday, with the threat peaking during the
  day Wednesday.

&&

.UPDATE...
Issued at 1138 PM EDT SAT JUN 22 2024

Most cu dried up during the evening and skies have largely been
clear for a while. Based on obs/trends, have reduced sky cover
through the night.

UPDATE Issued at 509 PM EDT SAT JUN 22 2024

Greatest amount of shower activity (still not much) has developed
in the far northwest part of the area outside of original places
with a POP in the forecast. Have expanded a 20 percent POP area
wide for a few hours until things die down toward sunset.

&&

.SHORT TERM...
-- Changed Discussion --
(This evening through Sunday night)
Issued at 425 PM EDT SAT JUN 22 2024

19Z sfc analysis shows high pressure to the southeast of Kentucky
supporting relatively light winds and a continuation of the hot
and humid weather - likely currently peaking. The high has not
completely suppressed the convection over the area with a decent
cu field in place along with a few small showers developing that
have a potential for thunder. These will stick around the area
for the next few hours, amid a touch of haze. Temperatures are
peaking in the low 90s most places with dewpoints in the upper 60s
and lower 70s - yielding heat indices in the mid to upper 90s for
the majority while a few spots hitting 100 degrees.

The models, and their individual ensemble suites, continuing to be
in very good agreement aloft through the short term portion of
the forecast. They all depict strong ridging to the south of the
area retreating a bit to the southwest in the face of more energy
and troughiness moving through the Ohio Valley tonight through
Monday morning. The lead impulse associated with this passes by to
the northeast early Sunday with another going by during the
afternoon. As a result, 5h height falls work in from the north
tonight into Sunday with the best push arriving that night as a
more distinct shortwave crosses the eastern Great Lakes. The
model spread through the short term remains small so the NBM was
used as the starting point for the grids through Monday morning
with little deviation aside from the incorporation of some terrain
distinctions for temperatures tonight. Did also enhance the PoPs
on Sunday and Sunday night per the latest CAMs ideas.

Sensible weather features the heat wave holding on for one more
day before a passing cold front brings a chance for showers and
storms along with a slightly cooler and drier air mass. Until
that boundary arrives, we will have another very warm and muggy
night along with limited amounts of river valley fog. The front
then helps to kick off showers and thunderstorms through the area
later in the day, Sunday. CAMs suggest that peak heating will
contribute to storm development later in the afternoon into the
evening with a better wind field aloft allowing decent venting and
a potential for organization. In addition, the storm scale
dynamics of mergers could also contribute to strong storms with
damaging wind gusts as the main threat. The boundary continues to
settle through the area that night with a small potential for a
shower or storm into the night. Expect temperatures to not be
quite as warm Sunday night compared to tonight - as well as more
uniform.

The main changes to the NBM starting point consisted of tweaking
the temperatures in order to better reflect some limited terrain
details tonight. PoPs were adjusted on Sunday and Sunday night per
the latest guidance from the CAMS.

.LONG TERM...(Monday night through Saturday)
Issued at 346 AM EDT SUN JUN 23 2024

The forecast starts off with one of the few dry spells of the
extended period, as an area of high pressure passes over and upper
level heights are on the rise behind the exiting trough that will
impact us today. Dry weather is expected to remain in place through
the day Tuesday. However, KY will find itself in the return flow
backside of the passing high on Tuesday, allowing WAA into the
region. This will couple with good radiational heating, allowing
temps to rise to around or just above 90 degrees again by the
afternoon.

This pattern won`t continue past Tuesday, unfortunately, as another
upper level system passes into South-Central Canada Tuesday
afternoon. This will also result in a low pressure system in the
same vicinity, reaching the western border of Quebec by 0Z
Wednesday. From this system, a cold front will extend southwestward,
with showers and thunderstorms possible along it. This will make
it`s way into the state by Tuesday night, coupling with a
strengthening shortwave which will also be traversing the state late
Tuesday night and through Wednesday. While chance pops are expected
to begin infiltrating the CWA early Wednesday morning, the increased
energy of the shortwave, combined with daytime heating, will amplify
both pops and QPF during the afternoon Wednesday. Strong SW flow
just ahead of this frontal boundary will keep temperatures in the
low 90s for most locations, despite the clouds and rain.

Pops will continue into Wednesday night, slowly diminishing to the
east as the front and upper-level shortwave slowly transition away
from the state. Unfortunately they won`t be far enough away by
Thursday to not influence some continued precip chances, mainly in
the far SE. These should be mainly upslope flow and diurnally
driven, quickly diminishing by Thursday evening. Post-frontal temps
on Thursday will be a bit cooler than Wednesday, but still warm,
with highs in the mid and upper 80s.

Once this system finally exits Friday night, another round of high
pressure to our northeast will take hold. Models show generally dry
conditions then until Saturday, though the ECMWF and consequently
the NBM do try to show some pop up convection across the far eastern
CWA during the afternoon hours Friday. The current NBM only has it
impacting a couple counties for a few hours, but didn`t have the
confidence to remove it at this point, especially with one of the
models showing it. Again, during this spurt of high pressure, winds
will become more southerly and sunshine will be abundant, so
temperatures will easily climb back into the low to mid 90s on
Friday. Humidity will make it feel several degrees warmer still.

This SW flow and heat will only increase for Saturday, as yet
another system begins to approach the region. It will be very
similar to the mid-week system, with a surface low and upper level
trough passing across southern Ontario, and a cold front stretched
southwestward across much of the US. This front and associated
precip will move into the state Saturday night and continue into
Sunday. All the models also show generally isolated pop up
convection ahead of the system during the day Saturday as well.
Highs on Saturday will easily top the mid 90s in most locations,
with heat indices even higher.
-- End Changed Discussion --


&&

.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
ISSUED AT 148 AM EDT SUN JUN 23 2024

Valley fog will affect many of the typical warm-season fog prone
locations in southeast KY early this morning, but is not expected
to affect TAF sites. Scattered to numerous showers and thunderstorms
are forecast to develop for most of the area on this afternoon
and evening ahead of an approaching cold front and will bring
localized sub-VFR conditions. Wind will generally be variable at
less than 10 knots early this morning before picking up out of the
southwest by late morning and early afternoon with gusts to
around 20 kts.

&&

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

$$

UPDATE...HAL
SHORT TERM...GREIF
LONG TERM...JMW
AVIATION...GEERTSON