536
FXUS63 KJKL 181925
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
325 PM EDT Tue Jun 18 2024

.KEY MESSAGES...

- Hot weather persists through the week. Afternoon heat indices
  may peak around 100 at some locations. A few thunderstorms will
  be possible into the evening, otherwise it will be dry through
  Friday.

- The upper level high/ridge bringing our heat wave will weaken
  next weekend and allow a cold front to move into the area,
  possibly bringing thunderstorms Sunday and Monday.

&&

.SHORT TERM...(This evening through Wednesday night)
Issued at 325 PM EDT TUE JUN 18 2024

18Z sfc analysis shows a moderately strong area of high pressure
holding forth over the East Coast and stretched west back into
Kentucky. This has made for light winds throughout the area along
with a continuing bout of heat and humidity. However, it is not
strong enough to suppress all convection for the area with
scattered showers and storms popping up south of the JKL radar.
Plenty of cu also developed this afternoon beneath some high
clouds and this has helped to keep temperatures from maxing out
too high. As such, readings currently are running in the upper 80s
to low 90s most place while dewpoints are sticky in the low to
mid 70s - resulting in heat indices for many places reaching from
95 to 100 degrees. A few of the storms into the evening could
become strong with damaging wind gusts the main threat - but most
locations will be dry.

The models, and their individual ensemble suites, are in very
good agreement aloft through the short term portion of the
forecast. They all depict a burgeoning 5h ridge to the east of
Kentucky with a rising heights regime through the the end of the
week. This will effectively shield the state from the affects of
mid level southwest flow and any impulses that will pushed by to
the northwest of the JKL CWA - most notably an elongated one that
passes tonight into Wednesday morning. After this one goes by the
state, the heart of expansive 5h ridge will further extend over
this part of the state into Thursday morning. The model spread
through the short term is quite small so the NBM was used as the
starting point for the short term grids with little deviation
aside from the incorporation of some minor terrain distinctions
for temperatures tonight and Wednesday night. The latest CAMs runs
were also incorporated into the near term PoP grids through the
evening.

Sensible weather features hot and mostly dry weather continuing
through Thursday morning as the suppressive effects of the
dominant eastern ridge impacts eastern Kentucky. This will mean
highs in the low 90s for most with somewhat drier dewpoints around
on Wednesday keeping the heat index a bit lower than those of
this afternoon - just shy of 100 degrees. At night, temperatures
will be coolest in the sheltered valleys - but even then not fall
out of the mid to upper 60s - providing only a little relief.
Also, radiational fog will be found in the river valleys each
morning - particularly spots that manage to pick up rain from
scattered convection through this evening - mostly northeast of
the Cumberland Valley.

The main changes to the NBM starting point consisted of adjusting
the temperatures in order to better reflect terrain details
tonight and Wednesday night. PoPs were nudged up through the
evening in accordance with radar trends and the latest guidance
from the CAMS.

.LONG TERM...(Thursday through Tuesday)
Issued at 244 PM EDT TUE JUN 18 2024

Persistent upper-level ridging will surface high pressure over much
of the eastern CONUS through much of the long-term forecast period.
Temperatures are expected to continue to be in the 90s with heat
indices approaching 100 degrees. Starting on Thursday, the forecast
597 decameter high will be overhead with easterly flow at the
surface. This dry easterly flow will keep moisture to a minimum on
Thursday which would also keep heat indices relatively lower for
Thursday and Friday. This lack of moisture will more than likely
limit the potential for isolated showers and thunderstorms.

The surface high will gradually begin to shift to the east and as
that occurs, increasing moisture is expected. Also, to the
northwest, a shortwave trough is forecast to dive out of central
Canada into the Great Lakes. This upper-level shortwave and surface
low will increasing surface moisture ahead of a cold front that`s
forecast to dive toward the Commonwealth on Sunday. As for Saturday,
the potential hottest temperatures of the period are expected. Heat
indices are still expected to remain below 100 degrees thus likely
not going to issue head headlines for the weekend but caution should
still be exercised will doing outdoor activities.

The aforementioned cold front is forecast to continue to dive
southeast toward the Commonwealth through the day Sunday. However,
with moisture continuing to be a lacking phenomenon, the overall
strength of the front will be limited. Can`t rule out a few
thunderstorms with FROPA. Models have the boundary slowing down and
stalling out across the CWA which will help to keep enough lift in
place to favor precipitation into Monday. A reinforcing upper-level
wave for Tuesday will bring increased and more widespread showers
and thunderstorm chances for the end of the period. Otherwise, the
area will continue to see high temperatures in the low to mid-90s
with overnight lows in the mid-60s to low-70s and isolated to
scattered thunderstorms each day minus Thursday and Friday.

&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
ISSUED AT 145 PM EDT TUE JUN 18 2024

Scattered convection can be expected into the early evening hours
today, though confidence is low as to specific timing and location
of any storms. Given this nature, just going with VCTS for the
northeast sites, at this time. Winds will average less than 5 kts
through the period. The typical valley fog is likely late
tonight - only impacting any TAF sites if/where rain occurs
through this evening.

&&

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

$$

SHORT TERM...GREIF
LONG TERM...VORST
AVIATION...GEOGERIAN/GREIF