429
FXUS63 KJKL 271908
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
308 PM EDT Thu Jun 27 2024

.KEY MESSAGES...

- Hotter weather is expected to make a comeback on Friday and
  Saturday, and may now extend into Sunday, with afternoon highs
  around 90 or in the low 90s and heat index values peaking around
  or in excess of 100 degrees.

- A cold front will likely bring additional rain to the area from
  late Saturday into Sunday. Any storms on Saturday afternoon and
  evening could produce strong wind gusts and heavy rain.

- Another shorter-lived cooldown is anticipated for early next
  week followed by a mid week warm up. Heat indices may reach or
  exceed 100 degrees once again Wednesday of next week.

&&

.SHORT TERM...(This evening through Friday night)
Issued at 308 PM EDT THU JUN 27 2024

Differential heating boundary is slowly moving south toward the
Tennessee and Virginia borders. However, this activity is tapping
into some remaining weak instability and moisture, resulting in
isolated showers. Cannot rule out an isolated thunderstorm or two
south of the Hal Rogers Parkway/KY Highway 80 through this
afternoon, but overall the trend through the rest of today will be
for drying and clearing skies.

Heading into tonight, a dry air mass settles over the area under
surface high pressure, with some residual low-level moisture
remaining along the Tennessee border area. This will support fog
formation in the typically foggy sheltered river valley locations
tonight into Friday morning, with lower confidence in fog
formation elsewhere. Lows will generally be in the mid-60s, but a
few 50s are possible in the cooler sheltered valleys.

For Friday, east-west ridging across the Upper Tennessee Valley in
the upper levels is expected. However, a weak mid-level low over
the Deep South will weaken into an open trough and begin moving
toward the area. This will allow for moisture to stream north
across eastern Kentucky through the day. Sufficient moisture and
instability will exist for isolated to widely scattered shower and
thunderstorm activity in the afternoon, with continued low-end
chances (20 to 30 PoPs) into the evening and overnight as a low-
level jet develops and pushes additional moisture north into the
area. This will make the low temperature forecast tricky for
Friday night into early Saturday morning. However, with the warm
advection and moisture transport into the area expect lows to
remain elevated especially on the ridgetops and Bluegrass
locations where lows may remain in the 70s, with some sheltered
valley locations possibly falling to as low as the mid-60s,
especially if there is sufficient clearing despite the increasing
warm advection.


.LONG TERM...(Saturday through Thursday)
Issued at 217 PM EDT THU JUN 27 2024

The forecast period will begin with southerly flow ahead of an
approaching shortwave. This upper-level feature is tracking through
the Upper Great Lakes. A trough pivoting into the Upper Midwest into
the Great Lakes will push a surface low through the region as well.
Extending southwest from the low a cold front will extend from the
Great Lakes toward the Commonwealth. Locally, surface high pressure
will be in place and will advect warmer temperatures and Gulf
moisture into the region. Highs for Saturday will be climbing into
the upper-80s to low-90s with heat indices approaching the 100
degree mark. As the front approaches the region, increasing showers
and thunderstorms are possible through the day Saturday. The SPC has
placed the entire CWA under a Day 3 Marginal Risk for severe weather
as forecast soundings ahead of the boundary show decent severe
weather indices. Instability, steep lapse rates and high PWs are in
place but the main ingredient lacking is sufficient shear to produce
and maintain severe storms. Also, if there`s widespread cloud cover,
instability value will remain meager and thunderstorms will become
more limited. However, with PWs over 2.00", an efficient shower
could put down some decent rainfall. Showers and storms continue
into Saturday night through Sunday before the front passes mid-
Sunday morning through Sunday afternoon.

Height rises and surface high pressure will begin to nudge back into
the region for Sunday night. A pretty decent temperature drop is
expected for Monday as highs and dewpoints drop 10-15 degrees making
it rather comfortable going into next week. However, this is short-
lived as a forecast 594 dm dome of high pressure builds in overhead.
This will allow for temperatures to climb back into the upper-80s to
low-90s and a return of heat indices approaching 100 degrees. This
pattern will remain in place through early Wednesday before another
shortwave dives out of the Upper Midwest. The shortwave is forecast
to track easterly with a cold front diving southeast into the
Commonwealth and bring another round of showers and thunderstorms
for the end of the forecast period.

&&

.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
ISSUED AT 138 PM EDT THU JUN 27 2024

At TAF issuance, VFR conditions were occurring under clearing
conditions from earlier cloud cover, with MVFR conditions and
light rain over far southern parts of the forecast area south of
KLOZ and KSME. High pressure continues to build over the area and
is bringing drier conditions, resulting in cig bases rising to
above 040. Winds are expected to be light and variable through the
period. Valley fog with IFR or MVFR reductions is expected to
develop between 04Z and ~12z, and this could lift into or affect
a couple of the TAF sites, though confidence in this is low at
this time. The latest statistical guidance is mixed on fog
development tonight, but is most aggressive at KLOZ tonight.
However, will pass on mentioning fog for late tonight with this
TAF package pending newer (and hopefully more consistent) model
guidance.

&&

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

$$

SHORT TERM...CMC
LONG TERM...VORST
AVIATION...CMC