260
FXUS63 KJKL 170729
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
329 AM EDT Wed Jul 17 2024

.KEY MESSAGES...

- Showers and thunderstorms will impact the region through early
  next week, with the highest probability and greatest coverage
  today.

- Some minor flooding of low-lying areas will also be possible
  through this evening, if storms pass repeatedly over the same
  locations.

- A welcomed relief from the heat follows for Thursday through the
  middle of next week, with afternoon high temperatures in the
  upper 70s to lower 80s.

&&

.SHORT TERM...(Today through Thursday)
Issued at 328 AM EDT WED JUL 17 2024

The models are in very good agreement through the short term
regarding the upper level pattern and surface patterns. The trough
will shift southeast with time, occupying the northeastern portion
of the CONUS by early Thursday and spreading 500 mb height falls
across the Ohio and Tennessee valleys today through Thursday. The
surface cold front will gradually ease southeast, moving through the
Commonwealth primarily late this afternoon through the overnight
tonight. This will result in an active period of showers and
thunderstorms across eastern Kentucky, providing beneficial rainfall
to much of the area.

A large MCS continues to push east and southeast across much of the
Commonwealth early this morning. CAMS and SPC Mesoanalysis depict
meager instability over areas mainly north of the Mountain Parkway,
with greater instability towards the KY-80/Hal Rogers Parkway
corridor, especially along and west of Interstate 75. Would thus
expect new convection to develop at times along and ahead of the
current MCS activity and impact southwestern and southern parts of
the forecast area the remainder of this morning. Meanwhile, to the
north of the Mountain Parkway would expect primarily rain with
embedded heavier showers owing to the weaker instability this
morning.

By afternoon, the cold front will be moving southeast across the
northern part of the forecast area. Any partial clearing along and
to the south of the front will destabilize the atmosphere and
allow for development of additional showers and thunderstorms.
Much of the rain will be beneficial, but will need to monitor for
training of the heaviest cells over any one area which may result
in some localized flooding issues in low-lying areas. With the
high humidity and cloud cover today, highs will be much cooler
than in recent days, with highest temperatures in the south where
clouds and convective activity may be able to hold off the
longest.

Convection will gradually diminish from northwest to southeast
Wednesday night with the loss of heating and as the front eases off
to our southeast. Lows will range from the mid to upper 60s.

For Thursday, despite the front stalling well to the southeast of
the region, the trailing upper trough will be moving southeast
across the Ohio River Valley in the afternoon and early evening.
Despite cooler surface temperatures, residual moisture and
instability from steepening lapse rates aloft will result in a
continued chance for afternoon showers and thunderstorms across
the southeastern half of the forecast area. Temperatures will
only reach the upper 70s to lower 80s across the area with cool
dry air advecting in with surface high pressure nosing into the
area from the north behind the cold front.


.LONG TERM...(Thursday through Tuesday)
Issued at 345 PM EDT TUE JUL 16 2024

The period will begin much cooler than of late, as there is good
agreement in the ensembles and deterministic guidance that mid-level
ridging breaks down. At the surface, the guidance remains some what
uncertain just how far south the cold front gets, but will still be
much cooler and drier to begin the period from Thursday into Friday.
The uncertainty on the front will affect the far southeast the most,
with fairly low PWATs of only around an inch expected in these areas
that could lead to showers and perhaps a few thunderstorm mainly in
the afternoon and early evening Tuesday and Friday. Outside of
that far southeast areas PWATs will be below 1 inch and will lead
to much drier feel on Friday. The highs will top put in the upper
70s and lower 80s each day and this is about 5 degrees below the
climate normals for this time of year.

The ensembles and deterministic models show some height rises as
we move toward the weekend into early next week. However, it looks
meager as we see a mid-level low push toward the Midwest and the
Ohio Valley looks to get stuck in between these features. Given
this we will continue to see slightly below to near normal
temperatures through the weekend into early next week. We will
also be stuck on the periphery of the ridging and this should
open the door for a slightly more active pattern to possibly lead
to a few bouts of showers and thunderstorms through the period.
Even so, storm total QPF from Saturday into Tuesday is still
around a quarter of an inch in the Bluegrass to around and inch
near the Cumberland Valley. The afternoon highs will also remain
in the low to mid 80s as a result of more unsettled pattern and
cloud cover. Not to mention the 850 mb temperatures flat line in
the around 17 celsius range at best through the remainder of the
period. Right now peak area wide chances of rain will be Tuesday
at around 50-70 percent.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
ISSUED AT 115 AM EDT WED JUL 17 2024

VFR conditions prevail for the most part, though pretty much all
TAF sites will have at least brief periods of sub-VFR conditions
in and near showers and thunderstorms, especially from late
Wednesday morning into Wednesday evening, but also possibly at
times during the remainder of the early morning hours this morning
as a decaying convective system moves across parts of the area. The
reductions to MVFR or lower may be more widespread near KSYM
between 12Z and 18Z with anticipated greater coverage of
convection. Generally light and variable winds are expected
through 14Z outside of any thunderstorms, with southwest to west
winds thereafter at generally less than 10KT with higher gusts in
and near any storms. Winds should begin to shift to the northwest
upon frontal passage from northwest to southeast later this
afternoon through tonight. Fog will become at concern at most if
not all TAF sites, especially after 03z Thu.

&&

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

$$

SHORT TERM...CMC
LONG TERM...DJ
AVIATION...CMC