945
FXUS63 KJKL 251953
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
353 PM EDT Wed Sep 25 2024

.KEY MESSAGES...

- Showers and thunderstorms could result in heavy rain and
  isolated flooding through tonight.

- The remnants of tropical system Helene are forecast to bring a
  widespread, soaking rain event later in the week.

- Flash flooding could result from the remnants of Helene, but
  the potential may be limited by the quick movement of the
  system.

- High temperatures will average near normal the rest of the
  week.

&&

.UPDATE...
Issued at 1236 PM EDT WED SEP 25 2024

Hourly grids were freshened up based on recent observations and
radar trends. This led to only minor adjustments to temperatures
and dewpoints, while pops across the southeastern portions of the
CWA near the VA border were increased per radar trends as well as
trends of recent CAMS.

&&

.SHORT TERM...(Today through Thursday)
Issued at 608 AM EDT WED SEP 25 2024

A large upper low will drop slowly south from the mid Mississippi
Valley during the period, becoming more closed with time. Our flow
aloft will initially be from the southwest, still pulling deep
moisture over our area, and continuing showers/thunderstorms at
times for most places today and tonight. Clouds and precip will
limit destabilization today and keep the severe weather threat
much lower than on Tuesday.

As we move into the day Thursday, tropical system Helene moving
north through the eastern gulf will interact more strongly with
the mid latitude upper low to our west. Our flow aloft will turn
toward the southeast while low level flow sets in from the east.
Even though precipitable water is expected to increase to near 2"
by evening, the downslope wind components will probably work to
limit precip amounts until Helene gets closer in the long term
period.

.LONG TERM...(Friday through Wednesday)
Issued at 352 PM EDT WED SEP 25 2024

The forecast period begins with the area beginning to feel the
impacts from the remnants of Helene. The hurricane is expected to
make landfall on the Florida Panhandle Thursday evening and through
the overnight hours quickly track north-northwestward toward the
Commonwealth. By the start of the extended forecast window, the NHC
has Tropical Storm Helene moving up the spine of the Appalachian
Mountains but getting sheared apart by frictional forces from the
mountains. The bulk of the remnants are expected to take a hard
westerly turn to the northwest and fizzle out and get absorbed into
a cut-off upper-level closed circulation. However, before that
occurs, wind and rain will pound the entire CWA starting Thursday
night and persisting through Saturday morning. Total QPF through the
duration of Helene is expected to range from 1.00" to 1.50" along
the eastern mountains to upwards of almost 2.00" to 3.00" along and
west of the I-75 corridor. The easterly flow across the southeastern
mountains will create a rain shadow effect for counties along the
mountains and diminish overall QPF; however, the further away from
the mountains; the less impact rain shadowing has on the QPF. Near
high wind warning criteria winds are expected across the high
terrain of the eastern mountains with sustained winds approaching 20
mph in the lower elevations are expected through Friday evening.
Higher upper-level winds exist; however, with no widespread
convection or mechanism to translate those winds to the surface,
those winds will remain aloft. Through the evening Friday into
Saturday, Helene will drift west-northwest toward western Kentucky
and eventually be absorbed into a closed circulation that`s been
largely stationary all week.

After the merging of the closed circulation and the remnants of
Helene takes place, the closed circulation will continue to
aimlessly spin over the Commonwealth and keep persistent chances of
showers and thunderstorms through the weekend. Models continue to
remain in rather good agreement going into next week with the
circulation getting picked up by the mean flow and ejecting out of
the area by Monday morning but lingering PoP chances will exist
through the end of the period as an upper-level trough, moving
through southern Canada, drags a cold front through the region
Tuesday afternoon which will then usher in cooler and drier weather
for the middle of next week.

Overall, the forecast period will be highlighted by multiple rounds
showers and thunderstorms. The remnants of Helene will bring the
best chances through Friday afternoon before the closed circulation
keeps PoP through the middle of next week. Temperatures through the
period will remain rather seasonal as highs are forecast to in the
upper-60s to upper-70s. Overnight lows, will be warmer with the
approach of Helene but with the approach of a cold front on Tuesday,
cooler temperatures and fall-like weather will be in place for the
end of the period.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
ISSUED AT 221 PM EDT WED SEP 25 2024

A mixture of mainly MVFR and VFR was reported at issuance time,
though IFR was reported in and near some of the heavier showers.
Showers and storms are expected from time to time through the
period. The prevailing MVFR or lower should prevail the longest
nearer the VA border during the first 6 hours of the period. A
couple of hours of MVFR or lower ceilings are probable at the TAF
sites to begin the period with the exception of KSME. A general
deterioration to MVFR is expected from southeast to northwest
between 00Z and 12Z with some IFR while MVFR should generally
prevail for most areas from 12Z to 18Z. Winds will be light and
variable.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
High Wind Watch from Thursday evening through Friday evening for
KYZ087-088-118.

&&

$$

UPDATE...JP
SHORT TERM...HAL
LONG TERM...VORST
AVIATION...JP