283
FXUS63 KJKL 171758
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
158 PM EDT Tue Sep 17 2024

.KEY MESSAGES...

...Insert KEY MESSAGES Here or Use the Ones Below...

- A cool-down arrives today, with a warming trend expected
  through the remainder of the week.

- Shower chances taper off this evening.

- Additional shower (and possible thunderstorm) chances will
  occur through midweek.

&&

.UPDATE...
Issued at 120 PM EDT TUE SEP 17 2024

Continue to see moisture flow into the area from the east-
southeast. However, it is apparent in radar trends that the
better forcing is beginning to wane across the area and our more
significant patches of rainfall are just moving out of our western
zones at this time. CAMs suggest a decrease in activity through
the afternoon as well. Will continue with the current forecast
PoPs, generally 20-30% chance of rain for the remainder of the
afternoon. Was tempted to reduce afternoon highs just a bit, but
with a general waning of activity and realizing some brief, quick
upticks in temperatures where passing clouds have thinned,
believe will leave afternoon highs where they are at, and possibly
even tweaked them up a degree or so at a couple locations.
Updated zones and grids have been sent. No other changes to the
forecast package at this time.

UPDATE Issued at 1045 AM EDT TUE SEP 17 2024

Main changes to the forecast package for the mid morning update
were to PoPs. Kentucky mesonet is showing accumulating rainfall
across much of the area this morning, especially along and south
of the Mountain Parkway. Based on radar trends, it appears everyone
south of the I-64 corridor has a good chance to see some much
needed rain today as a series of bands of showers track east to
west across eastern Kentucky. No other major changes at this time,
though did freshen up the zones to capture some minor adjustments
made to second period as well. Will update the zones again at mid
day to remove morning references and to take a closer look at
afternoon high temps. Updated grids and forecast products have
been issued.

&&

.SHORT TERM...(Today through Wednesday)
Issued at 516 AM EDT TUE SEP 17 2024

Current radar trends show light rain entering the state out of
the southeast from an upper level low. Ceilings will continue to
lower throughout the day as the remnant tropical-like low
continues its progression westward. At current, measureable
rainfall has been observed at in Pike, Letcher, Knox, and Harlan
Counties, with 0.32 inches of rain being measured at Harlan since
midnight. 00Z Soundings showed PWAT values of 1.30 inches to the
east at RNK. This moisture will continue to advect into throughout
the morning and afternoon.

With lowering ceilings through the peak heating period expected,
high temperatures will be on the cooler side, ranging in the low
to mid 70s across eastern Kentucky. Clouds will remain through
the overnight, limiting radiational cooling, which is expected to
keep night time lows up a few degrees. Lows will generally range
in the lower 60s.

Wednesday, showers and an isolated thundershowers or two will be
possible, with a few hundredths to a tenth of an inch possible.
The highest amounts will likely be across the higher terrain of
southeast Kentucky. Highs are forecasted slightly warmer than
today, in the upper 70s, with a few spots sneaking into the lower
80s.

.LONG TERM...(Wednesday night through Monday)
Issued at 535 AM EDT TUE SEP 17 2024

The extended period is expected to begin with a broad are of upper
level low pressure over the eastern Conus from the Mid Atlantic
states to the Carolinas, a narrow upper level ridge centered in
northern Mexico and extending northeast to the Ozarks to the
western Great Lakes and to the west of that, upper level troughing
from portions of the Northern Plains to Northern Rockies to CA
and into portions of the eastern Pacific. Within that area of
general troughing an upper level low is expected to initially be
centered over the eastern MT to western ND area with another upper
low centered off the the central CA coast.

Wednesday night to Thursday, the upper level ridge is expected to
build north to James Bay and southern portions of Hudson Bay as
further east into the Lower OH Valley and remain in place across the
Southern Plains to Ozarks region. At the tame time, the upper
level begins to weaken and trend toward more of an open eave as
ridging in the western Atlantic to its east weakens allow the
upper level trough/low to shift east toward the eastern seaboard.
Further west and northwest, the upper level low initially over
the northern High Plains ares is progged to move northeast to
Manitoba while the other upper level low meanders into CA.
Meanwhile, a ridge of sfc high pressure should initially extend
from the Mid South to mid MS Valley region to southern Quebec
while a sfc low associated with the upper low/trough in the
eastern Conus should initially be centered east of the mid
Atlantic coast with a trailing frontal zone into the southeast to
eastern TX. Locally in eastern KY, convection should diminish
prior to sunset on Wednesday. Then, on Thursday, enough moisture
may linger in easter and southeastern portions of the area and
combine with the potential for a weak shortwave to be moving
across the mid OH Valley to central Appalachians for a return of
convection during peak heating.

Thursday night to Saturday, the northern portion of the upper level
ridging initially extending to the James Bay is expected to become a
separate centered of upper level ridging while the axis of upper
level troughing to the east of the Commonwealth and Appalachians
moves further east. The initial upper level low over Manitoba is
expected to track north across the western Hudson Bay region and
into northern Canada while another upper level low/shortwave trough
moves toward the Canadian Rockies/prairies and to Manitoba. To
the south, weak disturbances may work across the Plains and
portions of the midwest and perhaps the OH Valley around the
second upper level ridge that becomes centered over southeastern
TX. During this time, the upper level low further south/southwest
treks to the Four Corners region. During this time, a ridge of
sfc high pressure will shift east across the Great Lakes, OH
Valley and Southeast and become centered in the Appalachians. The
sfc low off the mid Atlantic coast will move on off into the
Atlantic with the trailing front expected to sweep south to the
Gulf of Mexico and Florida. High temperatures will moderate to
about 5 to 7 degrees above normal under the influence of sfc and
upper level high pressure to end the week, with widening diurnal
ranges, especially valleys, under that regime as well with the
ridging combining with a drier column and less cloud cover.

Saturday night to Monday, the axis of upper level ridging is
expected to gradually shift east across the Commonwealth with the
upper ridge initially centered in TX becoming increasingly west
to east oriented and weaker across portions of the Gulf Coast
States and Gulf of Mexico with the axis then turning north along
the east coast to Quebec to end the period. In addition, the
upper level low in the Four Corners region is expected to have
weakened to an open wave as it moves across the Plains and should
approach the mid MS to Lower OH Valley region to end the period.
Uncertainty remains with the evolution of upper level ridging and
upper level troughing further north in the Upper MS Valley and
Central to Northern Plains. Once the axis of the upper level ridge
moves east and the axis of sfc high pressure moves east, at least
a modest increase in low level moisture and through out the
column may occur. Above normal temperatures, especially for highs
continues into Sunday with the NBM suggesting dry weather likely
continuing though some guidance suggests a small chance for
convection on Sunday. The most likely scenario is that after a dry
end to the weekend, that a possible passing shortwave may lead to
at least minor height falls and combine with diurnal heating for
isolated convection on Monday. For Monday, highs are again
expected to be above normal, generally in the low to mid 80s while
the airmass may moisten.

&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
ISSUED AT 158 PM EDT TUE SEP 17 2024

Shower activity continues across the area this afternoon, though
there is a gradual decrease in activity. CIGS have been hovering
in MVFR territory, with brief rises into VFR flight conditions
where some thinning of clouds/breaks in shower activity have
occurred. Lower stratus will develop and build down overnight,
bringing CIGS down into IFR territory for a period of time through
the early morning and pre-dawn hours Wednesday. Light fog will
also lower VSBYS. These lower flight conditions will be slow to
improve late in the forecast period, but are expected to rise into
VFR conditions by around 14-15Z. Winds will be light, around 5
kts or less with an east-southeast tendency.

&&

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

$$

UPDATE...RAY
SHORT TERM...GINNICK
LONG TERM...JP
AVIATION...RAY