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658
FXUS63 KJKL 240931
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
531 AM EDT Tue Sep 24 2024

.KEY MESSAGES...

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- A potential for showers and thunderstorms will persist through
  much of the next several days, bringing eastern Kentucky some
  much needed rain.

- The remnants of Potential Tropical Cyclone 9, currently forecast
  to strike the Florida Panhandle as a hurricane late Wednesday,
  may impact eastern Kentucky with an increased chance for a
  widespread, soaking rain event late in the week. However, any
  flooding potential is likely to be mitigated by the quick
  movement of this system.

- Seasonably warm temperatures will average just a few degrees
  above normal through the week.
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&&

.SHORT TERM...
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(Today through Wednesday)
Issued at 531 AM EDT TUE SEP 24 2024

A nearly stationary frontal zone continues to lie along the Ohio
River this morning, just to our northwest. Aloft, a trough will
move eastward into the Ohio Valley today, weakening as it slides
eastward in response to a stronger trough dropping southward into
the Missouri Valley. However, this trough is still strong enough
to increase wind fields over the Commonwealth as it lifts
northeast into the region by late today. Strengthening winds aloft
in combination with a developing 30-40kt H850 southwesterly jet
nosing its way into the area will result the development of 40-50
kts of bulk shear across eastern Kentucky, southeast Ohio, and
West Virginia by this afternoon along with increasing diffluent
flow aloft. Models also show MLCAPE climbing to between 1000-2000
J/kg across eastern Kentucky this afternoon. This will set the
stage for the potential of strong to severe thunderstorms over the
region today, conditional on how exactly how much sunlight and
heating we are able to achieve. Consequently, the Storm Prediction
Center has placed our area in a Slight risk for severe weather
today.

In addition, the Weather Prediction center has our area in a
Marginal risk for excessive rainfall. Storm motions are 30 kts or
greater today. Freezing levels are generally around 13 kft and
PWATS max out at around the 75th percentile, climatologically.
Thus conditions are not ideal for flooding issues. All things
considered, feel that any hydro issues will be localized, and more
dependent on how organized convection becomes and the potential
of training/back building of storms over a specific locations.

Regional radar mosaic shows a band of showers and thunderstorms
moving into central Kentucky this morning. This main band will
likely entering our Bluegrass counties over the next 2-3 hours,
with additional convection poised to track across the rest of the
area through the remainder of the day. H850 temps of 16-17 C will
drop to between 14-15 C by tomorrow. This will lead to afternoon
highs of around 80 today, dropping into the low to mid 70s
tomorrow, aided by clouds and rain cooled processes

.LONG TERM...(Wednesday night through Monday)
Issued at 531 AM EDT TUE SEP 24 2024

There continues to be two large scale features which will
interact with each other and dominate our weather during the long
term period. One of these is a large closed low which will start
the period centered near the Missouri bootheel. The other is a
tropical system which will evolve from the area of unsettled
weather currently near the Cayman Islands. The flow around the upper
low will initially be drawing on deep moisture being pulled north
from the gulf. With this, precip is expected to be ongoing over
at least the southern part of the JKL forecast area at the start
of period, and this scenario should last into Thursday. The
tropical system, expected to reach hurricane status, is currently
forecast to make landfall in the Big Bend region of Florida on
Thursday. It is still expected to be captured in the flow around
the upper low and move rapidly north, with its remnant circulation
reaching the vicinity of eastern KY on Friday. Our POP will
increase from the south on Thursday night as it approaches, with
rain expected area wide on Friday.

The persistent feed of deep moisture (precipitable water of
1.5-2") drawn north by the closed low may result in significant
rainfall of more than an inch Wednesday night into Thursday,
particularly in our southern counties. Precipitable water should
further increase to above 2" as the tropical system remnants move
through. However, the system will be moving swiftly north
northwestward and crossing the Appalachians-- both factors which
will limit excessive rainfall potential. While hydro problems
won`t be ruled out Wednesday night through Friday, we are
currently primarily in marginal excessive rainfall outlooks from
WPC.

Once the tropical system passes by, both the GFS and ECMWF show a
dry slot curling around the upper low and moving over eastern KY
Friday night into Saturday night. This will limit precipitation,
but some convection capped in the mid levels may occur, and at
least a slight chance of precip has been maintained during this
time.

The upper low finally wobbles slowly eastward Sunday through
Monday. Although its exact track and how quickly it weakens and
gets absorbed back into the prevailing westerlies aloft are
uncertain, it is probable that deep moisture associated with the
low will move back over our region and bring at least scattered
showers.
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&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
ISSUED AT 220 AM EDT TUE SEP 24 2024

Very challenging forecast as evening convection has moved out of
the area, and we are currently experiencing some clearing,
though it will be short lived. Can not rule out some lingering
isolated shower and thunderstorms through the overnight. Evening
rainfall, residual boundary layer moisture, temporary clearing,
southwest flow, etc. are all playing havoc on fluctuating flight
conditions. Model guidance is not doing well capturing trends and
as a result is not as reliable as normal. Thoughts are that there
is an ongoing modification of the boundary layer across our area
through a combination of advective and mixing processes as air
moves in from the southwest within the warm sector, south of the
frontal zone located just to our north near the Ohio River. Went
old school and relied on advecting upstream conditions into our
area for the first few hours of the forecast. This resulted in a
more optimistic forecast as compared to guidance overall, at
least through the beginning of the forecast period. Went with
worst case MVFR VSBYS for some of the terminals showing that
tendency. Will need to watch for low stratus that typically forms
in nearby valleys after a good rain and which also tends to lift
into the terminals at times. Thus in general went with MVFR/VFR
VSBYS and LIFR/VLIFR CIGS where low stratus is showing signs of
forming and impacting terminals. Flight conditions improve
rapidly through the morning as additional convection and the
threat of strong to severe storms overspreads the area through the
day. Winds will be light, around 5 kts or less with a predominant
southwest tendency through the daylight hours. Locally erratic
and stronger winds will be possible in the vicinity of storms.

&&

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

$$

SHORT TERM...RAY
LONG TERM...HAL
AVIATION...RAY