490
FXUS63 KJKL 230523
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
1223 AM EST Sat Nov 23 2024

.KEY MESSAGES...

- Any remaining precipitation will taper off tonight and early
  Saturday.

- Milder temperatures will return over the weekend, and rain is
  expected late Monday into early Tuesday.

- Another round of potentially more significant rain is forecast
  late in the week, centered around the Thanksgiving holiday.

&&

.UPDATE...
Issued at 1100 PM EST FRI NOV 22 2024

No significant changes to the forecast with just the inclusion of
the latest obs and trends for the T/Td/Sky grids and a touch up
to the PoPs per radar (mostly) and CAMs tendencies. These minor
adjustments have been sent to the NDFD and web servers along with
a freshening of the zones, HWO, and SAFs.

UPDATE Issued at 815 PM EST FRI NOV 22 2024

00Z sfc analysis shows cyclonic flow through eastern Kentucky this
evening on account of a deep low off to the northeast of the
state. This, along with some support aloft in the form of energy
rotating around the 5h low in northwest flow. As a result a main
area of light pcpn - mostly rain, has pivoted southeast of the
area while additional pockets of more patchy pcpn follow. In the
higher elevations this pcpn is in the form of snow but models
indicate that the cloud tops will not be cool enough to remain as
snow and likely any lingering PoPs will result in some freezing
drizzle for those mountain locations. The current forecast has
this well in hand so mainly just the current obs and trends for
the T/Td/Sky grids were included with this update. Specifically,
temperatures are running in the upper 30s and lower 40s below 2500
feet - closer to freezing or below above that elevation. At the
same time, amid west to northwest winds on the order of 10 to 20
mph, dewpoints are generally in the mid to upper 30s. The grid
adjustments have been sent to the NDFD and web servers along with
a freshening of the zones and SAFs.

&&

.SHORT TERM...(This evening through Saturday night)
Issued at 456 PM EST FRI NOV 22 2024

A very large, stacked low pressure system is over the northeast
CONUS late today. Weak warm air advection has wrapped around the
back side of the system, possibly augmented by air mass
modification over the relatively warm Great Lakes. Vorticity lobes
are also rotating around the upper level low, enhancing precip.
The last such disturbance to affect us with this system is
currently moving over our area, and coupled with the warm air
advection, is resulting in an area of light precipitation.
Temperatures have warmed to the point so that it is generally
falling as rain. However, it is still below freezing at elevations
above about 2-2.5K ft, and precip should be occurring as snow
along those ridges in southeast KY.

The system aloft will depart this evening and deep moisture will
shrink away to the east, with precip over our area declining as
this happens. However, a subtle increase in upslope low level
flow is also expected this evening, which will help light precip
to linger in southeast KY near the VA border. As deep moisture is
lost, there is a possibility that precip could go over to
freezing drizzle at the higher elevations near the VA border.
However, considering that there has already been accumulating snow
there, and the fact that any freezing drizzle would be very
light and roads should already be treated, impacts should be
negligible.

The main question on Saturday into Saturday night will be the
extent that clouds decrease. Low level flow will back and upslope
component will be lost. However, weak warm air advection will also
occur and there won`t be any good influx of drier air.
Have used a model blend at this point, but confidence in the sky
cover forecast is rather low. Whenever the decrease in clouds
occurs on Saturday and Saturday night, it should overall be
arriving from the southwest.

.LONG TERM...(Sunday through Friday)
Issued at 336 PM EST FRI NOV 22 2024

The large scale flow pattern in the extended starts off with a
strong area of low pressure situated just off the northeast coast of
Maine. Clouds and precipitation from this system will affect a large
area including most of New England and far southeastern Canada.
Another large system will be sitting just of the coast of the
Pacific Northwest, and will be moving slowly onshore on Monday. This
system will bring repeated rounds of heavy low elevation rains and
higher elevations snows to Washington, Oregon, and northern
California as it moves toward and eventually onto land. In between,
strong high pressure will be in place across the central portion of
the country. This upper level ridge will be elongated from west to
east, and will cover regions from the Great Lakes through southern
New England, the mid-Atlantic, the Ohio and Tennessee Valleys and
most of the Great Plains. A surface ridge will be in place across
the southeastern CONUS and the Gulf of Mexico to begin the period.

With high pressure in place, we will see dry and steadily warming
weather for eastern Kentucky Sunday and Monday, as skies remain
mostly clear and southerly flow becomes well established. We will
see clouds on the increase during the day on Monday, as low pressure
moves our way from the west. In spite of the clouds, brisk southerly
winds will allow warm Gulf of Mexico air to continue pushing into
the region, leading the high temperatures that day in the lower 60s
around the area. With low pressure rapidly moving through, we could
see scattered rain showers moving into the I-64 corridor by early
Monday afternoon, and the I-75 corridor by mid-afternoon. The rain
will become widespread during the evening hours Monday, as a cold
front pushes through the region. Due to the speed of the incoming
system, the rain should be out of our area by early Tuesday morning,
as another ridge of high pressure moves in behind the trough. This
ridge of high pressure should persist over the area through most of
the day on Wednesday. After that, yet another area of low pressure
will be quickly moving into the region, as high pressure departs to
our east. Based on the latest long term model data, this second
system will move much more slowly as it across the eastern CONUS and
phases with a northern stream system that is forecast dive southeast
out of east central Canada. The second system also looks like it
will also produce quite a bit more rain than the early week system.

Temperatures for most of the period look to quite cool and well
below normal for this time of year, as much cooler air spills into
the region behind the first departing low pressure system. Daily
highs from Tuesday onward will range from the mid 40s to lower 50s,
with max values in the upper 30s and lower 40s possible on Friday.
That being said, some snow may mix with the rain on Friday due to
the cold air that will be moving in. As far as weather hazards go,
we aren`t expecting any at this point, but we will watch the end of
period low pressure system carefully to see if locally heavy rain
ever becomes a possibility. Nightly lows will start off in the upper
30s and lower 40s, but should bottom out in the upper 20s and lower
30s Tuesday night onward, as the second colder system moves through
the region.

&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
ISSUED AT 1223 AM EST SAT NOV 23 2024

Light rain will gradually diminish through the remainder of the
overnight, but with IFR or low MVFR cigs remaining. Have opted to
keep at best MVFR conditions at most if not all TAF sites for
much of the day Saturday, generally following the more pessimistic
MET guidance, with cigs gradually rising at all sites, and with
partial clearing commencing late in the period toward KSME and
KLOZ as winds back from west or west-northwesterly to a more
southwesterly direction. West to northwest winds will continue to
be brisk but generally on a diminishing trend through the
remainder of the overnight, with light winds becoming more
southwesterly late in the TAF period.

&&

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

$$

UPDATE...GREIF
SHORT TERM...HAL
LONG TERM...AR
AVIATION...CMC