860
FXUS63 KJKL 220418 AAB
AFDJKL

AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
1118 PM EST Thu Nov 21 2024

.KEY MESSAGES...

- A large area of widespread steady light snow continues, but
  tapers off from northwest to southeast late tonight.

- Locations most likely to receive travel impacts overnight to
  early Friday are those elevations above 1500 feet.

- Snow changes to rain toward midday Friday as warmer air moves
  into the area from the west, with the latest changeover at
  higher elevations along the Virginia border.

&&

.UPDATE...
Issued at 1115 PM EST THU NOV 21 2024

The heavier of the steady snow has moved into eastern KY and the
majority of the accumulating snow for locations south of
Interstate 64 should occur over the next few hours. Hourly
temperatures were also freshened up based on recent observations
and trends.

UPDATE Issued at 752 PM EST THU NOV 21 2024

A few minor adjustments were made to hourly pops based on recent
radar trends of reflectivity increasing/enhancing across the
southeastern portion of the area. Also, some locations, especially
locations above 2000 feet were running cooler than forecast so
hourly T and min T were lowered for those areas a few degrees.

&&

.SHORT TERM...(This evening through Friday night)
Issued at 355 PM EST THU NOV 21 2024

A cold front has advanced across most of the area this afternoon. We
seeing some lingering 925mb frontogenesis and steep low level lapse
rates that are still keeping some robust snow showers going this
afternoon mainly in southeast Kentucky. These have been producing
lowering visibilities to a quarter mile at times and even a brief
slushy accumulation mainly on grassy surfaces. However, some of
this has overachieved at times leading to some accumulations
possibly on roads mainly above 2000 feet based on observations.
However, where snow showers were earlier, such as Slade, are
seeing wet pavement at best. These will relent through the
afternoon as forcing for ascent continues to decrease through the
remainder of the afternoon.

Tonight, we are watching the the next lobe of mid-level vorticity
rotating around the mid-level low across the Great Lakes this
afternoon. This feature will rotate through the Ohio Valley and
eventually through eastern Kentucky this evening into tonight. In
response to this feature expect lift will increase through the
evening and overnight hours, as omega values increase toward the 2
AM to 4 AM hours late tonight with the better frontogenesis. This
will lead to another round of accumulating snow through the evening
and overnight hours. This round of snow could lead to reduction in
visibilities at times and as low as a quarter mile at times. We
will also see some decent snow accumulations mainly on grassy
surfaces, but during times of heaviest snow we could see this
overcome the warm surface temperatures late tonight into early
Friday morning mainly above 2000 feet. Now given this will keep
the advisory where we have it for now and let the subsequent
shifts evaluate the situation. In the Lake Cumberland area, we
will see some of this activity change over to rain and/or snow
early Friday morning, as a little warmer air tries to push into
the area. There is some question if we keep low level moisture
enough for some drizzle, but right now leaning away from any real
significant drizzle or freezing drizzle given the set up seem like
we dry out quickly in the wake of the boundary.

Friday, we will see yet another disturbance drop southward Friday
afternoon and bring in another round of mainly rain for most of the
area. This as afternoon highs warm into the lower 40s in most
locations. However, higher terrain near the Virgina border could see
additional snow and/or rain through the afternoon and evening, as
temperatures stay near freezing. Overall impacts and
accumulations will be minimal. This will exit the area through
Friday evening.

.LONG TERM...(Saturday through Thursday)
Issued at 340 PM EST THU NOV 21 2024

Active pattern expected in the extended portion of the forecast, as
a series of low pressure systems move through the region. The period
will start off with a large trough of low pressure situated off the
Mid-Atlantic region. This system will spread clouds and
precipitation from northern New England all the way south the
southeast CONUS coastline. Another area of low pressure is forecast
to be moving onshore from the Pacific Northwest southward to
northern and central California. A large, sprawling ridge of high
pressure, both at the surface and aloft, will be in place from the
northern Rocky`s south to the desert southwest, and then eastward
across the Great Plains and the Mississippi and Tennessee Valleys,
and parts of the western Ohio Valley. There will be a few rain
showers exiting our far eastern counties Saturday morning, as high
pressure pushes to the east. The ridge will settle over the region
over the weekend, and will bring dry and warmer weather back to
eastern Kentucky for a brief period of time. However, the western
trough will move along the northern periphery of the ridge and will
dive southeastward into the Great Lakes, and Ohio and Tennessee
Valleys. This system will bring widespread, soaking rain to the area
Monday night through Tuesday night. After another brief respite from
precip Tuesday and Tuesday evening, two more areas of low pressure
are forecast to move our way as they form over the Great Plains and
four corners region and push off to the east in rapid succession.

We will see periods of rain from time to time Wednesday through
Thursday night. Some snow may mix with the rain at times late
Tuesday night into early Wednesday morning. Temperatures will
generally be below normal, with daytime highs in the upper 40s and
lower 50s during the coolest days, and in the upper 50s and lower
60s Sunday and Monday. The warmer days will also feature persistent
southerly flow. The cooler days will coincide with the passage of
multiple low pressure systems and wind shifts to the west,
northwest, north, and eventually northeast. Not expecting any
weather hazards in the extended at this time.

&&

.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
ISSUED AT 735 PM EST THU NOV 21 2024

An area of light to moderate snow is moving across the area this
evening, with some more intense snow upstream over Indiana. The
light to moderate snow and eventually some heavier periods of
snow are expected for the evening and much of the overnight. The
heaviest snow and most reduction of visibility and ceilings should
occur between 03Z and 09Z when LIFR to below airport mins are
anticipated. Outside of the heaviest snow, IFR and some MVFR
reductions are expected. In fact, as the steadier snow tapers off
from northwest to southeast between 06Z and 12Z, visibility
should return to VFR. However, once the steadier snow ends, IFR
and MVFR ceilings will linger with another band of rain possibly
mixed with snow moves southeast across the area between 15Z and
the end of the period. Winds will average between southwest and
west through 06Z at generally around 10KT or less before becoming
northwest between 06Z and 12Z behind the first system. West winds
should return between 12Z and 16Z and then increase thereafter to
10KT if not more in some cases with gusts to near 20KT.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 7 AM EST Friday for KYZ044-050>052-
058>060-068-069-080-086-104-106>112-114-116-119.

Winter Weather Advisory until 10 AM EST Friday for KYZ087-088-
113-115-117-118-120.

&&

$$

UPDATE...JP
SHORT TERM...DJ
LONG TERM...AR
AVIATION...JP