Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 201247
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
747 AM EST Sun Jan 20 2019

.UPDATE...
Issued at 747 AM EST SUN JAN 20 2019

The latest scans of the WSR-88D radar shows much of the snow is
now tapering off, but some snow showers or flurries will linger
through the day. Did opt to drop the WSW for most of the area
given the heaviest snow has come to an end for most locations,
but will keep the advisory going on the higher terrain near the
Virginia border for a bit longer given some better upslope
potential. Adjusted grids to better match the latest trends and
blend in the latest obs and trends.

&&

.SHORT TERM...(Today through Monday)
Issued at 340 AM EST SUN JAN 20 2019

The morning surface analysis shows an area of low pressure has
now progressed east in West Virginia. On the backside of this we
are experiencing strong northwest winds and periods of snow or
snow showers. There are two different processes occurring this
morning that can be identified by radar trends. The first is
northwest flow is leading some some upslope snow and the second is
the deformation zone that is progressing east out of central
Kentucky. This deformation zone is loosing definition this morning
as better lift associated with this is lost. The northern half of
this feature is still defined, but this will also weaken as it
progresses east. Overall think the snow amounts will be lesser in
general due to this weakening trend, but the northwest flow will
continue to provide periods of snow showers mainly in far eastern
Kentucky locations. The area that will probably see the least will
be the Lake Cumberland region based on the current trends.
Although will keep the Winter Weather Advisory going as is given
the strong winds, cold air, and flash freeze potential at least.
In terms of temperatures, did blend toward the RUC that seemed to
maintain a better handle on the speed of the cold air this
morning.

The rest of today will feature lessening chances of snow showers
through the morning and afternoon. Did maintain low chance POPs
to flurries in the far east given the lingering stratus and
upslope flow potential. Otherwise we are looking at a diurnally
limited day today, with cold northwest flow leading to teens and
even single digits for wind chills. That said some may not make
it out of the teens for air temperatures through much of the
daylight hours. Tonight the cold air continues to be the story the
question will be on clouds and mixing. the soundings suggest we
loose the lower deck of clouds, but maintain mixing tonight.
Given this remained close to the previous forecast of mostly
single digits and not a lot of ridge/valley split potential.
Monday will be another cold day for eastern Kentucky, but clear
skies will be the story as high pressure and upper level ridging
begin settling in. The afternoon high temperatures on Monday will
remain in the low to upper 20s.

.LONG TERM...(Monday night through Saturday)
Issued at 430 AM EST SUN JAN 20 2019

The extended portion of the forecast begins on Monday night with
upper level ridging pushing through the eastern CONUS. This along
with surface high pressure, will keep dry weather in place across
the area Monday night and through the day on Tuesday. However,
the pattern being slightly progressive will put the surface high
to the east and thus bringing southerly flow to the region by
Tuesday afternoon. Thus, the arctic air mass in place from Monday
will quickly moderate by Tuesday with high temperatures warming
into the mid and upper 40s. The active part of the extended
features a system where the jet sets up another split flow with
the southern jet digging south into the lower MS Valley. This
feature however does not dig as far south as in previous runs and
as well, the northern stream features another shortwave that
tracks into the Great Lakes region. This set up is quite
different than in previous runs as there is also some differences
in the operations models at this time. Nevertheless, strong
ridging develops just off the east coast as the enlongated trough
develops over the eastern CONUS and shortwave ejects to the
northeast Wednesday and into Thursday. As this occurs, a secondary
low develops along the front in the southern Appalachian Range
and develops a deep low before this too lifts northeast. The
latest runs of the models suggest that as this feature lifts
northeast, the deformation zone will bring some additional snow
across eastern Kentucky. For now, this setup hastily pushes east
leaving little snowfall across eastern Kentucky Wednesday night
and Thursday. For now, will keep rain in the forecast through
Wednesday with a change over to snow Wednesday night and a slow
arrival of the colder air for Thursday as snow will likely chance
back over to rain on Thursday afternoon.

By Thursday night and into Friday, the passage of the previous
front will be followed by a seemingly arctic front as models to
continue to point at a more prolonged cold air set up. Thus, will
see a clipper type system move into the area Thursday night and
Friday morning with a chance of snow showers lasting into the day
on Friday. The change into the upper level pattern sets up a
northwest flow pattern with the Hudson Bay low in place and
possibly a bit further south in the Euro. This set up keeps the
cold air anchored in place heading into next weekend. Thus, will
expect the extended to end colder than normal in a northwest flow
pattern. This tends to be a more drier pattern, a drastic change
from the wetter pattern we have had over the last month or so.

&&

.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
ISSUED AT 624 AM EST SUN JAN 20 2019

A band of snow continues to progress into southeast Kentucky this
morning, with some sites seeing snow come to an end this morning.
Those still seeing snow are seeing VIS restrictions of MVFR or
lower and CIGs have been mostly MVFR. The CIGs and VIS will
improve through the day, as the snow exits east and lower stratus
relents. The question is how much and if we get additional
stratus later tonight. For now kept at least a low to mid deck in
the TAF sites as we move toward the evening. The winds have been
brisk at times and this is leading to instances of blowing snow as
well. The winds will continue gust 20 to 25 knots or greater at
times through the day out of the northwest.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until noon EST today for KYZ088-118-120.

&&

$$

UPDATE...DJ
SHORT TERM...DJ
LONG TERM...SHALLENBERGER
AVIATION...DJ


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