Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 011652 AAB
AFDJKL

AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
1152 AM EST Thu Dec 1 2016

.UPDATE...
Issued at 1152 AM EST THU DEC 1 2016

Hourly grids were freshened up based on satellite and observation
trends. Overall this led to no substantial changes. The strato cu
will continue to mix into cu across the region stratocu but a
considerable amount of cu should linger well into the afternoon as
moisture remains near 850 mb and just below.

UPDATE Issued at 711 AM EST THU DEC 1 2016

Stratus has built south as expected this morning as it pushes
through eastern Kentucky. A few valley locales have dropped to
freezing across the Cumberland Valley and south of Mountain
Parkway where clearer skies prevailed longer. Still expecting
temperatures to make it into the mid-upper 40s this afternoon.

&&

.SHORT TERM...(Today through Friday)
Issued at 351 AM EST THU DEC 1 2016

A stacked low pressure system pulling east/northeast across the
Great Lakes will act to bring weak subsidence into eastern Kentucky
today. However, with weak cyclonic flow remaining in place locally
on the southern fringes of this departing system,
heights/thicknesses will be slow to increase. This along with a
stagnant cold dome across the Ohio Valley will keep lingering
stratocumulus in place across eastern Kentucky, particularly
northeastern Kentucky in closer proximity to the core of the
cyclonic flow and cold dome. Temperatures for this first day of
meteorological winter will thus only rise into the mid-upper 40s,
roughly five degrees below normal. Gusty west to southwest winds
will develop by late this morning through this afternoon as surface
ridging from the Great Plains to Gulf of Mexico coast will be slow
to build eastward. Sustained winds will top out at 10-15 mph with
gusts of up to 20 to perhaps 25 mph at times.

Winds will diminish to near or below 5 mph late this afternoon and
evening as high pressure slowly migrates north into the Tennessee
Valley toward the Cumberland Valley. A passing mid level impulse may
try to skirt across the region later this evening into tonight,
although this will result in nothing more than possibly an uptick in
cloud cover as winds will continue to exhibit a southwesterly
component thus negating more pronounced low level cloud cover and
precipitation prospects with the lack of upslope flow. Radiational
cooling should allow for temperatures tonight to fall into the
mid-upper 20s in valleys to low 30s on ridgetops, with the lower
of these ranges being nearer the Cumberland Valley where less
cloud cover will prevail.

Upper ridging will then attempt to amplify from the gulf coast into
the Mississippi Valley Friday as an upper low digs into Mexico.
However, northern stream energy will keep any appreciable warmth
from advecting into the Ohio Valley as high temperatures only warm
a degree or two from those on Thursday.

.LONG TERM...(Friday night through Wednesday)
Issued at 351 AM EST THU DEC 1 2016

Much more rain is on the way as we head from late in the weekend
through next week.  Models have certainly come into better agreement
in the past 24 hours.  Dry weather will persist Friday through
Saturday as high pressure remains in control. It now looks like the
GFS solution of a weaker system for Sunday is going to win out as
the ECMWF has come into agreement.  Overrunning light precipitation
will develop late Saturday night into Sunday.  Wet bulb temperatures
through the column will remain around or below freezing early on
suggesting mainly light snow or flurries at the onset. However, as
we head into late Sunday morning, those wet bulb temperatures will
come up in the low levels, allowing for a switch over to rain by
midday.  Not anticipating any snow accumulation for a number of
factors. First, snowfall will be on the very light side. Second,
ground will be warm. Third, temperatures may hold around or even
stay slightly above freezing.  Thus, no impacts expected from any
snow.  The best precipitation chances will come through the middle
of the day where mainly rain will be seen. Left some rain chances
into Sunday evening as there is still some uncertainty with how fast
the moisture departs.  It does look like we dry out temporarily late
Sunday night into Monday.  A southern stream wave will then push
northeast into the region late Monday and Monday night with a
surface low tracking northward across the Ohio river valley. Strong
isentropic ascent will lead to another round of rain for the area.
We will have to see how southeast flow off the high terrain eats
into overall QPF amounts, but as far as rain chances, they look
excellent.  Those rain chances will linger into Tuesday. Dry weather
will return Tuesday night into Wednesday and have undercut model
blend guidance.

Finally by late Wednesday night and Thursday, a strong mid/upper
level trough will push across the region with a strong arctic cold
front pushing across the region. This will provide another good shot
at rainfall.  The cold air looks to arrive on Thursday, and we could
see a few snow flakes on the tail end of the system, although
moisture should be departing as the cold air arrives, so the window
for snowfall will be short.  Flow appears very hostile for upslope
snow showers, but given how cold the airmass is, some flurries or
light snow showers may be possible with any lingering moisture,
especially Thursday night and Friday.

&&

.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
ISSUED AT 711 AM EST THU DEC 1 2016

A stratus deck will continue to move across eastern Kentucky,
resulting in MVFR ceilings at JKL/LOZ. Could see these materialize
at SJS/SYM and possibly SME this morning, before clouds lift and
break up by late morning. West/southwest winds will increase to
5-10 knots with gusts of 15-20 knots later this morning through
this afternoon. These winds will diminish by late afternoon/early
evening to less than 5 knots as VFR conditions prevail tonight.

&&

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

$$

UPDATE...JP
SHORT TERM...GUSEMAN
LONG TERM...KAS
AVIATION...GUSEMAN



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