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FXUS63 KJKL 240757
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
357 AM EDT Fri Mar 24 2017

.SHORT TERM...(Today through Saturday)
Issued at 357 AM EDT FRI MAR 24 2017

Morning surface analysis indicates surface high pressure centered
off the coast of VA/NC. A weak warm front is progressing NE and
while there is a slight kink in isobars the front is tough to
define. Winds have already switched to a more southeast to south
direction around the surface high this morning. Therefore
temperatures are mild at the more mixed sites. The exception to
the rule are the deeper valley locales where decoupling is leading
to lower 40s. First forecast challenge of the day will be cloud
cover. We have seen clouds streaming out of the TN Valley and
southward likely associated with isentropic ascent ahead of the
approaching system in the Front Range. Most of the model soundings
indicate some lower clouds are not out of the question as we move
through the day. Right now keeping the better coverage across the
western and northern portions of the CWA and seems reasonable
right now based on the SAT trends. The next challenge will be how
much moisture recovery do we get particularly in the far east
toward the Big Sandy. There will be decent afternoon mixing and
given the strengthening LLJ would lead to 15 to 20 mph gusts
particularly in the Lake Cumberland and Bluegrass. Overall think
recovery should be enough to lead to higher RH than yesterday, but
even so far east could be looking at lower 30 RH values. All of
this will play a crucial role in temperatures and did lean up a
bit given SUPERBLEND was higher than previous forecast.

Tonight the cloud challenge will continue as the lower deck is
expected to dissipate. However, we will keep a higher deck at
minimum, but the deeper valleys could see a decent split once
again. Think this will be more confined to the far eastern valleys
given the better LLJ to the west. Moving into Saturday the clouds
will continue to be on the increase through the day and more a
top down saturation seen in the model sounding data. The one
caveat to the increased cloud cover will be the backed flow by
Saturday afternoon which could promote downslope flow in the far
east. That said, did opt to keep lesser coverage as you move east.
Also think most will remain dry on Saturday given upper level
trough will negatively tilt across the Midwest and slow surface
features down. However, did opt to bring slight POPs in the Lake
Cumberland region by late Saturday given some CAMs support the
possibility.

.LONG TERM...(Saturday night through Thursday)
Issued at 357 AM EDT FRI MAR 24 2017

A stacked low pressure system over MO at the start of the period
will be weakening as it slowly moves northeast, reaching the Great
Lakes Sunday night. A stream of moisture off the Gulf of Mexico
coupled with the approaching upper level system will bring showers
to most places Saturday night and Sunday. Weak instability should
also be present, and justifies including a mention of thunderstorms.
As the disintegrating system passes to our north, its cold front is
expected to dissolve and leave us without a change in air mass.
Models show another weakening low pressure system coming out of the
southern plains early in the work week and moving up the Ohio
Valley. This time around, cold frontal passage is expected to occur,
accompanied by an increase in the POP for Monday night into Tuesday.
The GFS and ECMWF are in a little bit better agreement now, as
compared to 24 hours ago, and are both showing the front settling
far enough to our south to allow a period of mainly dry weather from
Tuesday night into Thursday. Yet another in a parade of systems is
expected to track from the southern plains to the Ohio Valley at the
end of the week. While precip from this system can't be ruled out on
Thursday, it's more likely to hold off just a bit longer.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
ISSUED AT 120 AM EDT FRI MAR 24 2017

A surface high pressure is setup off the Mid Atlantic coast this
overnight hour. This combined with the upper level ridging will
keep our CIGS VFR despite how complicated the layers may in fact
be. This more complicated cloud cover is partly due to some
isentropic ascent that will eventually kick in. That said, the
strengthening LLJ will leave the overnight period with possible
LLWS issues until 14Z. Then by 14Z the winds will kick in and we
could see some gusts of 15 knots at SME/LOZ/SYM in the afternoon.

&&

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

$$

SHORT TERM...DJ
LONG TERM...HAL
AVIATION...DJ
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