Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 161123
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
623 AM EST Mon Jan 16 2017

.UPDATE...
Issued at 553 AM EST MON JAN 16 2017

The fog has been fairly erratic and therefore did keep the SPS
going given the uncertainty in the valley locales. Some of the
sites to the south have already seen wholesale improvements and
would think this will be the story through the morning. No major
changes needed this update.

&&

.SHORT TERM...(Today through Tuesday)
Issued at 330 AM EST MON JAN 16 2017

Surface analysis shows high pressure has moved east and is parked
along the Mid Atlantic Coast this morning. That said, the winds
are generally out of the northeast and east this hour. The fog is
fairly sporadic this morning. therefore do not see a need for a
NPW this morning, but will keep the SPS going at this point. Today
the quasi stationary front is expected to lift north through the
day and bring unseasonably warm air mass into the region.
Temperatures are expected to climb into the mid and upper 60s in
near the TN border and this will lead to near record high
temperatures. Also some of the short term guidance and even the
lower resolution guidance would suggest showers form near the warm
front. Therefore kept some mostly isolated POPs nearer the
boundary.

Tonight all eyes toward low pressure across Central Oklahoma this
morning. There is good agreement on this vertically stacked system
ejecting into the Upper Midwest through the night. A trialing cold
front will slowly press east along with jet energy. The first
part of this will be upper level jet dynamics punch into the
region, as left exit region comes through the Ohio Valley leading
to divergence aloft. This will induce a moderate 850mb jet
approaching 60 knots by early Tuesday morning. These elements will
lead to deep layer moderate to strong omega seen in the time
heights, as mid to upper level short waves ride the flow into the
region. Therefore could not argue with CAT POPs as we move toward
dawn hours on Tuesday morning. Right now best axis of precip is
lining up in areas generally along and north of the Hal Rogers
Parkway. Overall amounts will be around a quarter to three tenths
of an inch through the morning. That said, the dynamics are such
that a few rumbles of thunder would be possible and this lines up
with best MUCAPE and SPC.

Now this is a two part system as the cold front will lag behind
the initial mid and upper level dynamics. The front will approach
the region on Tuesday with band of precip moving through from west
to east through the afternoon. Did opt to go a bit lower QPF wise
for the far SE, given the better dynamics are early in the day
mainly north of the Hal Rogers Parkway. Either way did keep CAT
POPs given the chances of seeing measurable precip are reasonably
high. Also keep the slight thunder along the highest areas of
POPs through the day and again this seems to follow best areas of
MUCAPE.

.LONG TERM...(Tuesday night through Sunday)
Issued at 348 AM EST MON JAN 16 2017

The GFS and ECMWF have come into better agreement since yesterday.
There are some differences in the details at long range, but they
show good agreement on the overall pattern. It`s still an
expectation of overall mild temperatures and periodic showers.

For specifics, a cold front will be exiting southeast out of the
area on Tuesday evening. Showers may linger, especially in our
southeast counties. They will be due not only to exiting deep
moisture along the front, but also residual shallow moisture in the
post cold frontal regime, with an upper trough axis not passing
until Wednesday morning. Will look for the last of the showers to be
gone by Wednesday afternoon. Ridging at the surface and aloft then
builds in by Wednesday evening, with decreasing clouds.

The respite from inclement weather will be short-lived. The ridging
will be moving to our east by Thursday morning, and an upper level
low coming out of the southwest CONUS will begin its influence. The
Gulf of Mexico will open up for overrunning moisture. Clouds should
already start to thicken from southwest to northeast by Thursday. In
fact, the NAM and ECMWF even have light precip arriving in our
southwest counties by Thursday morning. Initially, the better
moisture transport and highest POP will remain to our southwest.
Eventually, the entire system moves northeast, and an area of
showers is expected to move northeast over the JKL forecast area
late Thursday night into Friday. This is largely an upper level
system, and we will still be left in a mild air mass after it
passes. Weak upper level ridging moves in again Friday night, with
fair weather that lasts through Saturday.

Yet another upper level system should emerge from the southwest
CONUS during the weekend. This one is forecast to grow into a much
larger trough over the Mississippi Valley before the weekend is
finished. Gulf moisture flowing northward around the storm system
will lead to another round of showers moving in from the southwest
before the weekend is finished.

&&

.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
ISSUED AT 623 AM EST MON JAN 16 2017

The period is beginning with a wide variety of restriction levels
across the region. Most are beginning with no more than IFR for
VIS and/or CIG restrictions with exception of improving SW sites.
These restriction issues will wane through the morning. A warm
front will advance north across the region today with isolated
showers possible this afternoon. All sites will see improvements
to VFR no later than early afternoon before restrictions return
tonight, with upper level disturbance advancing NE toward the end
of this TAF cycle. Winds will remain light out of the east and
northeast to begin the period before veering around to the
southeast to south by this afternoon.

&&

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

$$

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



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