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FXUS63 KJKL 230540
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
1240 AM EST Wed Jan 23 2019

.UPDATE...
Issued at 1240 AM EST WED JAN 23 2019

The forecast remains on track for the most part. Updated the grids
to input the latest observations and trend them through the
overnight hours.

UPDATE Issued at 1035 PM EST TUE JAN 22 2019

Several updates have been made over the last several hours. Ended
up changing the diurnal curve a bit overnight to better reflect
the current cloud cover's impacts on the temperatures over the
next few hours, and how that will play into the trends throughout
the rest of the overnight. This included raising the minimum
temperature in most of the deeper valleys since cloud cover is
preventing some of the valleys from dropping off. Still expecting
temperatures to begin warming through the second half of the night
as southerly winds begin to increase.

The second major updates was to the winds. A strong low level jet
at 950mb will set up during the overnight and into the day
tomorrow. These winds will mix down to the surface at times late
tonight and into the day tomorrow, and could produce gusts higher
than that originally forecast. That being said, still don't feel
confident that we will see gusts high enough to constitute a wind
advisory, other than just along the high terrain. The increase in
gusts to 20 to 30 mph does match up better with LMK as well as our
afternoon HWO wording.

Finally, the latest hi-res model data is in fairly good agreement
of a slowing trend of the precip as it tries to make it into much
of the western CWA heading into Wednesday morning. Tapered back
pops a bit, slowing onset by a couple of hours in some locations.
The change pops also constituted a rerunning of the weather grids.

All updates have been published and sent to NDFD/web. A new
forecast package was also sent out to reflect changes as well as
to change to overnight wording.

UPDATE Issued at 649 PM EST TUE JAN 22 2019

Clouds may be pushing into the region just a tad faster than
originally forecast. Adjusted the current cloud cover up a bit,
especially in the western CWA, and interpolated into the ongoing
grids several hours later. Will continue to monitor temperatures
with the cloud cover, as the quicker influx of clouds may deter
from the valleys falling off as much as is currently forecast. As
for now, no major updates are needed. Made sure the current obs
for temps, dew points and winds matched up with the near term
forecast. All updates have been published and sent to NDFD/web.

&&

.SHORT TERM...(This evening through Wednesday night)
Issued at 501 PM EST TUE JAN 22 2019

The latest surface map features high pressure gradually settling
towards the western Atlantic. Low pressure resides near the KS/MO
border, with a warm front branched to the southeast into Arkansas
and a cold front aligned southwest across Texas. Southerly flow
has commenced across eastern Kentucky in between the two systems,
with temperatures responding nicely. Current readings range from
the lower 40s north of I-64, with most other locations varying
from 45 to 50. The warm spot today has been the Whitesburg
Mesonet, having warmed to 54 degrees. Aloft, a positively tilted
trough is aligned from south central Canada down across the Desert
Southwest, with a potent short wave trough noted across the
southern Plains.

The models are in good agreement through the short term, with the
southern Plains short wave trough becoming more negatively tilted
as it moves into the Midwest and eventually the Great Lakes region
by Wednesday. Consequently, the surface low pressure will follow
suit and deepen as it heads northeast. Meanwhile, the southern
stream portion of the trough will also swing across the lower and
middle Mississippi Valley, with a secondary area of surface low
pressure deepening across the central and southern Appalachians by
Wednesday night.

This will result in another widespread precipitation event across
eastern Kentucky from Wednesday into Wednesday night. For tonight,
a strong 850 mb jet on the order of 70-75 kts will develop across
the Tennessee and Ohio valleys, bringing breezy conditions to our
area late tonight into Wednesday, especially across the higher
elevations, where winds could gust as high as 50 mph. The
inversion looks too stout to bring down the full extent of the
strong winds hallowing aloft in the valleys, with some locations
seeing gusts of 25 to 30 mph. Besides a quick eastern valley drop
off into the lower 30s early this evening, most locations will see
readings steadying if not slowly rising late tonight, as thicker
clouds move in and southerly winds continue to increase across the
region. Most locations will remain dry through dawn, with some
shower activity affecting locations out west.

The main batch of rain will move in Wednesday and Wednesday night
as the cold front draws closer to the area. Overall, the QPF has
trended down somewhat, with less than an inch in the Bluegrass,
and around an inch and a third for far southeastern Kentucky.
This will eventually result in some action stages once again at
some of the typical downstream points on the Cumberland and
main stem of the Kentucky rivers, given the elevated base flows.
Highs on Wednesday will range from the low 50s near the Bluegrass,
to the upper 50s in the far east. Colder air will move in late
Wednesday night, with models generally on the decrease with the
snowfall totals by early Thursday morning. Most locations will see
less than an inch, with deeper moisture exiting quickly before
the better cold air arrives. Lows will range from the mid 20s
north to around 30 in the valleys in the southeast.

.LONG TERM...(Thursday through Tuesday)
Issued at 356 PM EST TUE JAN 22 2019

A dynamic extended period will be on tap as a CONUS wide trough
with progressive shortwaves dominates the upper level pattern. A
surface cold front will move through the area late Wednesday
night. This will bring rain and then a changeover to light snow
accumulations on the back side of the system Thursday. Snow totals
have trended down the last few model runs, with generally an inch
or less now expected. Another cold front will then pass quickly
behind this system, with the possibility of a few snow flurries
late Thursday night. Drier and colder weather is expected Friday
through Saturday morning as surface high pressure builds in,
although it will not be as potent as this past weekend's system.
Low temperatures Friday morning look to be in the teens and
Saturday morning lows in the mid teens to around 20 degrees.

The models show multiple rounds of shortwave energy that could
bring potential rain and snow chances to the area once again. A
surface boundary will approach the Ohio Valley Saturday, then
weaken as it progresses through the region into Sunday. This will
bring at least slight chances for some snow Saturday night into
Sunday morning, with a changeover to rain during the day Sunday.
Little to no snow accumulation is expected. Surface high pressure
will then build over the lower Mississippi Valley, leading to a
brief period of drier weather Sunday night into Monday morning for
eastern Kentucky. A surface low pressure system will progress
over the Great Lakes and upper Ohio Valley regions late Monday
into Tuesday. This will bring a cold front through the
Commonwealth, increasing chances for precipitation into Tuesday.
With this system being at the tail end of the forecast period,
there is high uncertainty in timing as well as precipitation type
and amounts.

High temperatures will generally increase through the weekend to
be just above normal by the start of the work week. Lows will
generally be in the 20s for the weekend through Tuesday.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
ISSUED AT 1240 AM EST WED JAN 23 2019

Clouds will increase and lower with time as a cold front
approaches from the west, but still expecting generally VFR
conditions to remain across the area through overnight and morning
hours. A strong low level jet will develop across the region
tonight and continue into Wednesday. This will bring the threat of
low level wind shear from this evening through Wednesday morning.
S winds of around 10 kts, with occasional gusts of 10 to 20 kts
will veer to the SW and WSW during the day Wednesday. The
strongest surface winds will occur the afternoon hours Wednesday,
as stronger winds aloft mix down at times. Rain will also
gradually overspread the area from west to east on Wednesday, with
CIGS and VIS lowering generally to MVFR during the afternoon and
into the evening hours towards the end of the TAF period.

&&

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

$$

UPDATE...SHALLENBERGER
SHORT TERM...GEOGERIAN
LONG TERM...CGAL/HC
AVIATION...SHALLENBERGER/WIX
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