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000 
FXUS63 KJKL 181455
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
1055 AM EDT Fri Oct 18 2019

.UPDATE...
Issued at 1055 AM EDT FRI OCT 18 2019

Update this morning consisted of some minor adjustments to the
hourly temp and dew point grids. Did allow the frost advisory to
expire and where there was no frost, fog had lifted and
dissipated. Updated zones to remove morning frost and wording.
Also updated other products related to the frost advisory. 
Remainder of the day looks about as ideal as you could wish. 
Afternoon high near or around 70 look on target. 

UPDATE Issued at 701 AM EDT FRI OCT 18 2019

Valley fog and frost will persist until mid morning when
temperatures begin to warm out of the mid 30s. Expect high
temperatures to warm into the mid 60s to round out the week.

&&

.SHORT TERM...(Today through Saturday)
Issued at 420 AM EDT FRI OCT 18 2019

Clear skies and light winds underneath a dome of high pressure have 
allowed for valley temperatures to cool into the mid 30s with ridges 
remaining closer to the upper 30s to low 40s. Frost may not end up 
being as profound as originally forecast as saturation and 
subsequent fog have taken a hold on valleys as evidenced by GOES 
Nighttime Microphysics imagery. Nonetheless, will allow the Frost 
Advisory to continue this morning as the possibility is certainly 
there given moisture and temperatures within a few degrees of 
freezing.

Upper level ridging sliding overhead will place eastern Kentucky in 
a warm air advection regime today as surface high pressure shifts 
east into the Appalachians, allowing high temperatures to generally 
warm into the low-mid 60s underneath clear skies. Temperatures will 
therefore not be quite as cold tonight into Saturday morning, with 
valley lows in the mid-upper 30s and ridges remaining in the low 40s.

Warm air and moisture advection will be in store for the first half 
of the weekend downstream of a tropical disturbance currently 
residing over the Gulf of Mexico. Rain chances look best across 
southeast Kentucky, in conjunction with being in closest proximity 
to the incoming moisture plume and parent low pressure system. Upper 
energy from a northern stream mid-latitude upper trough may also 
phase with energy from the southern stream wave, further promoting 
precipitation generation. The bulk of the rain should hold off until 
Saturday evening, but will certainly be fair game across southeast 
Kentucky by mid-late afternoon as precipitable water values increase 
to over 1 inch. While increasing moisture may put somewhat of a 
damper on a warmup, should still see afternoon high temperatures on 
Saturday reach the upper 60s to low 70s. 

.LONG TERM...(Saturday night through Thursday)
Issued at 425 AM EDT FRI OCT 18 2019

The models remain in decent agreement aloft through an active and
amplified pattern for the extended portion of the forecast. They 
all depict the wave associated with tropical cyclone 16 passing 
by just to the southeast of Kentucky on Sunday morning while 
height falls work in from the northwest associated with a deep 
trough dominating the much of the west and central portions of the
nation. In the wake of the tropical wave departing, heights will 
rise through the Southeast ahead of a sharp and deepening trough 
over the Central Plains Sunday night into Monday morning. As this 
cyclone wraps up on Monday, it will sweep its energy east into 
the Ohio Valley and bring renewed height falls to Kentucky. The 
GFS remains slightly faster and a tad further north than the ECMWF
throughout this pattern evolution. The core of its energy and a 
5h trough axis passes through eastern Kentucky Tuesday morning as 
the lower heights settle into the Ohio Valley south of the deep 
cyclone spinning over the northern Great Lakes. The model spread 
starts to increase by mid week with the ECMWF showing a more 
potent secondary surge of energy and lowering heights into 
Kentucky compared to the flattening out GFS. All models then 
embrace the relaxing of the pattern over the Ohio Valley for later
Wednesday into Thursday as zonal flow will slowly tilt more 
southwesterly late in the forecast period. Given the general model
agreement, and as a response to the increasing spread late, have 
favored a blend represented by the NBM with no large scale 
adjustments. 

Sensible weather will feature a brush by of the tropical moisture
and some showers Saturday night, from the wave that could become 
a tropical storm before landfall. Dry and milder conditions then
follow on Sunday into Monday morning as southwest flow ahead of a
well defined, but later occluding, cold front spreads into the
area. This front will likely push a band of gusty showers and
possible thunderstorms into eastern Kentucky later Monday and
overnight. There is some potential for heavy rains with this front
as it is slowing and well supplied with Gulf moisture, but is 
also weakening and that may limit the extent of the convection 
later Monday night for points further east in Kentucky. Look for a
few showers to linger in the far east on Tuesday before drier air
finally is able to push in later in the day. Cool high pressure 
will then slowly moderate through the rest of the week but not 
before bringing a potential for some patchy frost Tuesday night 
and perhaps again late Wednesday night. 

Again adjusted the NBM temperatures most nights of the extended 
to allow for more of a ridge to valley difference. Did also back 
away from the higher QPF from the NBM on Monday and Monday night - 
instead preferring the more middle of the road WPC guidance 
during this time.

&&

.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
ISSUED AT 701 AM EDT FRI OCT 18 2019

VFR conditions to prevail at all sites underneath high pressure. 
Valley fog should remain below all terminals this morning, with 
frost likely inhibiting more widespread fog potential.

&&

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

&&

$$

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