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fxus63 kjkl 182050 

Area forecast discussion
National Weather Service Jackson Kentucky
450 PM EDT Fri Oct 18 2019

Short term...(this evening through Saturday night)
issued at 450 PM EDT Friday Oct 18 2019

High pressure is centered over the central Appalachians, while
generally high level moisture is being spewed northward from
tropical storm Nestor into the Tennessee Valley. As such high clouds will
be on the increase over the next 18 to 24 hours, with more
substantial moisture holding off until Saturday night into Sunday
morning. Drier air had a difficult time mixing down this
afternoon. Observations from the Kentucky mesonet is showing
upper 30s to around 40 minimum afternoon surface dew points for
most locations. Seeing some mid 30s at a few stations located at
higher elevations. Surface dew points will recover somewhat by
sunset as well. That would not be conducive for frost overnight.
We only saw some patchy light frost reports this morning as valley
fog wound up being the more significant weather of the two. With
overnight low a bit warmer than last night, expecting the
potential of only a little patchy frost, mainly along and north of
the I-64 corridor but with some additional isolated areas further
south not totally out of the threat...where typically colder
temperatures rule under good radiative condition. Also, with
warmer overnight lows fog should not be quite as prevalent, but
should still see some in the main river valleys. Guidance seemed
to downplay this possibility, most likely because winds appear to
remain just high enough to keep some mixing in the boundary
layer. Evening shift will evaluate and likely beef up the fog in
the valley areas.

Operational models continue to trend a bit drier over eastern
Kentucky with Nestor as it tracks across the southeastern Continental U.S..
there is still some phasing of Nestor with a passing shortwave
trough across the region. Blends also continue to favor decent
pops across our far southeast, but lower quantitative precipitation forecast overall for Saturday
night into Sunday morning. But based on trends fear is that pops
and quantitative precipitation forecast might still be overdone. Just looked over some of the 18z
runs coming in and solutions generally support the drier trend.

Long term...(saturday night through thursday)
issued at 425 am EDT Friday 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 European model (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 European model (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

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 quantitative precipitation forecast 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 Friday 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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