Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 241419
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
1019 AM EDT Sat Sep 24 2016

.UPDATE...
Issued at 1019 AM EDT SAT SEP 24 2016

Fog has been slow to lift and dissipate in some areas this
morning (mainly the deeper river valleys in the far SE), but
latest observations have show improvement to clear conditions in
most locations over the last hour. This correlated fairly well
with the ongoing weather grids which had valley fog dissipating
over the 13z hour. Updated the near term forecast for temps, dew
points, and winds to make sure the latest observational data was
included in the forecast. Overall the forecast is very well on
track with few changes resulting. All updates have been sent to
NDFD/web. A new forecast package and HWO were also sent out to
remove morning fog wording.

UPDATE Issued at 720 AM EDT SAT SEP 24 2016

Touched up the grids to fine tune sky cover and the fog locations
through the first part of the morning based on the latest
observations and trends. These have been sent to the NDFD and web
servers.

&&

.SHORT TERM...(Today through Sunday)
Issued at 320 AM EDT SAT SEP 24 2016

06Z sfc analysis shows high pressure still in control of the
weather throughout the Ohio Valley and Central Appalachians. This
has been a persistent pattern and, as such, conditions are not
varying much day to day. For tonight, a few more high clouds may
affect our northeast counties through dawn, but skies have
been and will remain clear for the vast majority of the area into
Saturday morning. With light winds, and high pressure centered to
the northeast of the CWA, a good night for radiational cooling is
again underway resulting in readings varying by relative elevation
and valley slope steepness. Specifically, temperatures range
from the mild low 70s on the ridges to lower 60s in the most
sheltered locations - slightly up from this time last night.
Dewpoints are in the same ball park as last night - generally in
the low to mid 60s and fairly uniform throughout eastern Kentucky.
Unlike last night, there are some earlier hints of fog developing
in the river valleys with EKQ and an ob site near Williamsburg
reporting light fog this hour - along with the Harlan airport
site. Look for the fog to be a tad more extensive this morning,
but still mainly confined to the river valleys - locally dense.

The models continue to be in good agreement aloft through the
short term. They all depict ridging building into the area from
the southwest today and through the rest of the weekend. This
takes place north of a mid level weakness and lower heights over
the Deep South. It also serves to keep any energy far away from
the region - way off to the northeast and northwest. Given the
good model agreement have again favored persistence for the main
driver of the forecast with minor adjustments toward the latest
near term model blends.

Sensible weather will feature another unseasonably warm day with
humidity a bit higher than yesterday under mostly sunny skies. The
limited valley fog will all burn off and dissipate by 10 am today
and again a repeat anticipated for Sunday morning. Will allow for
a few more clouds this afternoon as the sfc moisture increases and
again on Sunday given a boundary off just to the northeast. The
night will be dominated by ridge to valley temperature differences
under mostly clear skies and light to calm winds. Readings will
likely continue their tick up for at least one more night in this
stagnant pattern.

Again used the CONSShort/ShortBlend as a starting point through
the evening and SuperBlend thereafter up to 00z Monday. Did bump
up temps a notch today and Sunday for highs given recent trends
for this pattern. Also, made more substantial changes to the
terrain based edit areas and point based temperatures tonight to
better reflect the ridge to valley differences. As for PoPs -
basically zeroed them out through Sunday morning, before allowing
for some mainly single digit values toward the end of the short
term forecast period - in line with all MOS guidance.

.LONG TERM...(Sunday night through Friday)
Issued at 335 AM EDT SAT SEP 24 2016

Models have come into much better agreement with the transition from
summer-like to seasonal fall weather during the first half of the
coming work week. This occurs as a deep upper level trough,
currently over Wyoming, splits with its northern piece shifting
eastward and breaking down the upper ridge currently in place over
the Tennessee Valley. The trough and closed low system will dig
southward from the Great Lakes into our area Tuesday and Wednesday,
then may push off the east coast. There are some discrepancies with
how the models handle the closed low beyond the Wednesday time
frame and this could have impacts on how long the cool air sticks
around as well as potential cloud cover. However, there is still
good agreement with the initial transition to cool weather. At the
surface, all models have trended toward the faster and drier
frontal passage solution shown in the past several ECMWF runs.

In terms of sensible weather, summer-like warmth comes to a close
Monday as a cold front approaches the region. Pops increase Monday
afternoon and continue through Monday evening as the front quickly
passes through East Kentucky during the evening time frame. Less
than a quarter inch of rain is generally expected with the frontal
passage, which won`t make much of a dent in the rain deficit for the
month of September. Some lingering showers may be possible along the
Virginia border Tuesday morning but otherwise the area should be dry
by dawn on Tuesday. A much cooler and drier air mass will invade the
region behind the front, with afternoon highs topping out in the low
and mid 70s for the remainder of the work week. Overnight lows will
dip below seasonable values with temperatures ranging from the mid
40s to low 50s.

&&

.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
ISSUED AT 725 AM EDT SAT SEP 24 2016

High pressure will remain in control of our weather through the
weekend resulting in VFR conditions for most areas with light and
variable winds. Patchy valley fog this morning will be a big more
extensive than what we saw yesterday affecting SME with some MVFR
BR for a couple of hours this morning, and again late tonight,
otherwise have kept the TAFs to one line.

&&

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

$$

UPDATE...JMW
SHORT TERM...GREIF
LONG TERM...JVM/ABE
AVIATION...GREIF



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