Area Forecast Discussion
Issued by NWS Greer, SC

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FXUS62 KGSP 242331
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
631 PM EST Fri Nov 24 2017

.SYNOPSIS...
High pressure will remain over the region tonight, before a
fast-moving cold front crosses the area Saturday afternoon. In the
front`s wake, another round of dry high pressure will overspread the
region and persist into the middle of next week.

&&

.NEAR TERM /THROUGH SATURDAY/...
As of 615 PM Friday...It remains clear acrs the cwfa, but IR
satellite imagery depicts encroaching cirrus ahead of the next
approaching cold front.

The flow aloft is still expected to become zonal tonight with the
sfc pressure gradient remaining weak. So, with some cirrus drifting
overhead there remains the probability of patchy lake and valley fog
early Saturday morning with minimums temperatures a few deg F above
climo.

With broad ridging across the western CONUS, mid to high clouds will
continue to gradually increase west to east on Saturday ahead of an
approaching cold front. As the front pushes through in the afternoon
hours, do not anticipate much in the way of precipitation given
limited moisture. However, have kept slight chance for light showers
along the NC/TN border in going forecast. Otherwise, clouds will
linger through the day as the upper trough axis propagates eastward,
remaining north of the area. High temperatures on Saturday again
will be slightly above normal, with light southwesterly winds in the
morning increasing to AOB 10 kts in the afternoon and veering
throughout the day.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
As of 200 PM EST Friday: the short term is very quiet, with cool,
dry high pressure building into the area from the west under an
eastern CONUS trough aloft. Skies should be mostly clear to clear
with temps near to slightly below normal both Sunday and Monday.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
As of 2pm EST Friday:  General flow pattern changes little for the
next 10 days with a mean trough over the eastern CONUS and
fluctuating ridge/trough behavior out west.  This pattern is
interrupted periodically by the passage of shortwaves (4 of them in
the Mon.-Friday period).  The passage of these features will be
accompanied by weak FROPAs, and some high clouds, but high
surface pressure remains mostly in control of the lower-levels, and
boundary layer moisture remains anemic, resulting in low POPs
through Thursday.  Both the GFS and EC models have a somewhat
better-defined shortwave trough moving east of the Plains Thursday
evening.  The GFS continues the pattern of relatively uneventful
wave passages, shearing this wave-out, and taking most of the energy
well northeast of the CWA.  The EC; however, develops it into a much
deeper, digging wave that could bring a round of significant and
varied weather approximately on Friday.  Current forecast is a blend
of these possibilities with limited POPs through Thursday, and some
chance for precipitation afterwards. Temperatures are forecast near
normal to 10 degrees above normal, but height falls behind the
Friday system depicted by the EC model would suggest some chance for
snow over the higher terrain, at least, should that scenario come to
pass.  Skies will be mostly clear and winds light and variable
through Thursday with some chance for change thereafter.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
At KCLT and Elsewhere: Clear with very light winds, tending from the
south tonight. There remains the probability of some degree of pre-
dawn valley and lake fog, but with the magnitude and cvrg expected
to be less than what it was this morning, there would be even less
of a chance of vsby reductions at any terminal location.  On
Saturday, expect VFR to continue as high clouds gradually increase
in opacity throughout the day ahead of an approaching cold front.
Light southwesterly winds will increase to around 5 to 8 kts by late
morning/early afternoon.

Outlook: Expect mainly VFR conditions through the forecast period as
generally dry and cool conditions prevail.

Confidence Table...

            23-05Z        05-11Z        11-17Z        17-18Z
KCLT       High 100%     High 100%     High 100%     High 100%
KGSP       High 100%     High 100%     High 100%     High 100%
KAVL       High 100%     High 100%     High 100%     High 100%
KHKY       High 100%     High 100%     High 100%     High 100%
KGMU       High 100%     High 100%     High 100%     High 100%
KAND       High 100%     High 100%     High 100%     High 100%

The percentage reflects the number of guidance members agreeing
with the scheduled TAF issuance flight rule category. Complete hourly
experimental aviation forecast consistency tables and ensemble forecasts
are available at the following link:

www.weather.gov/gsp/aviation

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.

&&

$$
SYNOPSIS...ARK
NEAR TERM...CSH/SGL
SHORT TERM...ARK
LONG TERM...WJM
AVIATION...CSH/SGL



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