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000
FXUS62 KGSP 051740
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1240 PM EST Sat Dec 5 2020

.SYNOPSIS...
Another fast-moving system could bring light precipitation to our
region Sunday night and Monday, and possibly another round of light
snow for the mountains. Seasonably cool and dry weather is otherwise
expected through Friday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 1230 PM Saturday...Radars have gone quiet. Satellite imagery
continues to show some low cloudiness over the nrn mountains,
but cloud top temps have continued to warm to the point where no
significant threat of snow exists, so precip prob has been removed
for the rest of the day. The clouds should gradually diminish
late in the day, as will the occasional wind gusts. Temps were in
relatively good shape.

Otherwise, the upper trof axis will continue to lift NE and off
the Atlantic Coast today/tonight. This will result in a brief,
nearly zonal upper pattern towards the end of the period early
Sunday before the next round of upper-lvl energy approaches the
fcst area from the north and west. At the sfc, the low pressure
system will continue to move northward and up the Atlantic/New
England Coast as broad high pressure spreads back over the region
in its wake. This will make for a sunny and breezy Saturday for
most of the CWFA with temps outside the mtns, near normal, if not
a couple degrees below. Highs across the higher terrain will be 1
to 2 categories below normal. Clouds and light NW-flow snow showers
will linger over the higher terrain and especially along the NC/TN
border thru late morning. Any accumulations should remain below
Advisory criteria, with the exception of a few isolated spots along
the NC/TN border. As we move into the aftn, guidance has bndy layer
moisture diminishing across the higher terrain and precip ending.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
As of 100 PM Sat: A developing light pcpn event is still expected
Sunday night as encroaching southern stream energy aids in
blossoming pcpn shield northeastward from the Gulf of Mexico.
Ensembles continue to adverise mean QPF of less than a tenth of an
inch through daybreak Monday and mainly limited to the piedmont.  In
the critical chillier air over the mountains, thermal profiles still
support frozen pcpn, but with only a few hundreths liquid accum
expected, hard to believe that any pre-dawn light snow accums would
be seen outside of the higher elevations of the SW mtns.

In conjunction with potent looking northern stream vort, showers are
expected to redevelop and expand on Monday, especially in the
mountains in conjunction with llvl caa and upslope flow.
Temperatures will remain cool enough across the higher elevations
for accumulating snow, maybe even for a higher elevation advisory
level event, into Monday evening.  With clouds and caa keeping maxes
well below normal and vertical temp profiles becoming increasingly
supportive of frozen pcpn even across the lower elevations as Monday
wears on, will be monitoring the situation closely to see if there
is enough lingering moisture to carry precip downstream of the
mountains.

After a chilly start to the day on Tuesday, widespread 20s for
morning minumums, a sunny, brisk and chilly day is on tap featuring
maximum temperatures several categories below climo.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 240 AM Sat: One more trailing shortwave is progged to traverse
the area Tuesday as upper trough shifts offshore, but without any
moisture to speak of. A broad ridge will replace these features,
bringing dry wx and moderating temps to the South Wednesday thru
Friday. Maxes will be a couple categories above normal Thu and Fri,
in the upper 50s and lower 60s for the mtn valleys and Piedmont. One
or more shortwaves will reach the Plains by the end of the work week;
GFS and ECMWF both depict cyclogenesis such that a cold front
approaches the area Friday night. The CMC GDPS instead shows the sfc
low crossing the Great Lakes. Given this disagreement, and this
development being very close to the end of the period, precip chances
are being kept below the mentionable threshold thru 12z Sat.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
At KCLT and elsewhere: VFR through the period, with only a
few stratocu across parts of NC through sunset. A few gusts are
possible at the NC sites as well. All this should diminish with
sunset, leaving us with clear sky and a light N or variable wind
overnight as high pressure settles in. Sunday should start out
clear, with wind returning light from the SE/S. Some high clouds
will start to invade in the afternoon.

Outlook: Moisture will return Sunday night with cig restrictions
possible at times on Monday as another low pressure system lifts
out of the Gulf and up the Atlantic Coast. Once that system departs
Monday night, the rest of the period should be VFR.

Confidence Table...

            17-23Z        23-05Z        05-11Z        11-12Z
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 are available at
the following link:

www.weather.gov/gsp/aviation

&&

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

&&

$$
SYNOPSIS...Wimberley
NEAR TERM...JPT/PM
SHORT TERM...Wimberley
LONG TERM...Wimberley
AVIATION...PM