Area Forecast Discussion
Issued by NWS Greer, SC

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FXUS62 KGSP 241749
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
149 PM EDT WED AUG 24 2016

.SYNOPSIS...
High pressure will persist over the region through midweek allowing
temperatures to climb back above normal. Another weak cold front will
approach the Western Carolinas from the northwest toward the end of
the work week, with high pressure building back to our north over the
weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 145 PM: Stratocu deck lingers over the wrn two-thirds of
the CWFA, evidently being maintained by weak westerly upglide
over the high pressure over the Eastern Seaboard. The deck is
becoming more cellular on visible satellite. Isolated showers
are also developing within it, as the surface warms. Assuming the
deck erodes in the next couple hours, there still is potential for
scattered showers/tstms to develop over the mtns if not foothills.

Tonight: Showers and/or storms that do develop should dissipate
quickly with loss of heating this evening. However, deep-layer
moisture will linger atop the CWFA, which will keep skies partly
to mostly cloudy overnight. The 850 mb flow will shift from SELY
to NWLY as the low-level high pres shifts westward slightly,
and in response to the ewd progression of a low-mid level trough
over the Great Lakes. So instead of stratocu from upslope flow,
perhaps more mid and high cloudiness. Temps will bottom out at or
slightly above normal.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
As of 315 AM EDT Wednesday...the short term fcst picks up at 12Z
on Thursday with broad upper ridging in place over the SE CONUS
that will persist well into the medium range. At the sfc, high
pressure will move farther NE of our area on Thursday allowing the
wedge to weaken and essentially dissolve. An area of pre-frontal
moisture will pass to our north later on Thursday and into Friday,
yet the model guidance has been trending a bit drier since yesterday
and keeps most of the deeper moisture out of the CWFA. As the front
lifts farther NE late Friday and into Saturday, another high slides
over the Great Lakes in its wake. As for the sensible wx, the models
have been trending a bit drier overall but still have more moisture
over the higher terrain especially on Thursday. Temps start out around
climatology if not just above, and warm thru the period with highs on
Friday and Saturday about a category above normal.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 3 AM EDT Wednesday...the medium range fcst picks up at 12Z
on Saturday with broad upper ridging in place over the SE region.
The ridge is expected to flatten a bit on Sunday and Monday but
still maintain control over the overall synoptic pattern. It is
noteworthy that the 12Z run of the ECMWF continues to develop a
tropical low over the Bahamas early in the period and move the
low due west across Southern Florida and then north over the
northern gulf coast by day 7. The newer 00Z run of the GFS also
tries to develop a low over the same area, but it remains considerably
weaker at this time. At the sfc, high pressure will be centered to
our north over the Great Lakes keeping things mostly dry for the
weekend and early next week. The big question comes just beyond
day 7 and the possibility of a tropical system moving into the
Gulf of Mexico and making landfall along the northern gulf coast.
It is still too early to have much confidence in any specific
model track, but it`s looking like a tropical low will develop
during that timeframe. As for the sensible fcst, no major changes
were necessary with below climo POPs for the period and temps about a
category above normal.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
At KCLT and elsewhere: Offshore Atlantic high pressure will
generally maintain southerly surface flow over the area thru
Thursday. However, moist west-southwest flow atop this airmass
has brought a persistent area of stratocumulus to the southern
Appalachians and vicinity. These clouds are showing signs of
breaking up and lifting at 18z, but will persist in some places
thru evening. Sufficient destabilization is expected over the
mtns to prompt VCTS inclusion at KAVL. Winds aloft will veer and
bring in additional moisture overnight. Low VFR cigs are likely
to come and go throughout the period. Models depict only a small
amount of restrictive clouds overnight, generally favoring the
production of fog instead. With so much higher cloud cover present,
and uncertainty about how much mixing/drying will occur in the
low levels this aftn, fog mention is included only in TEMPO at
KAVL/KHKY; at KAND nearby soaking rains earlier today will play
a factor.

Outlook: A deep ridge will remain in place over the Southeast thru
the weekend, keeping afternoon SHRA/TSRA chances below normal each
day, and generally confined to the mountains. However, sfc moisture
will gradually return, and morning vsby restrictions will become
increasingly likely during this time.

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  83%     Med   66%
KAVL       High  94%     High 100%     High  83%     Med   78%
KHKY       High  94%     High 100%     High 100%     High 100%
KGMU       High 100%     High 100%     High  83%     Med   66%
KAND       High 100%     High 100%     High 100%     Med   66%

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...JPT
NEAR TERM...ARK/Wimberley
SHORT TERM...JPT
LONG TERM...JPT
AVIATION...Wimberley



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