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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KGSP 251913
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
313 PM EDT Tue Sep 25 2018

.SYNOPSIS...
A cold front will move into the mountains Wednesday and stall across
the area. This front will help produce showers and thunderstorms as
it lingers over the forecast area into the weekend.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
-- Changed Discussion --
As of 255 PM EDT: A weak sfc low pressure system over the Great
Lakes continues to drag a neutrally tilted cold front across W
portions of the Ohio River Valley S to near New Orleans. Weak
southerly upglide has helped to sock in portions of the Upstate into
W NC with low clouds this afternoon with highs only into the 70s so
far today. Outside of this region highs have reached up to around 80
and will likely continue to climb a few degrees over the next few
hours. A few showers have developed over NE Georgia. Some of these
showers may push into the W Upstate of SC or W NC later this
afternoon or evening despite the stabilizing effects of the remnant
cool pool from the CAD. A thunderstorm or two may develop across far
SW portions of the FA this afternoon or early evening due to limited
instability.

Partly cloudy to mostly clear skies tonight along with remnant llvl
moisture will likely bring at least patchy fog to some areas east of
the mtns, although likely not as widespread or restricting as early
today. After a relative lull in precipitation later this evening, an
approaches cold front and some increase in mid level forcing will
provide increasing cloud cover and the opportunity for rain and
thunderstorms from W to E late tonight and through the day
Wednesday. Moderate instability and some upper level support will
likely support some gusty winds and small hail with the strongest
thunderstorms Wednesday afternoon and early evening.

The moist environment will continue to support mild overnight lows
from the 60s to near 70. High temperatures Wednesday are expected to
rebound into the 80s east of the mountains where better insolation
is expected to only 70s at best across most mountain locations.
-- End Changed Discussion --

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
-- Changed Discussion --
As of 255 PM EDT Tuesday: With an upper longwave trough across much
of the mid to eastern CONUS and Atlantic ridge well in place,
scattered to numerous showers and thunderstorms are expected
throughout the short term forecast period, which begins Wednesday
night, as a cold front becomes stationary across the Carolinas.
While the more favorable dynamics will stay just north of the FA on
Wednesday as the shortwave moves across the Great Lakes (as
highlighted in the current SPC Day 2 Convective Outlook), per latest
guidance, enough available instability and low yet notable shear in
place in the evening could still spark a few isolated strong to
severe storms around the beginning of the forecast period. Also,
would not entirely rule out heavy rainfall/localized minor flooding
with any storm as PW values will near 2 inches.

Into Thursday, latest guidance progs environmental conditions not as
conducive for a severe threat given persistent cloud cover/slightly
lower high temps and thus, less instability than on Wednesday.
However, with the front stationary across the FA, a bit of a shear
axis with lowered instability could still pose a threat for an
isolated stronger/severe storm. Temperatures throughout the forecast
period will remain just above normal.
-- End Changed Discussion --

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
-- Changed Discussion --
As of 220 PM EDT Tuesday: The cold front stalled over the area in
the short term finally moves south of the area Saturday as high
pressure builds in from the north. However, a moist low level flow
southerly flow develops bringing moisture in over the building high
pressure. This creates a cold air damming scenario which remains in
place through Monday. The flow over the high isn`t that strong and
there is dry air which works in from the north. Therefore, PoPs are
limited to the slight chance to low chance range through the period.
The air mass isn`t especially cool either, so temps remain near nor
a little above normal. The center of the high moves off shore
Tuesday as a front moves into the Ohio Valley. The moist low level
flow continues keeping a chance of rain in the forecast. Temps will
a little above normal.
-- End Changed Discussion --

&&

.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
-- Changed Discussion --
At KCLT and elsewhere: Low confidence in 18Z TAFs due to uncertainty
in ceiling improvements early in the period and timing of TSRA and
associated restrictions near the end. Low ceilings across the
afternoon expected to continue to improve this afternoon, with
terminals nearest the mountains likely being the slowest to improve.
Remnant moisture and mainly clear skies will likely lead to mainly
MVFR fog with lower restrictions possible in mtn valleys including
KAVL. TSRA activity expected to gradually spread from west to east
across the region between 10 and 18Z. Timing of shower and
thunderstorm activity and assoc restrictions may be off by 3 hours.

Outlook: A stalled front will across the region will continue to be
a trigger point for showers and thunderstorms through at least
Friday and possibly into this weekend.

Confidence Table...

            19-01Z        01-07Z        07-13Z        13-18Z
KCLT       High  96%     High  96%     High  96%     High 100%
KGSP       High  86%     High  96%     Med   66%     High  87%
KAVL       High  86%     Med   74%     Med   79%     High  83%
KHKY       High  91%     High  91%     Med   73%     High  87%
KGMU       High  91%     High 100%     High  84%     High  88%
KAND       High  91%     High 100%     High  93%     High  85%

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
-- End Changed Discussion --

&&

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

&&

$$
SYNOPSIS...RWH
NEAR TERM...Munroe
SHORT TERM...SGL
LONG TERM...RWH
AVIATION...Munroe