Area Forecast Discussion
Issued by NWS Greer, SC
FXUS62 KGSP 251043
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
643 AM EDT WED MAY 25 2016
High pressure will prevail over the Southeast most of this
week. Moist southerly flow will lead to warmer temperatures and
mainly afternoon chances of showers and thunderstorms each day
through Friday. A period of cooler and wetter weather may develop
late in the weekend as low pressure moves onshore from the Atlantic.
.NEAR TERM /THROUGH TONIGHT/...
As of 640 AM: Area of mid clouds has moved east, but additional mid
and high clouds are moving back in from the west ahead of a weak
short wave moving toward the area. Southwesterly low level flow will
bring increasing moisture and warmth to the area today. This will
lead to weak instability across the mountains this afternoon.
Isolated to scattered convection will develop across the mountains
this afternoon then diminish during the evening. Forecast soundings
show a capped atmosphere or very high LFC levels outside of the
mountains today. The synoptic scale guidance is in good agreement on
this scenario. Some of the convection allowing models show a line of
convection developing to our west ahead of the aforementioned weak
short wave. This convection moves into the mountains, including NE
GA and the Upstate, this afternoon and dissipates as it reaches the
foothills of the three states. For now, have followed the synoptic
model scenario given the weak short wave and weak instability.
Clouds will linger much of the night even as the convection wanes.
Highs today and lows tonight will be around 5 degrees above normal.
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
As of 245 AM Wed: Generally speaking, a western Atlantic ridge
will be the dominant feature over the Southeast Thursday and
Friday. Moist southerly low-level flow will continue. On Thursday
a broad warm front will extend from low pressure over the northern
Plains southeastward into the upper Ohio Valley and vicinity, but
unlike some previous runs there is no longer indication this will
enhance lift over our CWFA. Diurnal destabilization will result
in PoPs slightly above climo and extending to all zones. The
ridge deepens by Friday afternoon and lapse rates are not quite
as good, so chances are correspondingly lower then. Max temps will
be slightly above climo, and mins will be several degrees above.
.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 310 AM Wed: The upper pattern progresses little into the
weekend, with the Bermuda High holding back the central CONUS
trough. While this by itself would suggest a continuation of mainly
diurnal convection and near- or above-normal temps, the "wildcard"
in the forecast continues to be the track of low pressure moving
out of the Bahamas and toward the South Atlantic coast Saturday and
beyond. Global models continue to show poor run-to-run consistency
with this feature, but the latest consensus (if you can call it
that) suggests the low will approach the Charleston area. Some
guidance stagnates the low along the coast and eventually takes
it toward the Outer Banks; the GFS and some GEM Ensemble members
instead bring it onshore near the mouth of the Savannah River. While
most guidance suggests deeper tropical moisture spreading over the
Carolinas as the low approaches, they do so to varying degrees,
and the timing thereof is not agreed upon. For now, a blend of
favored guidance produces suppressed diurnal PoPs on Saturday as a
pocket of dry air swings over the area ahead of the low, but then
a slow but steady increase in chances from Saturday night into
Monday. Max temps will fall to a couple degrees below climo early
next week under mostly cloudy and damp conditions; this will keep
diurnal ranges limited and thus min temps will be well above climo.
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
At KCLT and elsewhere: area of mid clouds has moved east, but mid
and high clouds are moving back into the area from the west. Any
patchy fog will quickly burn off this morning. Expect cumulus to
develop with heating after daybreak. Isolated to scattered mountain
ridge top convection will develop through the afternoon then taper
off during the evening. Confidence too low for any mention at KAVL
or the other airfields. SW winds will increase in speed through the
day, then taper off during the evening.
Outlook: Mainly VFR conditions will prevail through the period, but
patchy morning fog chances continue at KAVL. Scattered afternoon
SHRA/TSRA coverage will increase Thursday through Friday - with more
uncertainty on Sat.
10-16Z 16-22Z 22-04Z 04-06Z
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 schedule TAF issuance flight rule category. Complete hourly
experimental aviation forecast consistency tables and ensemble forecasts
are available at the following link: