000
FXUS62 KGSP 301343
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
943 AM EDT Thu Jun 30 2022

.SYNOPSIS...
High pressure off the Southeast coast will take over today and
Friday, with a southerly flow of moisture fueling daily shower
and thunderstorm chances into the weekend. Another weak front will
approach from the north during the weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 930 AM: Forecast appears pretty much on track today. The
patchy dense fog which formed soon after daybreak has generally
dissipated; mountain valleys still have some stratus and perhaps
localized light fog, but it is quickly eroding.

Upper-level ridging builds back over the Carolinas and northeast
Georgia throughout the day which should mostly suppress convective
initiation today. With S/SE`ly return flow off the Atlantic, could
still see isolated diurnal shower and thunderstorm activity develop,
mainly across the mountain zones, as CAMs have mostly a muted
response east of the mountains. Very low-based cumulus field is
already breaking out in parts of the GA/SC zones, which lends some
confidence to RAP CCLs/profiles, and in turn suggests a mention of
isolated showers/storms remains warranted for the southern half of
the Piedmont, although CAMs have trended slightly further down in
their coverage there. Did make very minor update to PoPs to bring
the numbers down a little. Even over the mountains only scattered
wording is warranted, due to there being no real trigger in place
for convection.  SBCAPE values from 1,000-1,200 J/kg are expected
during peak daytime heating, however with minimal shear in place
as well as mostly cloudy skies, the severe weather threat should
be low, if any. With less than 10 knots of shear in place this
afternoon, any showers and thunderstorms that develop will be slow
moving. So, heavy rain would be the main potential concern today,
especially if convection were to sit directly over one location
for an extended period of time.

High temps look good as-is, and will be near climo to a few degrees
above climo this afternoon, climbing back into the upper 80s and
low 90s east of the mountains. Low 70s to low 80s can be expected
across the mountains.  Cloud cover will remain in place again
overnight leading to lows about 3 to 5 degrees above climo lows.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY/...
As of 330 AM EDT Thursday: As we go into the weekend, high pressure
at the sfc and aloft sets up shop off the Southeast Coast while
a weakness in the elongated west-to-east mid/upper ridge develops
just to the west of the srn Appalachians. This pattern is favorable
for greater than normal coverage of diurnally-driven showers and
thunderstorms, so Friday is the beginning of a regime of daily
likely precip probs over the mtns and good chance across the
Piedmont of the Carolinas. Extensive cloud cover and more shower
activity is expected to keep temps a degree or two on the cool
side of normal. Poor lapse rates, modest sfc-based CAPE, high
precipitable water, deep warm cloud depth, weak flow, and slow
storm motion suggest more of a threat for locally heavy rain and
flooding than severe wind gusts. However, confidence isn`t high
enough to mention in the HWO.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
As of 243 AM EDT Thursday: Looks like fairly classic summer
weather out in the medium range, as the Bermuda High remains in
position to supply a light southerly flow of moisture through
the period. Meanwhile, some weakness in the upper ridge extending
across the Deep South will keep the environment favorable for mainly
diurnal convection with either differential heating over the mtns
or a weak lee sfc trof providing some focus/trigger each afternoon
through the period. Precip probs will be above climo and temps
will be right at climo each day. In this pattern, it is reasonable
to expect a few strong/severe pulse storms with perhaps also some
locally heavy rain, but this does not warrant a mention in the HWO.

&&

.AVIATION /14Z THURSDAY THROUGH MONDAY/...
At KCLT and elsewhere: Patchy fog has developed across portions
of the fcst area this morning. KAVL is the only terminal really
affected by fog and low stratus this morning with with IFR vsbys and
LIFR cigs in place. Fog should lift an hour or two after daybreak.
KGSP, KGMU, and KAND are seeing MVFR cigs this morning, but these
should lift to VFR near daybreak. Dry conditions are expected to
continue through the morning hours. Winds start out calm to light
and variable early this morning, becoming S/SE`ly and light later
this morning. Isolated shower and thunderstorm chances look best
across the mountains this afternoon and evening with mostly dry
conditions east of the mountains. So, for now have dry conditions
east of the mountains with only a mention of VCSH at KAVL. Winds
become light and variable again this evening into tonight with VFR
cloud cover. IFR cigs and vsbys are possible at KAVL daybreak
Friday. KAND may see MVFR cigs daybreak Friday as well. Shower and
thunderstorm chances return Friday afternoon and as the KCLT TAF
goes through 18z Friday, have VCSH mentioned for this potential.

Outlook: Diurnal chances of SHRA/TSRA continue into the weekend. Low-
end fog restrictions will be possible each morning, especially for
any locations that received rain the previous afternoon.

&&

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

&&

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

NWS GSP Office Area Forecast Discussion