779
FXUS62 KGSP 070606
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
206 AM EDT Tue May 7 2024

.SYNOPSIS...
A summerlike weather pattern lingers through mid-week with mainly
diurnal showers and thunderstorms expected. Temperatures will trend
well above normal through Thursday. Showers and thunderstorms will
become more numerous ahead of a strong cold front on Thursday.
Activity may linger through early Friday as the cold front pushes
east of the western Carolinas. Drier conditions and below normal
temperatures return for the weekend as high pressure builds in from
the west.

&&

.NEAR TERM /THROUGH TODAY/...
As of 100 AM EDT Tuesday: A second line of convection is now pushing
across the NC/TN border as of the writing of this AFD. Another line
of convection continues tracking eastward across the NC Piedmont and
eastern SC Upstate this morning. Storms have weakened compared to
the previous update, but a few strong storms will remain possible
with this activity. The main hazards with stronger storms are small
hail and gusty winds. Locally heavy rainfall may develop and lead to
minor flooding issues overnight, especially for areas that
repeatedly see storms track overhead. Once again increased PoPs
based on the latest KGSP radar loops so have high high-end chance to
low-end likely PoPs the next few hours.

Otherwise...as flow turns NW aloft, CAM guidance continues to depict
additional waves of scatter showers and thunderstorms through the
overnight hours...which should eventually fizzle as instability
wanes. Instability will be minimal but nonzero, and shear will
remain elevated...such that a few stray strong storms couldn`t be
ruled out. Low temps early tomorrow will be roughly 10 degrees above
climatology again.

&&

.SHORT TERM /TONIGHT THROUGH THURSDAY/...
As of 215 PM EDT Monday: A flat upper ridge will be in place across
the area Wednesday with weak short waves rippling through the flow
and across the area. A stronger short wave crosses the area early
Thursday as an upper low moves into the Great Lakes. At the surface,
a weak east/west oriented front stalls over the area Wednesday, with
a cold front moving in from the west on Thursday. The air mass
becomes very unstable Wednesday with moderate shear and mid level
dry air leading to increased DCAPE and sfc delta Theta-E values.
Coverage will be higher across the mountains, but severe storms will
be possible at any location across the area given these parameters.
Moisture increases on Thursday with less mid level dry air, DCAPE,
and sfc delta Theta-E values. Instability also falls, but could
remain in the moderate range while shear increases, approaching
strong territory. Convective coverage still favors the mountains,
but at least likely PoP will be featured across the area. Severe
storms will again be possible, but overall chance is more uncertain.
Highs Wednesday will push 90 degrees outside of the mountains, and
mid to upper 80s in the valleys then fall a few degrees Thursday.
Lows will be well above normal as well.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
As of 240 PM EDT Monday: The Great Lakes low opens into a trough
which moves into the area Friday. A series of short waves keeps the
general troughiness over the eastern CONUS through the end of the
period. With the trough moving in on Friday, cyclogenesis takes
place near the Carolina coast along the cold front that moves
through on Thursday. Guidance keeps going back and forth on the
location of the front and cyclogenesis, along with any lingering
moisture and resulting precip. Have continued the trend of chance
PoP for now given the uncertainty. A series of weak clipper-like low
pressure centers of frontal systems move near or over the area
through the rest of the period. This leads to isolated to possibly
low end scattered showers for the mountains each day with dry
conditions elsewhere. Temps fall to a few degrees below normal by
Saturday, then rise back to near normal through the end of the
period.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
At KCLT and elsewhere: Pesky convection continues this morning
across the SC Upstate, NC Piedmont, and the northern and central NC
mountains with some sites seeing MVFR restrictions. Thunder
potential has really died down within last few hours. Thus, only
isolated lightning is expected with activity this morning. SHRA is
currently impacting KCLT, KGMU, and KGSP as of 06Z. Went with a
TEMPO for SHRA at KCLT from 06Z-10Z and VCSH at KGSP and KGMU from
06Z-08Z. KAVL will see another round of SHRA impact the terminal
here shortly, so have a TEMPO for SHRA from 06Z-09Z. KHKY will see
another round of -RA from 08Z-11Z, with VCSH in place prior to 08Z.
KAND is expected to remain dry the rest of the TAF period. Cigs are
expected to lower through daybreak, becoming IFR to MVFR. Vsbys are
expected to drop through daybreak as well thanks to the rainfall
from yesterday and this morning. Most locations should see MVFR
vsbys, although KAVL may see vsbys drop to LIFR around daybreak.
Vsbys and cigs should gradually improve after sunrise, becoming VFR
by 13-14Z. VFR conditions will linger through the rest of the 06Z
TAF period outside of isolated thunderstorms tracking across western
NC this afternoon into early this evening. Went with PROB30s at all
of the NC TAF sites to account for TSRA. Afternoon cumulus will
develop thanks to daytime heating and low-end wind gusts will be
possible at KAVL and the SC Upstate terminals this afternoon. Wind
direction should generally be SW east of the mtns and W/WSW across
the mtns through the TAF period.

Outlook: Diurnal convection returns again on Wednesday. There is
potential for restrictions associated with widespread fog and/or low
stratus each morning for any terminals that receive rainfall the
day/night prior. A cold front will approach out of the west on
Thursday before tracking over the terminals Thursday night into
Friday morning. This will lead to better convective chances,
as well as restrictions, towards the end of the workweek.

&&

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

&&

$$

SYNOPSIS...AR
NEAR TERM...AR/MPR
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...AR