787
FXUS62 KGSP 042341
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
741 PM EDT Tue Jun 4 2024

.SYNOPSIS...
Scattered showers and thunderstorms are on tap with afternoon
storms persisting into Thursday. Dry air will mix in Friday and
persist into the weekend with a small chance of mainly
mountain thunderstorms returning for Sunday afternoon.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
As of 600 PM EDT Tuesday: Latest radar and satellite show scattered
thunderstorms across the CWA, developing from the south and moving
northward. Given the limited upper support, showers and
thunderstorms are still expected to remain sub-severe, but an
isolated severe storm or two cannot be ruled out. Storms should
start to diminish after sunset. Adjustments for PoPs and current
temps made to account for cooling in areas near storms.

Meanwhile, GSP finds itself beneath a weak upper ridge this
afternoon, with convection just firing up across the area.  The
synoptic setup will remain largely unchanged through the duration of
the near term, with the Carolinas ensconced in a strengthening warm
advective regime. Heights will fall ever-so-gently aloft in response
to a deepening upper low over Manitoba and peripheral shortwave
trough sliding up the central Ohio Valley.  As the localized ridge
axis drifts east of the area, high pressure over the west Atlantic
will intensify and drive ever more moisture into the forecast area.

All the action today will come from mesoscale elements.
This afternoon, basically all the CAMs depict some flavor of
1200-1600 J/kg sbCAPE across the region, in advance of a remnant MCV
drifting out of TN.  So that will manifest as continuing scattered
convection, triggering especially over the NC mountains, during
the early/mid afternoon, followed by the arrival of a somewhat more
organized line picking up out of Georgia in the late afternoon and
evening hours.  Generally speaking, lapse rates will be poor and
deep layer shear minimal, but where there`s organization associated
with the MCV, a some strong storms - perhaps even a severe -
can`t be ruled out.  Isolated heavy rain will also be a concern,
with RAP profiles indicating 1.6-1.9" PWs...but flow aloft will
be strong enough to keep storms moving, so only in locations where
multiple cells train will there be problems.

Tonight, another round of fog is expected, for the mountain valleys
and for any locations that receive appreciable rainfall this
afternoon and evening.  Some light sprinkles may linger well into
the overnight, but should become less in coverage and intensity
as the night progresses.  Kind of like this morning, a few early
morning showers can be expected over the Upstate and southern
NC mountains Wednesday, but impacts are expected to be minimal.
The bulk of CAMs then depict another round of scattered showers
and thunderstorms tomorrow afternoon, in an environment of better
instability and synoptic support than today`s, but similarly
paltry shear.  Severe risk looks overall a little higher on
Wednesday compared to today, owing to the stronger forcing and
better instability.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
As of 2:25 PM Tuesday...the short-term fcst picks up at 00z on
Thursday with a fairly robust upper shortwave approaching the
Western Carolinas from the west. Over the next 24 to 48 hours,
the shortwave will move thru our area and then offshore as broader
upper level trofing morphs into a large, closed h5 low centered
over the Great Lakes. At the sfc, another moist cold front will
be moving into our fcst area from the west as the period begins.
The front will move thru early Thursday and is expected to be
moving off the coast by late Thursday. It will likely produce
sct to numerous showers and thunderstorms on Thursday across
our CWA, however most of the model guidance continues to depict
weak low to mid-level lapse rates. Thus, the severe potential
appears to minimal at best. In its wake, broad but fairly weak
high pressure will gradually spread over our area on Friday and
linger into the weekend keeping us dry for the latter half of the
period.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
As of 2:15 PM Tuesday...the extended forecast picks up at 00z on
Saturday with a broad upper trof having morphed into an h5 low
centered over the eastern Great Lakes. Over the next few days,
the upper low will get reinforced from the NW with additional
upper level energy and become larger. By early next week, the
low begins to open back up to the mean flow as the western peri-
phery of the low dives southward. This will allow the upper low/
trof axis to translate over our area by the end of the period
next Tuesday. At the sfc, broad but fairly weak high pressure
will be spreading over the Southeast as the period begins late
Friday. The is expected to be transitory and weaken/move off the
Atlantic Coast on Saturday. On Sunday, low pressure well to our
north will move a weak/moist cold front to our doorstep from the
NW. This boundary is expected to linger over our area into early
next week. As it does, most of the long-range guidance has multiple
weak lows trying to spin up over our area along what`s left of the
boundary. As for the sensible wx, I expect mostly dry conditions
for Saturday with a return to more diurnally-driven climo PoPs
for the rest of the period.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
At KCLT and elsewhere: Starting off the TAF period with ongoing,
widespread showers and thunderstorms across most terminals. Most
have remained sub-severe, but gusty winds and frequent cloud to
ground lightning are causing issues. TEMPOs for KCLT, KGSP, KAND,
and KGMU have been extended through at least 02z for TSRA.
Intermittent showers could occur after this timeframe through
midnight, creating additional VSBY concerns. CIGS during the
overnight period will drop to MVFR and then IFR with scattered
patchy fog and low level stratus. This will be more likely in areas
that received higher rainfall amounts from evening storms. Similar
to this morning, CIGS are not expected to improve until mid-morning
when clouds can mix out and bring back MVFR/VFR conditions. If any
showers can develop in the morning hours, this could also hinder
CIG/VSBY improvements. Another round of typical summertime showers
and thunderstorms likely for Wednesday afternoon, hence a PROB30 for
TSRA. Winds outside of TS activity will prevail S/SW with speeds 5-
10kts at all sites.

Outlook: Afternoon thunderstorms likely through Wednesday and
morning fog/low stratus development through Thursday morning. Drier
air moves into the area by the end of the week improving
restrictions into the weekend.

&&

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

&&

$$

SYNOPSIS...DEO
NEAR TERM...CP/MPR
SHORT TERM...JPT
LONG TERM...JPT
AVIATION...CP