553
FXUS62 KGSP 091531
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1131 AM EDT Sun Jun 9 2024

.SYNOPSIS...
A cold front moves in today with returning shower and thunderstorm
chances, mainly this afternoon and evening. The front moves south of
the area Monday and Tuesday with dry conditions expected. Forecast
confidence lowers through the rest of the week as overall pattern is
uncertain. For now, a chance of afternoon and evening showers and
thunderstorms is expected to return late in the week with above
normal temperatures.

&&

.NEAR TERM /THROUGH TONIGHT/...
Key Messages...

1) Lingering Cloud Cover and Light Rain May Limit Both the Severe
Weather Potential and High Temperatures this Afternoon

2) Another Round of Rain is Expected to Develop Overnight

As of 1125 AM EDT Sunday: Cloud cover across the forecast area
has allow temps to stay much cooler than forecast so far so
lowered temps a few degrees through the morning hours to factor
in the limited insolation. No other changes were needed this
update. Otherwise, light rain continues tracking eastward across
the central portion of the CWA this morning but it continues to
gradually fall apart the farther east it goes.

Large scale height falls will carve out a broad trough across the
East by end of the period, with a series of embedded MCVs expected
to ripple across our region, esp this afternoon and evening. A cold
front is forecast to move into the forecast area this afternoon, and
move steadily east throughout the afternoon/evening. This will
provide the primary focus for initiation of deep convection.
Uncertainty persists regarding the magnitude of destabilization this
afternoon, owing primarily to uncertainty re: the extent, longevity,
and thickness of this morning`s debris cloud cover and attendant
impacts on insolation. Our best guess based upon a consensus of
deterministic and probabilistic guidance is that sbCAPE will peak at
around 1500 J/kg across much of the area this afternoon. With deep
layer shear expected to range from 30-40 kts, instability is
expected to be just enough to yield a marginal severe storm threat.
Shear values may support a couple of rotating cells, but forecast
low level shear and SRH values are such that the tornado threat is
minimal, and isolated damaging wind gusts and large hail will be the
main threats.

Max temps are forecast to be about a category above normal, with
temps likely reaching or exceeding the 90 degree mark across the
southeast quadrant of the CWA. However, cloud cover from this
morning may limit highs somewhat this afternoon. Convective chances
linger into the overnight hours, especially across the southern half
of the CWA, as the front takes its time clearing the area of
moisture. However, overnight convection is expected to be
tame...likely more showery than anything...as instability quickly
weakens owing to very poor mid-level lapse rates. Min temps are
expected to be close to normal.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
As of 145 AM EDT Sunday: The aforementioned cold front will be in
the vicinity of the southern portion of the CFWA and may keep a few
lingering showers across the Upstate and northeast Georgia through
mid-morning Monday. Otherwise, drier air filters in by Monday
afternoon thanks to a continental surface high building in from
the northwest and the front continuing to push southward. Cyclonic
flow aloft will remain in place as the area of high pressure sets
up shop across the southern/central Appalachians by the end of
the forecast period. A shortwave will carve out of the base of the
cyclonic flow and shift the axis offshore by 12Z Wednesday. Either
way, the sensible weather will remain dry after Monday morning
with temperatures at or slightly below normal for max/min through
the short term.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As of 300 AM EDT Sunday: Run to run consistency is still out of
whack amongst the guidance, especially for the second half of the
medium range. One thing that seems evident is the airmass will
moderate, with hot and muggy conditions returning by the extended
forecast period. Model guidance continue to develop a surface low
over the eastern Gulf, but becomes nearly stationary due to very
weak steering flow. The GFS and ECMWF keeps the CFWA dry for a good
portion of next week, with some resemblance of a rex blocking
pattern developing. Going to stick with the NBM due to the low
confidence in the forecast, but will need to monitor the position of
this low as a heavy rainfall threat will occur if it lifts north
into the region at any point due to the plume of deep tropical
moisture associated with this system. Temperatures will be slightly
above normal for much of the period.

&&

.AVIATION /16Z SUNDAY THROUGH THURSDAY/...
At KCLT and elsewhere: VFR conditions are forecast to prevail
through the period. Mid and high level clouds will remain across
much of the Terminal Forecast Area...especially western areas this
morning as a weakening complex of showers and storms moves across
the region. This feature is not expected to produce any convection
or restrictions at the terminals this morning, although KAVL may see
-RA for a short period this morning. However, increasing moisture
and instability ahead of an approaching cold front is expected to
support scattered shower/thunderstorm development across the area
during the afternoon. Prob30s for TSRA are warranted at most sites,
primarily from late afternoon into the evening hours. Shower chances
will linger well into the overnight, esp across the southern half of
the area, as the cold front takes its time pushing through. Winds
will favor light SW or light/vrbl this morning, increasing to SW at
around 10 kts late morning into the afternoon, with some gusts in
the 15-20 kts range possible. Directions will turn toward the W/NW
during the late afternoon and evening as the cold front pushes
through the area, with light winds turning steadily toward the N
overnight.

Outlook: Drying sfc high pressure is expected to gradually spread
over the area on Monday and linger through the first half of the
week.

&&

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

&&

$$

SYNOPSIS...CAC
NEAR TERM...AR/JDL
SHORT TERM...CAC
LONG TERM...CAC
AVIATION...JDL