135
FXUS62 KGSP 091355
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
955 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/...
As of 950 am EDT Sunday: Remnant small convective complex continues
to weaken as it tracks eastward across the forecast area this
morning. Went ahead and increased PoPs where it`s currently raining
(extreme NE GA and the southern NC mtns). Since this cluster of
showers is holding together better than expected, bumped up PoPs
across the western zones through the morning hours. With cloud cover
quickly increasing across the area, bumped up cloud cover as well
through the morning hours.

Otherwise, 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. 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 /14Z 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