970
FXUS62 KGSP 061723
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
123 PM EDT Thu Jun 6 2024

.SYNOPSIS...
Scattered showers and thunderstorms will develop this afternoon and
linger into the evening. Dry Canadian air will mix across the area
Friday and persist into the weekend. A chance of thunderstorms
returns to the region Sunday, before deeply dry air builds back in
Monday though Tuesday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 120 PM Thursday: Convection developing across the area at this
time, ahead of a short wave and cold front. Latest guidance showing
better chance across NC than NE GA or the Upstate. Still expect
scattered convection across NE GA and the Upstate, so basically
tweaking PoP to show this scenario. Meso analysis shows DCAPE has
not increased as quickly as 12Z soundings would have suggested.
Still, a couple of severe storms with damaging winds are possible.

Otherwise, a deep negatively tilted trough over the Midwest is
forecast to slide into the Great Lakes region today. The Southern
Appalachians will remain on the southern periphery of forcing for
ascent within the base of the trough. Subtle height falls are still
expected to overspread the area, however, in advance of a surface
cold front dropping out of the Ohio Valley. The main focus will be
for another round of convection this afternoon, which could be more
robust compared to what we`ve seen the last several days.
Compressional warming ahead of the front along with warming low-
level temperatures will support afternoon highs climbing into the
mid to upper 80s.

Resulting insolation couple with upper 60s to low 70s dewpoints will
yield 2000-3000 J/kg of surface-based CAPE. Increasing flow within
the base of the trough in concert with a low-level jet translating
across the area will also contribute 20-30kts of deep-layer vertical
wind shear. Limited downdraft CAPE and modest lapse rates within a
moist environment will limit the magnitude of any severe threat, but
given the enhanced flow and shear several severe storms capable of
locally damaging winds will be possible. This will especially be
true for any multicell clusters/linear segments that can become
organized along a composite cold pool. Near storm forecast soundings
also depict weak low-level hodograph curvature as the low-level jet
helps to elongate the wind fields. While not overly impressive by
any means, 0-1km SRH nearing 100 m2/s2 could support a
brief/transient circulation or two, which has been picked up on by
several of the CAMs with brief updraft helicity streaks mainly along
and south of I-85. Thus, a brief tornado cannot be completely
discounted. A few storms may linger into the early evening hours,
but will remain progressive ahead of the impending front and should
push out of the area by or shortly after sunset. Thereafter, the
cold front is expected to move through the area overnight with much
drier air advecting into the region in its wake.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
As of 1255 AM Thursday...The short range period remains dry as deep
nw/ly flow commences while a subTrop high shifts east across the srn
Plains. This pattern will support a Canadian sfc high building south
bringing lowering column moisture to the FA. Cooler temps are
associated with this high as well, but downsloping h9-h8 flow will
modify the airmass warmer and allow for max temps arnd normal levels
Fri and Sat. Along with increasing subsidence, the llvls will dry
out with the downsloping and make for dry afternoons with RH values
dropping into the 30 percent range each day. Not much cloud cover
outside of Ci Fri and lowering clouds aloft by Sat afternoon. Mins
will fall to normal levels Thu night and abt 5 degrees cooler Sat
night with no great fog threat each morning.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
As of 115 AM Thursday...No sigfnt changes were made to the ext range
fcst outside of lowering PoPs a bit Sun and Mon. The atmos becomes
more dynamic Sat night with a stg embedded h5 s/w traversing the flow
thru Sun morning. Low level moisture will be limited and only expect
increasing mlvl cloud cover thru mid day. A cold front makes it to
the NC mtns Sun afternoon, but with little upper support, expect the
best precip chances across the NC mtn/fthills due to added mech
lift. Decent agreement is had in the guidance with the progression
of the front as it tracks across the FA during the evening and
overnight. The atmos remains quite stable ahead of the front, but
increasing sfc convg could spawn a few general tstms east of the
mtns by late afternoon Sun. Another dry Canadian airmass mixes in Mon
and likely lingers into Tue, which will make for low RH values
during the afternoon periods. The next chance of precip will be Wed
as moist return flow ensues. Temps will pretty much remain arnd
normal levels each day.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
At KCLT and elsewhere: Convection beginning to develop across the
area ahead of a cold front. CAM guidance shows better chance over
the NC sites than the SC sites. Have kept a TEMPO in all areas given
the radar presentation but toned down some of the impacts except for
KCLT where CAMs show the highest chance. Gusty SW to WSW winds
continue ahead of the front with a wind shift to NW but diminishing
wind behind the front. Drier air moves in behind the front as well
limiting the chance of restrictions overnight. Dry conditions with
NW wind continues Friday. KAVL will see NNW wind overnight with
gusts redeveloping on Friday.

Outlook: High pressure will linger through Saturday before another
frontal system moves in on Sunday possibly lingering into Monday.

&&

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

&&

$$

SYNOPSIS...SBK
NEAR TERM...RWH/TW
SHORT TERM...SBK
LONG TERM...SBK
AVIATION...RWH