722
FXUS62 KGSP 012330
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
730 PM EDT Mon Jul 1 2024

.SYNOPSIS...
Drier and cooler high pressure continues over the region through
Tuesday. As this high moves off the East Coast middle of the week,
temperatures will warm back up again Wednesday into Thursday. Expect
increasingly hot and humid conditions going into the weekend with
some scattered afternoon and evening showers and storms, especially
in the mountains.

&&

.NEAR TERM /THROUGH TUESDAY/...
As of 550 PM EDT Monday...Made some tweaks to the slight chance (25%
or less) PoPs across the southwestern fringes of the forecast area
through 00Z Tuesday as some very isolated showers have been trying
to develop late this afternoon. Any showers that manage to develop
quickly fizzle before coming close to producing thunder, so also
removed any mention of thunder where there are currently PoPs.
Daytime cumulus filed should gradually dissipate around sunset and
as lower dewpoints filter into the region from the north.

Otherwise,a  1028 mb sfc high will drift east from the Great Lakes
to the New England Coast through Tuesday. Dry NE`ly flow around this
high will continue to lower dewpoints across the forecast area,
while the 850 mb flow veers E`ly, then SE`ly through the period.
Enough moisture within that flow may keep some stratocu around,
especially over the southern half of the forecast area and near the
Blue Ridge Escarpment. The clouds will be capped, however, so not
expecting any precip. The dry air advection should preclude fog
development overnight. Lows will be slightly below normal, mainly in
the 60s.

Tuesday looks like a quiet and rather pleasant day for early July,
as dewpoints dip into the 50s for most of the area under a fair
weather cumulus field. Highs will end up around 5 degrees below
normal, which will feel quite nice compared to the last several
days.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
As of 155 PM Monday: Synoptically, high pressure continues to
amplify over the south and sets the stage for many days of warming.
Height rises max out by Thursday and remain stout through the
period. Guidance from the GFS develops an extremely weak shortwave
to the north of the CWA on Thursday and attempts to bring a very
small amount of DPVA near the mountains. However, this is not
depicted in any other model and given the strong area of high
pressure, confidence for any shower development is very low.
Moisture, in at least the mid levels, looks to start returning
Wednesday night into Thursday as the anticyclonic flow advects
moisture from the Gulf. As for any fire concerns, these should start
to decrease through the period. Wednesday looks to have a well mixed
BL, but with less mid level dry air than Tuesday. RH values should
remain in the upper 40 to 50 percent range. Winds will also be
light. The main concern is drier vegetation, especially in the NC
Piedmont and NE GA zones. Highs on Wednesday will struggle to reach
the low 90s in the southern portion of the CWA. But, Thursday high
temps start ramping up as the high amplifies. The heat index could
also reach the low 100s as the influx of moisture returns to the
area.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
As of 200 PM Monday: Summertime remains alive and well into the
extended. Thursday night the strong area of high pressure continues
to grow over the southeast, while beginning to be pinched off a bit.
Guidance from the GFS/EURO/Canadian all show a developing trough
across the upper CONUS that gently pushes the high eastward slightly
and turns flow aloft more SW by Saturday. This turning should
amplify moisture advection into the south, raising the risk for high
heat indices Friday and Saturday. Confidence in triple digit heat
index values is increasing, given the persistent height rises and
moisture return. Guidance has PWAT values topping the 2 inch mark,
setting up a very muggy day for Friday and Saturday. The areas of
concern are for areas south of I-85 and the eastern NC Piedmont.
Will continue to monitor. By Sunday, the trough to the north could
help heights fall a bit and cool the CWA down by a few degrees. This
is still too far out to pinpoint or have any confidence in given
variations from model guidance. Once moisture returns, there could
be an increase in more diurnal convection and shower chances,
especially over the mountains. But, at this point, QPF response is
minimal and again concentrated over the NC mtns. Low confidence in
precipitation making a dent in rainfall needs for the CWA over the
next 7 days.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
Key Messages...

1) BKN to OVC VFR Cloud Cover is Possible Tonight but Confidence is
Very Low

2) Low-End Wind Gusts are Possible Overnight into Tuesday Morning at
KAVL and the SC Upstate Terminals

At KCLT and elsewhere: VFR and dry through the 00Z TAF forecast
period thanks to high pressure filtering in from the north. Cloud
cover will be the trickiest part of the forecast as the 18Z HRRR
shows BKN to OVC skies developing late this evening into the
overnight hours. However, confidence on this is very low (due to
much drier filtering into the region from the north) so went with
FEW to SCT cloud cover for now (as drier air may limit cloud
coverage somewhat). Winds remain NW at KAVL as of 00Z but should
gradually turn SE later this evening, remaining SE through the end
of the period. Winds east of the mtns are mostly E/ENE as of 00Z but
should gradually turn more NE after midnight. Wind speeds will
remain elevated this evening into tonight, ranging from mostly 5-11
kts. Winds will increase around daybreak slightly, with low-end
gusts possible at KAVL and the SC Upstate Terminals. Only have gusts
mentioned at KAND for now. With winds not expected to decouple, fog
formation is not anticipated. Winds east of the mtns will remain NE
through Tuesday morning before turning E/ESE Tuesday afternoon.
Winds will gradually decrease in speed Tuesday afternoon/evening.
Cloud cover should generally be less during the daytime Tuesday but
may increase again Tuesday evening.

Outlook: Dry high pressure remains in place through Wednesday. A
return of more typical mid-summer diurnal convection is expected
starting on Thursday and will linger into the weekend.

&&

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

&&

$$

SYNOPSIS...AR/DEO
NEAR TERM...AR/ARK
SHORT TERM...CP
LONG TERM...CP
AVIATION...AR