-- Discussion containing changed information from previous version are highlighted. --
954
FXUS62 KGSP 100017
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
817 PM EDT Sun Jun 9 2024

.SYNOPSIS...
A cold front moves south of our area becoming stationary through
mid week with dry conditions under weak high pressure for Monday
through Thursday.  Isolated to widely scattered showers and
thunderstorms are expected by next weekend as a weak cold front
approaches from the north.  Temperatures are expected to be well
above normal at end of the week.

&&

.NEAR TERM /THROUGH MONDAY/...
Key Messages...

1) Strong to severe storms possible this evening.

2) Another round of sct to numerous showers is likely overnight and
into early Monday morning, largely confined to the I-85 Corridor and
south of it.

3) Dry conditions return Monday afternoon.

As of 5:25 PM EDT Sunday: A fairly robust cluster of showers with
some embedded thunderstorms associated with a weak cold front is
currently approaching the NC/TN border. The latest CAM guidance has
this activity moving into the NC mtns over the next couple of hrs
and continuing its SE trajectory and eventually moving SE of our
CWA later tonight. 1000 to 1500 J/kg of Sfc-based CAPE has already
developed across much of our area and 30 to 40 kts of deep-layer
shear is also in place. This should allow isolated strong to severe
thunderstorms to develop as this activity moves thru our area this
evening. The SPC Day 1 Severe Wx Outlook has the majority of our
fcst area in a Marginal Risk and this still seems reasonable. The
main hazards with any severe storms that develop are damaging wind
gusts and large hail. The most likely window for severe wx appears
to be slightly later, ie, from roughly 6pm to 10pm EDT.

Otherwise, a brief drying period is expected once the cold front
pushes south and east of the fcst area later this evening. Upper
shortwaves will track overhead the forecast area overnight into
early Monday morning allowing for widespread cloud cover and rain
showers to develop. Instability will be lacking so maintained no
mention of thunder overnight. Lows tonight will end up a few degrees
above climatology thanks to both cloud cover and precip limiting
radiational cooling. Timing of the second wave of convection will
be from roughly 3am-9am. However, some isolated activity may linger
across the southern zones throughout the morning hours. Dry high
pressure will gradually build in from the west throughout Monday
allowing dry conditions to return by Monday afternoon. Temperatures
will be cooler on Monday, around 2-4 degrees below climo, with highs
only reaching the low 80s east of the mtns.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
As of 205 PM EDT Sunday: Short waves drop across the area through
an upper trough on Tuesday. The trough moves east Wednesday with
weakening NW flow over our area. The cold front from the near term
slowly moves south away from the area Tuesday with dry high pressure
building in on Wednesday. Can`t rule out an isolated shower Monday
evening with lingering low level moisture and weak forcing, but
chance too low to include in the forecast for now. It will be breezy
Monday night and Tuesday though. Dry conditions and light winds
expected Wednesday. Below normal lows Monday night rise to near
normal Tuesday night. Near normal highs Tuesday rise a couple of
degrees above normal Wednesday.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
As of 220 PM EDT Sunday: Still some run to run consistency issues
with the guidance. That said, there does seem to be a trend toward a
drier forecast. A series of weak short waves move through the flow,
mainly north of our area through Friday. Then a semblance of a Rex
Block develops Saturday into Sunday with an upper anti-cyclone
sliding into the Southeast by Sunday, and a weak upper low moving
east across the Gulf of Mexico. The result is weak and generally dry
high pressure Wednesday and Thursday with the potential for diurnal
convection Saturday as a weak cold front crosses the area. Diurnal
convection possible again Sunday as a moist southerly flow develops.
A warming trend takes place with highs nearly 10 degrees above
normal by Saturday, which drop back a few degrees for Sunday. Lows
rise to around 10 degrees above normal.

&&

.AVIATION /00Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --
At KCLT and elsewhere: The cold front is currently moving thru
our area along with sct to numerous showers and some embedded
thunderstorms. Have TEMPOs for tsra at KCLT and KHKY for the
first couple hrs of the period, with just a vcts at the Upstate
terminals as thunderstorm coverage will be less over that area.
At KAVL, convection is moving SE of the terminal as we speak,
but still kept a TEMPO for heavier showers and 1sm visby for
the first hr of the period. All terminals get a VCSH overnight
and into the morning for another round of showers that are
expected to develop as the front stalls out just to our south.
I remove the vcsh by roughly 08z at KAVL and KHKY as any linger-
ing shower activity should be to their south and/or east by that
time. For the other taf sites, I remove the vcsh later in the
morning as showers could linger longer the further south you
go. Otherwise, cigs should remain low-end VFR thru the morning
and eventually sct out by late morning. There`s still some poten-
tial for lower MVFR cigs to spread over the area from the south
before sunrise. The most likely terminals that would see lower
cigs would be the Upstate sites, however my confidence was not
high enough to include in the tafs at this time. Otherwise, sfc
high pressure will eventually spread over the region Monday aftn
and evening leading to drier conditions and VFR clouds. Winds
will become NWLY to NLY overnight in the wake of the front and
then weaken going light and vrb thru the morning. They will
eventually become SWLY tomorrow aftn outside of the mtns, yet
at KAVL winds will remain NLY to NWLY thru the taf period.

Outlook: Dry sfc high pressure will linger thru mid-week with any
restrictions unlikely.
-- End Changed Discussion --

&&

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

&&

$$

SYNOPSIS...DEO
NEAR TERM...AR/JPT
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...JPT