945
FXUS62 KGSP 031832
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
232 PM EDT Mon Jun 3 2024

.SYNOPSIS...
Scattered afternoon showers and thunderstorms are expected
again on Tuesday with temperatures warming back into the mid to
upper 80s. Showers and thunderstorms will increase in coverage
Wednesday into Thursday morning as a cold front crosses our area.
Drier weather is expected to return by the end of the week and
persist into the weekend, although a few isolated mountain showers
will remain possible.

&&

.NEAR TERM /THROUGH TUESDAY/...
As of 150 pm: A weak short wave ridge will progress steadily across
the forecast area over the next 18-24 hours. Meanwhile, persistent
SW low level flow is supporting quite moist conditions, with 12Z
regional Raobs indicating precipitable water values at around the
75th percentile in terms of climatology. Strong insolation has
resulted in moderate destabilization across the forecast area this
afternoon, with sbCAPE of 1500-2000 J/kg analyzed across much of the
CWA. Isolated convection is developing in the favored high terrain
locations this afternoon, and coverage is expected to expand to at
least widely scattered territory across the mtns, with more like
isolated activity elsewhere, as the presence of the upper ridge
should act to somewhat limit the overall coverage. Locally heavy
rainfall will be the main threat, but mean cloud-bearing winds of
around 15 kts should result in relatively progressive cell movement,
keeping the excessive rainfall threat muted. Absence of robust
instability will also limit the severe storm threat, but can`t rule
out a stray pulse storm producing a microburst. While activity will
diminish in coverage this evening, weak height falls and continued
enhanced moisture is expected to result in some degree of coverage
persisting across western areas into the overnight, with a continued
threat of locally heavy rainfall. Min temps should be 2-4 degrees
above climo.

The upper ridge is forecast to have pushed east of the CWA by Tue
afternoon, with the upper flow becoming increasingly cyclonic/open
to passing vorticity lobes downstream of an upper low over the
western Ohio Valley. If anything, moisture is forecast to increase
further, while a consensus of guidance indicates another afternoon
of moderate destabilization. These factors should support scattered
to numerous coverage of diurnal convection...with PoPs ranging from
40-60% across much of the CWA. Although shear parameters will remain
meager and cell movement rather progressive, the increase in
"targets of opportunity" should yield an uptick in the threat for a
couple of pulse severe storms and isolated excessive rainfall. Max
temps will be a degree or two warmer than today.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
As of 1245 PM Monday: The coverage of diurnally enhanced deep
convection has the potential to remain numerous, especially acrs the
mountains, into the evening hours on Tuesday, as synoptic scale
forcing, in the form of subtle s/wv energy. lifts into the Tenn
Valley.  Regionally, the potential for strong tstms Tuesday night is
mainly west of the mtns, within the zone of better flow and
instability.  The mean flow atop the cwfa through Wednesday is
progged to be moderately fast with a subtle cyclonic curvature.
Within a plume of developing instability and PWAT values nearing 2
inches, diurnally enhanced tstms should become widespread within
this favorable pattern.  Since there is the potential for storms to
be blossoming and/or ongoing during the morning hours, it remains to
be seen on just how unstable the atmosphere becomes.  Select 12z
short range model solutions depict moderate destabilization and
given the progged shear, clusters of severe tstms are possible.

A less than common June cool frontal passage is slated for Thursday.
Sensible wx could wind up being limited to just morning showers
along the front itself in the mountains, and then within the veered
llvl flow and falling dwpts, deep convective redevelopment could
hold off until the bndry translates to the coastal plain, we`ll see.
Fcst sndgs continue to advertise developing deep mixing coincident
and in the wake of the frontal passage, along with downslope
warming. We will have to monitor for the possibility of max temps
nearing 90 in parts of the piedmont.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
As of 130 PM Monday: The SE CONUS is progged to be under the broad
cyclonic flow within the southern periphery of closed upper low
rotating toward the mid-atlantic at the start of the period.  A dry
continental airmass is progged to be in place, maintained by
moderately deep mixing.  Seasonably warm conditions are on tap for
Friday, but accompanied by much lower than climo sfc dwpts.  Closed
upper low will wobble into the NE CONUS and eventually offshore over
the weekend maintaining the seasonably warm and mostly dry
conditions acrs the southern Appalachians within the NW and
cyclonically curved flow limiting any daily small shower chances to
just the nc mtns thanks to wrap around moisture or upslope.

&&

.AVIATION /19Z MONDAY THROUGH SATURDAY/...
At KCLT and elsewhere: Isolated to widely scattered convection is
expected across the Terminal Forecast Area this afternoon into the
evening. Convection is most likely to impact KAVL and KHKY, and
these two sites have tempos for TSRA this afternoon. Convective
chances diminish toward the southeast, but chances are such that
VCSH is warranted at the other sites...except for perhaps KAND.
Coverage of convection will begin to diminish this evening, but some
showers and perhaps a storm or two will remain possible into the
overnight, mainly across the Upstate SC terminals and perhaps KAVL.
Prob30s for SHRA or TSRA are carried at these sites, generally from
03-06Z. Low clouds, as well as mountain valley fog will likely
develop toward daybreak, with IFR conditions forecast at KAVL, and
MVFR clouds (along with SCT IFR layers) at most other sites.

Clouds are expected to begin lifting to VFR by late Tue morning.
Another round of afternoon convection...with increased coverage
expected over today`s activity is expected Tue afternoon. Prob30s
for TSRA are included at KAVL from 15-18Z, and at KCLT after 18Z.
Winds will generally favor SW at 5-10 kts during the daylight hours
and light/variable during the night and early morning.

Outlook: Coverage of diurnal convection is expected to increase Wed
as a frontal boundary moves into the region. Morning low clouds and
fog will also be possible Wed morning and Thu morning. Drier air
will filter into the area Thu and Fri, reducing chances for
convection and restrictions, with relatively dry conditions
continuing into the weekend.

&&

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

&&

$$

SYNOPSIS...DEO
NEAR TERM...JDL
SHORT TERM...CSH
LONG TERM...CSH/TW
AVIATION...JDL