191
FXUS62 KGSP 102028
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
428 PM EDT Fri May 10 2024

.SYNOPSIS...
Strong storms are possible thru this evening southeast of Interstate
85. Dry high pressure will keep most areas dry through the weekend,
with mild temperatures. An unsettled pattern will take shape late
Monday, with rain chances returning and lasting through Wednesday.

&&

.NEAR TERM /THROUGH SATURDAY/...
As of 415 PM...Minor tweaks to the PoPs to reflect latest radar
trends. A boundary is sagging south into Union and Chester
counties in SC. With Cherokee, York and Union, NC north of the
boundary with less CAPE, have canceled the SVR Tstm Watch for those
counties. Still a severe storm in Chester County. The severe threat
should slowly wane as the boundary continues to to push south and
east. Activity across the mountains has weakened, with mainly just
scattered showers and occasional general thunderstorm.

Otherwise, convection ongoing across the ern Piedmont associated
with a sfc bndry will continue active this afternoon. Soundings
across the area indicate sbCAPE values reaching arnd 1200 J/kg
while latest mesoanalysis shows 0-6 bulk shear on the order of
30-35 kts moving in from the west. So, a few of these storms
could become quite strong to severe with large hail and damaging
outflows being the main threats. A secondary bndry will push in
from the northwest this afternoon arnd 22z and this could help
maintain tstm activity into the evening hours, altho direr llvl
air will also be accompanying this bndry, which could hinder convec
development. Winds outside the storm areas will become low-end to
moderately gusty and lessen after sunset. No great chance of fog
overnight as drier air mixes into the llvls, yet some mtn locales
could see spotty dense fog. Upper heights fall thru the day Sat as
an upper wave approaches from the northwest. This wave will bring
it/s own moisture and will likely instigate a few showers across
the NC mtns during the afternoon into the evening. Lows tonight will
drop a little below normal and highs Sat will also be held a couple
degrees below normal as the new airmass mix begins to modify warmer.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
As of midday Friday: Confluent upper flow between NE CONUS closed
low, and a ridge in the lower MS Valley, will allow dry sfc high
pressure to build into the CWA beginning Saturday night. This looks
to suppress diurnal convection Sunday. Mild, near-normal temps,
fairly low humidity, and light winds look to make for a nice Mother`s
Day.

Ridge will migrate east and sfc high will set up just off the East
Coast by Monday morning. Southerly flow will develop atop it within
moisture plume on warm side of occluded low moving into the Ozarks;
surface front still looks likely to be well south of the CWA. Models
vary in how quickly they develop precip; some do so Monday and others
Monday night. The setup could foster in-situ CAD once precip
develops. With increased cloud cover temps Monday should be a little
cooler than Sunday.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
As of 200 PM Fri: Low pressure will track into the lower Ohio Valley
Tuesday, and PWATs will peak that afternoon or early evening as
southerly moisture flux comes to a head in advance of the low.  Main
shortwave trough likely will be centered over west-middle TN during
the afternoon, but some degree of DPVA could be present to further
enhance lift. How well CAD becomes entrenched may be critical, as by
the same token SBCAPE could creep into our lower Piedmont. GFS
soundings are rather skinny and not indicative of much more impact
than convectively enhanced rainfall rates. Per NAEFS and EPS member
soundings, a few hundred J/kg could overlap with around 40 kt of deep
layer shear, so a strong to severe thunderstorm is not completely out
of the question. That said, leaned slightly toward the low end of
guidance given potential CAD. Tuesday likely will be the coolest day
of the week with highs in the mid-70s, but if CAD does form highs may
stay in the 60s.

Low-level flow will turn westerly and some upslope driven precip is
possible Tue night into Wed near the TN border. The shortwave itself
will cross the CWA Wednesday morning. Temps will rebound above normal
for Wed with skies clearing and downslope winds east of the
mountains. Gradient aloft will be weaker and near-sfc winds more
veered, so less shear will be present but stronger CAPE. As such
scattered t-storms look somewhat more likely but severe threat
probably lesser. Precip chances diminish Wed night as another ridge
moves overhead behind the shortwave. Dry weather will last until the
next low approaches from the west and warm front lifts over the area.
That currently looks likely to occur Thursday night or Friday, but as
a nod to the few solutions depicting it earlier, PoPs tick upward
again Thu afternoon. Thursday temps also will be a little above
normal.

&&

.AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
At KCLT and elsewhere: An upper wave will cross the area this
afteroon and evening which will bring a nw/ly wind shift outside the
mtns. Some precip will be associated with this wave, but instability
looks suspect for a great thunder threat. So have included a TEMPO
-TSRA for CLT aft 22z til 00z. Otherwise, VFR conds persist and north
to northwesterly gusty winds will prevail this afternoon across most
sites and weaken overnight. No great chance of fog in the morning
with the drier air mixing in.

Outlook: VFR conditions continue this weekend. Moisture returns late
Monday with active weather possible by Tuesday.

&&

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

&&

$$

SYNOPSIS...Wimberley
NEAR TERM...ARK/SBK
SHORT TERM...Wimberley
LONG TERM...Wimberley
AVIATION...SBK