892
FXUS62 KGSP 100536
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
136 AM EDT Fri May 10 2024

.SYNOPSIS...
A cold front will continue to push east of the area, before another
system approaches Friday. Showers and thunderstorms are possible
Friday afternoon, before dry high pressure builds in from the north
through the weekend.

&&

.NEAR TERM /THROUGH TODAY/...
As of 135 AM: Widespread cirrus ahead of a thunderstorm complex to
out SW will remain over the area early this morning. There will be
some stratocu across the mountains and low stratus elsewhere. The
copious high clouds should limit fog potential and will slow the
previous cooling.

Otherwise, mostly clear skies this evening should permit good
radiational cooling for a time. Some dry advection will begin
overnight as weak sfc low passes by to our north, pulling very weak
sfc front through the area. This will promote just enough drying to
maintain a dewpoint depression of a few degrees in the foothills and
upper Piedmont, and furthermore some gradient wind is expected to
persist. Thus, the likelihood of radiation fog/stratus looks small
in those areas and mins will remain several degrees above normal.

Mountain valleys are likely to see some fog, along with the
SE CWA border where that weak front doesn`t reach and instead
may serve to pool moisture. A couple hundred joules of CAPE may
persist there thru daybreak. An MCV or other remnant of convection
looks to round the base of the main trough in the morning and some
guidance depicts a round of showers passing thru the Piedmont at
that time. Partly cloudy skies will permit the return of warmer
temps, again being a few degrees above normal. 700-500mb lapse rates
will increase as main shortwave swings in, and isolated convective
development is not out of the question over the mountains. For
the aforementioned Piedmont areas, guidance members differ as
to how soon low-level airmass change begins; GFS for example
maintains poor low level lapse rates above the PBL and develops
only small diurnal instability. The NAM depicts favorable lapse
rates thru a deep layer and develops 1000 J/kg or more of CAPE in
the afternoon. All models depict strong deep layer shear, perhaps
60+ kt, so if timing of the shortwave trends slightly slower or
the low level lapse rates improve, we could see an isolated severe
threat develop mainly southeast of I-85 or east of I-77. The setup
warrants only a chance PoP in our south and east; FV3 and HRRR
show short updraft helicity streaks from a lone cell.

&&

.SHORT TERM /TONIGHT THROUGH SUNDAY/...
As of 1245 PM Thursday...An upper shortwave axis continues to swing
east of the area Fri night as a cP air mass mixes into the lower
levels. This airmass will slowly modify warmer over the weekend as a
small scale ridge gives way to another diving Canadian h5 trof Sat
afternoon. This trof looks to bring it/s own moisture and will
probably produce some rain showers across the NC mtns Sat afternoon
into the evening. No good chance of thunder during that time as sfc
td/s drop into the 40s and potential instability remains nil or
quite low. Drier conds with warming temps across the FA Sun as a
broad sfc high builds over the area from the west. Generally, both
days will be rather pleasant with highs a couple degrees below
normal Sat, then back to normal levels on Sun. Mins will likely fall
a couple degrees below normal each night.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
As of 120 PM Thursday...A more springtime pattern returns during the
ext range. The latest guidance contines to show a subs zone becoming
displaced by waves of srn stream energy while a mlvl trof/low
travseres the MS to OH valleys. The surface response indicates an
opening GOM flow, which will supply a good amt of moisture to a
broad frontal system each day. Onset precip timing Mon is suspect
with the majority of models indicating a later timeframe than the
moister insitu wedge pattern progged by the latest GFS. In any case,
thunder probabilty remains low with non-conducive llvl thermal
profiles. By Tue, expect a better chance of afternoon thunderstorms
as a wavy cold approaches from the west and sfc dewps rise into the
u50s to l60s. The pattern remains uncertain, yet possibly active
into Wed as another round of srn stream energy may be pushing east
across the GOM coastline by then. High Temps remain near normal Mon,
then drop abt 5 degrees below normal Tue with the best chance of
widespread precip and cloud cover. Highs rebound to normal values
Wed. Lows begin the period near climo, then warm abv normal Tue/Wed
nights.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
At KCLT and elsewhere: Copious high clouds will remain over the
area this morning. Some VFR stratocu will also be seen at KAVl and
KHKY. IFR to LIFR stratus is floating around over or near the rest
of the sites. This could become BKN by daybreak into mid-morning.
Any low cigs should scatter out or lift by noon. Guidance showing
better chance of convection at KCLT than the rest of the sites, so
have limited PROB30 to that location. W to SW wind this morning
becomes gusty and more WSW for the afternoon. The gusty winds
continue from the NW to N into the evening before diminishing. KAVL
will see NNW wind throughout with very gusty conditions during the
afternoon and evening.

Outlook: Drier and likely VFR conditions can be expected this
weekend. Moisture returns late Monday with active weather possible
by Tuesday.

&&

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

&&

$$

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