325
FXUS62 KGSP 120600
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
200 AM EDT Mon Aug 12 2024

.SYNOPSIS...
A stalled frontal boundary over the Carolinas will lead to scattered
showers and thunderstorms through early this morning. High pressure
builds in throughout the workweek while the front stalls over the
Southeast and keeps daily shower and thunderstorm chances around.
High temperatures will continue on a cooling trend through the
workweek, with a warming trend expected over the weekend ahead of an
approaching cold front.

&&

.NEAR TERM /THROUGH TODAY/...
As of 155 AM EDT Monday: Shower coverage has really picked up over
the last hour or so, as 1000-2000 J/kg of MUCAPE remains across
the Piedmont. A mid-level shortwave perhaps is helping initiate
the activity and the CAMs generally agree that showers may linger
thru daybreak. Cannot rule out an isolated strong storm, but the
main threat will likely be locally heavy rainfall, as rain rates
have ticked up. Fortunately, cells have a steady, though slow,
eastward drift.

Otherwise, the rest of the night should remain cloudy enough and
winds should stay elevated enough to preclude more than some patchy
mountain valley fog. Temperatures will fall into the low 70s or
even upper 60s across the I-40 corridor and the NC Foothills.
Tomorrow, convection once again looks to remain isolated, with
virtually all the hi-res guidance depicting initiation remaining
confined to zones south of I-85.

&&

.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
As of 1250 PM Sunday...A broad upper trof gives way to a large
scale subs regime during the short range. This will enable more of a
convectively suppressed atmos with warming mid levels and dry dense
column air.

The latest NAM/GFS soundings show a strong cap arnd h7 in place by
Tue evening persisting thru the period, while deep shear increases a
little abv h85. A reinforced Canadian sfc high will dominate at the
surface which will make deep convec hard to come by each afternoon
owning to lowering sfc tds and maxTs. Also, PWAT values go down yet
remain a little abv normal...so storms that do develop will be
capable of producing stg downpours. Otherwise, not expecting much in
the way of stg/svr tstm development each afternoon with the NC mtns
likely receiving the brunt of the activity. The 12Z GFS is a notable
outlier in keeping a sfc trof active east of the mtns each afternoon
and this soln has been given little weight in the fcst process. Will
side with the lower PoP guidance values based on the overall
pattern, which includes a mix of consMOS.

Max temps will reach right arnd normal levels Tue, then drop a
couple degrees below normal Wed in continued n/ly to ne/ly llvl
flow. Mins will hover a little abv normal each morning.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
As of 135 PM Sunday...Broad sfc high pressure remains dominant and
becomes reinforced Thu as a 1021 mb center develops across the srn
Glakes and builds down the east coast. This high will be supported
by a stg subs pattern aloft which will inhibit convec chances Thu
outside of upslope -shra/tstms instigated by moist e/ly flow within
the BL. The upper ridge begins to shift east early Fri and energy
rounding the axis may bring a nocturnal MCS to the NC mtns by
daybreak. Too far out for much detail in this scenario, but it may
be one to keep an eye on.

A transition occurs thru the rest of the ext range with a stg ulvl
trof pushing south out of Canada across the Midwest. The op models
as usual this far out have various timing and strength solns with
the GFS the most aggressive with an approaching cold front. However,
all models have the cold front activated and there looks to be good
shear and decent instability as it crosses into the area late Fri
evening or perhaps Sat morning per the more conservative GEM. In any
case, Sat daytime looks to be a convectively active day as the front
slows due to upstream occlusion. Thus, will keep abv normal PoPs
mentioned during this timeframe. Max temps will remain a little
below normal as a weak cP airmass mix continues, while mins remain
right arnd seasonal levels.

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
At KCLT and elsewhere: Plenty of elevated instability and moisture
is allowing for scattered showers and isolated tstms to develop at
time of 06z TAF issuance. This activity should push east of KGSP by
07z, while KCLT may see VCSH around thru at least 10z. TS coverage
seems to low for any tempos (just SHRA for now). Otherwise, plenty
of mid clouds should limit fog and low stratus development across
the Piedmont. The mountain valleys may see some fog development,
but stratocu hanging near KAVL makes it too uncertain to put in
the TAF. The mid clouds are expected mostly clear out by midday,
leaving just cirrus and few-sct convective cu. Guidance keeps things
pretty suppressed thru the aftn, with just very isolated showers
thru 00z. Tonight, another uptick in activity may occur overnight,
but most likely after 06z. Winds will be light out of the N to NE.

Outlook: Expect generally isolated to scattered diurnal convection
across the region each day through the work week. Patchy fog and
low stratus will be possible each night in the mountain valleys
and in locations that receive rainfall.

&&

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

&&

$$

SYNOPSIS...AR
NEAR TERM...ARK/MPR
SHORT TERM...SBK
LONG TERM...SBK
AVIATION...ARK