157
FXUS62 KGSP 201054
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
654 AM EDT Mon May 20 2024

.SYNOPSIS...
Warm high pressure will persist across the region through the
middle of the week. A cold front approaches from the northwest on
Thursday, bringing a chance of showers and storms mainly to the
mountains. The front will stall over the area Friday, keeping rain
chances through weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 645 AM: Weak sfc high beginning to shift into NC from the
north, supported by positively tilted upper ridge. Dense mountain
valley fog and low stratus expected to linger thru 9-10 AM, with
less impactful and variable fog occurring near the Piedmont rivers
likely dissipating somewhat sooner. Touched up temp trends this
morning, and sky cover thru the day. Beyond that, fcst appears
on track.

Flow will veer to SE as sfc high builds slightly further south
and east. Max temps will rebound back to normal or even a couple
degrees above. Some cumulus will break out beneath the weak
inversion across the area. Despite that, most prog soundings over
the mountains depict some skinny CAPE developing, perhaps a few
hundred J/kg. With upslope flow some convection is expected to
fire there. Tame PWATs of generally an inch or less, mostly via
low to midlevel moisture. Profiles are quite dry above 700 mb. Dry
air entrainment will keep coverage isolated or widely scattered
at best. Not particularly concerned for severe wx or for flash
flood threat, but will point out any cells will be slow-moving
and fairly healthy accums still may be seen. This activity will
wane diurnally. SE flow will result in some areas of cloud cover
persisting near the Blue Ridge Escarpment, similar to what we`re
seeing this morning, and with dewpoints not expected to mix out
much this aftn. Mins near normal.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
As of 300 AM EDT Monday: An upper ridge axis extending from the
Gulf of Mexico northeast along the Appalachians will keep the
atmosphere rather suppressed atop the forecast area thru the short
term. Isolated showers and perhaps a couple of garden-variety tstms
may develop along the ridgetops with strong daytime heating. But
otherwise, just some fair wx cu and temps continuing a warming
trend. Highs will be in the mid 80s on Tuesday and mid to upper 80s
Wednesday across the lower mountain valleys and the Piedmont. Lows
will be mainly in the 50s in the mountains and lower to mid 60s
elsewhere.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 315 AM EDT Monday: Thursday has the potential to be the
hottest day of the week with highs approaching 90 degrees in parts
of the lower Piedmont. However, convective debris clouds may spill
over the area from the west, as upper flow begins to flatten out,
and this may limit insolation. While shortwave energy works to
flatten the eastern CONUS ridge, guidance still is in disagreement
on how far east an approaching cold front will get to our area. The
ECMWF continues to keep Thursday dry, while the NBM PoPs suggest
at least scattered diurnal convection returns to the mountains
and possibly the I-40 corridor east. The front should sag into
the area Friday, as a more pronounced wave rides thru the upper
flow across the region. This should provide for better diurnal
convective coverage Friday, with more shear and instability for a
few strong storms. Then the front basically stalls out across the
Southeast, as it becomes oriented parallel to the upper flow. So
above climo PoPs looks on tap for the weekend with temps remaining
a few degrees above normal.

&&

.AVIATION /12Z MONDAY THROUGH FRIDAY/...
At KCLT and elsewhere: Mountain valley fog/stratus will last
thru 13-14z at KAVL. Patchy/variable fog also being reported
in parts of the Piedmont, mainly near rivers, but this likely
will lift/dissipate in the first hr of the TAF period. NE winds
will continue until early afternoon owing to weak high pressure
to our north, with diurnal cu forming at MVFR to low VFR level
but probably not causing cigs. Winds go SE with aftn mixing and
southward migration of sfc high. Ridgetop SHRA or even TSRA are
possible but too isolated to mention at KAVL. SE flow tonight
will produce VFR to MVFR stratus in the foothills. KAVL likely to
see valley fog develop again hence prevailing IFR mention after
07z. River valley fog appears possible, most likely affecting KHKY
which gets MVFR late.

Outlook: High pressure remains dominant over our area thru
Wed, but isolated mountaintop convection still expected each
afternoon. Precip and restrictions possible with next front arriving
late Thu or Fri.

&&

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

&&

$$

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