174
FXUS62 KGSP 230618
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
218 AM EDT Sun Jun 23 2024

.SYNOPSIS...
Hot temperatures will linger through next week, with humidity
increasing east of the mountains starting Wednesday.  A cold front
will track across the area overnight tonight into daybreak Monday
bringing a weak line of showers and isolated thunderstorms to the
area. Drier conditions return the rest of the day Monday, lingering
into the first half of Wednesday. Another cold front will push
across the area Wednesday night into Thursday, potentially bringing
better shower and thunderstorm chances to the area mid to late week.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 150 AM: Upper anticyclone now centered over Texas, and
upper low off the Carolina/Georgia coast. Thus we are currently
in a relatively neutral pattern without much forcing, but also
with less suppression. Low-level flow is solidly out of the
SW. Some degree of low-level convergence persists across our
area between the maritime airmass and the dry air associated with
the anticyclone. A few patches of clouds persist as a result but
otherwise skies are clear; the convergence seems to be the cause
for spotty QPF response early this morning, but all depictions
thereof, going back to last night, have proven overdone, so we
retain a dry fcst this morning. Low levels remain fairly mixed,
and with light wind continuing radiation fog/stratus is not much
of a concern despite moist sfc conditions.

The anticyclone will continue to retrograde slowly today, and a
shortwave crossing the Great Lakes eventually will promote height
falls across the Eastern Seaboard. This mainly occurs in the late
afternoon and evening, thus a little late to coincide with peak
heating. Lapse rates are good in the low levels and modest above
about 600 mb, but model progs still depict a warm layer around
there, and neutral to downward vertical motion above that layer,
much like they did yesterday. CAM response is also similarly paltry
like it was the past couple of days, when we had little to no deep
convection. PoPs this aftn and early evening have been limited to
a low slight-chance mainly in the NC Foothills and Piedmont. Some
of the models kick off their convection around 00z in that area,
presumably in response to the height falls, so the small chances
tick upward a little then, to scattered/chance wording in some
spots. The trough also will bring a weak cold front across the
Appalachians overnight, which will bring the best chance of the
period for the NC mountains and GA/SC Piedmont, but still no better
than scattered coverage.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY/...
As of 120 PM Sat...Canadian high pressure mixes in thru the day
Monday and winds become n/ly to nw/ly. However, this airmass
will be rather warm so little CAA, if any, can be expected and
temps shud have no problem rising to the m90s east of the mtns
and u80s mtn valleys. Will be close to heat indices reaching 105
F across NE GA and the western Upstate Lakeland region as sfc
dewpts will mix out the least compared to other areas. A Heat
Adv may be needed for Mon. The pattern remains quite warm and
supressive Mon night into Tue as upper heights continue to rise
while a subTrop high becomes more dominant. Soundings show
parcels possibly breaking the cap across the mtn ridges Tue
afternoon for brief -shra/tstms, but most areas will remain dry.
Still, another hot day in store with temps similar to Mon yet a
little better dewp mixing may hold heat index values shy of
advisory criteria across the FA.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
As of 155 PM Sat...No major changes were made to the ext range fcst.
The latest guidance is still at odds with the development and
evolution of an upstream trof / frontal system Tue night thru Thu.
The GFS is a moist outlier with better h92-h85 moist adv off the wrn
GOM and is much faster and energized than the other op models. The
GFS dProg/dt trends have been holding consistent however, so the
latest run has been given good weight in the fcst. The ECMWF on the
other hand is slower and only develops isol precip across the NC
mtns Wed and reluctantly develops more widespread activity on Thu as
the sfc front likely stalls. So, backed off the NBM PoPs east of the
mtns for Wed and Thu, yet still have low likely chances across the
mtns and mid chance PoPs east each afternoon. The upper levels
remain quite warm thru the period and with limited shear or forcing,
most storms shud remain below severe criteria. Wednesday will be
another hot one before temps cool a little Thu and Fri. Could need a
heat advisory Wed for the srn zones as higher dewpts are pooled
north ahead of the Tue night cold front.

&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
At KCLT and elsewhere: VFR expected thru the period aside from
the possibility of MVFR level stratus developing near daybreak
at KCLT on moist southerly flow, or from very brief MVFR cigs
from diurnal cu at their onset in the late morning, before they
mix up to VFR level. Retained TEMPO for KCLT to this effect. A
light S`ly breeze will continue thru daybreak, veering to SW
late morning and picking up slightly this aftn. Some instability
will develop again today with profiles similar in nature to the
previous two days; again forcing will be very weak and profiles
dry aloft, so expect no better than very isolated coverage of SHRA
this aftn. Trough exiting the Midwest however could realize some
elevated instability this evening, so SHRA or a stray TSRA becomes
more likely then primarily near the NC sites. That said, chance is
too low to mention. Associated front should promote drying early
Monday, with light winds continuing, making radiation fog/stratus
unlikely, although KAVL could see low clouds develop via upslope
lift after 06z.

Outlook: Drying trend now expected to continue Mon-Tue with little
to no diurnal convection. Summertime humidity return Wed-Thu with
SHRA/TSRA chances also returning.

&&

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

&&

$$

SYNOPSIS...AR
NEAR TERM...Wimberley
SHORT TERM...SBK
LONG TERM...SBK
AVIATION...Wimberley