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156
FXUS62 KGSP 222156
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
556 PM EDT Sat Jun 22 2024

.SYNOPSIS...
Hot and humid air will remain over the area this weekend and into
the middle of next week. A weak yet active cold front tracks across
the area Sunday into Monday before drier air returns on Tuesday.
Another moist and stormy frontal system should push in Tuesday night
and slowly cross the area through Thursday.

&&

.NEAR TERM /THROUGH SUNDAY/...
-- Changed Discussion --
As of 553 PM Saturday: No major changes to the forecast apart from
some tweaks to dewpoint; widespread cloud cover over the Balsams
and Smokies have only resulted in a handful of weak showers thus
far, and as we get past peak heating it`s unlikely we`ll see much
else on radar.  Parts of the NC mountains south of I-40 currently
boast the highest sbCAPE of 1000-1500 J/kg, so if anything else
gets going it`ll likely be in these zones.

Otherwise...over the next 24 hours, the effects of the old upper
anticyclone will finally come to an end as it relocates to the srn
Plains and we come underneath a broadly sagging cyclonic flow aloft
with a nrn stream upper system over the upper Great Lakes. Altho
this might seem favorable, there is a distinct lack of support for
convection. That little swirl you see along the GA coast will not
be able to make it close enough to our forecast area. The slight
increase in westerly flow aloft by Sunday afternoon should allow
temps to warm a few degrees above what we had today, making Sunday
feel like the hottest day of the season thus far. Fortunately,
the RH will merely be like usual summer, so the Heat Index will
fall well short of Heat Advisory criteria. The arrival of the
cyclonic flow should also eliminate the cap finally, so expect a
bit better coverage of showers and storms in the late afternoon,
similar to climo.
-- End Changed Discussion --

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
As of 120 PM Sat...A weak ulvl wave will cross the area Sun night
and bring a decent chance of precip, mostly rain across the NC mtns
thru daybreak. Not much of a chance east of the mtns and maintained
slight PoPs there thru the afternoon as h5 heights rebound and
forcing wont be enuf to overcome the warm mlvl cap. Canadian high
pressure mixes in thru the day 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 /22Z SATURDAY THROUGH THURSDAY/...
At KCLT and elsewhere: A healthy cu field was noted in the satellite
imagery this afternoon, so expect most terminals to be in and
out of a sct/bkn cloud layer at 045-050 thru peak heating. Shower
activity will be limited to the ridgetops. Wind will be generally
light S. Expect another quiet night with light/var wind. For
Sunday, more of the same but with wind coming around to light
SW. There is some indication of a low cloud deck MVFR making a
run for KCLT around daybreak, but this is not certain enough to
go prevailing. Thunderstorms might be a little more likely Sunday
afternoon, so will go with a PROB30 at KCLT in anticipation.

Outlook: Expect a return to more typical scattered convection
across the region Monday.  Slight drying may follow for Tuesday,
but humidity goes back up for Wednesday.

&&

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

&&

$$

SYNOPSIS...SBK
NEAR TERM...MPR/PM
SHORT TERM...SBK
LONG TERM...SBK
AVIATION...PM