989
FXUS62 KGSP 010658
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
258 AM EDT Mon Jul 1 2024

.SYNOPSIS...
Drier and cooler conditions are expected today behind a cold front
to our east.  This`ll continue tomorrow, before the heat starts to
build back in on Wednesday and Thursday.  It`ll get increasingly
hot and humid going into the weekend, and some scattered afternoon
showers will be possible, especially over the mountains.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 248 AM Monday...Altho the actual cold front remains hung
up on the west side of the mtns, the effective front has moved
off to the southeast, taking the remaining precip with it. There
remains a small chance along the TN border near the front for
another few hours. Also won`t rule out a stray shower east of the
mtns as long as the front is still to our west, but the chances
are small outside of perhaps the southeastern fringe of metro
Charlotte. Precip probs have been adjusted accordingly. Patchy fog
could be a problem through daybreak or until the drier air starts
to filter in, especially in the mtn valleys.

The main story for today will be the more reasonable temperatures
and the lower humidity, what with the front slipping southward early
in the day followed by the sfc high building in from the NW. It
should be noticeable. The high temp fcst is on the order of ten
degrees less than what we had yesterday, and actually a few degrees
below average. The lower RH will feel much nicer, though. Can`t
totally rule out a stray shower in the leftover convergence zone
that should set up through the afternoon in the Savannah R valley
to the Blue Ridge Escarpment in SC, so a small precip chance will
be kept there for the time being. Any shower activity should end
by sunset. Fair weather tonight as well, with the center of high
pressure moving over PA/NY. The dry air mass should allow temps to
fall about a category below normal. After the last week or two,
the break, no matter how brief, will be welcome. Alas, the whole
time, the center of a large upper anticyclone over the srn Plains
will be creeping eastward and toward us.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
As of 207 AM EDT Monday: By Tuesday morning, subtropical ridge will
be established over the southeastern CONUS, with attendant high
pressure drifting off the New England coast.  The western Carolinas
will be locked into NE flow for much of Tuesday, which will keep
dewpoints in the mid-50s and limit afternoon high temperatures to
the low- to mid-80s.  A robust subsidence inversion should all but
completely suppress convective activity.  On the flip side...GFS
and NAM profiles continue to depict a deep, bone-dry layer just
above this inversion.  Such a setup, while not common for June,
often results in dewpoints crashing below what any model forecasts,
especially at this time range.  So, in keeping with the last few
rounds of official forecasts...leaned toward the drier side of
guidance for afternoon dewpoints.

By Wednesday, low level flow in the 850-700mb layer will shift
from predominantly E to predominantly S...so there`ll once again
be a dry layer aloft, but it should be a modicum less impressive
than Tuesday`s.  The bulk of long-range ensembles also suggest that
the BL-top subsidence inversion will be stronger on Wednesday,
so it`ll also be harder to mix this dry air down on Wednesday.
Expect diurnal dewpoint minima to be a couple categories higher
on Wednesday than on Tuesday.  Otherwise...temperatures will
climb into the upper 80s outside the mountains...amid mostly
quiet conditions.  The bulk of operational guidance keeps the
forecast area completely dry on Wednesday.  The NBM, in contrast,
continues to forecast a sliver of 15-25% rain chance across the
Smokies and Balsams Wednesday afternoon...but even this may simply
be an artifact resulting from the NBM taking time to "catch up"
from wetter member forecasts in previous cycles.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 223 AM EDT Monday: Little change to the medium range.  Deep
ridging will remain in place through the end of the week, keeping
convection suppressed while increasingly potent low-level moisture
flux results in higher and higher dewpoints, and increasingly
small chance of mixing those dewpoints out, each afternoon.
Some diurnal convective initiation over the mountains will be
possible on Thursday, and especially by Friday and Saturday,
may even break containment and enter the Piedmont and Upstate.
But, sans any real synoptic forcing such development shouldn`t
have much oomph to it.

Now, by the end of the weekend, that may change to some extent.
Through the entire period, wave after wave will lift out of the
central Great Plains and ride up over the ridge dominating our
pattern locally...having little effect here, but helping to chip
away at said ridge.  There`s some indication that by Sunday, the
central ridge axis will be displaced enough to our east that a cold
front associated with the latest upper wave could make a run across
the Tennessee Valley on Sunday.  As much as 1/3 of the latest LREF
cycle depict such a solution...although any boundary trying to push
into the Carolinas would have a tough time staying together in the
increasingly unfavorable environment it`d encounter here.  For now,
minor tweaks to the NBM`s shotgun chance PoP seemed reasonable
on Sunday and Monday.  Saturday still looks like the hottest day,
with temps in the upper 90s and associated heat index values well
over 100 across a wide swath of the CWA.  Sunday and Monday look
more iffy, and will hinge on how the large-scale pattern plays out.

&&

.AVIATION /07Z MONDAY THROUGH FRIDAY/...
At KCLT and elsewhere: Prevailing VFR at all terminals through the
period, with a few caveats. As long as the sfc cold front remains
hung up on the west side of the mtns, there is the possibility
of a fog restriction developing locally. This is especially
true at KAVL and KHKY, so altho the new fcst does not include
any restrictions at this time, a restriction all the way down to
VLIFR is not out of the question at those two locations. The front
should finally slip southeast early in the day and bring the dry
air in from the NW. Wind will continue to veer around to N and
NE in response. The rest of Monday should be fair with only a few
high based stratocu. Wind will be occasionally gusty at KCLT with
some deeper mixing, courtesy of high pressure building in from
the N. Fair again tonight.

Outlook: A cold front will stall just south of the area, resulting
in quiet weather thru mid-week. A return of more typical mid-summer
diurnal convection is expected by Thursday into the weekend.

&&

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

&&

$$

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