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184
FXUS62 KGSP 020227
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1027 PM EDT Sat Jun 1 2024

.SYNOPSIS...
Dry high pressure moves off the Carolina coast on Sunday with
warming temperatures and increasing moisture. A typical summer
pattern will develop during the first half of the week with daily
afternoon thunderstorm chances. Showers and thunderstorms will
likely increase in coverage for Wednesday and Thursday as a cold
front approaches our area, with drier weather expected to return by
the end of the week.

&&

.NEAR TERM /THROUGH SUNDAY/...
-- Changed Discussion --
As of 1020 PM EDT Saturday: The forecast remains on track as mid- to
upper-level clouds have become entrenched over the area.
Reflectivity becoming more widespread with locations in the
southwest NC mountains likely seeing some of the raindrops at the
surface, while the rest is likely evaporating before reaching the
ground. Expect coverage to gradually expand overnight and become
widespread by daybreak. Low temps early Sunday should remain near-
normal due to increased cloud cover tonight/overnight and higher
dewpts.

Otherwise, upper level ridging will deamplify and shift east and
off the Atlantic Coast this evening and early Sunday as an upper
shortwave moves over our area from the west. At the sfc, broad
high pressure will continue to gradually move off the Atlantic
Coast thru the near-term period as a moist frontal boundary moves
into the Western Carolinas from the west. Forcing ahead of the
above-mentioned upper shortwave has already reached our western
zones, however more substantial moisture advection from the Atlan-
tic will be slow to saturate the lower levels. The latest near-term
guidance still generates the bulk of the low-level moist transport
after midnight. Nonetheless, some iso to sct showers will likely
materialize across the NC mtns before that. More widespread precip
will spread over our fcst area overnight, but with very limited
instability and meager mid-level lapse rates thru the morning hrs,
thunder is unlikely until Sunday aftn, with the severe potential
still looking minimal at best for Sunday. Highs should remain 1 to
2 categories below climatology.
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&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
As of 200 pm Saturday: The upper air pattern will become
increasingly anticyclonic across our region early in the short term,
as a weak ridge builds from the Deep South through the Great Lakes.
As a result, a deep moisture plume will gradually shunt east of the
forecast area early in the period. In the interim, scattered
coverage of showers along with a few storms will continue into
Sunday evening before steadily tapering off. Decreasing deep layer
moisture will yield less in the way of cloud cover, but also
improved potential for destabilization Monday afternoon. Diurnal
convection is forecast to initiate...esp across the high terrain.
While coverage is expected to be more limited than on Monday, sbCAPE
of around 1500 J/kg should allow for a few stronger storms, with
perhaps a stray pulse severe storm not completely out of the
question. With little change in the pattern and thermodynamic
profiles expected, Tuesday should be very similar to Monday, with
scattered diurnal convection expected, and perhaps a slight uptick
in the threat for a pulse severe storm with hotter conditions
expected. The first half of the period is expected to see temps
average around...or slightly above normal...while the short term is
expected to end around 5 degrees above climo.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
As of 215 pm Saturday: An expansive/deep upper low will wobble from
the Canadian Prairie at the start of the period to the Great Lakes
by Thursday evening. Height falls associated with a vorticity lobe
lifting ahead of the low is expected to send a frontal boundary
into the region by late Wed, enhancing convective chances across the
southern Appalachians and vicinity Wed into Wed night. Indications
in global model guidance are that the afternoon will see at least
moderate instability, albeit in a modestly sheared environment. A
few strong-to-severe pulse storms and/or multicell clusters will be
possible.  An additional round of storms is possible Thursday,
although this is a bit more uncertain, as some global model guidance
suggests drier air will be filtering into the area in the wake of
the frontal boundary Thu afternoon. PoPs are generally advertised in
the solid chance range during that time. The latter half of the
period should become more inactive as lower theta-E air advects into
the region. PoPs for Fri/Sat are limited to token slight chances,
mainly over the mtns. Temperatures are forecast at around 2-4
degrees above normal through the period.

&&

.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
At KCLT and elsewhere: VFR conditions will prevail through much of
the overnight before cloud bases begin to lower with increasing
moisture. Model guidance continue to place MVFR cigs across KAVL and
the Upstate TAF sites after daybreak Sunday and continue through the
end of the forecast period, with likely some form of scattering
during portions of the daytime period. Low VFR is expected at KCLT
and KHKY, but MVFR can`t be fully ruled out. Shower coverage will
begin to increase overnight and spread across the terminals through
the end of the forecast period. Winds will toggle southeasterly and
turn the dial to a south-southwesterly component by mid-morning
Sunday. Placed a VCSH mention at all sites due to the scattered
nature of the showers that are expected. PROB30 for shower
development for when the models highlight the best overall coverage.
Instability will build in during peak heating, so included another
PROB30 to highlight thunderstorm chances and associated
restrictions.

Outlook: Diurnal shower and thunderstorm chances with associated
restrictions will linger through the middle of next week.

&&

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

&&

$$

SYNOPSIS...DEO
NEAR TERM...CAC/JPT
SHORT TERM...JDL
LONG TERM...JDL
AVIATION...CAC