912
FXUS62 KGSP 191844
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
244 PM EDT Fri Jul 19 2024

.SYNOPSIS...
A nearly stationary front will meander across our region
through the first half of next week providing a focus for
above-normal chances of mainly afternoon and evening showers and
thunderstorms. Temperatures will be near normal or just a bit
cooler than normal.

&&

.NEAR TERM /THROUGH SATURDAY/...
As of 2:25 PM Friday: Sct showers with some embedded thunderstorms
have developed across our fcst area over the past couple of hours.
A couple of storms have warranted an SPS, but we`ve yet to see any-
thing stronger than that. Still expect coverage to increase thru
the late aftn/early evening and then shift more over the eastern
half of the CWA after that.

Otherwise, broad upper trofing to our north will flatten/deamplify
today and tonight as broad upper ridging persists to our west and
to our east. A weak upper shortwave will lift over our area from
the SW later tonight providing some amount of additional support
for sct showers and thunderstorms. At the sfc, we will remain sand-
wiched between weakening high pressure to our NW and the western
extent of the dominate Bermuda High to our SE. A weak low pressure
center will move off the NC Coast and along what`s left of a stalled
frontal boundary today/tonight. With deeper moisture lingering over
our region, we can expect another round of scattered to numerous
showers and thunderstorms this afternoon and evening with showers
likely lingering into the overnight. Despite the increased cloud
cover today, there should be enough instability across our area
for thunderstorms, but less instability compared to the past few
days. In addition, lower amounts of dCAPE and effective shear should
keep severe chances minimal at best. The main threat will likely be
localized heavy rain with the potential for flooding. Convective
coverage tapers off tonight but will likely linger into the over-
night, especially over our eastern zones. Lows overnight should be
near normal for mid-July, with areas of fog/low stratus likely
developing again early Saturday morning.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
As of 130 PM Fri: Not really any meaningful change in the forcing
regime across the region thru Monday. Upper troughing generally will
persist over the lower Mississippi Valley; as shortwave fills and/or
advects toward the Mid-Atlantic coast late Sat into early Sun, weak
height rises over the Southeast are soon negated by upper low
swinging south out of the Missouri Valley. The seasonably diffuse
boundary or convergence zone remaining from the central Gulf Coast to
the VA/NC coast won`t become any better defined, but could pivot
and/or shift slightly further north by Monday. Its presence near the
region, combined with relatively deep SW flow and above-normal PWAT
values, suggest elevated precip chances each day: basically likely
for most of the Piedmont and categorical for the mountains. Any
northward movement in the boundary would probably result in a slight
uptick in daily dewpoints and PWAT, although only a minimal change in
those fields is depicted in synoptic guidance, so we cannot say with
much confidence that will actually increase precip coverage.

Mean cloud-layer flow and deep layer shear are nonzero but small, so
storms are likely to move only slowly, and could organize loosely
into clusters. Widespread cloud cover should limit diurnal temps,
keeping them 2-3 degrees below normal, and so diurnal CAPE should be
on the low side for the season as well. Sfc-midlevel delta-theta-e
values also will be muted on account of the moist profiles.
Altogether main impact weather for the short term looks to remain
locally heavy rainfall particularly where cells train.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
As of 200 PM Fri: On a large scale, the overall setup remains in
place through late next week: deep Bermuda anticyclone to our east,
persistent trough centered in the mid-Mississippi Valley, and broad,
ill-defined frontal zone in between, likely remaining just to our
northwest.  The Bermuda high does look to strengthen Tue-Wed, and
that would seem only to push the front northward. However, by then
some guidance members depict the upper low or another embedded
disturbance moving toward the NE CONUS and driving the sfc boundary
eastward thru the Mid-Atlantic. This could allow the peak convergence
zone to shift back south into our area as soon as late Thursday, but
if so it would probably stall SE of the Appalachians to end the week.
Altogether, without a major pattern shift indicated by any of the
available guidance sources, we can`t confidently advertise a
significant trend in temps or precip chances. Daytime temps will
remain a little below normal due to cloud cover; PoPs diminish
slightly by Day 6-7 simply due to lower confidence with increasing
forecast range. Main concern will be slow-moving or training storms
producing locally heavy rainfall, and potential for deteriorating
antecedent conditions following what will by then be almost a week
under the influence of this moist and somewhat active pattern.

&&

.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
At KCLT and elsewhere: Expect another round of sct to numerous
showers and thunderstorms and associated restrictions this aftn/
evening across the fcst area. This was handled with VCSH and
TEMPOs for TSRA going thru roughly 23 to 24z. SHRA may linger
overnight with at least MVFR cigs becoming IFR overnight with
a decent chance for MVFR visby as well. Expect the lower cigs
to linger thru late morning at most sites with VFR returning
for the last few hours of the period. Winds will remain light
thru the period and eventually favor a SWLY direction by the
end of the period early tomorrow afternoon.

Outlook: Expect sct to numerous showers and thunderstorms each
afternoon/evening into early next week. Morning fog/low stratus
will be possible each day, especially in the mtn valleys and over
areas that received rainfall from the previous day.

&&

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

&&

$$

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