390
FXUS62 KGSP 190711
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
311 AM EDT Fri Jul 19 2024

.SYNOPSIS...
A nearly stationary front will meander across our region through
early next week providing a focus for above normal chances of mainly
afternoon and evening showers and thunderstorms. Another cold front
will approach from the north later next week. Temperatures will be
near normal or just a bit cooler than normal.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 305 AM: A broad upper trough remains over the eastern CONUS
through the period with a short wave moving into the area in the SW
flow. A weak low pressure center moves along the stalled frontal
boundary across the area. With copious deep moisture over the area,
this will create enough forcing for widespread showers this
afternoon and evening, with showers lingering overnight. There will
be enough instability for thunderstorms, but overall instability
will be on the lower side with clouds keeping a lid on strong
heating. The lack of dCAPE and effective shear will keep severe
chances on the low side. Given the amount of moisture and convective
coverage, isolated heavy rain and localized flooding will be
possible. Morning clouds will also help delay convective initiation
until mid to late afternoon, with convection continuing into the
evening. Coverage tapers off overnight but likely lingers through
the night. Highs should end up as much as 5 degrees below normal,
with lows near to slightly above normal.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
As of 207 AM Friday...The synoptic pattern will remain
largely stagnant heading into the weekend with a stout upper ridge
over the Four Corners region slowly retrograding into the Great
Basin. Associated tall ridging will extend as far north as British
Columbia and Alberta where temperatures will make a run at 40 C.
Downstream troughing is progged to extend from the Great Plains into
the Appalachians with another upper ridge centered over the
Atlantic. This synoptic pattern will keep the Southern Appalachians
within a broad convergent southwest flow regime. A deep plume of
1.75-2.25" PWATs entrenched across the area combined with the
influence of a nearby stalled frontal boundary just west of the
mountains will support above average chances for afternoon and early
evening showers and thunderstorms both Saturday and Sunday. As with
any summer convection, moderate instability could support several
instances of severe pulse storms with water loaded microbursts being
the primary threat. In addition, repeated rounds of rainfall could
lead to isolated flash flooding, especially where any storms are
able to train and/or become focused by mesoscale influences.
Increased clouds and coverage of showers and storms will also keep
temperatures in check with highs a couple degrees below average and
mild overnight lows.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
As of 224 AM Friday...An active pattern will continue well into the
extended forecast with little change to the position of synoptic
features. Upper ridging will meander across the Great Basin/Four
Corners while downstream troughing continues to reload as periodic
shortwave perturbations dive through the Great Plains. Thus, a deep
moisture plume will be maintained across the area within persistent
southwest flow. Above normal chances for showers and thunderstorms
will continue through next week along with below average
temperatures. Repeated rounds of convection may eventually heighten
a threat for flash flooding, but this will be predominately driven
on the mesoscale and near impossible to pin down at this time range.
Some members of guidance depict a period of increase flow through
the column around mid week, which if realized could provide a boost
in moisture transport and a possible focus for flash flooding.
Otherwise, at least isolated pulse severe storms cannot be ruled out
any given day with wet microbursts being the primary hazard.

&&

.AVIATION /07Z FRIDAY THROUGH TUESDAY/...
At KCLT and elsewhere: Low stratus and fog have developed across
portions of the area early this morning. Expect a mix of MVFR to
LIFR cigs with VFR to IFR Vsby as the stratus and fog expand to
cover more locations. Expect MVFR stratocu to linger through the
morning at most sites, but coverage is uncertain. This should create
a later start to convection this afternoon, but most sites will see
TSRA by late afternoon or early evening. SHRA may linger overnight
as well with at least MVFR conditions developing. Light winds this
morning will become NE at the KHKY and KCLT by afternoon with SW
elsewhere Light winds develop during the evening.

Outlook: Expect sct to numerous showers and thunderstorms each
aftn/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...DEO
NEAR TERM...RWH
SHORT TERM...TW
LONG TERM...TW
AVIATION...RWH