647
FXUS62 KCHS 021212
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
812 AM EDT Tue Jul 2 2024

.SYNOPSIS...
A stalled front will linger near the area today before
dissipating offshore. A hot and humid air mass will build over
the region during the latter half of the week. A weak cold
front could approach the region by Monday.

&&

.NEAR TERM /THROUGH TONIGHT/...
Today: Sfc analysis continues to show a stalled boundary/front
extending east to west across the local area, from the South
Carolina coastal waters just south of the Savannah, GA area and
inland just south of the I-16 corridor. The environment remains
very moist along and south of this feature (PWATS around 2+
inches), and continues to be a focus for showers and thunderstorms
early morning. Very little movement is expected of this
feature, given a lack of large scale features to steer the
front. However, a slightly northward nudge is possible this
morning before weak h5 shortwave energy rounds the eastern
periphery of a ridge extending across the Deep South. Until this
occurs, an onshore wind will continue to drive deep moisture
onshore, leading to additional showers/thunderstorms during late
morning into afternoon hours. Given PWATs approaching 2.25
inches and slow storm motions, some showers and thunderstorms
could be heavy rainfall producers, particularly where moisture
convergence is enhanced along the coast and the nearby
front/boundary. WPC does currently have southern most portions
of the South Carolina coast and much of southeast Georgia under
a Marginal Risk for excessive rainfall, which falls in line with
latest guidance and current trends. A few Flood Advisories are
not out of the question given the setup. High temps today will
be cooler with clouds and precip across the area, generally
ranging in the mid- upper 80s, warmest across southeast Georgia.

Tonight: Latest guidance has trended a bit more toward holding onto
precip activity south of the front across southeast Georgia.
However, diurnal heat loss should result in most convection to wane
during evening hours. Additional showers and thunderstorms could
redevelop across coastal waters and make a run toward the coast
late. At this time, scattered showers and thunderstorms remain in
the forecast across coastal areas through much of the night to
account for this possibility. Low temps should range between the low-
mid 70s inland to upper 70s near the beaches.

&&

.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
High pressure off the mid-Atlantic coast will extend across the area
on Wednesday, while a stalled front lingering nearby eventually
dissipates. Aloft, a mid level ridge will build over the Southeast.
Best potential for convection will be near the southern South
Carolina coast and across southeast Georgia where deepest moisture
resides. Further inland and to the north should not see as much
activity. Highs will be in the upper 80s to lower 90s. Lows
Wednesday night will range from around 70 inland to upper 70s at the
beaches.

Mid level ridge will dominate the pattern aloft Thursday and Friday.
The surface will feature high pressure offshore and a trough of low
pressure inland. Mainly just isolated to perhaps scattered diurnally-
driven showers and thunderstorms are expected each afternoon and
evening. Otherwise, temperatures and humidity will be on the rise.
Highs will be in the low to mid 90s on Thursday, with heat indices
topping out in the 100-105 range. Friday will be a bit hotter, and
heat indices could approach local Heat Advisory criteria of 108
degrees in spots. Lows will be in the 70s.

&&

.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
Guidance is in good agreement in the extended. Mid level ridge will
hold over Southeast coast into the weekend, before weakening. At the
surface, a trough of low pressure will persist inland with high
pressure offshore. It should get a bit more convectively active than
previous days with better instability and possibly weak upper
support. Current forecast highlights chance PoPs (generally 40-50%)
each day with coverage peaking in the afternoon and evening. We are
continuing to monitor the potential for excessive heat. Highs temps
mainly in the mid to perhaps upper 90s combined with elevated dew
points will make it feel even hotter. Heat indices are forecast to
approach or exceed 108 in many locations, with some potential to
even hit 113. Excessive heat headlines could eventually be needed.
Convection could disrupt temperature trends.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
KCHS/KJZI: IFR cigs are possible during the next few hours before
gradually improving to MVFR mid-late morning and persisting into
early afternoon. Should a few showers redevelop across northern
areas today, tempo groups of low-end MVFR or even IFR could return.
Otherwise, conditions should improve to this afternoon, then prevail
through 12Z Wednesday.

KSAV: Prevailing IFR cigs will continue for the next few hours
before attempting to improve to MVFR later this morning. However,
moderate to heavy showers (and potentially thunderstorms) should
impact the terminal by mid morning, bringing periods of IFR or even
lower conditions through late morning and potentially into early
afternoon. Otherwise, conditions should slowly improve mid-late
afternoon to VFR and persist into early night. However, there are
signs of MVFR cigs returning overnight, thus prevailing MVFR groups
have been included from 02Z-12Z Wednesday.

Extended Aviation Outlook: Brief flight restrictions are possible in
showers and thunderstorms, mainly in the afternoon and evenings
through the period.

&&

.MARINE...
Today and Tonight: A fairly enhanced pressure gradient has developed
across northern SC waters off the Charleston County coast outside of
convection. Given recent obs across local waters a Small Craft
Advisory is now in effect until 2 PM for gusts around 25-30 kt and
seas up to 4-6 ft. Thereafter, guidance continues to indicate that
the gradient will begin to relax while a ridge of high pressure
persists aloft. Otherwise, expect northeast winds between gusting
around 20 kt outside shower/thunderstorm activity across southern SC
nearshore waters and nearshore GA waters, and more easterly and
light south of a stalled front/boundary across offshore Georgia
waters. Overnight, the front should begin to drift south of local
waters and/or dissipate, but showers and thunderstorms will continue
to pose localized higher wind gusts and reduced vsbys at times until
that occurs. Outside of this activity, winds should gradually weaken
(10-15 kt) and seas should subside to 2-4 ft.

Wednesday through Sunday: Northeast/east winds initially will turn
southerly by late week. Marine conditions should stay solidly below
small craft advisory criteria with speeds 15 knots or less and seas
no higher than 4 feet.

Waterspouts: We`re well into the local "Waterspout Season", and an
in-house Waterspout Index provides us with at least a Moderate Risk
this morning with light winds, weak shear, and ample low-lvl
moisture in place. For this reason along with latest radar trends, a
Marine Weather Statement has been issued for waterspout potential
across nearshore waters of Southeast South Carolina south or Edisto,
SC and nearshore waters of Southeast Georgia until noon today.

&&

.TIDES/COASTAL FLOODING...
Favorable onshore winds and the approach of the new moon will lead
to elevated tides over the next few days along the Charleston and
Colleton county coasts. Tides levels could approach minor coastal
flooding criteria of 7 ft MLLW in the Charleston Harbor. Further
south, no tide issues are expected.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...Small Craft Advisory until 2 PM EDT this afternoon for AMZ350.

&&

$$

NEAR TERM...DPB
SHORT TERM...ETM
LONG TERM...ETM
AVIATION...DPB/ETM
MARINE...DPB/ETM