042
FXUS62 KCHS 090518
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
118 AM EDT Tue Jul 9 2024

.SYNOPSIS...
A surface trough will remain over inland areas this week while
high pressure persists over the western Atlantic.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
The majority of convection from earlier has come to an end
across the CWA. However, a weakening upper low over the
Southeast Atlantic will retrograde southwest toward the FL/GA
coast tonight. PWATs should remain elevated through the night,
nearing a whopping 2.5 inches. With an abundance of available
moisture, upper forcing could initiate isolated showers across
the nearshore waters and along the coast tonight. Also, there
remains a small area of untapped instability (SBCAPE around 2000
J/kg) across the Charleston County coastal waters and along the
immediate coast, which is likely where activity will initially
generate. However, we will maintain slight chance to chance
POPs through the night across the coast and all our marine
zones. Later tonight, winds will go calm inland and guidance
has been showing small areas of fog development far inland,
largely across the Georgia Midlands. It is not out the question
that patchy fog could develop across portions of our CWA in
Southeast Georgia, especially where previous rainfall totals of
2-4 inches exist. With some clouds expected, in addition to
model soundings pointing to surface dew point depressions
around 1-3 degrees, we may only see a shallow layer of low
stratus; thus, fog has not been mentioned in tonight`s
forecast. Expect low temperatures in the mid to upper 70s most
places and around 80 degrees at the beaches and Downtown
Charleston.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY/...
Mid level ridge will extend across the region Tuesday and Wednesday,
in between a trough to the west and a low over the Atlantic that
will likely translate towards the Florida coast. At the surface, a
trough of low pressure inland will become more prominent over the
area as a cold front approaches the region from the west. Continuous
moisture feed will keep PWats well over 2 inches. Scattered to
numerous showers and thunderstorms are expected each day, especially
in the afternoon and evenings, with an active sea breeze and
possibly some weak upper support. Severe weather threat is low, but
locally heavy rain is possible. High temperatures forecast in the
low 90s each day with elevated dew points will result in heat
indices peaking in the 105-108F range. There remains potential for
Heat Advisories across portions of the area. Lows will average in
the mid to upper 70s.

On Thursday, another upper disturbance over the Atlantic looks to
track westward towards the Southeast coast. The aforementioned front
is expected to stall with most models indicating a weak wave of low
pressure developing along it over or near the area. Some drier air
could move into inland areas on Thursday with slightly less
convective coverage anticipated. Highs again peak in the lower
90s.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
A mid level wave over the Atlantic will largely get absorbed in the
larger scale trough as it approaches the Southeast coast early in
the period, before ridging reasserts itself over the weekend.
Scattered diurnal showers and thunderstorms will be possible each
day. We again lowered PoPs from the initial NBM output with no
higher than 50% in the forecast. Temperatures will be on a warming
trend through the period.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
KCHS/KJZI/KSAV: Convection is still ongoing near the Charleston
coast early this morning thanks to a weakness aloft which is
slowly heading southwest. Showers and thunderstorms will likely
continue to propagate slowly to the southeast, or off the South
Carolina coast as the overnight land breeze takes over. During
the day Tuesday, another round of showers and thunderstorms
appear possible with the greatest chance of precipitation again
being towards KSAV (which is in the path of the weak forcing).
However, all terminals will include a mention of thunder given
the widespread instability available. Mostly VFR conditions are
forecast through the period.

Extended Aviation Outlook: Scattered afternoon showers and
thunderstorms may produce brief flight restrictions.

&&

.MARINE...
Tonight: Outside of isolated showers and perhaps a thunderstorm,
generally quiet conditions are expected across the marine zones.
Seas will range from 2 to 3 ft with SSW winds 5 to 10 kt.

Tuesday through Saturday: Southerly flow will persist through the
period. Conditions remain below small craft advisory criteria with
wind speeds largely in the 10-15 knot range and seas 2-3 feet.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...None.

&&

$$

NEAR TERM...BRM
SHORT TERM...ETM
LONG TERM...ETM
AVIATION...BRM/ETM/Haines
MARINE...CPM/ETM