Areal Flood Advisory 89, NWS Charleston, SC

Area Forecast Discussion
National Weather Service Charleston SC
200 PM EDT Sun Aug 8 2021

.SYNOPSIS...
High pressure will prevail across the area through much of the
week.

&&

.NEAR TERM /THROUGH TONIGHT/...
The upper level trough axis stretches from Pennsylvania down
through the Carolinas into Georgia with a well defined short-
wave center spinning along the North/South Carolina border.
Surface high pressure is building along the Appalachians to the
Gulf with a stalled boundary extending through the Carolinas
into southern Georgia. Deep layer moisture axis (PWAT > 2
inches) has been shunted just offshore.

The upper trough axis and aforementioned short-wave circulation
will slowly slip eastward across the region today to just off
the coast this evening. Daytime heating will destabilize things
a bit with MLCAPE values building to 1000-1500 J/Kg, perhaps a
bit more. Combination of modest background forcing for ascent
with the trough, sea breeze development and any old boundaries
lurking about should kick off some showers/thunderstorms as we
head into the afternoon. Initially along the coast, with
convection pushing inland through the afternoon. As is typical
for this time of year, some localized heavy rainfall remains a
possibility in areas that the thunderstorms hover over for an
extended period of time. High temperatures may actually hit
normal (~90 degrees) across our entire area today.

Convection lingers into this evening before ending by the
overnight. Some fog will again be possible, particularly for
areas that do see rainfall today/evening.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
What remains of a mid-upper lvl trough will slowly shift further
northeast and offshore Monday before high pressure strengthens
across the Atlantic, then spreads across the Southeast United States
through mid week. With a typical summertime pattern taking shape,
few to scattered showers/thunderstorms are possible each day,
primarily triggered by a sea breeze circulation shifting inland
during afternoon into early evening hours. Ample low-lvl moisture
will be in place, but overall instability is rather modest and shear
is quite weak, suggesting mainly diurnally driven showers and pulse
type thunderstorms. Overnight periods should remain mainly dry. High
temps should be near normal each day, peaking in the mid-upper 80s
near the coast to lower 90s inland. Overnight lows will remain mild,
generally ranging in the low-mid 70s inland to upper 70s at the
beaches.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Very little change is expected to the overall pattern through late
week while broad high pressure extends from the Atlantic and
prevails across the region. There are hints of an upper lvl low
approaching the Florida/Georgia coast late week and perhaps a front
approaching from the northwest early next week, suggesting a slight
uptick in precip coverage, but overall confidence in timing of these
features and local impacts is quite low. Regardless, conditions
should be typical of a summertime pattern across the Southeast
United States through much of the week with scattered showers and
thunderstorms possible each afternoon and early evening, mainly
associated with an inland moving seabreeze. Overnight periods should
remain drier due to diurnal heat loss. High temps will remain near
normal, peaking around 90 degrees away from the beaches. Lows will
remain mild, ranging in the low-mid 70s away from the coast each
night.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
18Z TAFs: Convection has developed across our area it's expected
to last until ~23Z. We have VCTS as all of the TAF sites and
will amend to add a TEMPO if radar trends show extremely likely
restrictions to the TAF sites. Otherwise, the convection will
dissipate this evening. The MOS indicates increased
probabilities of fog overnight. We kept the TAFs simple, with
MVFR due to MIFG from 08-15Z. This will need to be adjusted with
future TAFs.

Extended Aviation Outlook: Brief flight restrictions possible at
CHS/JZI/SAV terminals due to showers/thunderstorms each afternoon
into early evening hours. Otherwise, VFR conditions should prevail
at the terminals through midweek.

&&

.MARINE...
Today and Tonight: South to southwest winds 5 to 15 knots will
continue with seas 2 to 3 feet, except near the coast where
development of a sea breeze by afternoon will turn winds more
onshore. Some showers/storms will be found in the marine zones
this morning. The risk of waterspouts is rapidly dropping as
this convection moves further offshore and out of our area.

Monday through Friday: Atlantic high pressure will build over the
waters and remain the dominate weather feature through late week,
although a weak upper lvl low could help produce greater
thunderstorm coverage across local waters heading into the weekend.
Given the pattern, expect conditions to remain well below small
craft advisory levels. In general, south-southeast to south-
southwest winds will peak near 10-15 kt each day, highest near the
coast as a sea breeze circulation develops and shifts inland each
afternoon. Seas will average no higher than 2-3 ft.

&&

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

&&

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

Hazardous Weather Outlook
National Weather Service Charleston SC
434 AM EDT Sun Aug 8 2021

GAZ087-088-099>101-114>119-137>141-SCZ040-042>045-047>052-091000-
Jenkins-Screven-Candler-Bulloch-Effingham-Tattnall-Evans-
Inland Bryan-Coastal Bryan-Inland Chatham-Coastal Chatham-Long-
Inland Liberty-Coastal Liberty-Inland McIntosh-Coastal McIntosh-
Allendale-Hampton-Inland Colleton-Dorchester-Inland Berkeley-
Inland Jasper-Beaufort-Coastal Colleton-Charleston-Coastal Jasper-
Tidal Berkeley-
434 AM EDT Sun Aug 8 2021

This Hazardous Weather Outlook is for southeast Georgia and
southeast South Carolina.

.DAY ONE...Today and tonight.

The probability for widespread hazardous weather is low.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter assistance is not anticipated at this time.

AMZ330-350-352-354-374-091000-
Charleston Harbor-
Waters from South Santee River to Edisto Beach SC out 20 NM-
Waters from Edisto Beach SC to Savannah GA out 20 NM-
Waters from Savannah GA to Altamaha Sound GA out 20 NM, including
Grays Reef National Marine Sanctuary-
Waters from Savannah GA to Altamaha Sound GA from 20 to 60 NM-
434 AM EDT Sun Aug 8 2021

This Hazardous Weather Outlook is for Atlantic coastal waters.

.DAY ONE...Today and tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter assistance is not anticipated at this time.