Special Weather Statement, NWS Charleston, SC

Area Forecast Discussion
National Weather Service Charleston SC
131 PM EDT Sun Aug 9 2020

.SYNOPSIS...
The region will remain positioned between Atlantic high
pressure centered offshore, and an inland area of broad low
pressure.

&&

.NEAR TERM /THROUGH TONIGHT/...
The newest CAMs seem to paint a similar picture of afternoon
convection, initiating along the sea breeze and then moving
inland. Temperatures topping out in the 90s will help MLCAPEs
rise to ~2,500 J/kg resulting in scattered convection. Storm
motion will be dominated by outflow and local enhanced
convergence so training of storms or nearly stationary storms
could result in locally heavy rainfall, especially with PWATs
~2". With DCAPEs exceeding 800 J/kg, a few marginally severe
pulse storms with damaging winds remain a concern into the
evening. The convection should dissipate by late evening, but
then the convective focus shifts over the coastal waters. A few
showers could brush the coast late tonight. Lows tonight will
range from the lower 70s well inland to the upper 70 near the
coast.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
The large scale pattern will continue to be nearly locked in place
through the period with a broad, deep layer trough of low pressure
well west of the region, and an Atlantic ridge of high pressure well
to the southeast. Models show a hint of a weak upper level short
wave to drift over the region Monday, but other than that, no real
discernible large scale features to help focus and force convection.
Therefore, the sea breeze will be the primary initial trigger for
convection, followed by convective outflow boundaries during the
afternoon and evening. Lingering outflow boundaries may spawn
isolated showers or thunderstorms through the night each night.
Winds will be light southerly less than 10 mph, becoming onshore
near the coast each afternoon in the form of a weak seabreeze.  With
abundant moisture and light, unidirectional deep layer flow, locally
heavy rainfall will again be possible. High temperatures close to
normal, reaching 90 to the lower 90s. Lows will continue warm, in
the lower to mid 70s most areas, around 80 close to the coast.
Afternoon heat indices expected to reach 100 to 105 each day as
surface dewpoint temperatures stay in the lower to mid 70s.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Very little change in the large scale pattern is shown by
global models through the period as a broad trough persists
inland and higher pressure well offshore over the Atlantic. This
will continue light southerly winds with afternoon sea breezes
each day. Although deep layer moisture will be sufficient with
PWs 1.5 to 2 inches, lack of any significant large scale forcing
will mean that the sea breeze will continue to be the primary
way convection will initiate. Model blended PoPs continue to be
in the likely range each afternoon, which is about 20 percent
above climo. Continue to feel a little uncomfortable with PoPs
in that range so far out. However, the higher blended PoPs
collaborate well with surrounding offices. Did adjust PoPs
downward by 5-10 percent, especially toward the end of the
period. High temperatures will continue near normal, while low
temperatures likely to continue a few degrees above normal.
Given light steering flow, locally heavy rainfall cannot be
ruled out each afternoon.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
18Z TAFs: Sea breeze thunderstorms could bring brief flight
restrictions to either TAF site into this evening. Since the
time window for this is several hours, we opted to maintain the
VCTS. If radar trends indicate a direct impact, then an
amendment will be made to add a TEMPO group. Otherwise, the
thunderstorms are forecasted to dissipate this evening, followed
by a dry night. Though, it's possible some ground fog could
occur in areas where there is heavy rainfall. The probabilities
of this happening at either TAF site is currently too low to
mention. Another round of convection is possible Monday
afternoon.

Expect showers and thunderstorms to develop this afternoon and
continue into the evening. Due to uncertainty regarding timing,
location, and duration of activity and any impacts to the
terminals, opted to include VCTS at both KCHS and KSAV starting
at the sea breeze passage, 19Z @ KCHS and 20Z @ KSAV and
continue it into the evening. It is quite possible that TRW will
need to be included in at least one of the terminals in later
forecasts/updates and it is possible that could occur prior to
the current inclusion of VCTS, but most likely during the
forecast VCTS time frame. Outside of showers and thunderstorms
at the terminals, expect VFR conditions to prevail. There is a
low chance for some light fog or patchy ground fog late tonight,
but this seems more likely to occur if significant rain falls
at the site later this afternoon or this evening. Should that
occur or become likely to occur, later forecast may need to
include it.

Extended Aviation Outlook: Scattered to numerous mainly
afternoon and early evening showers and thunderstorms could
result in brief flight restrictions at both sites each day.

&&

.MARINE...
Today and tonight: Extremely tranquil period outside of any
convection with winds greatest near the coast in association
with afternoon/evening sea breeze, but even there winds will
only be around 10 knots. Seas will be from 1 to 2 feet.

Monday through Thursday: No highlights are expected through the
period. The waters will remain between Atlantic high pressure
to the east and a broad area of lower pressure well inland. This
pattern will continue generally south-southwest winds of 15
knots or less and seas of 1 to 3 feet. Winds are expected to
veer to south-southeast each afternoon near the coast due to
the sea breeze circulation.

&&

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

&&

NEAR TERM...
SHORT TERM...RFM
LONG TERM...RFM
AVIATION...
MARINE...

Hazardous Weather Outlook
National Weather Service Charleston SC
324 AM EDT Sun Aug 9 2020

AMZ330-350-352-354-374-GAZ087-088-099>101-114>119-137>141-SCZ040-
042>045-047>052-100730-
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-
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-
324 AM EDT Sun Aug 9 2020

This Hazardous Weather Outlook is for Atlantic coastal waters,
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.

The probability for widespread hazardous weather is low.

.SPOTTER INFORMATION STATEMENT...

Spotter assistance is not anticipated at this time.

Special Weather Statement
National Weather Service Charleston SC
247 PM EDT Sun Aug 9 2020

GAZ101-116-118-091915-
Effingham-Inland Chatham-Inland Bryan-
247 PM EDT Sun Aug 9 2020

...STRONG THUNDERSTORMS WILL IMPACT PORTIONS OF BRYAN...EFFINGHAM AND
CHATHAM COUNTIES...

At 246 PM EDT, National Weather Service doppler radar indicated a
strong thunderstorm over Meldrim, or 7 miles west of Pooler, moving
northeast at 5 mph.

  HAZARD...strong winds 45 to 55 mph and up to penny sized hail.

  IMPACT...Expect minor damage to tree limbs and blowing around of
           light, unsecured objects. Minor hail damage to plants,
           trees and crops is possible. Damage to windshields is
           unlikely.

Some locations in the path of this storm include...
Pooler, Godley Station, Savannah International Airport, Port
Wentworth, Bloomingdale, Blitchton, Meinhard and Eden.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with this storm and may lead to
flooding of low lying and poor drainage areas. Do not drive your
vehicle through flooded roadways.

Report damage directly to the Charleston National Weather Service at
1-888-383-2024 when it is safe to do so. You can also email your
report to nws.charlestonsc@noaa.gov.

&&

LAT...LON 3203 8133 3215 8154 3227 8135 3217 8118
TIME...MOT...LOC 1846Z 227DEG 6KT 3212 8138

NED