Special Weather Statement, NWS Charleston, SC

Area Forecast Discussion
National Weather Service Charleston SC
413 PM EDT Sat Jul 15 2017

.SYNOPSIS...
Between Atlantic and inland high pressure, a weak trough of low
pressure will persist over the Southeast into next weekend.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
Until Sunset: Radar shows showers and thunderstorms ongoing
across most of the area. These storms have been tapping into
MLCAPEs of at least 2,000 J/kg in areas where PWATs are ~2".
Convection is expected to continue, especially in areas that
have yet to receive any convection. SPC meso analysis indicates
MLCAPEs in these area is ~2,500 J/kg. The sea breeze and cold
pool boundaries will drive a lot of this pulse convection.
DCAPES approaching 1,200 J/kg will continue to equate to a
damaging wind threat. Most of the storms are generating heavy
rainfall, but at least they're moving at a decent speed to limit
the flooding threat. If any training does occur, then flood
advisories may be needed.

Tonight: Heights will lower as mid-level troughing moves
southward and over our region. Additionally, short waves are
forecasted to round the base of this trough, passing nearby or
over us late. At the surface, the weak cold front over the
Appalachians will continue to drift southward, weakening as it
does so. Moisture will remain high across the area, with PWATs
~2". Despite the nighttime hours, instability will remain in
place over land. The GFS suggests LI's approaching -5, BLCAPEs
exceeding 1,000 J/kg, and Showalters approaching -4. Given all
of the factors, convection is expected to persist overnight,
with the highest probabilities being across the Charleston Tri-
County, lowering as one heads southward. There could be a brief
window where there is very little convection, but that will get
refined in the upcoming hours. It's still not out of the
question that we could get high wind gusts in the strongest
storms. But the overall severe threat should remain low. Again,
the storms could generate heavy rainfall and move little given
the light winds aloft. If any training does occur, then flood
advisories may be needed. Low temperatures will be in the mid
70s to near 80 degrees, but this is highly depending on the
timing and coverage of convection.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
Sunday through Monday: A plume of PWATs 2-2.25 inches will settle
over the region as an upper trough amplifies toward the Southeast.
Within this regime, showers/thunderstorms could develop and/or move
into the region at any time. Greatest coverage of showers /
thunderstorms, justifying at least likely POPs, should occur from
the late morning/early afternoon into the evening hours. Given deep-
layered moisture and weak tropospheric flow, a few thunderstorms
could produce excessive rainfall/localized flooding. Also, isolated
thunderstorms could briefly become severe with damaging wind gusts,
especially Sunday. Meanwhile, cloud cover/precipitation will hold
temps below those of Sunday afternoon.

Tuesday: The upper trough will continue to press S/E, but deepest
moisture will retreat offshore, replaced by slightly drier air.
However, the environment will likely not dry sufficiently to prevent
decent coverage of diurnal showers/thunderstorms, and the latest
forecast includes high chance POPs Tuesday afternoon.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
Troughing aloft weakens by mid-week as deep layer ridging gradually
builds in from the west through the rest of the period. The general
trend through this period will be decreasing POPs from near climo
Tuesday to below climo late in the week, in mainly isolated
convection along the sea breeze each day. As is typical with this
pattern, a few strong to severe storms would be possible each
afternoon, but there are no indications of any
significant/widespread severe weather threat. Temps will also trend
above climo as stronger ridging builds in late in the week.

&&

.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
Showers and thunderstorms have developed across the area and
are expected to impact the airports over the upcoming hours.
VCTS and TEMPOs will cover this potential, with amendments
being made as radar trends develop. Temporary flight
restrictions to at least MVFR can be expected with any SHRA/TSRA
that directly impact the airports. SHRA will persist into
tonight, mainly at KCHS due to boundary interactions and energy
aloft moving in. Another round of SHRA/TSRA is expected to
develop towards the end of the TAF period.

Extended Aviation Outlook: Flight restrictions are possible within
showers and thunderstorms at both KSAV and KCHS, especially Sunday
through Tuesday.

&&

.MARINE...
Tonight: The coastal waters will remain between the extreme
western periphery of the Atlantic surface high with a weak cold
front over the Appalachians drifting southward and weakening.
Winds will generally be from the SW 10-15 kt, veering and
weakening slightly by daybreak as the land breeze develops. Seas
will average 2-4 ft.

Sunday through Thursday: Outside thunderstorms which will
produce localized hazardous conditions and will alter local
winds, southerly winds 20 knots or less and associated seas of 1
to 3 feet will prevail. Thunderstorms will be common Sunday
through Tuesday; then, coverage of thunderstorms should increase
mid to late week.

&&

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

&&

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

Hazardous Weather Outlook
National Weather Service Charleston SC
340 PM EDT Sat Jul 15 2017

GAZ087-088-099>101-114>119-137>141-SCZ040-042>045-047>052-161945-
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-
340 PM EDT Sat Jul 15 2017

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

.DAY ONE...This Afternoon and Tonight.

The probability for widespread hazardous weather is low.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

Severe thunderstorms and heavy rain: Numerous thunderstorms are
expected Sunday, especially from late morning into the evening.
Isolated thunderstorms could briefly become severe with damaging wind
gusts. Also, some thunderstorms will produce very heavy rain, and
localized flooding is possible.

.SPOTTER INFORMATION STATEMENT...

Spotter assistance is not anticipated at this time.

AMZ330-350-352-354-374-161945-
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 extending from 20 to
60 nm-
340 PM EDT Sat Jul 15 2017

This Hazardous Weather Outlook is for Atlantic coastal waters.

.DAY ONE...This Afternoon and Tonight.

The probability for widespread hazardous weather is low.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

Strong thunderstorms: Thunderstorms will impact coastal waters Sunday
into Monday. Some thunderstorms could produce hazardous conditions
for small craft, including strong wind gusts, rough seas, frequent
cloud to water lightning and poor visibility in heavy rainfall.

.SPOTTER INFORMATION STATEMENT...

Spotter assistance is not anticipated at this time.

Special Weather Statement
National Weather Service Charleston SC
323 PM EDT SAT JUL 15 2017

GAZ114-137-152000-
Tattnall-Long-
323 PM EDT SAT JUL 15 2017

...STRONG THUNDERSTORMS WILL IMPACT PORTIONS OF LONG AND TATTNALL
COUNTIES...

At 323 PM EDT, National Weather Service doppler radar indicated a
strong thunderstorm over Glennville, or 17 miles southeast of
Reidsville, moving south at 5 mph.

  HAZARD...strong winds 45 to 55 mph and up to nickel 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...
Glennville and Mendes.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This storm may intensify. Be certain to monitor local radio and TV
stations as well as local cable TV outlets for additional information
and possible warnings from the National Weather Service.

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 3202 8198 3195 8181 3175 8190 3178 8195
      3179 8195 3179 8196 3186 8208
TIME...MOT...LOC 1923Z 010DEG 6KT 3190 8193

NED

Special Weather Statement
National Weather Service Charleston SC
410 PM EDT SAT JUL 15 2017

SCZ045-152045-
Inland Berkeley-
410 PM EDT SAT JUL 15 2017

...STRONG THUNDERSTORMS WILL IMPACT PORTIONS OF BERKELEY COUNTY...

...MARINERS ON LAKE MOULTRIE AND EASTERN LAKE MARION SHOULD SEEK SAFE
HARBOR...

At 410 PM EDT, National Weather Service doppler radar indicated a
strong thunderstorm over Eadytown, or 16 miles northwest of Moncks
Corner, moving east at 35 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...
St. Stephen, Bonneau, Southern Lake Moultrie, Eadytown, Cross,
Northern Lake Moultrie, Bonneau Beach and Eastern Lake Marion.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Boaters on Lake Moultrie and Eastern Lake Marion should seek safe
harbor immediately. If caught on the open water, stay as low as
possible and wear a personal flotation device. Remember, if you can
hear thunder you are at risk for being struck by lightning.

This storm may intensify. Be certain to monitor local radio and TV
stations as well as local cable TV outlets for additional information
and possible warnings from the National Weather Service.

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 3343 7987 3341 7986 3322 7997 3331 8025
      3344 8022 3346 8016 3345 8016 3345 8015
      3346 8015 3345 8014 3348 8015 3349 8012
TIME...MOT...LOC 2010Z 289DEG 29KT 3340 8016

NED

Special Weather Statement
National Weather Service Charleston SC
417 PM EDT SAT JUL 15 2017

GAZ116-138-152045-
Inland Liberty-Inland Bryan-
417 PM EDT SAT JUL 15 2017

...STRONG THUNDERSTORMS WILL IMPACT PORTIONS OF LIBERTY COUNTY...

At 417 PM EDT, National Weather Service doppler radar indicated a
strong thunderstorm over Riceboro, or 12 miles southeast of
Hinesville, moving south at 20 mph.

  HAZARD...strong winds 45 to 55 mph, up to nickel sized hail and
           excessive cloud to ground lightning.

  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. All outdoor activities should cease. Move
           indoors immediately.

Some locations in the path of this storm include...
Riceboro and Retreat.

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 3173 8154 3189 8145 3184 8135 3183 8136
      3182 8132 3181 8132 3179 8131 3180 8129
      3179 8127 3166 8136
TIME...MOT...LOC 2017Z 021DEG 16KT 3177 8141

NED

Special Weather Statement
National Weather Service Charleston SC
445 PM EDT SAT JUL 15 2017

SCZ045-152115-
Inland Berkeley-
445 PM EDT SAT JUL 15 2017

...STRONG THUNDERSTORMS WILL IMPACT PORTIONS OF BERKELEY COUNTY...

...MARINERS SHOULD REMAIN OFF LAKE MOULTRIE AND IN SAFE HARBOR...

At 444 PM EDT, National Weather Service doppler radar indicated a
strong thunderstorm over Southern Lake Moultrie, or 8 miles north of
Moncks Corner, moving southeast at 15 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...
Moncks Corner, St. Stephen, Bonneau, Southern Lake Moultrie,
Eadytown, Cross, Northern Lake Moultrie and Bonneau Beach.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Boaters should remain off Lake Moultrie and in safe harbor.

Excessive cloud to ground lightning is occurring with this storm.
Lightning can strike 15 miles away from a thunderstorm. Seek safe
shelter inside a building or vehicle.

&&

LAT...LON 3349 7995 3345 7988 3343 7987 3343 7988
      3340 7986 3337 7981 3315 7999 3332 8025
      3351 8005 3351 8002 3350 8002 3351 8001
      3351 7999
TIME...MOT...LOC 2044Z 298DEG 15KT 3331 8006

Special Weather Statement
National Weather Service Charleston SC
501 PM EDT SAT JUL 15 2017

SCZ045-052-152130-
Inland Berkeley-Tidal Berkeley-
501 PM EDT SAT JUL 15 2017

...STRONG THUNDERSTORMS WILL IMPACT PORTIONS OF BERKELEY COUNTY...

At 500 PM EDT, National Weather Service doppler radar indicated
strong thunderstorms extending from near Old Santee Canal State Park
to near Naval Weapons Station Charleston to Honey Hill, moving
northeast at 15 mph.

  HAZARD...strong winds 45 to 55 mph, up to nickel sized hail and
           excessive cloud to ground lightning.

  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. All outdoor activities should cease. Move
           indoors immediately.

Some locations in the path of these storms include...
Charleston, Goose Creek, Moncks Corner, St. Stephen, Bonneau,
Jamestown, Old Santee Canal State Park and Huger.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3343 7987 3340 7985 3337 7980 3338 7979
      3332 7974 3327 7956 3324 7950 3325 7948
      3321 7945 3319 7949 3314 7952 3316 7956
      3313 7964 3305 7970 3292 7994 3322 8000
      3347 7993
TIME...MOT...LOC 2100Z 199DEG 13KT 3322 7994 3301 7991

Special Weather Statement
National Weather Service Charleston SC
504 PM EDT SAT JUL 15 2017

SCZ043-049-152130-
Coastal Colleton-Inland Colleton-
504 PM EDT SAT JUL 15 2017

...STRONG THUNDERSTORMS WILL IMPACT PORTIONS OF COLLETON COUNTY...

At 503 PM EDT, National Weather Service doppler radar indicated a
strong thunderstorm over White Hall, or 10 miles south of Walterboro,
moving east at 10 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...
Walterboro, Hendersonville, Round O, Green Pond, Ashepoo, Ritter and
White Hall.

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 3271 8078 3292 8074 3294 8052 3264 8054
TIME...MOT...LOC 2103Z 274DEG 8KT 3276 8069