Special Weather Statement, NWS Charleston, SC

Area Forecast Discussion
National Weather Service Charleston SC
333 PM EDT Sun Aug 19 2018

.SYNOPSIS...
The area will be situated between an inland trough and Atlantic
high pressure through Tuesday. A cold front will approach the
area from the northwest on Wednesday, then stall over or near
the region through the end of the week.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
Expect scattered showers and storms to develop through early
evening as the sea breeze meanders inland and combines with
additional convection and associated boundaries farther inland.
This convection will diminish overnight as the best instability
and forcing shift offshore. Given DCAPEs near 1000 J/kg near
the coast, especially in GA, we cannot rule out a severe storm
or two through early evening if convection can organize a bit.
Also, fog may develop late, mainly inland where rain falls. Lows
will generally range from the lower to mid 70s to the upper
70s/near 80 at the coast.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
Monday: Short wave ridging will develop aloft in response to building
heights from the parent anticyclone between Bermuda and the Bahamas,
while a digging trough will cross the Great Plains and MS Valley
during the day, eventually reaching the OH and TN valleys by 12Z
Tuesday. At the surface, the pattern is basically the same as it has
been of late, featuring a weak inland trough and the Bermuda-Azores
High aligned just off to the SE and S. The environment remains
fairly capped with more large scale subsidence and the warm mid
levels, and it'll take until around 2-3 pm to reach our convective
temps that are near 90F. With less overall moisture than recent
days, as PWat ranges from near 1.6" S to 2.0" N, the risk for
showers/t-storms is nothing higher than 20-30% chances during the
mid afternoon into the evening. Any pulse severe risk is non-zero,
since DCAPE is still forecast as great as 1000 J/kg.

Some late night marine convection from offshore could brush
Charleston County, but with the steering flow WSW, we have kept any
mentionable PoP over the Atlantic. Status quo on max and min temps;
with both slightly warmer than normal.

Tuesday: The upstream short wave trough will pass through the OH and
TN valleys during the daytime hours, dampening somewhat as it heads
toward the mid-Atlantic and NE at night. As this transpires a cold
front will push SE and approach the forecast district late at night,
as the oceanic ridge is nudged further to the SE. The prospects for
diurnal convection is near or actually a little below normal, as
moisture profiles are even less than on Monday, as PWat is down ~1.5-
1.8". Thus we have nothing higher than 20-30% POP in the afternoon
when convective temps are achieved. DCAPE is again near 1000 J/kg,
so the severe risk is non-zero.

The tail of the short wave and its accompanying RRQ of the upper jet
will move into the area during the late evening and overnight, and
this should keep at least isolated to scattered PoP in the forecast
even during the typical nocturnal minimum period.

Little change in both max and min temps from recent days, although
if coverage of convection is more than now forecast Tuesday night,
overnight lows would be a few degrees lower than now forecast.

Wednesday: The short wave from at night will cross into the Atlantic
during the morning, followed by DNVA into the afternoon. However, a
secondary short wave will drop through the western Great lakes and
help to maintain a broad mid and upper trough across a good part of
the eastern states. This forces a cold front to push into or near
the forecast zones, and that will be the main mechanism for the
development of showers and t-storms. The latest guidance shows the
main axis of moisture just off the coast, and due to this we are
hesitant to go anything more than scattered PoP, which "meshes" well
with surrounding WFO's. The forecast could require adjustments
though, pending where the cold front positions itself, and where the
best moisture plume sets up. Temps mainly 90-93F inland from the
coast.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Models show a long wave trough over the eastern half of the country
Wednesday night. This trough will gradually shift eastward and then
lift to the north into Friday, followed by zonal flow on Saturday.
At the surface, a front is forecasted to stall over or just offshore
of our area during this time period. This will lead to above normal
POPs and near or maybe even below normal temperatures. But if the
front positions itself further offshore, then large changes in the
forecast would be needed.

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
18Z TAFs: Generally VFR conditions expected. There is a small
risk of MVFR cigs at KCHS/KSAV this afternoon. Otherwise, the best
chance of impacts from showers and thunderstorms looks to be
late this afternoon into early evening.

Extended Aviation Outlook: Small probabilities of brief flight
restrictions Monday and Tuesday due to afternoon/evening convection.
Higher probabilities of brief flight restrictions due to convection
associated with a front Wednesday through Friday.

&&

.MARINE...
Tonight: Typical late-summer pattern with S/SW winds this
evening shifting to SW overnight. Speeds will average 15 kt with
some higher gusts with seas 2-4 ft. Some stronger storms are
possible across the waters, mainly through this evening.

Monday and Monday night: A modest SW'erly gradient will exist
between an inland trough and the Atlantic High to the SE and S. With
a boost from the sea breeze influences and subtle nocturnal low
level jetting, winds will be as high as 15 kt and gusty. With little
swell energy, seas will be generally be no larger than 2 or 3 ft.

Tuesday through Wednesday: The offshore ridge is forced a little
further SE as a cold front eventually slips closer to the SE coast
during mid week. The gradient tightens between these two large scale
features, especially late Tuesday and into Tuesday night, where S-SW
winds will reach as high as 15-20 kt with higher gusts. Seas will
respond and build to as high as 3-4 ft, maybe even 5 ft across the
northern AMZ350 waters.

Thursday through Friday: The cold front will become stationary over
or near the waters the second part of the week, as continental high
pressure builds to the NW and N. Depending upon where the front
stalls out and the exact strength to the land based high, there
could be adjustments to the latest wind and sea forecasts.

&&

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

&&

NEAR TERM...RJB
SHORT TERM...33
LONG TERM...
AVIATION...33/RJB
MARINE...33/RJB

Hazardous Weather Outlook
National Weather Service Charleston SC
306 AM EDT Sun Aug 19 2018

AMZ330-350-352-354-374-GAZ087-088-099>101-114>119-137>141-SCZ040-
042>045-047>052-200715-
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-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-
306 AM EDT Sun Aug 19 2018

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
703 PM EDT SUN AUG 19 2018

SCZ047-048-051-192330-
Inland Jasper-Coastal Jasper-Beaufort-
703 PM EDT SUN AUG 19 2018

...STRONG THUNDERSTORMS WILL IMPACT PORTIONS OF BEAUFORT AND JASPER
COUNTIES...

At 703 PM EDT, National Weather Service doppler radar indicated a
strong thunderstorm over Pritchardville, or near Bellinger Hill Area,
moving east at 15 mph.

  HAZARD...strong winds 45 to 55 mph.

  IMPACT...Expect minor damage to tree limbs and blowing around of
           light, unsecured objects.

Some locations in the path of this storm include...
Bluffton, Jasper, Hardeeville, Calawassie Island, Pritchardville,
Rose Hill and Sun City.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

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 3218 8099 3228 8110 3239 8090 3225 8078
TIME...MOT...LOC 2303Z 247DEG 15KT 3225 8100

Special Weather Statement
National Weather Service Charleston SC
732 PM EDT SUN AUG 19 2018

SCZ047-048-051-200000-
Inland Jasper-Coastal Jasper-Beaufort-
732 PM EDT SUN AUG 19 2018

...STRONG THUNDERSTORMS WILL IMPACT PORTIONS OF BEAUFORT AND JASPER
COUNTIES...

At 731 PM EDT, National Weather Service doppler radar indicated a
strong thunderstorm near Old House, or near Ridgeland, moving
northeast at 20 mph.

  HAZARD...strong winds 45 to 55 mph and excessive cloud to ground
           lightning.

  IMPACT...Expect minor damage to tree limbs and blowing around of
           light, unsecured objects. All outdoor activities should
           cease. Move indoors immediately.

Some locations in the path of this storm include...
Beaufort, Ridgeland, Clarendon, Jasper, Grahamville, Coosawhatchie,
Lemon Island and Switzerland.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 3257 8065 3229 8087 3236 8110 3265 8102
TIME...MOT...LOC 2331Z 207DEG 24KT 3242 8093

ETM

Special Weather Statement
National Weather Service Charleston SC
754 PM EDT SUN AUG 19 2018

GAZ101-116-118-119-200030-
Effingham-Coastal Chatham-Inland Chatham-Inland Bryan-
754 PM EDT SUN AUG 19 2018

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

At 754 PM EDT, National Weather Service doppler radar indicated a
strong thunderstorm near Meldrim, or 8 miles west of I-16/I-95
Interchange, moving northeast at 40 mph.

  HAZARD...strong winds 45 to 55 mph and excessive cloud to ground
           lightning.

  IMPACT...Expect minor damage to tree limbs and blowing around of
           light, unsecured objects. All outdoor activities should
           cease. Move indoors immediately.

Some locations in the path of this storm include...
Savannah, Pooler, Richmond Hill, Pembroke, I-16/I-95 Interchange,
Lanier, Rincon and Garden City.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 3233 8128 3218 8112 3212 8112 3209 8106
      3209 8103 3207 8101 3189 8121 3189 8123
      3187 8123 3181 8130 3189 8139 3194 8141
      3195 8146 3197 8148 3197 8149 3212 8168
TIME...MOT...LOC 2354Z 239DEG 33KT 3205 8139

ETM

Special Weather Statement
National Weather Service Charleston SC
806 PM EDT SUN AUG 19 2018

GAZ088-100-101-200030-
Bulloch-Screven-Effingham-
806 PM EDT SUN AUG 19 2018

...STRONG THUNDERSTORMS WILL IMPACT PORTIONS OF SCREVEN...BULLOCH AND
EFFINGHAM COUNTIES...

At 805 PM EDT, National Weather Service doppler radar indicated a
strong thunderstorm over Oliver, or 14 miles east of Statesboro,
moving northeast at 35 mph.

  HAZARD...strong winds 45 to 55 mph.

  IMPACT...Expect minor damage to tree limbs and blowing around of
           light, unsecured objects.

Some locations in the path of this storm include...
Brooklet, Newington, Oliver, Egypt, Shawnee, Leefield, Clyo and
Kildare.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 3256 8170 3269 8148 3263 8141 3262 8141
      3259 8137 3257 8135 3257 8133 3245 8120
      3237 8165
TIME...MOT...LOC 0005Z 243DEG 29KT 3249 8155

ETM

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHARLESTON SC
824 PM EDT SUN AUG 19 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0814 PM     TSTM WND GST     HUNTER ARMY AIRFIELD    32.01N  81.13W
08/19/2018  M47 MPH          CHATHAM            GA   ASOS

            HUNTER ARMY AIRFIELD...KSVN...MEASURED A 41 KNOT WIND
            GUST.

&&

EVENT NUMBER CHS1800767

BSH

Special Weather Statement
National Weather Service Charleston SC
826 PM EDT SUN AUG 19 2018

GAZ101-SCZ047-048-051-200100-
Effingham-Inland Jasper-Coastal Jasper-Beaufort-
826 PM EDT SUN AUG 19 2018

...STRONG THUNDERSTORMS WILL IMPACT PORTIONS OF EFFINGHAM...BEAUFORT
AND JASPER COUNTIES...

At 826 PM EDT, National Weather Service doppler radar indicated
strong thunderstorms along a line extending from Springfield to
Whitemarsh Island, and moving northeast at 25 mph.

  HAZARD...strong winds 45 to 55 mph.

  IMPACT...Expect minor damage to tree limbs and blowing around of
           light, unsecured objects.

Some locations in the path of these storms include...
Hilton Head Island, Bluffton, Springfield, Bellinger Hill Area,
Jasper, Rincon, Port Wentworth and Hardeeville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 3210 8100 3208 8104 3209 8106 3214 8112
      3215 8111 3216 8113 3217 8111 3219 8112
      3219 8111 3223 8115 3223 8121 3237 8133
      3243 8100 3222 8073 3207 8095
TIME...MOT...LOC 0026Z 203DEG 23KT 3237 8129 3205 8100

ETM