Special Weather Statement, NWS Charleston, SC

Area Forecast Discussion
National Weather Service Charleston SC
1040 AM EDT Wed May 20 2020

.SYNOPSIS...
Deep low pressure will linger to the northwest through Friday.
A ridge of high pressure will build over the area this weekend
and persist through much of next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 1030 AM: Radar indicate a line of stratiform precipitation
moving across our GA counties while in advance of it there are
stronger showers/thunderstorms developing as they tap into
instability. We updated the forecast to raise POPs to
categorical for the next few hours and to lower temperatures due
to the rain cooled air. We expect more changes will be needed as
radar trends evolve.

Today: The center of mid-level low is expected to wobble over
eastern TN, while retrograding slowly, during the daylight hours. As
a result, heights across the forecast area may increase slightly
between 12Z-0Z. At the sfc, the center of low pressure is expected
to track from the southern GA/AL line this morning to over the
southern Savannah River by early this evening. As the sfc low
approaches, a warm front is expected to lift north across the SC
Lowcountry. Temperatures are forecast to warm to around 80 degrees
for much of the CWA, with mid 80s possible across coastal areas of
SE GA. Near-term guidance indicates that weak to moderate SBCAPE
will develop south of the front during the heat of the day.
Thunderstorm coverage is expected to gradually increase from late
morning through the afternoon, especially across the inland
counties. It is possible that a weak supercell or two may form,
possibly yielding isolated severe wind or hail events.

Tonight: The sfc low will likely to continue to track slowly NE
across the forecast area through the night. At least weak
instability is forecast to remain along and east of the low. I
suspect that portions of the forecast will be worked over from the
convection that has occurred during the afternoon and evening.
However, I will keep a broad SCHC to CHC PoPs across the CWA
tonight, greatest values over the CHS Tri-county. Using a blend of
MOS, low temperature are forecast to range from near 70s along the
coast to the low 60s inland.

&&

.SHORT TERM /THURSDAY THROUGH SATURDAY/...
A weak surface front is forecast to linger just off the coast on
Thursday with somewhat drier boundary layer air in place over
land. A weak shortwave may move through during the afternoon
which could provide enough forcing combined with moderate
instability to trigger isolated to scattered showers and tstms.

An upper ridge will gradually build over the Southeast Friday
through Saturday. A shortwave could move through southern SC
Friday afternoon so we included a 30 PoP. Building upper heights
and NVA should limit the potential for convection on Saturday.
Temperatures will warm well into the 80s Friday and Saturday.

&&

.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
Deep layered ridging late in the weekend through the middle part
of next week should limit the potential for convection. The best
chance looks to be Sunday and Sunday night as a back door cold
front drops through the area ahead of building high pressure.

&&

.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
15Z Update: A complex scenario is expected for the near term. Radar
indicates stratiform precipitation with MVFR ceilings and or
visibilities moving eastward. Ahead of this is stronger showers
and thunderstorms, bringing TEMPO IFR. Further ahead of these
is prevailing IFR ceilings. Expect various flight restriction at
both CHS and SAV as these showers/thunderstorms move through,
perhaps into the afternoon hours. The center of sfc low pressure
will slide over the forecast area late tonight. Light winds and
warm dewpoints will remain across the region tonight. The
environment appears suitable for stratus and fog after 8Z.

Extended Aviation Outlook: Isolated showers/tstms Thursday
afternoon. No concerns thereafter.

&&

.MARINE...
Today and Tonight: The center of low pressure will approach the near
shore waters through the near-term period.  As the low approaches, a
warm front will lift north of the waters. As a result, winds will
veer from the south today to the southwest tonight, speeds generally
ranging from 10-15 kts. Seas are forecast to gradually build from 1-
3 ft this morning to 2-4 ft this afternoon. Back swells from Post
Tropical Storm Arthur are expected to increase tonight. It is
possible that seas could increase to 6 ft across the outer portions
of AMZ374 late tonight. It is possible that a Small Craft Advisory
may be issued for the outer GA waters, beginning late tonight.

Long period back swells from former TS Arthur will likely
maintain marginal Small Craft Advisory seas beyond 40 nm in the
offshore GA waters Thursday through Friday morning. Otherwise no
significant concerns through Saturday night as moderate
southerly flow persists. A period of northeast flow is
anticipated Sunday night into Monday as high pressure builds in
from the north. At this time, winds/seas are forecast to remain
below advisory levels.

Rip Currents: Long period back swells from TS Arthur and the
upcoming new moon will lead to a Moderate Risk for rip currents
Thursday.

&&

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

&&

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

Hazardous Weather Outlook
National Weather Service Charleston SC
343 AM EDT Wed May 20 2020

GAZ117-119-139-141-SCZ048>051-210745-
Coastal Bryan-Coastal Chatham-Coastal Liberty-Coastal McIntosh-
Beaufort-Coastal Colleton-Charleston-Coastal Jasper-
343 AM EDT Wed May 20 2020

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

.DAY ONE...Today and tonight.

There is a low probability for widespread hazardous weather.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

Rip Currents: The combination of small swells arriving at the
beaches and the upcoming new moon will support a Moderate Risk of
rip currents at area beaches Thursday.

.SPOTTER INFORMATION STATEMENT...

Spotter assistance is not anticipated at this time.

AMZ330-350-352-354-374-GAZ087-088-099>101-114>116-118-137-138-140-
SCZ040-042>045-047-052-210745-
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-Inland Chatham-Long-Inland Liberty-Inland McIntosh-
Allendale-Hampton-Inland Colleton-Dorchester-Inland Berkeley-
Inland Jasper-Tidal Berkeley-
343 AM EDT Wed May 20 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...Thursday through Tuesday.

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
1106 AM EDT Wed May 20 2020

SCZ044-049-050-201545-
Coastal Colleton-Charleston-Dorchester-
1106 AM EDT Wed May 20 2020

...STRONG THUNDERSTORMS WILL IMPACT PORTIONS OF CHARLESTON AND
DORCHESTER COUNTIES...

At 1105 AM EDT, National Weather Service doppler radar indicated
strong thunderstorms along a line extending from Yonges Island to
Edisto Island, and moving north at 10 mph.

  HAZARD...excessive cloud to ground lightning.

  IMPACT...All outdoor activities should cease. Move indoors
           immediately.

Some locations in the path of these storms include...
Edisto Beach, Johns Island, West Ashley, Hollywood, Ravenel, Seabrook
Island, Meggett and Rockville.

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.

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

These storms may intensify and there has been weak rotation with
these storms as well. 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.

&&

LAT...LON 3288 8011 3287 8025 3266 8033 3248 8032
      3270 8005
TIME...MOT...LOC 1505Z 200DEG 8KT 3269 8022 3255 8029

Special Weather Statement
National Weather Service Charleston SC
1125 AM EDT Wed May 20 2020

SCZ044-045-201615-
Inland Berkeley-Dorchester-
1125 AM EDT Wed May 20 2020

...STRONG THUNDERSTORMS WILL IMPACT PORTIONS OF BERKELEY AND
DORCHESTER COUNTIES...

At 1125 AM EDT, National Weather Service doppler radar indicated a
strong thunderstorm near Givhans, or 7 miles south of Givhans Ferry
State Park, moving northeast at 25 mph.

  HAZARD...up to penny sized hail and excessive cloud to ground
           lightning.

  IMPACT...Minor hail damage to plants, trees and crops is possible.
           Damage to windshields is unlikely. All outdoor activities
           should case. Move indoors immediately.

Some locations in the path of this storm include...
Summerville, Givhans Ferry State Park, Ridgeville, Givhans,
Knightsville and Jedburg.

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.

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 3316 8013 3301 8013 3302 8016 3301 8016
      3301 8018 3299 8015 3285 8032 3291 8041
      3293 8040 3295 8041 3318 8033
TIME...MOT...LOC 1525Z 218DEG 23KT 3293 8034

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHARLESTON SC
1146 AM EDT WED MAY 20 2020

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

1142 AM     HAIL             WADMALAW ISLAND         32.68N  80.17W
05/20/2020  M0.75 INCH       CHARLESTON         SC   NWS EMPLOYEE

&&

EVENT NUMBER CHS2000319

MS

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHARLESTON SC
1232 PM EDT WED MAY 20 2020

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

1150 AM     HAIL             3 NW JOHNS ISLAND       32.76N  80.11W
05/20/2020  E1.25 INCH       CHARLESTON         SC   PUBLIC

            HALF DOLLAR SIZE HAIL WAS REPORTED ON JOHNS ISLAND.

&&

EVENT NUMBER CHS2000320

DPB

Special Weather Statement
National Weather Service Charleston SC
1234 PM EDT Wed May 20 2020

SCZ050-201715-
Charleston-
1234 PM EDT Wed May 20 2020

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

At 1234 PM EDT, National Weather Service doppler radar indicated a
strong thunderstorm near Downtown Charleston, moving northeast at 20
mph.

  HAZARD...strong winds 45 to 55 mph, up to penny 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...
Mount Pleasant, Fort Sumter, Downtown Charleston, James Island, Isle
Of Palms, Sullivan's Island, Awendaw and Boone Hall Plantation.

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.

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 3273 7984 3272 7988 3278 7994 3301 7964
      3288 7956
TIME...MOT...LOC 1634Z 246DEG 15KT 3281 7989