Special Weather Statement, NWS Charleston, SC

Area Forecast Discussion
National Weather Service Charleston SC
340 PM EDT FRI JUL 15 2016

.SYNOPSIS...
Through next week, Atlantic high pressure will extend west over
the region, and a trough of low pressure will linger inland.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Tonight: Ongoing convective activity is expected to diminish this
evening and become confined mainly inland closer to the Midlands.
Residual outflow boundaries in this area could continue to kick off
at least isolated shallow convection beyond sunset. Thereafter, the
focus then turns to what appears to be mainly speed convergence
within the enhanced gradient between the inland trough and the high
over the Atlantic. Models all show varying degrees of showers and
storms getting started after midnight, though most of the activity
looks to be focused over the coastal waters and along the coast.
Have kept POP's in this area in the 20 percent chance range for now,
and higher values may eventually be needed based on evening model
runs. Otherwise, expect a warm and muggy night with lows in the
upper 70s in most areas.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
Typically strong instability will support showers/thunderstorms
through this period, with the best coverage across northern/western
counties during the early afternoon through late afternoon/early
evening hours. Showers/thunderstorms could also develop over coastal
counties/adjacent coastal waters during the late night/early morning
hours.

A few afternoon/evening thunderstorms could briefly become
severe with damaging wet microbursts, while PWAT values around 2
inches could support locally excessive rainfall especially where
thunderstorms move slowly/erratically or redevelop/train over the
same areas. Daily differences will be subtle and will be addressed
within the following paragraphs.

Saturday: A weak upper trough and associated enhanced moisture as
depicted by 850-500 mean relative humidity progs will push into
areas north of I-16. Meanwhile, on the periphery of the upper trough
SW 850-500 mb winds 10-20 knots should support relatively
progressive multicell thunderstorms with an isolated damaging wind
threat but a limited potential for excessive rainfall. Thus, raised
pops into the low-end likely category across inland counties
Saturday afternoon.

Sunday: The weak upper trough and enhanced moisture featuring PWAT
values around 2 inches should persist. Weaker low/mid level winds as
compared with Saturday will support a complex mesoscale boundary
environment which will promote slower, more erratic thunderstorm
propagation marked by brief pulse severe thunderstorms and a greater
chance for locally excessive rainfall. Capped max pops around 50
percent north of I-16 Sunday afternoon, but locally greater pops
could eventually be required.

Monday: Guidance suggests a subtle trend toward upper ridging, so
coverage of afternoon/evening showers/thunderstorms could be
somewhat reduced as compared with Saturday/Sunday. Thus, capped
maximum pm pops in the 30-40 percent range. Once again, a weak
steering environment will translate to complex mesoscale boundaries
including the sea breeze and thunderstorm outflow which will
support erratic thunderstorm movement, brief episodes of pulse severe
thunderstorms with damaging wet microbursts and locally excessive
rainfall.

Through this period, guidance depicts sufficient convection over
coastal counties/adjacent coastal waters to justify at least slight
chance/chance pops during the late night/early morning hours.
However, model signals remain mixed with respect to the potential
for more significant convection/locally heavy rainfall during any
nocturnal convection episodes. Will continue to assess.

Otherwise, expect high temps in the lower to mid 90s except
mid/upper 80s on the beaches and lows mid/upper 70s inland and
lower 80s on the beaches through the period. daily heat index values
will peak over 100F but should remain below 110F, so Heat Advisories
are not expected. As always, temperatures will quickly fall into
the 70s where afternoon/evening thunderstorms occur.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
Atlantic high pressure will extend westward over the southeast U.S.
while a trough persists inland. This will lead to a continuation of
mid-July weather with diurnal convection. The models are in good
agreement breaking/weakening the mid/upper level ridge over the
southeast in half as a trough develops to our north. This should
result in temperatures closer to normal, but little change from the
typical day to day chances for diurnal convection.

&&

.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
Based on current radar trends, and visible satellite imagery, it
appears the best chance for direct thunderstorm impacts will be at
KCHS. Still, most showers and storms are developing inland of the
terminals. Have maintained VCTS at both KCHS and KSAV since
confidence isn't high enough to introduce TSRA. Once storms
diminish this evening the rest of the period is expected to be
VFR.

Extended Aviation Outlook: Mainly VFR outside showers/thunderstorms.

&&

.MARINE...
Tonight: Basically a persistence forecast for the local waters as
the set up remains the same. The waters will continue to be caught
between the inland trough and high pressure to the east. This will
drive a moderate south to southwest flow, with some enhancement
within a nocturnal surge. Winds are expected to top out in the 15-20
knot range, highest across the South Carolina waters. Seas will
range 2-4 feet.

Saturday through Wednesday: No significant changes from recent
conditions are expected through this period. S/SW winds will be
enhanced by the diurnal sea breeze and will surge for several hours
each night. Capped maximum winds at 20 knots through the period.
Seas of 2-4 feet will prevail, highest beyond 20 nm. Thunderstorms
will create locally hazardous conditions.

&&

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

&&

NEAR TERM...BSH
SHORT TERM...SPR
LONG TERM...MS
AVIATION...BSH/SPR
MARINE...BSH/SPR

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE CHARLESTON SC
347 AM EDT FRI JUL 15 2016

AMZ330-350-352-354-374-GAZ087-088-099>101-114>119-137>141-SCZ040-
042>045-047>052-161345-
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-
347 AM EDT FRI JUL 15 2016

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...SATURDAY THROUGH THURSDAY.

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
204 PM EDT FRI JUL 15 2016

SCZ040-151830-
ALLENDALE SC-
204 PM EDT FRI JUL 15 2016

...STRONG THUNDERSTORMS WILL IMPACT PORTIONS OF ALLENDALE COUNTY
UNTIL 230 PM EDT...

AT 203 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM NEAR ALLENDALE...MOVING NORTHEAST AT 20 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...
ALLENDALE...FAIRFAX...SYCAMORE...ULMER...SEIGLING...MARTIN...BARTON
AND APPLETON.

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 3311 8137 3312 8120 3303 8108 3296 8121
      3294 8124 3291 8124 3289 8128 3288 8127
      3281 8142 3284 8142 3285 8146 3287 8145
      3288 8148 3290 8147 3296 8151 3301 8149
      3304 8153 3312 8141
TIME...MOT...LOC 1803Z 242DEG 18KT 3297 8138

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHARLESTON SC
415 PM EDT FRI JUL 15 2016

SCZ045-152045-
INLAND BERKELEY SC-
415 PM EDT FRI JUL 15 2016

...STRONG THUNDERSTORMS WILL IMPACT PORTIONS OF BERKELEY COUNTY UNTIL
445 PM EDT...

AT 415 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM 8 MILES EAST OF OLD SANTEE CANAL STATE PARK...OR
10 MILES EAST OF MONCKS CORNER...MOVING NORTHEAST AT 20 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... MONCKS
CORNER...ST. STEPHEN...BONNEAU...JAMESTOWN...PINOPOLIS...BONNEAU
BEACH...SAINT STEPHEN AND OLD SANTEE CANAL STATE PARK.

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 3343 7987 3343 7988 3340 7985 3337 7980
      3338 7979 3332 7974 3332 7970 3330 7966
      3327 7956 3325 7953 3324 7948 3312 7992
      3318 8030 3346 7992
TIME...MOT...LOC 2015Z 223DEG 17KT 3324 7984