Special Weather Statement, NWS Charleston, SC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
151 PM EDT TUE JUL 10 2012

.SYNOPSIS...
A STATIONARY FRONT WILL REMAIN INLAND BEFORE LIFTING BACK NORTH
AS A WARM FRIDAY AS ATLANTIC HIGH PRESSURE EXPANDS ACROSS THE AREA.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
EARLY TUESDAY AFTERNOON...THUNDERSTORMS WERE READILY FIRING ALONG
THE SC SEA BREEZE AND NEAR INLAND MESOSCALE BOUNDARIES. EXPECT
UPSCALE GROWTH IN THUNDERSTORM COVERAGE/INTENSITY AS COMPLEX
OUTFLOW BOUNDARIES...SEA BREEZE CONVERGENCE AND SOME POTENTIAL FOR
MID LEVEL COLD POOLING WILL SUPPORT PROPAGATION OF MULTICELL
THUNDERSTORMS WITH PULSE SEVERE CHARACTERISTICS DEEPER INTO THE
FORECAST AREA. SINCE THE REMNANTS OF THE MID LEVEL CAP REMAIN IN
EVIDENCE ACROSS S/W COUNTIES...THUNDERSTORMS COULD HOLD OFF IN
THIS AREA UNTIL MID TO LATE AFTERNOON.

PRE-THUNDERSTORM SBCAPES AT LEAST 3500-4000 J/KG...0-3 KM CAPES
AROUND 150 J/KG AND DOWNDRAFT CAPES 1000-1500 J/KG...ACCOMPANIED BY
PWATS APPROACHING 2 INCHES....WILL PRIMARILY SUPPORT OCCASIONAL
DAMAGING WET MICROBURSTS. SINCE THE ENVIRONMENT HAS NOT BEEN
OVERTURNED BY ANY DEEP MOIST CONVECTION SINCE LATE LAST
WEEK...SOME MORE CONCENTRATED/PERSISTENT DAMAGING WIND EPISODES
WILL BE POSSIBLE. GIVEN -10C TO -30C CAPES EXCEEDING 1000 J/KG
ISOLATED LARGE HAIL CANNOT BE RULED OUT..BUT FREEZING LEVELS ABOVE
15 KFT AGL SUGGEST THAT THE POTENTIAL FOR HAIL WILL REMAIN
LIMITED.

RAISED POPS TO LIKELY ACROSS NORTHERN/INLAND COUNTIES THIS
AFTERNOON/EVENING...BUT GREATER COVERAGE OF HIGHER POPS COULD
EVENTUALLY BE REQUIRED IF PERSISTENT MULTICELL THUNDERSTORM
CLUSTERS DEVELOP.

IN ADVANCE OF CONVECTION...TEMPERATURES WILL TOP OUT IN THE LOWER
TO MID 90S AT MANY INLAND LOCATIONS...PERHAPS IN THE UPPER 90S AT
ISOLATED INLAND GA LOCALES...A COUPLE OF DEGREES LOWER THAN RECENT
DAYS. THUNDERSTORMS WILL PRODUCE RAPID/LOCALIZED TEMPERATURE
CHANGES.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
THIS EVENING...CONVECTION MAY BECOME FAIRLY WIDESPREAD N OF I-16 AND
W OF U.S. 17 GIVEN RECENT MODEL TRENDS. DEPENDENT ON WHETHER TSTMS
CAN CONGEAL LATER TODAY AND IF IT CAN DIG S ON BOUNDARIES INTO UNTAPPED
ATMOSPHERE PROFILES S OF I-16 REMAIN UNCERTAINTIES. LATER SHIFTS
MAY NEED TO RAISE SOME INLAND POPS TO LIKELY THIS EVENING WITH SOME
STRONGER STORMS AND LOCALLY HEAVY DOWNPOURS A POSSIBILITY. LOW
TEMPS IN THE 70S ONCE AGAIN...SLIGHTLY LOWER THAN PREVIOUS MORNINGS
FOR MANY AREAS GIVEN THE BETTER CHANCES OF DIURNAL CONVECTION.
COVERAGE SHOULD DIMINISH AFTER MIDNIGHT BUT WOULD NOT BE SURPRISED
TO SEE SOME RENEWED NEAR COASTAL CONVECTION AFTER 2 AM.

A RELATIVELY ACTIVE PATTERN SHOULD CONTINUE MUCH OF THIS WEEK DUE
TO A BROAD UPPER TROUGH PARKED TO OUR WEST WITH A SURFACE FRONT
DRAPED ACROSS CENTRAL NC/SC. PREVAILING SOUTHEAST SURFACE WINDS
WILL ALLOW THE SEABREEZE TO MOVE INLAND FAIRLY EARLY IN THE
AFTERNOON. WE EXPECT THE GREATEST SHOWER AND THUNDERSTORM COVERAGE
TO BE ACROSS FAR INLAND AREAS CLOSER TO THE SURFACE TROUGH/FRONT
WITH VERY LITTLE COVERAGE ALONG THE IMMEDIATE COAST WHERE THE
MARINE LAYER MOVES INLAND DURING PEAK HEATING. ACTIVITY SHOULD
CONTINUE INTO THE EARLY EVENING BEFORE THE BRUNT OF IT
DISSIPATES...LEAVING ONLY ISOLATED SHOWERS/STORMS OVERNIGHT.
DECREASING THICKNESSES AND STRENGTHENING ONSHORE LOW-LEVEL FLOW
WILL BRING TEMPS BACK CLOSER TO CLIMATOLOGICAL NORMS.

&&

.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
HIGH PRESSURE WILL STRENGTHEN ACROSS THE WESTERN ATLANTIC LATE IN
THE PERIOD...RETURNING US TO A MORE NORMAL MID-JULY PATTERN.
ISOLATED CONVECTION WILL PRIMARILY DEVELOP ALONG THE SEABREEZE AS IT
PUSHES INLAND EACH AFTERNOON. HIGH TEMPS WILL BE IN THE LOWER TO
MIDDLE 90S.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
CONFIDENCE IS MODERATE TO HIGH FOR DIRECT THUNDERSTORM IMPACTS AT
KCHS THIS AFTERNOON. THUNDERSTORMS COULD ALSO IMPACT KSAV LATE
THIS AFTERNOON OR THIS EVENING...BUT CONFIDENCE IN THIS SCENARIO
REMAINS INSUFFICIENT FOR ANY TEMPO GROUPS WITHIN THE 18Z TAFS.
WILL AMEND AS NEEDED.

OUTSIDE THUNDERSTORMS...VFR THROUGH THE 18Z TAF PERIOD. IF/WHERE
THUNDERSTORMS OCCUR...THE PROBABILITY FOR BRIEF MVFR OR LOWER
CONDITIONS AROUND DAYBREAK WEDNESDAY WILL INCREASE SOMEWHAT.

EXTENDED AVIATION OUTLOOK...LOW CHANCE OF MVFR/IFR CONDITIONS IN
MAINLY AFTERNOON/EVENING SHOWERS/THUNDERSTORMS EACH DAY THROUGH
THE WEEK.

&&

.MARINE...
OFFSHORE FLOW WILL GIVE WAY TO THE SEA BREEZE CIRCULATION ONCE
AGAIN TODAY. THE DAILY SURGE TRENDS WILL CONTINUE THROUGH TONIGHT
WITH MODEL PROGS NOT QUITE AS STRONG FOR TONIGHT AS SOME PREVIOUS
OUTPUT. ALSO...THUNDERSTORMS COULD GREATLY ALTER THE PRESSURE
PATTERN/LOCAL WINDS THIS AFTERNOON AND TONIGHT. SSW FLOW 10-20 KT
AND SEAS 2 TO 4 FT WILL CONTINUE TO BE AVERAGE CONDITIONS.
NOCTURNAL SURGING MAY PUSH WATERS CLOSER TO 20 KT THIS EVENING BUT
SMALL CRAFT ADVISORY CONDITIONS UNLIKELY. MARINERS IN THE
INTRACOASTAL WATERS SHOULD KEEP AN EYE OUT FOR TSTM WIND SHIFT
BOUNDARIES THIS AFTERNOON AND EVENING.

ATLANTIC HIGH PRESSURE WILL MAINTAIN CONTROL OVER THE MARINE AREA
WEDNESDAY INTO THE WEEKEND. SOUTHEAST WINDS WILL PREVAIL BUT
CONDITIONS SHOULD STAY WELL BELOW ADVISORY THRESHOLDS.

&&

.EQUIPMENT...
THE KCLX WSR-88D REMAINS OUT OF SERVICE. UNTIL REPAIRS ARE
COMPLETE...WE WILL BE LIMITED TO OCCASIONAL SCANS IN VCP 11 OR
VCP 21.

&&

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

&&

SYNOPSIS...
NEAR TERM...SPR
SHORT TERM...JRL
LONG TERM...JRL
AVIATION...SPR
MARINE...JRL/SPR
EQUIPMENT...SPR

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE CHARLESTON SC
1039 AM EDT TUE JUL 10 2012

AMZ330-350-352-354-374-GAZ087-088-099>101-114>119-137>141-SCZ040-
042>045-047>052-111445-
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-
1039 AM EDT TUE JUL 10 2012

...A FEW SEVERE THUNDERSTORMS POSSIBLE THIS AFTERNOON AND TONIGHT...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR ATLANTIC COASTAL
WATERS...SOUTHEAST GEORGIA AND SOUTHEAST SOUTH CAROLINA.

.DAY ONE...TODAY AND TONIGHT.

SEVERE THUNDERSTORMS...SCATTERED TO NUMEROUS THUNDERSTORMS ARE
EXPECTED TO TO DEVELOP EARLY THIS AFTERNOON ACROSS SOUTHEAST SOUTH
CAROLINA. THEN...THUNDERSTORMS ARE EXPECTED TO DEVELOP SOUTH AND
SOUTHWEST DURING THE AFTERNOON THROUGH THIS EVENING. A FEW
THUNDERSTORMS COULD BECOME SEVERE. THE PRIMARY THREAT WILL BE
DAMAGING WIND GUSTS EXCEEDING 60 MPH...ALTHOUGH ISOLATED HAIL
TO 1 INCH IN DIAMETER WILL ALSO BE POSSIBLE.

THE RISK FOR SEVERE WEATHER WILL BE PRIMARILY LOCATED ALONG AND
NORTH INTERSTATE 16...ESPECIALLY BETWEEN 1 PM AND 10 PM.

CHECK WITH NOAA WEATHER RADIO ALL HAZARDS OR OTHER MEDIA OUTLETS
FOR UPDATED INFORMATION TODAY. IF YOU PLAN TO BE OUTSIDE THIS
AFTERNOON AND EVENING...PREPARE TO MOVE QUICKLY TO SAFE SHELTER IF
THREATENING WEATHER APPROACHES.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION COULD BE REQUIRED THIS AFTERNOON AND EVENING.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHARLESTON SC
138 PM EDT TUE JUL 10 2012

SCZ044-045-101815-
DORCHESTER-INLAND BERKELEY-
138 PM EDT TUE JUL 10 2012

...STRONG THUNDERSTORMS WILL IMPACT PORTIONS OF DORCHESTER AND
BERKELEY COUNTIES THROUGH 215 PM EDT...
...MARINERS ON LAKE MOULTRIE SHOULD SEEK SAFE HARBOR...

AT 133 PM EDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A
STRONG THUNDERSTORM...NEAR TEXAS...MOVING EAST AT 5 MPH.

SOME LOCATIONS THAT WILL BE AFFECTED INCLUDE...
DORCHESTER...HARLEYVILLE...INDIAN FIELD...JEDBURG...REEVESVILLE...
RIDGEVILLE...SAINT GEORGE AND SUMMERVILLE...

PREPARE NOW FOR THE FOLLOWING HAZARDS...
GUSTY WINDS OF 40 TO 50 MPH...
PENNY SIZE HAIL...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THESE STORMS ARE EXPECTED TO IMPACT LAKE MOULTRIE. BOATERS SHOULD
SEEK SAFE HARBOR IMMEDIATELY. IF CAUGHT ON THE OPEN WATERS...STAY AS
LOW AS POSSIBLE AND WEAR A PERSONAL FLOATATION DEVICE. SWIMMERS
SHOULD GET OUT OF THE WATER AND INTO A STURDY BUILDING. REMEMBER...IF
YOU CAN HEAR THUNDER YOU ARE AT RISK OF BEING STRUCK BY LIGHTNING.

HAVE AN ACTION PLAN READY IN THE EVENT THIS STORM STRENGTHENS OR A
WARNING IS ISSUED. CONTINUE TO MONITOR NOAA WEATHER RADIO ALL HAZARDS
FOR THE LATEST WEATHER INFORMATION.

BE ALERT FOR RAPIDLY CHANGING WEATHER CONDITIONS AS STORMS APPROACH.
BE READY TO TAKE IMMEDIATE ACTION IN CASE A SEVERE THUNDERSTORM
WARNING IS ISSUED FOR YOUR LOCATION.

&&

LAT...LON 3301 8013 3302 8014 3301 8017 3305 8044
      3307 8046 3307 8063 3325 8065 3331 8049
      3328 8047 3326 8043 3327 8037 3328 8035
      3327 8030 3330 8026 3339 8025 3341 8021
TIME...MOT...LOC 1737Z 270DEG 3KT 3313 8053

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHARLESTON SC
209 PM EDT TUE JUL 10 2012

SCZ045-050-101915-
CHARLESTON-INLAND BERKELEY-
209 PM EDT TUE JUL 10 2012

...STRONG THUNDERSTORMS WILL IMPACT PORTIONS OF CHARLESTON...BERKELEY
AND GEORGETOWN COUNTIES THROUGH 315 PM EDT...

AT 204 PM EDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED
STRONG THUNDERSTORMS...ALONG A LINE EXTENDING FROM HAMPTON PLANTATION
STATE PARK TO AWENDAW...MOVING NORTHEAST AT 5 MPH.

SOME LOCATIONS THAT WILL BE AFFECTED INCLUDE...
AWENDAW...CAPE ISLAND...CAPE ROMAIN...HAMPTON PLANTATION STATE
PARK...LIGHTHOUSE ISLAND...MCCLELLANVILLE AND SANTEE COASTAL
RESERVE...

PREPARE NOW FOR THE FOLLOWING HAZARDS...
GUSTY WINDS OF 40 TO 50 MPH...
PENNY SIZE HAIL...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

BE ALERT FOR RAPIDLY CHANGING WEATHER CONDITIONS AS STORMS APPROACH.
BE READY TO TAKE IMMEDIATE ACTION IN CASE A SEVERE THUNDERSTORM
WARNING IS ISSUED FOR YOUR LOCATION.

&&

LAT...LON 3308 7933 3300 7936 3299 7950 3303 7953
      3301 7955 3298 7954 3301 7955 3300 7957
      3297 7955 3295 7956 3299 7958 3297 7961
      3307 7975 3325 7952 3324 7945 3316 7935
      3314 7926
TIME...MOT...LOC 1808Z 240DEG 2KT 3324 7938 3304 7960