Severe Thunderstorm Warning 201, NWS Charleston, SC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
138 PM EDT MON OCT 25 2010

.SYNOPSIS...
AN UPPER-LEVEL DISTURBANCE WILL MOVE NORTH AND EAST OF THE AREA
TODAY. MEANWHILE...SURFACE HIGH PRESSURE WILL STEADILY SHIFT AWAY
FROM THE CAROLINA COAST AND WILL WEAKEN THROUGH MIDWEEK. A COLD
FRONT WILL MOVE ACROSS THE AREA ON THURSDAY...FOLLOWED BY HIGH
PRESSURE THROUGH THE UPCOMING WEEKEND.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SEVERE THUNDERSTORM WATCH 715 HAS BEEN ISSUED FOR ALL OF SOUTHEAST
SOUTH CAROLINA AND MUCH OF SOUTHEAST GEORGIA UNTIL 7 PM EDT.
SHOWERS AND TSTMS CONTINUE TO FIRE ACROSS THE MIDLANDS...CSRA AND
EAST-CENTRAL GEORGIA AS OF 25/1550Z AS STRONG UVM ASSOCIATED WITH
THE APPROACHING SHORTWAVE APPROACHES. ACTIVITY SHOULD CONTINUE TO
DEVELOP AND INTENSIFY THROUGH THE AFTERNOON AS BOTH SURFACE BASED
INSTABILITY AND LOW-LEVEL SHEAR INCREASE. NEAR TERM SEVERE
ACTIVITY SHOULD CONCENTRATE ACROSS THE WESTERN HALF OF THE
FORECAST AREA FOR THE NEXT FEW HOURS...BUT ADDITIONAL ACTIVITY
CURRENTLY DEVELOPING NORTHWEST OF VALDOSTA AND EAST OF
TALLAHASSEE FLORIDA MAY SHOW THE BEGINNING SIGNS FOR RENEWED
CONVECTIVE DEVELOPMENT FARTHER TO THE SOUTH. SHOULD THIS ACTIVITY
FORM AND ORGANIZE...IT WOULD IMPACT THE SOUTHERN PORTIONS OF THE
LOCAL FORECAST AREA LATER THIS AFTERNOON. INCOMING SHORT-TERM
GUIDANCE CONTINUE TO HINT AT A POSSIBLE SQUALL LINE OR QLCS MOVING
THROUGH MUCH OF THE REGION LATER THIS AFTERNOON AS TSTMS ENCOUNTER
DEWPOINTS POOLING IN THE LWR-MID 70S ALONG AND EAST OF I-95.

WE ARE RELEASING A SPECIAL 17Z SOUNDING TO SUPPORT SEVERE WEATHER
OPERATIONS THIS AFTERNOON. GOES-EAST RAPID SCAN ALSO CONTINUES.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
TONIGHT...CONVECTION SHOULD WIND DOWN FROM WEST TO EAST AS THE
UPPER SHORTWAVE TROUGH MOVES WELL NORTH AND EAST OF THE AREA.
HOWEVER...THERE IS NO CLEARING FRONT...SO REMAINING LOW LEVEL
MOISTURE AND DECREASING MID/HIGH CLOUDS WILL ALLOW FOR THE
FORMATION OF LOW CLOUDS AND SOME FOG...MAINLY AFTER MIDNIGHT. THE
AMOUNT OF RAIN WILL LIKELY PLAY A ROLE IN THE COVERAGE/INTENSITY
OF THE FOG.

TUESDAY THROUGH THURSDAY...HEIGHTS WILL BEGIN TO INCREASE OVER
THE REGION THROUGH WEDNESDAY AS MID AND UPPER LEVEL RIDGING
STRENGTHENS OVER THE SOUTHEASTERN STATES. MEANWHILE AT THE
SURFACE...ATLANTIC HIGH PRESSURE WILL KEEP A DEEP SOUTH-SOUTHWEST
FLOW IN PLACE...ALLOWING FOR SIGNIFICANT MOISTURE ADVECTION INTO
THE REGION. THE RIDGING WILL BEGIN TO ERODE WEDNESDAY NIGHT AS A
LONG WAVE TROUGH MOVES INTO THE GREAT LAKES REGION...ALLOWING AN
ASSOCIATED COLD FRONT AT THE SURFACE TO APPROACH FROM THE
NORTHWEST. THE FRONT WILL THEN MOVE ACROSS THE AREA ON THURSDAY.

THIS SYNOPTIC PATTERN WILL FAVOR THE DEVELOPMENT OF SHOWERS OVER THE
COASTAL WATERS DURING THE OVERNIGHT AND EARLY MORNING HOURS THROUGH
WEDNESDAY. FAVORABLE TRAJECTORIES COULD ALLOW SOME ISOLATED SHOWERS
TO PUSH INLAND ALONG NORTH COASTAL GEORGIA AND SOUTH COASTAL SOUTH
CAROLINA...POSSIBLY EXTENDING AS FAR INLAND AS PORTIONS OF THE
CHARLESTON TRI-COUNTY AREA. FOG AND LOW STRATUS ARE ALSO POSSIBLE
EARLY EACH MORNING AREA-WIDE. THERE IS A SLIGHT CHANCE OF SHOWERS
EACH DAY AS WELL THROUGH WEDNESDAY GIVEN THE PLENTIFUL LOW LEVEL
MOISTURE...ESPECIALLY ACROSS INTERIOR SOUTHEAST GEORGIA AND FAR
INLAND SOUTHEAST SOUTH CAROLINA WHERE WEAKER RIDGING/SUBSIDENCE WILL
BE FOUND. THERE WILL BE A SLIGHT CHANCE OF SHOWERS WEDNESDAY NIGHT
AHEAD OF THE COLD FRONT...WITH A SLIGHT OR LOW CHANCE OF SHOWERS AND
THUNDERSTORMS ON THURSDAY AS THE FRONT MOVES THROUGH.

AS FOR TEMPERATURES...EXPECT THEM TO RISE THROUGH WEDNESDAY GIVEN
THE INCREASING HEIGHTS/TEMPERATURES ALOFT AND DEEP SOUTH-SOUTHWEST
FLOW IN PLACE. HIGHS TUESDAY AND WEDNESDAY WILL BE IN THE MID TO
UPPER 80S AWAY FROM THE IMMEDIATE COAST /AROUND 10 DEGREES ABOVE
NORMAL/...BUT MODERATE SLIGHTLY ON THURSDAY WITH THE FRONT. MORNING
LOWS ON WEDNESDAY AND THURSDAY WILL BE IN THE MID TO UPPER 60S
/AROUND 15 DEGREES ABOVE NORMAL/.

&&

.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
GUIDANCE IS IN FAIRLY GOOD AGREEMENT SHOWING THE FLOW ALOFT BECOMING
FAIRLY PROGRESSIVE DURING THE LONG TERM PERIOD. SURFACE HIGH
PRESSURE WILL INITIALLY BUILD FROM THE MISSISSIPPI VALLEY THURSDAY
NIGHT AND FRIDAY...BEFORE SHIFTING ACROSS THE CAROLINAS ON SATURDAY
THEN INTO THE ATLANTIC LATE IN THE WEEKEND INTO EARLY NEXT WEEK.

VERY DRY AND COOL CONDITIONS WILL BE IN PLACE THROUGH SATURDAY...
ALONG WITH BELOW NORMAL TEMPERATURES. A SOUTHERLY RETURN FLOW WILL
DEVELOP BY LATE IN THE WEEKEND...RESULTING IN AN INCREASE IN
MOISTURE. HOWEVER...STRONG SUBSIDENCE WILL KEEP RAIN-FREE CONDITIONS
IN PLACE. TEMPERATURES WILL ALSO RETURN TO NEAR NORMAL BY LATE IN
THE WEEKEND.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
BOTH KCHS AND KSAV HAVE POTENTIAL TO SEE DETERIORATING CONDITIONS AS
A LINE OF SHOWERS AND THUNDERSTORMS TRACK NORTHEASTWARD ACROSS THE
FORECAST AREA. HAVE INCLUDED CBS FOR BOTH SITES THIS AFTERNOON...BUT
ACCORDING TO CURRENT RADAR TRENDS...PRECIP CHANCES APPEAR HIGHER AT
KCHS THAN KSAV FOR THIS AFTERNOON. HOWEVER...STILL EXPECT ADDITIONAL
DEVELOPMENT FURTHER WEST AND SOUTH WHICH COULD EVENTUALLY LEAD TO
AMENDMENTS TO BOTH TAFS. EVEN ONCE PRECIP PASSES THE AREA...PLENTY
OF LINGERING LOW LEVEL MOISTURE WILL RESIDE AT BOTH SITES. THIS WILL
LEAD TO FAVORABLE CONDITIONS FOR A LOW STRATUS LAYER EARLY TUESDAY
MORNING. HAVE ALSO INCLUDE SOME MVFR VISIBILITIES...BUT EXPECT WINDS TO
REMAIN 5 KNOTS OR GREATER THROUGH THE OVERNIGHT PERIOD WHICH
SHOULD HINDER SIGNIFICANT FOG DEVELOPMENT.

EXTENDED AVIATION OUTLOOK...LOW STRATUS AND/OR FOG WILL LIKELY
RESULT IN MVFR OR LOWER CONDITIONS DURING THE EARLY MORNING HOURS ON
TUESDAY AND WEDNESDAY. SHOWERS ASSOCIATED WITH A PASSING COLD FRONT
COULD ALSO BRIEFLY REDUCE CEILINGS AND/OR VISIBILITIES TO MVFR
LEVELS ON THURSDAY. OTHERWISE...VFR CONDITIONS ARE EXPECTED TO
PREVAIL.

&&

.MARINE...
SEAS AT 41004 ARE UP TO 5 FT...IN LINE WITH THE 06Z WW3. GUIDANCE
BUILDS SEAS TO 6 FT OVER THE GEORGIA OFFSHORE WATERS BY MID
AFTERNOON SO A SMALL CRAFT ADVISORY WILL BE ISSUED FOR AMZ374.

TONIGHT...MODERATE SLY FLOW TO CONTINUE...REACHING UP TO 20 KT AT
TIMES...MAINLY BEYOND 20 NM FROM SHORE. SEAS WILL
BUILD...ESPECIALLY OFF THE SC COAST. 6 FT SEAS ARE POSSIBLE ACROSS
THE EASTERN PORTION OF THE GA WATERS LATE TONIGHT BUT FELT
CONFIDENCE WAS LOW ENOUGH TO FOREGO AN ADVISORY ATTM.

TUESDAY THROUGH FRIDAY...ATLANTIC HIGH PRESSURE WILL PREVAIL
THROUGH WEDNESDAY...KEEPING A STRONG SOUTHERLY FLOW IN PLACE
ACROSS THE WATERS WITH WIND SPEEDS AS HIGH AS 15-20 KT AT TIMES.
THE FAVORABLE FETCH COULD ALSO CAUSE SEAS TO REACH SMALL CRAFT
ADVISORY LEVELS...ESPECIALLY OVER THE OUTER GEORGIA WATERS. A
STRONG COLD FRONT WILL PUSH OFFSHORE ON THURSDAY...WITH SMALL
CRAFT ADVISORY CONDITIONS EXPECTED TO DEVELOP IN ITS WAKE ACROSS A
PORTION OF THE WATERS INTO FRIDAY.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EDT TUESDAY FOR AMZ374.

&&

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE CHARLESTON SC
1147 AM EDT MON OCT 25 2010

AMZ330-350-352-354-GAZ087-088-099>101-114>119-137>141-SCZ040-042>045-
047>052-261000-
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-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-
1147 AM EDT MON OCT 25 2010

...SEVERE THUNDERSTORM WATCH 715 IN EFFECT UNTIL 7 PM EDT THIS
EVENING...

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

.DAY ONE...THIS AFTERNOON AND TONIGHT.

PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV ON THE
INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS.

   SEVERE THUNDERSTORM WATCH.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER GROUPS AND EMERGENCY MANAGEMENT SHOULD ACTIVATE AT THIS
TIME.

AMZ374-261000-
WATERS FROM SAVANNAH GA TO ALTAMAHA SOUND GA EXTENDING FROM 20 TO
60 NM-
1147 AM EDT MON OCT 25 2010

THIS HAZARDOUS WEATHER OUTLOOK IS FOR ATLANTIC COASTAL WATERS.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHARLESTON SC
1237 PM EDT MON OCT 25 2010

GAZ087-251730-
JENKINS-
1237 PM EDT MON OCT 25 2010

...STRONG THUNDERSTORMS WILL IMPACT PORTIONS OF JENKINS COUNTY
THROUGH 130 PM EDT...

AT 1233 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM...13 MILES SOUTHWEST OF HERNDON...MOVING
NORTHEAST AT 35 MPH.

SOME LOCATIONS THAT WILL BE AFFECTED INCLUDE...
BUTTS...EMMALANE...HERNDON...MILLEN AND PERKINS...

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FREQUENT CLOUD-TO-GROUND LIGHTNING IS OCCURRING. POSTPONE OUTDOOR
ACTIVITIES PROMPTLY. SEEK SHELTER INSIDE AN ENCLOSED BUILDING.

A SEVERE THUNDERSTORM WATCH IS ALSO IN EFFECT. THUNDERSTORMS CAN
PRODUCE LARGE HAIL...DAMAGING WINDS...AND ISOLATED TORNADOES
SUDDENLY...SOMETIMES WITH LITTLE OR NO WARNING. BE ALERT FOR RAPIDLY
CHANGING WEATHER CONDITIONS AND BE READY TO ACT QUICKLY IF SEVERE
WEATHER IS OBSERVED OR A WARNING IS ISSUED.

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 3287 8213 3292 8208 3292 8195 3295 8185
      3292 8177 3274 8185 3265 8208 3267 8210
      3282 8215
TIME...MOT...LOC 1638Z 243DEG 30KT 3270 8223

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHARLESTON SC
128 PM EDT MON OCT 25 2010

GAZ087-088-SCZ040-251830-
ALLENDALE-JENKINS-SCREVEN-
128 PM EDT MON OCT 25 2010

...STRONG THUNDERSTORMS WILL IMPACT PORTIONS OF JENKINS...SCREVEN AND
ALLENDALE COUNTIES THROUGH 230 PM EDT...

AT 125 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM...NEAR LAWTON...MOVING NORTHEAST AT 25 MPH.

SOME LOCATIONS THAT WILL BE AFFECTED INCLUDE...
HILLTONIA...MILLHAVEN...PERKINS...APPLETON...MARTIN...MILLETT...
SEIGLING AND ULMER...

PREPARE NOW FOR THE FOLLOWING HAZARDS...
GUSTY WINDS OF 40 TO 50 MPH...
FREQUENT CLOUD TO GROUND LIGHTNING...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FREQUENT LIGHTNING IS OCCURRING WITH THIS THUNDERSTORM. IF
OUTDOORS...STAY AWAY FROM ISOLATED TALL OBJECTS. IF INDOORS...STAY
AWAY FROM WINDOWS AND DOORS. AVOID USING PLUMBING AND ELECTRICAL
APPLIANCES UNLESS IT IS AN EMERGENCY.

A SEVERE THUNDERSTORM WATCH IS ALSO IN EFFECT. THUNDERSTORMS CAN
PRODUCE LARGE HAIL...DAMAGING WINDS...AND ISOLATED TORNADOES
SUDDENLY...SOMETIMES WITH LITTLE OR NO WARNING. BE ALERT FOR RAPIDLY
CHANGING WEATHER CONDITIONS AND BE READY TO ACT QUICKLY IF SEVERE
WEATHER IS OBSERVED OR A WARNING IS ISSUED.

&&

LAT...LON 3295 8185 3291 8176 3304 8156 3309 8161
      3316 8154 3311 8137 3312 8119 3310 8116
      3277 8190 3292 8197
TIME...MOT...LOC 1728Z 241DEG 22KT 3287 8188