Area Forecast Discussion
Issued by NWS Charleston, SC

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000
FXUS62 KCHS 271159
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
659 AM EST FRI FEB 27 2015

.SYNOPSIS...
HIGH PRESSURE WILL BUILD NORTH OF THE REGION THROUGH TONIGHT AND
WEDGE SOUTHWARD OVER GEORGIA AND SOUTH CAROLINA OVER THE WEEKEND
WHILE A COASTAL TROUGH DEVELOPS OFF THE SOUTHEAST COAST. A COLD
FRONT WILL STALL OVER OR JUST SOUTH OF THE REGION LATE MONDAY...
THEN LIFT NORTH AS A WARM FRONT ON TUESDAY. A COLD FRONT WILL
SHIFT THROUGH THE AREA LATE WEDNESDAY INTO THURSDAY... FOLLOWED BY
COOLER HIGH PRESSURE NEXT WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
DRY WEATHER WILL CONTINUE TODAY AND TONIGHT AS EXPANSIVE HIGH
PRES BUILDS FROM THE NORTHERN PLAINS TO THE MID ATLC REGION BY
EARLY ON SATURDAY. THE BAROCLINIC ZONE IS FORECAST TO REMAIN
ACROSS THE SOUTHERN HALF OF FLORIDA WITH THE FRONT STALLED OVER
THE KEYS AND BAHAMAS. OUR MAIN FORECAST ISSUES THROUGH TONIGHT
REVOLVE AROUND CLOUDS AND TEMPS. MODELS PROG THE BACK EDGE OF THE
THICK HIGH CLOUD SHIELD TO WORK INTO THE I-95 CORRIDOR EARLY TO
MID AFTERNOON WITH GREATER COVERAGE OF STRATOCU LINGERING INLAND
TODAY. WE COULD NOT GO QUITE AS WARM AS SOME THE NUMERICAL
GUIDANCE INSISTED AT 00Z. WE CAPPED HIGHS IN THE LOWER TO MID 50S
AROUND THE CHARLESTON TRI- COUNTY AND MID 50S IN THE CHATHAM
COUNTY AREA. WARMEST READINGS SHOULD BE OVER INLAND GEORGIA ZONES
WITH POTENTIAL FOR THINNER CLOUDS LATER TODAY.

TONIGHT...HIGH PRES BUILDING TO THE NORTH WILL BEGIN TO PACK THE
GRADIENT OVER THE REGION AND IT WILL BECOME BREEZY ALONG THE
BEACHES AND BARRIER ISLANDS OVERNIGHT. SKIES SHOULD REMAIN PARTLY
CLOUDY AND LOW TEMPS WILL BE IN THE LOWER TO MID 30S NORTH OF I-16
AND INLAND OVER SOUTH CAROLINA WITH MID TO A FEW UPPER 30S CLOSER
TO THE ALTAMAHA REGION.

&&

.SHORT TERM /SATURDAY THROUGH MONDAY/...
SATURDAY AND SUNDAY....THE AREA WILL REMAIN PRIMARILY UNDER A
WEST/SOUTHWEST ZONAL FLOW ALOFT ALONG THE NORTHERN EDGE OF A BROAD
RIDGE OF HIGH PRESSURE THAT SLOWLY BUILDS NORTH INTO EARLY NEXT
WEEK. AT THE SFC...A WEAK COASTAL TROUGH WILL DEVELOP OFF THE
GEORGIA COAST SATURDAY WHILE A STRONG WEDGE OF HIGH PRESSURE
PERSISTS INLAND THROUGH MUCH OF SUNDAY. THE PATTERN WILL FAVOR
WIDESPREAD CLOUD COVER WITHIN THE WEDGE...AND A FEW SHOWERS THAT
SHIFT ONSHORE EACH DAY AS THE COASTAL TROUGH STRENGTHENS AND DRIFTS
CLOSER TO THE COAST. OVERALL HIGH TEMPS WILL REMAIN COOLER ON
SATURDAY...PRIMARILY DUE TO CLOUD COVER AND LIGHT NORTHEAST SFC
WIND. IN GENERAL...AFTERNOON HIGHS WILL REACH THE UPPER 40S
NORTH...TO LOWER 50S SOUTH. DESPITE GRADUAL RIDGING ALOFT...TEMPS
WILL STILL REMAIN BELOW NORMAL THROUGH SUNDAY DUE TO THE PERSISTENT
WEDGE OF HIGH PRESSURE OVER THE SOUTHEAST. THEREFORE HAVE LIMITED
SUNDAY AFTERNOON HIGHS TO THE LOWER 50S OVER MOST AREAS...ALTHOUGH
WE COULD SEE MID/UPPER 50S FOR AREAS SOUTH OF INTERSTATE 16 IN
SOUTHEAST GEORGIA.

MONDAY...THE WEDGE OF SFC HIGH PRESSURE WILL BEGIN TO BREAK DOWN
EARLY NEXT WEEK AS A LARGE AREA OF LOW PRESSURE TRACKS OVER THE
NORTHEASTERN UNITED STATES WITH A BACKDOOR COLD FRONT THAT
APPROACHES THE AREA BY THE EVENING. AHEAD OF THE FRONT...TEMPS WILL
BE NOTICEABLY WARMER...WITH HIGH TEMPS IN THE MID 60S NORTH...TO
LOWER 70S SOUTH OF INTERSTATE 16 IN SOUTHEAST GEORGIA. CHANCES OF
SHOWERS SHOULD ALSO BREAKOUT OVER THE COURSE OF THE DAY AS MOISTURE
DEEPENS HEAD OF THE APPROACHING FRONT.

&&

.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
A BACKDOOR COLD FRONT WILL STALL OVER OR NEAR THE AREA MONDAY
NIGHT...SUPPORTING CHANCES OF SHOWERS OVER THE AREA. THE STALLED
FRONT WILL THEN LIFT NORTH AS A WARM FRONT ON TUESDAY...BRINGING
WARMER CONDITIONS. IN GENERAL...EXPECT AFTERNOON HIGHS IN THE UPPER
60S/LOWER 70S ON TUESDAY. EVEN WARMER CONDITIONS WILL DEVELOP ON
WEDNESDAY AS A SOUTHERLY FLOW STRENGTHENS AND SOME COMPRESSIONAL
HEATING OCCURS AHEAD OF AN APPROACHING COLD FRONT FROM THE
WEST/NORTHWEST. STRONG FORCING WILL BE ASSOCIATED WITH THE
FRONT...SUPPORTING THE NEED FOR INCREASING SHOWERS AND SOME
THUNDERSTORMS IN THE FORECAST WEDNESDAY NIGHT INTO EARLY THURSDAY.
SHOWERS AND/OR THUNDERSTORMS WILL THEN SHIFT OFFSHORE WITH THE
COLD FRONT BY THURSDAY AFTERNOON...FOLLOWED BY DRY AND COOLER HIGH
PRESSURE ON FRIDAY.

&&

.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
VFR AT BOTH KSAV/KCHS THROUGH 12Z SAT. SURFACE WINDS FROM THE NE
THROUGH TONIGHT...AN UPTICK IN SPEEDS LIKELY LATE TONIGHT AS THE
PRES GRADIENT TIGHTENS.

EXTENDED AVIATION OUTLOOK...FLIGHT RESTRICTIONS ARE LIKELY SATURDAY
EVENING INTO SUNDAY AS A WEDGE OF HIGH PRESSURE PERSISTS OVER THE
AREA. VFR CONDITIONS SHOULD RETURN FOR PART OF MONDAY...BEFORE
FLIGHT RESTRICTIONS BECOME POSSIBLE MONDAY NIGHT INTO EARLY TUESDAY
AT EITHER TERMINAL.

&&

.MARINE...
NNE FLOW OVER THE WATERS THIS MORNING WILL GRADUALLY VEER NE LATER
TODAY AND INCREASE SIGNIFICANTLY TONIGHT AS STRONG HIGH PRES BUILDS
TO THE NORTH WITH THE ONSET OF A SIGNIFICANT SURFACE WEDGE PATTERN.
WE HAVE RAISED FLAGS THIS MORNING INITIALIZING ADVISORIES LATER
THIS AFTERNOON OVER THE GEORGIA WATERS AND THIS EVENING ON NEAR
SHORE SOUTH CAROLINA WATERS. STRONG PINCHING SHOULD PRODUCE
FREQUENT GUSTS TO 25 KT LATER TONIGHT IN PARTS OF THE CHARLESTON
HARBOR AND WE STARTED UP AN ADVISORY THERE OVERNIGHT AS THE PRES
GRADIENT STRENGTHENS. SEAS WILL BUILD FROM 2 TO 4 FT EARLY THIS
MORNING TO 4 TO 6 FT TONIGHT WITH HIGHER SEAS BUILDING TO 6 TO 8
FT OFF THE GEORGIA COAST FROM GRAYS REEF SEAWARD.

HIGH PRESSURE WILL WEDGE INLAND ON SATURDAY AND SUNDAY WHILE A
COASTAL TROUGH DEVELOPS OFF THE GEORGIA COAST. A STRONG PRESSURE
GRADIENT IS EXPECTED TO DEVELOP BETWEEN THESE TWO FEATURES...LEADING
TO DETERIORATING CONDITIONS OVER ALL MARINE WATERS SATURDAY AND
SUNDAY. A GALE WATCH HAS BEEN ISSUED FOR OFFSHORE GEORGIA WATERS ON
SATURDAY WHERE PINCHING BECOMES GREATEST ALONG THE NORTHERN EDGE OF
THE COASTAL TROUGH...AND SMALL CRAFT ADVISORIES WILL BE ONGOING FOR
ALL REMAINING WATERS THROUGH EARLY SUNDAY AFTERNOON. CONDITIONS WILL
BEGIN TO IMPROVE OVER ALL WATERS SATURDAY NIGHT...PROMPTING AN END
TO A SMALL CRAFT ADVISORY IN THE CHS HARBOR...BUT WILL TAKE TIME TO
IMPROVE IN ALL REMAINING WATERS.

WINDS/SEAS SHOULD FALL BELOW SMALL CRAFT ADVISORY LEVELS OVER ALL
WATERS BY SUNDAY EVENING AS HIGH PRESSURE SLIDES OVER THE WATERS AND
THE COASTAL TROUGH WEAKENS. SMALL CRAFT ADVISORY CONDITIONS COULD
RETURN LATE WEDNESDAY INTO THURSDAY AS A COLD FRONT SWEEPS THROUGH
THE SOUTHEASTERN UNITED STATES.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 4 AM TO 7 PM EST SATURDAY FOR AMZ330.
     SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 1 PM EST SUNDAY
     FOR AMZ350-352.
     GALE WATCH FROM SATURDAY MORNING THROUGH LATE SATURDAY NIGHT
     FOR AMZ374.
     SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 9 AM EST
     SATURDAY FOR AMZ374.
     SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 1 PM EST
     SUNDAY FOR AMZ354.

&&

$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...DPB
LONG TERM...DPB
AVIATION...
MARINE...DPB



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