000
FXUS62 KCHS 200529
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
129 AM EDT THU JUN 20 2013

.SYNOPSIS...
A COLD FRONT WILL SLOWLY PROGRESS THROUGH THE REGION TONIGHT. THE
FRONT WILL THEN STALL JUST SOUTH OF THE AREA THURSDAY AND LINGER
THROUGH SATURDAY...AS HIGH PRESSURE BUILDS FROM THE NORTH. THE
CENTER OF HIGH PRESSURE WILL SLIP INTO THE ATLANTIC EARLY NEXT
WEEK.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
OVERNIGHT...CONSIDERABLE CLOUDS WILL PERSIST OVER THE REGION BUT
THERE COULD BE A BIT OF CLEARING ALONG NW FRINGES OF OUR FORECAST
AREA ADJACENT TO THE MIDLANDS AND CSRA. A FRONTAL BOUNDARY WAS
ILL DEFINED OVER SE GEORGIA EXTENDING ACROSS THE ATLC COASTAL
WATERS. CHANCE POPS OVER FAR N AND S PORTIONS OF THE FORECAST AREA
WITH SLIGHT CHANCES IN THE MIDDLE ALONG THE SAVANNAH RIVER. TEMPS
69-72 DEGREES WITH LIGHT TO NEAR CALM WINDS.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY/...
THURSDAY...EXPECT A DECREASE IN SHOWER AND THUNDERSTORM COVERAGE
THURSDAY MORNING...AS A STALLED FRONT REMAINS JUST OFFSHORE AND
SOUTH OF THE FORECAST AREA. MODELS ARE FAIRLY CONSISTENT THAT A
WEAK LOW/COASTAL TROUGH WILL DEVELOP ALONG THE STALLED BOUNDARY
DURING THE DAY...THUS PROVIDING A FORCING MECHANISM FOR ADDITIONAL
SHOWERS/THUNDERSTORMS THURSDAY AFTERNOON FOR LOCATIONS WHERE
ABUNDANT LOW LEVEL MOISTURE LINGERS...MAINLY ALONG COASTAL SOUTH
CAROLINA AND SOUTHEAST GEORGIA COUNTIES. HAVE THEREFORE MAINTAINED
30-40 POPS OVER THESE LOCATIONS. OVERALL HIGH TEMPS SHOULD REMAIN
A DEGREE OR TWO BELOW NORMAL WITH INCREASING CLOUD COVER AND
PRECIP OVER THE AREA. EXPECT TEMPS TO PEAK IN THE MID/UPPER 80S.
SHOWERS AND/OR THUNDERSTORMS MAY LINGER INTO THE OVERNIGHT PERIOD
AS THE SFC LOW/COASTAL TROUGH REMAINS POSITIONED NEAR THE
SOUTHEAST COAST. FOR THIS REASON...HAVE MAINTAINED 20 POPS MAINLY
OVER ALL SOUTH CAROLINA AND GEORGIA COASTAL COUNTIES. OVERNIGHT
LOWS WILL RANGE IN THE UPPER 60S INLAND TO LOW/MID 70S ALONG THE
COAST.

FRIDAY AND SATURDAY...SURFACE HIGH PRESSURE WILL EVENTUALLY BUILD
OVER THE MIDLANDS FROM THE NORTH BY FRIDAY...WITH THE PATTERN
TRANSITIONING INTO AN INLAND WEDGE AND COASTAL TROUGH TYPE SCENARIO.
MODELS CONTINUE TO SUGGEST WEAK WAVES OF ENERGY DEVELOPING ALONG THE
COASTAL TROUGH WHICH GRADUALLY SLIDE THE TROUGH NEAR THE IMMEDIATE
COAST FRIDAY AFTERNOON...THUS PROVIDING ANOTHER DAY OF SHOWER AND/OR
THUNDERSTORMS...WITH THE GREATEST COVERAGE ALONG COASTAL COUNTIES.
BY SATURDAY...HIGH PRESSURE WILL GRADUALLY STRENGTHEN OVER THE
WESTERN ATLANTIC AND LIKELY FORCE THE COASTAL TROUGH OVER LAND BY
THE AFTERNOON OR EVENING. HAVE THEREFORE INDICATED A 30 PERCENT
CHANCE OF COASTAL SHOWERS AND/OR THUNDERSTORMS SATURDAY MORNING
GRADUALLY SHIFTING INLAND WITH THE TROUGH SATURDAY AFTERNOON.
OVERALL HIGHS WILL CONTINUE TO REMAIN A FEW DEGREES BELOW NORMAL ON
BOTH DAYS...WITH TEMPS EXPECTED TO REACH THE MID/UPPER 80S...HIGHEST
OVER INLAND GEORGIA. OVERNIGHT LOWS WILL RANGE IN THE UPPER 60S TO
LOWER 70S.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
THE INLAND WEDGE/COASTAL TROUGH PATTERN WILL TRANSITION ON
SUNDAY...AS THE TROUGH DAMPENS AND/OR MOVES INLAND WHILE THE
CENTER OF HIGH PRESSURE SETTLES OVER THE ATLANTIC. THE FORECAST
AREA WILL THEN REMAIN ALONG THE WESTERN PERIPHERY OF THE ATLANTIC
HIGH PRESSURE INTO EARLY NEXT WEEK...WITH A WEAK INLAND SURFACE
TROUGH DEVELOPING TOWARD THE MID WEEK PERIOD. HAVE INDICATED A
MORE SEASONAL CONVECTIVE SCENARIO....WITH THUNDERSTORMS GENERALLY
DEVELOPING ALONG AND INLAND OF THE SEABREEZE EACH
AFTERNOON...DIMINISHING IN COVERAGE AND/OR RE-DEVELOPING OVER THE
WATERS EACH NIGHT. 500 MB HEIGHTS PEAK EARLY NEXT WEEK...EVIDENCE
THAT THE INITIALLY WEAK UPPER LEVEL PATTERN WILL TRANSITION INTO
BROAD RIDGING ALOFT. AS A RESULT...EXPECT A GRADUAL WARMING TREND
THROUGH THE PERIOD. HIGH TEMPERATURES AROUND 90 DEGREES AWAY FROM
THE COASTLINE SUNDAY WILL INCREASE INTO THE LOWER 90S MONDAY
THROUGH WEDNESDAY.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
A LOW CONFIDENCE FORECAST THIS CYCLE AS THE TERMINALS ON THE
WESTERN EDGE OF DEEP MOISTURE WITH PERIODS OF SHOWERS A GOOD BET
THROUGH TONIGHT AND LOWER CHANCES OF TSTMS THAN ON WED. RADAR
TRENDS WILL NEED TO DICTATE PREVAILING/TEMPO SHOWERS AND CURRENT
IMAGERY NOT TOO TELLING FOR TIMING. OVERNIGHT...MOST OF THE
SHOWERS WILL BE N OF KCHS AND S OF KSAV BUT NOT BY MUCH...ERROR
MARGIN LOW. MVFR/IFR CIGS WERE AROUND THE REGION BUT MAINLY INLAND
AT 05Z. WE MAINTAINED PRIOR TRENDS FOR MVFR CONDITIONS DEVELOPING
BY DAYBREAK INTO MID MORNING. MVFR CIGS STILL POSSIBLE WITH RAINS
NEAR THE COAST INTO LATE DAY OR EVENING.

EXTENDED AVIATION...MVFR OR LOWER CIGS/VSBYS POSSIBLE THROUGH
SATURDAY WITH ISOLATED TO SCATTERED SHOWERS AND/OR THUNDERSTORMS
DEVELOPING NEAR A COASTAL TROUGH. VFR CONDITIONS MAY RETURN BY
SUNDAY.

&&

.MARINE...
TONIGHT...A COLD FRONT WILL CONTINUE SINKING SOUTHWARD AND INTO
THE VICINITY OF THE WATERS. MOST OF THE MARINE ZONES WILL MAINTAIN
WEST/SOUTHWEST FLOW TONIGHT...EXCEPT FOR THE CHARLESTON COUNTY
WATERS WHERE WIND DIRECTIONS HAVE BECOME VARIABLE BETWEEN
NORTHEAST AND EAST. OVERALL...CONDITIONS WILL REMAIN WELL BELOW
SMALL CRAFT ADVISORY LEVELS...WITH WINDS LESS THAN 15 KT AND SEAS
2-3 FT WITHIN 20 NM AND 3-4 FT BEYOND.

THURSDAY THROUGH SUNDAY...EAST/NORTHEAST WINDS AND SEAS ARE
EXPECTED TO REMAIN WELL BELOW SMALL CRAFT ADVISORY CRITERIA
THURSDAY AS A COLD FRONT STALLS OVER OR NEAR THE WATERS. A COASTAL
TROUGH IS THEN EXPECTED TO DEVELOP ALONG THE STALLED BOUNDARY BY
FRIDAY WHILE HIGH PRESSURE BUILDS FROM THE NORTH INLAND. THIS MAY
PRODUCE A MODEST PRESSURE GRADIENT OVER THE WATERS WITH WIND
SPEEDS PEAKING BETWEEN AROUND 15 KT AND WAVES BUILDING TO 3-4 FT.
ADDITIONALLY...SHOWERS AND/OR THUNDERSTORMS ARE POSSIBLE THROUGH
SATURDAY OVER ALL WATERS UNTIL HIGH PRESSURE BUILDS OVER THE
WESTERN ATLANTIC AND SHIFTS THE COASTAL TROUGH ONSHORE. WINDS/SEAS
ARE THEN EXPECTED TO DECREASE/SUBSIDE INTO SUNDAY AS HIGH PRESSURE
CONTINUES TO BUILD OVER THE ATLANTIC.

&&

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

&&

$$

SYNOPSIS...
NEAR TERM...
SHORT TERM...DPB
LONG TERM...WMS
AVIATION...
MARINE...BSH/DPB