000
FXUS62 KCHS 141409
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
1009 AM EDT TUE MAY 14 2013

.SYNOPSIS...
HIGH PRESSURE WILL EXTEND ACROSS THE REGION THIS WEEK. A WARMING
TREND WILL BEGIN MID WEEK WITH RAIN CHANCES INCREASING SLIGHTLY
BY LATE WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A VERY QUIET DAY OF WEATHER IS EXPECTED TODAY WITH HIGH PRESSURE
DOMINATING THE PATTERN. OVERALL HIGH TEMPS WILL BE A FEW DEGREES
WARMER THAN YESTERDAY AS MID LVL RIDGING GRADUALLY EXPANDS FROM THE
WEST. 1000-850 MB THICKNESSES ALONG WITH A FULL DAY OF SUN SUPPORT
TEMPS IN THE UPPER 70S OVER SOUTHEAST SOUTH CAROLINA TO AROUND 80
OVER SOUTHEAST GEORGIA. TEMPS SHOULD BE A FEW DEGREES COOLER ALONG
THE COAST AS A WEAK SEABREEZE DEVELOPS WHILE SFC HIGH PRESSURE
CURRENTLY CENTERED OVER THE SOUTHEASTERN UNITED STATES SLOWLY SLIDES
SOUTH THIS AFTERNOON.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
TONIGHT...HIGH PRESSURE WILL GRADUALLY SHIFT TO THE SOUTH TONIGHT
AS A COLD FRONT MOVES INTO THE CENTRAL PLAINS...MID-MISSISSIPPI
VALLEY AND OHIO VALLEY. ALTHOUGH THE HIGH SHIFTS TO THE
SOUTH...THE TIGHTEST PRESSURE GRADIENT LOOKS TO REMAIN JUST TO THE
NORTH OF THE LOCAL FORECAST AREA. THIS SHOULD ALLOW THE BOUNDARY
LAYER TO DECOUPLE ONCE AGAIN FOR MOST AREAS LATER THIS EVENING
WITH CLEAR SKIES AND CALM WINDS DOMINATING FOR MUCH OF THE NIGHT.
FAVORED THE COOLER SIDE OF GUIDANCE GIVEN THE FAVORABLE
RADIATIONAL REGIME WITH LOWS RANGING FROM THE LOWER 50S WELL
INLAND TO THE UPPER 50S/LOWER 60S CLOSER TO THE BEACHES. SOME OF
THE NORMALLY SHELTERED AREAS SUCH AS ALLENDALE AND JAMESTOWN COULD
BRIEFLY DROP INTO THE UPPER 40S PRIOR TO SUNRISE WEDNESDAY.

WEDNESDAY...THE FORECAST AREA WILL BECOME LOCATED BETWEEN SURFACE
HIGH PRESSURE SLIPPING INTO THE ATLANTIC AND A DEVELOPING INLAND
TROUGH EAST OF THE APPALACHIAN RANGE. THE AXIS OF THE UPPER LEVEL
RIDGE WILL MOVE DIRECTLY ACROSS THE EAST COAST...BEFORE DAMPENING
AND SHIFTING OFFSHORE OVERNIGHT. THE PROFILE WILL REMAIN QUITE DRY
MID WEEK...AND WHEN COMBINED WITH DECENT SUBSIDENCE...RAIN
CHANCES WILL BE AT ZERO PERCENT. WITH HEIGHTS ALOFT MAXIMIZED
DURING THE DAYTIME HOURS AND WARM SOUTHERLY FLOW PREVAILING...HIGH
TEMPERATURES WILL RISE SEVERAL DEGREES ABOVE SEASONAL NORMALS...
REACHING THE UPPER 80S AWAY FROM THE LOCALLY COOLER COASTLINE.
OVERNIGHT LOWS WILL HAVE MODERATED BACK TO NORMALS FOR THIS TIME
OF YEAR...GENERALLY IN THE LOWER 60S.

THURSDAY...A BROAD UPPER TROUGH WILL TRACK EASTWARD...ACCOMPANIED
BY SOME WEAK SHORTWAVE ENERGY. THE INLAND SURFACE TROUGH WILL
LIKELY BECOME BETTER DEFINED UNDER THE ENERGY ALOFT...WHILE MID TO
UPPER LEVEL MOISTURE INCREASES ACCORDINGLY. THERE IS SOME
DISAGREEMENT IN MODEL SOLUTIONS REGARDING PRECIPITATION POTENTIAL
ON THURSDAY...WITH THE WETTER GFS INDICATING STRONGER SHORTWAVES
TRACKING THROUGH THE AREA. FORECAST SOUNDINGS SUGGEST LOW LEVEL
MOISTURE WILL STILL BE LACKING...AND CONSIDERING THE DISAGREEMENT
BETWEEN THE MODELS AT THIS TIME...PREFER TO CAP RAIN CHANCES BELOW
15 PERCENT WHILE INDICATING INCREASING SKY COVER. HIGH TEMPERATURES
WILL BE QUITE WARM IN THE UPPER 80S INLAND...WHILE SUPPRESSED IN
THE LOW TO MID 80S ALONG THE COAST BEHIND THE SEABREEZE.

FRIDAY...THE BROAD TROUGH ALOFT WILL MOVE OVER THE SOUTHEAST
STATES BEFORE STEADILY SHIFTING OFFSHORE LATE IN THE DAY.
SHORTWAVE ENERGY WILL STILL BE IMPACTING THE AREA...AND ALTHOUGH
THERE IS STILL SOME DISCREPANCY IN MODEL SOLUTIONS...WILL
MAINTAIN MENTION OF A SLIGHT OF SHOWERS/THUNDERSTORMS DURING THE
CLIMATOLOGICALLY FAVORED AFTERNOON AND EARLY EVENING HOURS WITHIN
WEAKENING SUBSIDENCE. WITH THE TEMPORARY DECREASE IN THICKNESSES
AS THE UPPER TROUGH PASSES THROUGH THE AREA...HIGH TEMPERATURES
WILL BE A DEGREE OR TWO COOLER THAN THE PREVIOUS DAYS. EXPECT
TEMPERATURES TO PEAK MORE IN THE MID 80S INLAND...WITH JUST A FEW
LOCATIONS FAR INLAND TOUCHING THE UPPER 80S.

&&

.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
THE UPPER LEVEL PATTERN WILL REMAIN RATHER WEAK AND ILL-DEFINED
THROUGH MUCH OF THE EXTENDED PERIOD...WHILE ATLANTIC HIGH PRESSURE
PREVAILS AS THE MAIN FEATURE AT THE SURFACE. WITH LITTLE CHANGE IN
THE PATTERN UNTIL AS LATE AS TUESDAY...EXPECT SHOWER/THUNDERSTORM
POTENTIAL TO MAINLY BE DRIVEN BY TYPICAL DIURNAL HEATING/INSTABILITY
AND SEABREEZE FORCING. HAVE THUS INDICATED A SLIGHT CHANCE FOR
THUNDERSTORMS DURING THE CLIMATOLOGICALLY FAVORED AFTERNOON AND
EARLY EVENING HOURS SATURDAY THROUGH AT LEAST MONDAY. HIGH
TEMPERATURES EACH AFTERNOON WILL RANGE FROM THE MID TO UPPER 80S
INLAND...TO THE LOW 80S RIGHT ALONG THE COAST BEHIND THE
SEABREEZE. MEDIUM RANGE MODEL SOLUTIONS INDICATE AN UPPER TROUGH
SWINGING EAST/SOUTHEAST FROM THE GREAT LAKES REGION...PUSHING A
COLD FRONT INTO THE TENNESSEE VALLEY REGION. THIS FEATURE WILL
LIKELY REMAIN WEST OF THE FORECAST AREA UNTIL MID WEEK.

&&

.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
VFR CONDITIONS WILL PREVAIL AT BOTH CHS AND SAV TERMINALS THROUGH
12Z WEDNESDAY.

EXTENDED AVIATION OUTLOOK...NO CONCERNS.

&&

.MARINE...
TODAY...VERY QUIET CONDITIONS WILL PERSIST OVER THE COASTAL WATERS
WITH HIGH PRESSURE DOMINATING THE WEATHER PATTERN. EXPECT
NORTH/NORTHEAST WINDS TO VEER AND BECOME ONSHORE THIS AFTERNOON AS
HIGH PRESSURE SLOWLY SLIDES SOUTH. WINDS WILL GENERALLY REMAIN AT OR
BELOW 10 KNOTS...WITH OCCASIONAL 10-15 KT WINDS NEAR A DEVELOPING
SEABREEZE CIRCULATION THIS AFTERNOON. SEAS WILL RANGE 1-2 FT
NEARSHORE AND 2-3 FT OFFSHORE.

TONIGHT...SOUTH WINDS WILL VEER SOUTHWEST OVERNIGHT AS HIGH
PRESSURE SHIFTS TO THE SOUTH. WINDS WILL AVERAGE 5-10 KT WITH SEAS
1-2 FT NEARSHORE...2-3 FT OFFSHORE.

WEDNESDAY THROUGH SATURDAY...SOUTHERLY WINDS WILL SURGE SLIGHTLY
ON WEDNESDAY...AS THE GRADIENT TIGHTENS BETWEEN ATLANTIC HIGH
PRESSURE AND AN INLAND SURFACE TROUGH. WIND SPEEDS WILL REACH THE
15 TO 20 KT RANGE AT THIS TIME...HOWEVER SOLID SMALL CRAFT
ADVISORY THRESHOLDS ARE NOT EXPECTED TO BE REACHED. MODERATE
SOUTHERLY FLOW WILL CONTINUE INTO THURSDAY...BEFORE WINDS DIMINISH
A BIT FRIDAY AND SATURDAY AS THE INLAND TROUGH BECOMES LESS
DEFINED. WAVE HEIGHTS WILL GENERALLY RANGE FROM 2 TO 4
FT...HIGHEST IN THE OUTER WATERS.

&&

.CLIMATE...
RECORD LOWS FOR 14 MAY.
CHARLESTON AIRPORT.... 42/1941
DOWNTOWN CHARLESTON... 51/1917
SAVANNAH AIRPORT...... 49/1997

&&

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

&&

$$

SYNOPSIS...
NEAR TERM...DPB
SHORT TERM...ST/WMS
LONG TERM...WMS
AVIATION...DPB
MARINE...DPB/WMS
CLIMATE...