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000
FXUS62 KCHS 140745
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
345 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 /THROUGH TODAY/...
THROUGH SUNRISE...IT WILL BE A CHILLY START TO THE MORNING WITH
LOWS BOTTOMING OUT IN THE LOWER 40S WELL INLAND WITH UPPER
40S/LOWER 50S AT THE COAST. THE LOW AT SAVANNAH AS OF 14/0730Z IS
50 DEGREES AND IT LOOKS PROBABLE THAT THE RECORD LOW FOR TODAY
WILL EITHER BE TIED OR BROKEN THERE. THE RECORD LOWS AT BOTH THE
CHARLESTON AIRPORT AND DOWNTOWN CHARLESTON LOOK SAFE.

TODAY...HIGH PRESSURE WILL EXTEND ACROSS THE REGION AGAIN TODAY. A
WEAK WARM AIR ADVECTION PATTERN WILL DEVELOP THIS MORNING AND
PERSIST THROUGH THE DAY...HELPING TO PUSH BOTH H8 TEMPERATURES AND
LOW-LEVEL THICKNESSES HIGHER THAN MONDAY. EXPECT HIGHS TO BE A FEW
DEGREES WARMER AS A RESULT...TOPPING OUT IN THE UPPER 70S TO
AROUND 80. A RESULTANT SEA BREEZE WILL BEGIN TO TAKE SHAPE BY
EARLY AFTERNOON AND MOVE STEADILY INLAND AS THE AFTERNOON
PROGRESSES. SHOULD SEE SOME FAIRLY HEALTHY THERMAL FALLS OCCUR BY
MID-LATE AFTERNOON WITH ITS PASSAGE...ESPECIALLY ALONG THE SOUTH
CAROLINA COAST. SUNNY SKIES WILL DOMINATE TODAY WITH LITTLE
PROSPECTS FOR EITHER CIRRUS OR CUMULUS HUMILIS.

&&

.SHORT TERM /TONIGHT 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 /06Z TUESDAY THROUGH SATURDAY/...
VFR THROUGH TUESDAY.

EXTENDED AVIATION OUTLOOK...NO CONCERNS.

&&

.MARINE...
TODAY...THE EARLY MORNING WIND SURGE WILL GIVE WAY TO LIGHTER
WINDS AFTER SUNRISE WITH DIRECTIONS GRADUALLY VEERING MORE ONSHORE
THIS AFTERNOON. THERE COULD SOME SLIGHT ENHANCEMENT ALONG THE
LAND/SEA INTERFACE WITH THE DEVELOPING SEA BREEZE...BUT SPEEDS DO
NOT LOOK SIGNIFICANT. SPEEDS THIS AFTERNOON WILL GENERALLY RANGE
5-10 KT...BUT MAY BECOME VARIABLE AT TIMES OVER THE GEORGIA
OFFSHORE LEGS AS THE PREVAILING NORTH FLOW BECOMES INTERMINGLED
WITH THE INFLUENCES FROM THE SEA BREEZE CIRCULATION. SEAS WILL
RANGE 1-2 FT NEARSHORE...2-3 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.

&&

$$

ST/WMS