Area Forecast Discussion
Issued by NWS Charleston, SC

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000
FXUS62 KCHS 271129
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
629 AM EST THU NOV 27 2014

.SYNOPSIS...
A DRY COLD FRONT WILL MOVE OFFSHORE THIS MORNING. HIGH PRESSURE
WILL THEN BUILD INTO THE SOUTHEAST UNITED STATES AND PREVAIL
THROUGH EARLY NEXT WEEK. A COLD FRONT WILL APPROACH FROM THE NORTH
TUESDAY...WITH AN INLAND WEDGE OF HIGH PRESSURE BUILDING IN ITS
WAKE FOR THE MIDDLE OF NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
THE COLD FRONT WILL RACE OFFSHORE THIS MORNING WITH FAIRLY STRONG
LOW LEVEL COLD AIR ADVECTION TO TAKE PLACE PRIOR TO MIDDAY WITH A
SLOWER PROGRESSION THIS AFTERNOON AFTER THE INITIAL PUNCH. THE
MAIN STORY TODAY WILL BE GUSTY WNW WINDS THROUGH MUCH OF THE DAY
AS STRONG LOW LEVEL WINDS SHIFT OVER THE REGION AS THE MIXED LAYER
DEEPENS THIS MORNING INTO THE PEAK HEATING HOURS THIS AFTERNOON. A
SWATH OF 35 KT WINDS AT 925 MB FROM 14Z-17Z SUGGEST PREVAILING
WIND 20-25 MPH WIND GUSTS WILL COMMENCE BY MID MORNING WITH PEAK
WIND GUSTS OVER 30 MPH A GOOD BET AT LEAST OCCASIONALLY FOR MANY
LOCATIONS EARLY/MID AFTERNOON AS THE MIXED LAYER EXPANDS. WHILE
WIND ADVISORY CRITERIA SHOULD NOT BE MET...THERE IS POTENTIAL THAT
A SPECIAL WEATHER STATEMENT FOR GUSTY WINDS ON BRIDGES AND
ELEVATED SURFACES WILL BE ISSUED LATER THIS MORNING. THIS WOULD
OCCUR AFTER THE REGIONAL 12Z SOUNDING DATA REVEALS MORE ABOUT THE
POST-FRONTAL LOW LEVEL WIND FIELDS.

THE DOWN-SLOPING FLOW WILL BE COUNTERACTED GREATLY BY THE COLDER AIR
INTRUSION AND PERSISTENCE HIGHS IN THE UPPER 50S WERE MAINTAINED AS
SUNSHINE LOOKS ABUNDANT...SCATTERED CUMULUS ARE POSSIBLE THIS
AFTERNOON.

OVERNIGHT LOWS WILL RANGE BETWEEN THE LOW/MID 30S AWAY FROM THE
COAST...WITH FREEZING TEMPS INLAND. THERE COULD BE SOME LOCAL
UPPER 20S IN SHELTERED LOCATIONS BORDERING THE CSRA AND MIDLANDS.

LAKE WINDS...A 35-40 KT LOW LEVEL WIND FIELD WILL SHIFT OVER THE
AREA TODAY...RESULTING IN LAKE WIND ADVISORY CONDITIONS AS WARMER
WATERS MIX WINDS TO THE SFC. A LAKE WIND ADVISORY WILL THEREFORE BE
IN EFFECT THROUGH 5 PM.

&&

.SHORT TERM /FRIDAY THROUGH SUNDAY/...
FRIDAY THROUGH SUNDAY...SURFACE HIGH PRESSURE WILL STALL ALONG THE
EAST COAST FRIDAY AND SATURDAY...BEFORE SETTLING OVER THE NEARBY
ATLANTIC WATERS BY SUNDAY. IN THE UPPER LEVELS...A WEAK SHORTWAVE
WILL PASS OFF THE COASTLINE FRIDAY...FOLLOWED BY A BUILDING RIDGE
FROM THE BAHAMAS THROUGH SUNDAY. MODEL FORECAST SOUNDINGS
INDICATE A VERY DRY AIR MASS REMAINING IN PLACE...WITH
PRECIPITABLE WATER VALUES HELD AROUND HALF AN INCH OR LESS THOUGH
THE PERIOD. WILL THUS CONTINUE TO ADVERTISE DRY CONDITIONS AND RAIN
CHANCES AT ZERO THROUGH THE WEEKEND. DIMINISHING COLD ADVECTION ON
THE BACK SIDE OF THE WEAK SHORTWAVE...INCREASING SOUTHERLY
FLOW...AND THE BUILDING UPPER RIDGE...WILL SUPPORT A GRADUAL WARMING
TREND LATE WEEK INTO THE WEEKEND. TEMPERATURES WILL BE SUPPRESSED
FAR BELOW SEASONAL NORMALS FOR ONE MORE DAY ON FRIDAY. EXPECT
TEMPERATURES TO ONLY REACH THE LOW TO MID 50S DURING THE
AFTERNOON...AND THEN FALL BELOW FREEZING AWAY FROM THE COAST
WITHIN IDEAL RADIATIONAL COOLING FRIDAY NIGHT. HIGH AND LOW
TEMPERATURES WILL THEN REBOUND NEARLY 10 DEGREES ON
SATURDAY...PEAKING IN THE LOW TO MID 60S FOR HIGHS AND UPPER 30S
TO LOW 40S FOR NIGHTTIME LOWS. TEMPERATURES ON SUNDAY COULD
REBOUND AND RISE A DEGREE OR TWO WARMER THAN NORMAL...REACHING
THE UPPER 60S TO AROUND 70 DEGREES UNDER CONTINUED MOSTLY SUNNY
SKIES.

&&

.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
THE UNSEASONABLY WARM CONDITIONS WILL CONTINUE THROUGH
MONDAY...WITH HIGH TEMPERATURES RISING INTO THE LOW 70S AWAY FROM
THE COAST DURING THE AFTERNOON. ATLANTIC HIGH PRESSURE AT THE
SURFACE AND ALOFT WILL STEADILY SHIFT EAST/SOUTHEAST THROUGH
MONDAY...AS A COLD FRONT APPROACHES THE APPALACHIAN REGION LATE
MONDAY INTO EARLY TUESDAY. LATEST NUMERICAL MODEL SOLUTIONS
SUGGEST THE WEAKENING FRONT COULD TRANSITION INTO THE LEADING EDGE
OF HIGH PRESSURE BUILDING AN INLAND WEDGE FROM THE MID ATLANTIC
STATES THROUGH NORTHERN GEORGIA. NORTHEAST FLOW WITHIN THE
DEVELOPING INLAND WEDGE/COASTAL TROUGH PATTERN WILL CONTRIBUTE TO
A COOLING TREND...WITH HIGH TEMPERATURES RANGING FROM THE MID TO
UPPER 60S EACH AFTERNOON TUESDAY THROUGH THURSDAY. SLIGHT RAIN
CHANCES COULD ALSO RETURN EARLY TO MID WEEK...DEPENDING ON THE
PROGRESSION OF THE FRONT. HIGHEST CONFIDENCE IS IN ISOLATED RAIN
OVER THE MARINE ZONES AND PERHAPS THE IMMEDIATE COASTLINE
ASSOCIATED WITH THE COASTAL TROUGH ON THE PERIPHERY OF THE INLAND
RIDGE.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
VFR CONDITIONS WILL PREVAIL THROUGH 12Z FRIDAY AT KCHS AND KSAV. A
COLD FRONT WILL CROSS THE TERMINALS LATE TONIGHT...WITH A BRIEF
PERIOD OF LOW LEVEL WIND SHEAR AROUND SUNRISE. DEEPER MIXING WILL
COMMENCE BY MID MORNING TODAY...WITH GUSTS UPWARDS OF AROUND 24-28
KT EXPECTED THROUGH MUCH OF THE AFTERNOON.

EXTENDED AVIATION OUTLOOK...VFR CONDITIONS WILL PREVAIL.

&&

.MARINE...
SMALL CRAFT ADVISORIES ARE IN EFFECT TODAY FOR ALL COASTAL WATERS
AND THE CHARLESTON HARBOR AS STRONG LOW LEVEL WIND FIELDS SHIFT
OVER THE WATERS. WHILE SHELF WATER MIXING PROFILES SLOWLY IMPROVE
TODAY THE SETUP FOR ENHANCED JETTING PROFILES LOOK QUITE GOOD
THROUGH EARLY TO MID AFTERNOON. WE INCREASED WIND SPEEDS/GUSTS A
BIT BEYOND 10 NM OFFSHORE TO A MORE SOLID ADVISORY PATTERN WITH
SLIGHT BUMPS TO SEAS IN THE EASTERN FRINGES OF THE NEAR SHORE
ZONES.

TONIGHT...THE BEST PRES GRADIENT SHIFTS OFFSHORE BUT BETTER
NOCTURNAL MIXING PROFILES WILL EXIST AND WE MAINTAINED 15 TO 20 KT
OUTSIDE THE LAND/SEA INTERFACE WITH CONDITIONS LIKELY REMAINING IN
ADVISORY CRITERIA BEYOND 20 NM OFF THE GEORGIA COAST THROUGH
TONIGHT.

FRIDAY THROUGH MONDAY...THE REMAINING SMALL CRAFT ADVISORY WILL
LIKELY END EARLY FRIDAY MORNING ACROSS THE OUTER GEORGIA WATERS.
MARINE CONDITIONS WILL THEN CONTINUE TO IMPROVE FRIDAY AFTERNOON
AND REMAIN RATHER BENIGN INTO MONDAY...AS SURFACE HIGH PRESSURE
BECOMES CENTERED OVER THE WATERS AND ALLOWS THE PRESSURE GRADIENT
TO RELAX.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...LAKE WIND ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR SCZ045.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR AMZ350-
     352-354.
     SMALL CRAFT ADVISORY UNTIL 7 AM EST FRIDAY FOR AMZ374.
     SMALL CRAFT ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR AMZ330.

&&

$$

NEAR TERM...
SHORT TERM...WMS
LONG TERM...WMS
AVIATION...
MARINE...WMS






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