Area Forecast Discussion
Issued by NWS Charleston, SC

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FXUS62 KCHS 060526
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
1226 AM EST FRI MAR 6 2015

.SYNOPSIS...
A COLD FRONT WILL PUSH THROUGH THE REGION OVERNIGHT...THEN COLD
HIGH PRESSURE WILL BUILD OVER THE AREA THROUGH SUNDAY. NEXT
WEEK...AN UNSETTLED PATTERN WILL DEVELOP BETWEEN A STATIONARY
FRONT SOUTH AND EAST OF THE REGION AND HIGH PRESSURE CENTERED TO
THE NORTH.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
SECONDARY SURGE OF COLD AIR IS MOVING QUICKLY SOUTH AND IS MARKED
BY A FINE LINE ON KCLX 0.5 DEG REFLECTIVITY. THE FRONT WILL CLEAR
THE ALTAMAHA RIVER BY 4 AM BASED ON CURRENT TRENDS. RAIN IS
QUICKLY ENDING WITH LOW CLOUDS AND DRIZZLE FILLING IN BEHIND THE
SECONDARY COLD FRONT. AREAS OF DRIZZLE WILL PERSIST THROUGH
SUNRISE. H3R AND RAP WET-BULB FREEZING LINE IS PROGGED TO MOVE
INTO NORTHERN PARTS OF BERKELEY COUNTY AFTER 4 AM WITH
TEMPERATURES DROPPING TO NEAR FREEZING. THERE IS STILL A SLIGHT
CHANCE FOR SOME LIGHT FREEZING DRIZZLE...BUT NO IMPACTS ARE
EXPECTED. WILL MAINTAIN A MENTION OF A SLIGHT CHANCE OF -FZDZ IN
THE GRIDDED AND TEXT FORECASTS. THE REST OF THE FORECAST IS ON
TRACK.

LAKE WINDS...WINDS WILL SHIFT TO THE NORTH AND WILL INCREASE
BEHIND A STRONG COLD FRONT THIS EVENING AND OVERNIGHT. SPEEDS WILL
INCREASE TO THE 20-25 KT RANGE...AND GUSTS AS HIGH AS 30 KT WILL
BE POSSIBLE. A LAKE WIND ADVISORY REMAINS IN EFFECT.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY/...
THE COLD FRONT WILL GRADUALLY SHIFT OFFSHORE FRIDAY MORNING THOUGH
LOW LEVEL MOISTURE AND WEAK ISENTROPIC ASCENT WILL LINGER INTO MID
TO LATE MORNING. THIS COULD SPUR SOME LIGHT DRIZZLE THROUGH THE
MORNING HOURS UNTIL DRIER AIR SHIFTS IN DURING THE AFTERNOON.
MODERATE COLD ADVECTION AND PERSISTENT CLOUD COVER WILL RESULT IN
HIGH TEMPS IN THE MID TO UPPER 40S.

THE SURFACE HIGH WILL SETTLE OVER THE AREA FRIDAY NIGHT WITH MOSTLY
CLEAR SKIES AND LIGHT WINDS. THIS WILL FACILITATE STRONG RADIATIONAL
COOLING AND TEMPERATURES DROPPING BELOW FREEZING IN MANY AREAS. THE
EXCEPTION LOOKS TO BE THE GA COASTAL ZONES AND IMMEDIATE SC COAST.
WE ISSUED A FREEZE WATCH FOR ALL ZONES MINUS THE GA COASTAL AREAS
FOR FRIDAY NIGHT.

DRY TEMPS AND A WARMING TREND ARE EXPECTED SATURDAY INTO SUNDAY AS
THE SURFACE HIGH SHIFTS OFFSHORE AND A SOUTHERLY LOW-LEVEL FLOW
DEVELOPS. MOSTLY SUNNY SKIES EXPECTED SATURDAY BEFORE HIGH CIRRUS
INCREASES ON SUNDAY. HIGHS WILL BE IN THE LOWER 60S SATURDAY AND
UPPER 60S TO NEAR 70 ON SUNDAY.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
BETWEEN A STATIONARY FRONT OFF THE SOUTHEAST COAST AND ACROSS THE FL
PENINSULA AND HIGH PRESSURE CENTERED NORTH OF THE REGION...A
BAROCLINIC ZONE WILL WAVER OVER THE REGION AND WILL CONTRIBUTE TO
UNSETTLED CONDITIONS NEXT WEEK. WHILE A MOSTLY CLOUDY REGIME
PUNCTUATED BY PERIODS OF PRECIPITATION AND FINALLY DEVOID OF ANY
COLD AIR APPEARS LIKELY...CONFIDENCE REGARDING COMPLEX FORECAST
DETAILS REMAINS LOW. FOR INSTANCE...WE MAINTAIN CHANCE POPS MONDAY
AND TUESDAY...BUT SOME GUIDANCE SUGGESTS THAT LIKELY/CATEGORICAL
POPS WILL EVENTUALLY BE NEEDED FOR THIS PERIOD. ALSO...THE POTENTIAL
FOR THUNDERSTORMS COULD INCREASE...BUT THE UNCERTAIN DETAILS
REGARDING INDIVIDUAL WAVES OF LOW PRESSURE AND AN ASSOCIATED
UNCERTAIN POTENTIAL FOR AN INFLUX OF ANY SIGNIFICANT INSTABILITY
DOES NOT JUSTIFY ANY MENTION OF THUNDER.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
CIGS WILL TEETER BETWEEN IFR AND MVFR THROUGH MUCH OF THE
NIGHT...LIKELY SETTING IN TO IFR AFTER 09Z. THERE IS SOME MODEL
DISAGREEMENT ON THIS SO CONFIDENCE IS MODERATE AT BEST. WILL
MAINTAIN MENTION OF IFR CIGS AT BOTH KCHS/KSAV WITH CONDITIONS
IMPROVING TO MVFR 13-14Z. VFR IS EXPECTED TO RETURN BY 18Z AT BOTH
TERMINALS. GUSTY WINDS WILL PERSIST ALONG WITH OCCASIONAL BOUTS OF
-DZ.

EXTENDED AVIATION OUTLOOK...VFR LIKELY FRIDAY NIGHT THROUGH THIS
WEEKEND. FLIGHT RESTRICTIONS POSSIBLE IN RAIN EARLY NEXT WEEK.

&&

.MARINE...
NO CHANGES TO GOING FORECAST. GALE WARNINGS AND SMALL CRAFT
ADVISORIES LOOK WELL PLACED.

TONIGHT...A WIND SHIFT TO THE NORTHWEST AND A BRIEF PERIOD OF
SUB-SCA WINDS WILL GIVE WAY TO RAPID DETERIORATION AS A SECONDARY
COLD FRONT USHERS AN ABRUPT WIND SHIFT TO THE NORTH/NORTHEAST
AND QUICKLY INCREASING WINDS AS COLD ADVECTION AND A TIGHTENING
PRESSURE GRADIENT SPREAD ACROSS THE WATERS. THE ONGOING GALE
WARNING FOR THE CHARLESTON COUNTY WATERS AND THE OUTER GEORGIA
WATERS STILL LOOKS ON TRACK AND REMAINS IN EFFECT.
ELSEWHERE...INCLUDING CHARLESTON HARBOR...SMALL CRAFT ADVISORY
CONDITIONS WILL DEVELOP LATER THIS EVENING AND WILL CONTINUE
THROUGH THE OVERNIGHT.

GALES WILL TRANSITION TO SMALL CRAFT ADVISORIES ON FRIDAY AS THE
GRADIENT RELAXES AND HIGH PRESSURE CONTINUES TO BUILD IN FROM THE
NW. ELEVATED N/NE WINDS AND ASSOCIATED SEAS WILL PERSIST INTO
SATURDAY. A MORE TRANQUIL REGIME IS EXPECTED AS HIGH PRESSURE SHIFTS
OVER THE WATERS SATURDAY NIGHT THROUGH SUNDAY. THEN...FORECAST
CONFIDENCE DECREASES NEXT WEEK AS WINDS/SEAS WILL DEPEND ON A HIGHLY
UNCERTAIN STORM TRACK. THE LATEST FORECAST HOLDS WINDS/SEAS WELL
BELOW ADVISORY LEVELS...BUT AN OFFSHORE TRACK FOLLOWED BY DEEPER
AREAS OF LOW PRESSURE WILL TRANSLATE TO STRONGER WINDS AND HIGHER
SEAS.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...FREEZE WATCH FROM THIS EVENING THROUGH SATURDAY MORNING FOR
     GAZ087-088-099>101-114>116-118-137-138-140.
SC...FREEZE WATCH FROM THIS EVENING THROUGH SATURDAY MORNING FOR
     SCZ040-042>045-047>052.
     LAKE WIND ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR SCZ045.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR AMZ352-
     354.
     GALE WARNING UNTIL 11 AM EST THIS MORNING FOR AMZ350.
     GALE WARNING UNTIL 2 PM EST THIS AFTERNOON FOR AMZ374.
     SMALL CRAFT ADVISORY UNTIL 11 AM EST THIS MORNING FOR AMZ330.

&&

$$

ST



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