Area Forecast Discussion
Issued by NWS Charleston, SC

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206
FXUS62 KCHS 221131
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
731 AM EDT FRI MAY 22 2015

.SYNOPSIS...
HIGH PRESSURE WILL BUILD IN FROM THE NORTH TODAY...GRADUALLY
SHIFTING INTO THE WESTERN ATLANTIC. IT WILL REMAIN THE DOMINANT
WEATHER FEATURE THROUGH LATE NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
HIGH PRES WILL RAPIDLY BUILD EAST AND SOUTH OVER THE FORECAST AREA
IN THE WAKE OF THE COLD FRONT AND OFFSHORE LOW. THE HIGH WILL
SETTLE OVER THE MID ATLC REGION TONIGHT...GENERALLY BLANKETING
JUST ABOUT ALL OF THE EASTERN SEABOARD.

925 MB TEMPS THAT WERE RUNNING IN THE MID 70S YESTERDAY ARE PROGGED
TO BE IN THE MID TO UPPER 50S TODAY. THE PUSH OF LOWER LEVEL COOLER
AIR WILL STRENGTHEN THE INVERSION BETWEEN 3 AND 7 KFT. MOST OF THE
00Z MODELS INDICATE A THIN LAYER OF MOISTURE WILL RESIDE UNDER THIS
INVERSION THIS MORNING...MOST NOTABLY ACROSS INLAND AREAS NORTH OF I-
16. THESE MORNING STRATOCU AND HIGH CLOUDS THE FIRST PART OF THE DAY
COULD BE FACTORS THAT COULD KEEP TEMPS FROM REACHING 80 DEGREES IN
SOME AREAS NORTH OF I-16 TODAY. OVERALL WE MADE MINOR CHANGES TO THE
PREVIOUS HIGH TEMP TRENDS BUT LOWERED A FEW NORTHERN ZONES DOWN JUST
A TAD AS SUNSHINE THIS AFTERNOON IS STILL EXPECTED TO PREVAIL.

MUCH COOLER CONDITIONS TONIGHT AS WINDS DECOUPLE AWAY FROM THE
BEACHES AND BARRIER ISLAND AND LOWS FALL INTO THE MID/UPPER 50S
INLAND UNDER CLEAR SKIES. MANY COASTAL AREAS EAST OF U.S. 17 WILL
FALL TO AROUND 60 WITH MILDER CONDITIONS RIGHT AT THE LAND/SEA
INTERFACE.

&&

.SHORT TERM /SATURDAY THROUGH MONDAY/...
UNSEASONABLY DRY HIGH PRESSURE WILL SETTLE OVER THE AREA FROM THE
NORTH SATURDAY WHILE AN UPPER RIDGE STRENGTHENS OVERHEAD. THE
SURFACE HIGH WILL SHIFT INTO THE WESTERN ATLANTIC SUNDAY INTO MONDAY
THOUGH THE UPPER RIDGE WILL CONTINUE TO BUILD. WE WILL BE HARD
PRESSED TO INITIATE ANY CONVECTION SATURDAY OR SUNDAY GIVEN SUCH
MEAGER MOISTURE PROFILES AND STRONG CAPPING. WE INCLUDED A SLIGHT
CHANCE POP ACROSS FAR SOUTHWESTERN ZONES ON MONDAY WHERE PWATS
INCREASE TO AROUND 1.6" AND AFTERNOON TEMPS RISE INTO THE UPPER 80S.
COVERAGE SHOULD STILL BE QUITE LIMITED DUE TO SUCH WARM MID-LEVELS.
TEMPS WILL SHOW A WARMING TREND DURING THE PERIOD.

&&

.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
A STRONG DEEP LAYERED RIDGE WILL REMAIN THE DOMINANT WEATHER FEATURE
DURING THE LONG TERM PERIOD. INCREASING LOW-LEVEL THICKNESSES
SUPPORT A WARMING TREND WITH TEMPS SEVERAL DEGREES ABOVE NORMAL
THROUGH THE PERIOD. A STRONG MID-LEVEL CAP WILL MINIMIZE RAIN
CHANCES THROUGH WEDNESDAY. SOME SHORTWAVE ENERGY WILL BEGIN TO ERODE
THE RIDGE FROM THE WEST THURSDAY INTO FRIDAY...POTENTIALLY ALLOWING
FOR ISOLATED SHOWERS AND TSTMS TO MOVE INTO INLAND AREAS DURING THE
AFTERNOON HOURS.

&&

.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
VFR CONDITIONS WILL PREVAIL THROUGH 12Z SATURDAY AT KCHS/KSAV.

EXTENDED AVIATION OUTLOOK...MAINLY VFR.

&&

.MARINE...
A SIGNIFICANT BUT BRIEF SURGE FROM THE NNE IS ON TAP THIS MORNING
AS STRONG SURFACE PRES RISES BUILD OVER THE WATERS IN THE WAKE OF
DEPARTING LOW PRES OFF THE MID ATLC COAST. WINDS REACHING 20 KT
WITH OCCASIONAL HIGHER GUSTS AS THE SURGE BUILDS SOUTH FROM THE
WATERS OFF CHARLESTON SHORTLY AROUND DAYBREAK BEFORE DIMINISHING
LATER THIS MORNING TO 15-20 KT. WE OPTED TO KEEP FORECAST
CONDITIONS BELOW SMALL CRAFT ADVISORY CRITERIA FOR NOW GIVEN THE
BREVITY OF THE BEST SURGING CONDITIONS ASSOCIATED WITH LOW LEVEL
COOLER AIR ADVECTION. CHOPPY CONDITIONS OVER THE INTRA- COASTAL
WATERS ARE LIKELY THIS MORNING TO THE NORTH OF SAVANNAH AND 15-20
KT IN THE CHS HARBOR WITH HIGHER GUSTS ON THE OUTSIDE DURING THE
MAX SURGE AROUND MID MORNING.

THE TIGHTER GRADIENT TONIGHT WILL RESIDE OVER SOUTHERN GEORGIA
WATERS BY TONIGHT AND WITH A BETTER FETCH GEORGIA WATERS...SEAS
SHOULD WAVER FROM 4-5 FT OVER GEORGIA WATERS BEYOND 20 NM.

A LONG EAST-NORTHEAST FETCH WITH SLIGHTLY ENHANCED GRADIENT WILL
EXIST SATURDAY AND SUNDAY AS HIGH PRESSURE SHIFTS EAST FROM THE MID-
ATLANTIC REGION. WITH THE PREVAILING ONSHORE FLOW AND WARM LAND
TEMPS WE EXPECT A ROBUST AFTERNOON SEA BREEZE BOTH DAYS.
ADDITIONALLY...SEAS WILL GRADUALLY BUILD AND WE COULD SEE 6 FT SEAS
OVER OUTER PORTIONS OF THE OFFSHORE GA WATERS SATURDAY NIGHT THROUGH
SUNDAY. OTHERWISE...CONDITIONS WILL REMAIN BELOW ADVISORY LEVELS
THROUGH LATE NEXT WEEK.

&&

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

&&

$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...JRL
LONG TERM...JRL
AVIATION...
MARINE...JRL



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