Area Forecast Discussion
Issued by NWS Charleston, SC

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000
FXUS62 KCHS 302356
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
756 PM EDT SAT AUG 30 2014

.SYNOPSIS...
HIGH PRESSURE WILL PREVAIL THROUGH AT LEAST THE MIDDLE OF THE
WEEK. A COLD FRONT COULD DISSIPATE OVER OR NEAR THE REGION LATE
NEXT WEEK...FOLLOWED BY HIGH PRESSURE INTO NEXT WEEKEND.

&&

.NEAR TERM /THROUGH SUNDAY/...
AN UPPER LEVEL RIDGE OF HIGH PRESSURE WILL REMAIN OVER THE REGION
TONIGHT...WHILE ATLANTIC HIGH PRESSURE PREVAILS AT THE SURFACE.
ISOLATED SHOWERS AND THUNDERSTORMS HAVE DISSIPATED WITH THE LOSS
OF DAYTIME HEATING EARLY THIS EVENING AND THE FOCUS FOR ANY
ADDITIONAL SHOWERS AND THUNDERSTORMS SHOULD TRANSITION TO OVER THE
COASTAL WATERS DURING THE EARLY MORNING HOURS. THERE IS THE
POTENTIAL FOR ISOLATED CONVECTION TO ADVECT INLAND ALONG SOME OF
THE BEACHES AND BARRIER ISLANDS...MAINLY IN SOUTHEAST SOUTH
CAROLINA...TOWARD DAYBREAK SUNDAY.

INCREASING LOW LEVEL MOISTURE COULD BECOME TRAPPED BENEATH THE
INVERSION WITHIN CALM WINDS OVERNIGHT...HOWEVER FOG DEVELOPMENT IS
EXPECTED TO BE SHALLOW AND PATCHY AT BEST. LOW TEMPERATURES WILL
CONTINUE TO TREND MORE MILD...REACHING THE MID TO LOW 70S AWAY
FROM THE COAST.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
UNDER DEEP LAYERED HIGH PRESSURE...TYPICALLY HOT AND HUMID
CONDITIONS WILL PREVAIL SUNDAY THROUGH TUESDAY. MARINE MOISTURE
COULD SUPPORT ISOLATED/SCATTERED SHOWERS/THUNDERSTORMS ACROSS
COASTAL COUNTIES EACH MORNING...THEN DIURNAL SHOWERS/THUNDERSTORMS
WILL FIRE EACH AFTERNOON PRIMARILY ALONG THE SEA BREEZE. CONVECTION
SHOULD THEN DISSIPATE PER DIURNAL COOLING/STABILIZATION EACH NIGHT.

DUE TO THE INFLUENCE OF HIGH PRESSURE ALOFT...LIMITED POPS TO
SLIGHT/CHANCE/CHANCE THROUGH THE PERIOD. 30/12Z GUIDANCE SUGGESTS
THAT THIS RIDGE COULD WEAKEN SLIGHTLY MONDAY INTO TUESDAY...PERHAPS
SUPPORTING SOMEWHAT GREATER SHOWER/THUNDERSTORM COVERAGE. HOWEVER...
THESE CHANGES ARE SUBTLE...AND GIVEN THE PERSISTENT CAP DEPICTED BY
MODEL SOUNDINGS SIGNIFICANTLY HIGHER POPS ARE NOT JUSTIFIED MONDAY
AND TUESDAY.

AS PWATS INCREASE TOWARD 2 INCHES...THE POTENTIAL FOR LOCALLY HEAVY
RAIN WILL INCREASE...ESPECIALLY MONDAY AND TUESDAY. THE POTENTIAL
FOR SEVERE WEATHER SHOULD REMAIN LOW THROUGH THE PERIOD.

OTHERWISE...DAILY HIGHS IN THE LOWER TO MID 90S AND DEWPOINTS IN THE
UPPER 60S TO MID 70S WILL PRODUCE HEAT INDEX VALUES AROUND 100F EACH
DAY. NIGHTTIME TEMPS WILL BOTTOM OUT IN THE 70S MOST
LOCATIONS...PERHAPS REMAINING AROUND 80F ON THE BEACHES.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
LITTLE CHANGE WAS MADE TO THE GOING FORECAST IN THE LONG TERM
PERIOD. THE SOUTHEAST REGION WILL REMAIN UNDER THE INFLUENCE OF THE
RIDGE ALOFT...WHICH WILL ACTUALLY EXPAND BACK EASTWARD AND
STRENGTHEN IN THE MID/LATE TIME FRAME. ATLANTIC HIGH PRESSURE WILL
STILL BE THE PRIMARY SURFACE FEATURE AS IT EXTENDS WESTWARD ACROSS
THE FORECAST AREA. THERE ARE SOME INDICATIONS THAT A FRONT WILL
ATTEMPT TO APPROACH FROM THE NORTH LATE IN THE PERIOD...BUT GIVEN
THE OVERALL PATTERN THE EXPECTATION IS FOR IT TO REMAIN NORTH OF THE
AREA. ABOVE NORMAL TEMPERATURES ARE FORECAST THROUGH THE PERIOD.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
INCREASING LOW LEVEL MOISTURE WILL BECOME TRAPPED BENEATH AN INVERSION
DURING THE EARLY MORNING HOURS...AND COULD LEAD TO THE FORMATION
OF LOW STRATUS AND/OR FOG. MOS GUIDANCE IS MOST PESSIMISTIC AT
KSAV WHERE THE FORECAST NOW INDICATES PREVAILING MVFR CONDITIONS
FROM 08-13Z...BUT PREFER TO KEEP KCHS VFR AND JUST HINT AT SOME
REDUCED 6SM VISIBILITIES AND SCATTERED LOW CLOUDS IN THE SAME
08-13Z TIME FRAME UNTIL CONFIDENCE INCREASES. OTHERWISE...VFR
CONDITIONS ARE EXPECTED TO PREVAIL AT BOTH TERMINALS THROUGH 00Z
MONDAY.

EXTENDED AVIATION OUTLOOK...LOW CHANCES OF DIRECT IMPACTS FROM
ISOLATED SHOWERS/THUNDERSTORMS THROUGH THURSDAY. ALSO...LOW
CHANCES FOR EARLY MORNING FOG/STRATUS. OTHERWISE...MAINLY VFR.

&&

.MARINE...
TONIGHT...ONSHORE FLOW WILL STEADILY VEER TO MORE SOUTHERLY
OVERNIGHT...WHILE SPEEDS REMAIN LESS THAN 15 KT. SEAS WILL RANGE
FROM 2 TO 3 FT...EXCEPT FOR SOME BRIEF 4 FT HEIGHTS BEYOND 40 NM.

SUNDAY THROUGH THURSDAY...ATLANTIC HIGH PRESSURE CENTERED TO THE
EAST OF THE LOCAL WATERS WILL BE THE PRIMARY FEATURE THROUGH THE
MIDDLE OF NEXT WEEK. WINDS/SEAS ARE EXPECTED TO STAY BELOW SMALL
CRAFT ADVISORY THRESHOLDS.

SUNDAY...CONDITIONS COULD ONCE AGAIN BECOME FAVORABLE FOR
WATERSPOUTS IN THE MORNING. OTHERWISE...LIGHT/VARIABLE WINDS
INCLUDING THE LAND BREEZE WILL GIVE WAY TO S/SE WINDS LESS THAN 15
KT AS THE SEA BREEZE DEVELOPS. SUNDAY NIGHT...WINDS WILL TURN TOWARD
THE S/SW AT 10-15 KT. MONDAY THROUGH TUESDAY...S/SW WINDS WILL
PREVAIL. ENHANCED BY THE AFTERNOON SEA BREEZE AS HIGH AS 15 KT AND
BY NOCTURNAL SURGES AS HIGH AS 15-20 KT. SEAS WILL GENERALLY BE 1-3
FT ACROSS THE NEARSHORE WATERS AND AS HIGH AS 3-4 FT FOR THE OUTER
WATERS.

&&

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

&&

$$

NEAR TERM...JAQ/WMS
SHORT TERM...SPR
LONG TERM...BSH
AVIATION...JAQ/SPR
MARINE...






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