Area Forecast Discussion
Issued by NWS Charleston, SC

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000
FXUS62 KCHS 020538
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
138 AM EDT WED SEP 2 2015

.SYNOPSIS...
A WEAK TROUGH OF LOW PRESSURE WILL PERSIST OVER THE SOUTHEAST THIS
WEEK. THIS WEEKEND INTO EARLY NEXT WEEK...HIGH PRESSURE WILL BUILD
INTO THE REGION FROM THE NORTH...AND A TROUGH OF LOW PRESSURE WILL
DEVELOP OVER OR CLOSE TO COASTAL WATERS.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
EXTENSIVE MID AND HIGH CLOUDS STREAMING ACROSS THE REGION FROM THE
SOUTH IN ASSOCIATION WITH A DEEP LAYERED LOW PRESSURE SYSTEM OVER
THE FL PANHANDLE. THE LOW WILL MAKE VERY LITTLE NORTHWARD PROGRESS
OVERNIGHT. NEVERTHELESS...SOME SHORTWAVE ENERGY WILL EJECT OUT TO
THE NORTHEAST AND MOVE THROUGH THE WATERS OVERNIGHT. ISOLATED TO
SCATTERED SHOWERS SHOULD DEVELOP OVER THE WATERS AS THE NIGHT
WEARS ON...THOUGH FORCING FOR PRECIP OVER LAND IS QUITE LIMITED.
LOWERED POPS A BIT ALONG THE ALTAMAHA INITIALLY...KEEPING LOWER
CHANCES LATE. LOW TEMPS IN THE MID 70S MOST AREAS.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY/...
WEDNESDAY THROUGH FRIDAY...THE PATTERN ALOFT WILL FEATURE SHORTWAVE
RIDGING FOR MUCH OF THE PERIOD EXTENDING FROM A UPPER ANTICYCLONE
POSITIONED NEAR THE BAHAMAS. THE RIDGE BREAKS DOWN BY FRIDAY AS
TROUGHING FROM THE WEST PUSHES IN. EMBEDDED WITHIN THE RIDGE
WEDNESDAY INTO THURSDAY IS A SHORTWAVE THAT IS PROGGED TO PUSH
ACROSS SOUTH GEORGIA AND EVENTUALLY OFF THE SOUTHEAST COAST. AT THE
SURFACE...THE PATTERN IS RATHER BENIGN WITH NO PROMINENT FEATURES TO
SPEAK OF. WEAK HIGH PRESSURE WILL GENERALLY COVER THE AREA THROUGH
THURSDAY...WITH A LARGER AND BETTER DEFINED HIGH STARTING TO BUILD
IN FROM THE NORTHEAST ON FRIDAY. MODEL SOLUTIONS FOR THE MID TO LATE
WEEK TIME PERIOD DISPLAY A GOOD DEAL OF INCONSISTENCY REGARDING THE
COVERAGE AND AMOUNT OF CONVECTIVE PRECIPITATION. THE OVERALL
CONSENSUS IS TO FAVOR THE BEST COVERAGE ACROSS SOUTHEAST GEORGIA
WEDNESDAY AND THURSDAY WHERE THE BETTER MOISTURE WILL RESIDE. THEN
BY FRIDAY CHANCE POPS ARE WARRANTED ACROSS THE ENTIRE FORECAST AREA
WITH THE LARGER SCALE TROUGH BEING INTRODUCED ALOFT. POPS ARE ALONG
THE SAME LINES AS THE PREVIOUS FORECAST...WITH CHANCE POPS FOR
SOUTHEAST GEORGIA AND SLIGHT CHANCES ELSEWHERE WEDNESDAY AND
THURSDAY. TEMPERATURES ARE EXPECTED TO BE ON THE WARM SIDE
ESPECIALLY WEDNESDAY AND THURSDAY...WITH HIGHS INTO THE LOW 90S AND
LOWS IN THE LOW TO MID 70S. SUCH TEMPERATURES WOULD BE ABOUT 2-4
DEGREES ABOVE NORMAL FOR EARLY SEPTEMBER.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AT THE SURFACE...EXPANSIVE HIGH PRESSURE CENTERED NORTH OF THE
REGION WILL BUILD SOUTH NEXT WEEKEND INTO EARLY NEXT WEEK...AND A
COASTAL TROUGH SHOULD DEVELOP. ALOFT...A COMPLEX BLOCKING PATTERN
WILL DEVELOP...AND MEDIUM RANGE MODELS GENERALLY AGREE THAT THE
UPPER TROUGH WILL BECOME CUT OFF OVER THE SOUTHEAST THIS WEEKEND AND
WILL MEANDER OVER THE REGION INTO EARLY NEXT WEEK. THIS PATTERN
SHOULD FAVOR SLIGHTLY BELOW NORMAL TEMPS AND ABOVE NORMAL POPS.
UNCERTAINTY EXISTS REGARDING THE RELATIVE POSITIONS/STRENGTHS OF
CRITICAL FEATURES INCLUDING THE NORTH-SOUTH MOISTURE GRADIENT WHICH
TYPICALLY DEVELOPS IN THESE PATTERNS. THUS...CHANCE POPS ARE IN ORDER
DURING THE DAYTIME HOURS...HIGHEST SOUTH AND OVER COASTAL
WATERS...AND NIGHTTIME POPS ARE FOCUSED ACROSS SOUTHERN/COASTAL
COUNTIES AND ACROSS COASTAL WATERS. FORECAST ADJUSTMENTS WILL BE
NECESSARY AS DETAILS EMERGE OVER THE NEXT SEVERAL DAYS.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
VFR EXPECTED. CANNOT RULE OUT A FEW SHOWERS NEAR KSAV LATE THIS
AFTERNOON DUE TO MOISTURE MOVING INTO SOUTHEAST GA ASSOCIATED
WITH THE REMNANT LOW OF ERIKA.

EXTENDED AVIATION OUTLOOK THROUGH SUNDAY...MAINLY VFR. THE
PROBABILITY FOR FLIGHT RESTRICTIONS WILL INCREASE THIS WEEKEND.

&&

.MARINE...
A WEAK PRESSURE PATTERN WILL PERSIST WITH SYNOPTIC FLOW FAVORING
A MAINLY SSE TO SSW COMPONENT UNTIL ROUGHLY 10Z WHEN A LAND BREEZE
BEGINS TO TAKE OVER WITH PRIMARILY W TO NW FLOW FIRMLY INGRAINED
BY DAYBREAK AS THE LAND BREEZE WINDS DOWN. SPEEDS MAINLY 10 KT OR
LESS AND SEAS 2 TO 3 FT THROUGH TOMORROW MORNING.

WEDNESDAY THROUGH SUNDAY...THROUGH THE LATTER PART OF THE WEEK A
WEAK PRESSURE PATTERN WILL PREVAIL ACROSS THE LOCAL WATERS. WINDS
WILL GENERALLY BE 10 KT OR LESS...WITH SOME LOCAL ENHANCEMENTS ALONG
THE LAND/SEA INTERFACE WITH THE DIURNAL SEA BREEZE. DURING THIS
TIME...SEAS WILL STAY IN THE 1-2 FT RANGE. THEN OVER THE
WEEKEND...HIGH PRESSURE WILL BUILD IN FROM THE NORTH. WINDS WILL
INCREASE IN THE TIGHTER NORTHEAST GRADIENT AND SEAS WILL TICK UPWARD
AS WELL.

RIP CURRENTS...AN ELEVATED RISK FOR RIP CURRENTS COULD DEVELOP AGAIN
NEXT WEEKEND.

&&

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

&&

$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...BSH
LONG TERM...SPR
AVIATION...BSH
MARINE...


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