Area Forecast Discussion
Issued by NWS Charleston, SC

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FXUS62 KCHS 272311
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
711 PM EDT WED MAY 27 2015

.SYNOPSIS...
HIGH PRESSURE WILL EXTEND ACROSS THE REGION THROUGH EARLY NEXT
WEEK.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
THIS EVENING...LINGERING MESO-SCALE BOUNDARY INTERACTIONS WITH
WEAK-MODEST THERMODYNAMICS WILL ALLOW FOR ISOLATED TO SCATTERED
CONVECTION FAR WEST-NW SECTIONS. POOR LAPSE RATES THOUGH WILL KEEP
STORMS IN CHECK. CONVECTION WILL THEN DWINDLE WITH LOSS OF
DAYTIME HEATING AND INCREASING CINH AND WE HAVE ENDED ALL MENTION
OF SHOWERS/T-STORMS BY AROUND 10 PM ACROSS DISTANT INLAND ZONES.

TONIGHT...LARGE ATLANTIC HIGH PRESSURE WILL BE THE PROMINENT
FEATURE AS IT EXTENDS ACROSS THE LOCAL ZONES...WHILE ALOFT WE/LL
LIE ON THE WEST/NW EDGE OF DEEP-LAYERED RIDGING. THIS WILL ALLOW
FOR QUIET WEATHER CONDITIONS TO PREVAIL AS SKIES AVERAGE OUT TO BE
PARTLY CLOUDY AND WINDS DECOUPLE. THE ONSHORE SYNOPTIC FLOW AND
ELEVATED DEW POINTS WILL LIMIT OVERNIGHT MINIMUMS TO MID OR UPPER
60S MOST COMMUNITIES. THE OUTLIERS WILL BE IMMEDIATE SHORELINE
PLACES WITH 70-72 MORE COMMON.

CROSS-OVER TEMPS WILL BE OBTAINED ACROSS PARTS OF THE WEST/NW
LOCATIONS...AND GIVEN EARLIER RAINFALL THIS WILL LEAD TO PATCHY
FOG FORMATION LATE. HOWEVER...SOIL TEMPS ARE QUITE WARM AND THIS
WILL LIMIT THE AREAL COVERAGE/VISIBILITY REDUCTION. THUS FOR NOW
WE HAVE HELD OFF FROM ADDING FOG TO THE FORECAST. WE WILL CONTINUE
TO EVALUATE.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
WITH DEEP LAYERED HIGH PRESSURE IN PLACE THROUGH
SATURDAY...CONDITIONS SHOULD BE SEASONABLY WARM INTO THE FIRST
HALF OF THE WEEKEND WITH TEMPS RANGING FROM THE UPPER 70S AT THE
BEACHES TO THE UPPER 80S INLAND. WITH GENERAL SUBSIDENCE IN
PLACE...SEA BREEZE BOUNDARY WILL NOT GENERATE TOO MUCH CONVECTION
AS IT MOVES INLAND ON THURSDAY AND FRIDAY AFTERNOON/EVENING. RIGHT
NOW...JUST SOME ISOLATED SHOWERS/THUNDERSTORMS ARE EXPECTED AWAY
FROM THE COAST WITH MANY PLACES REMAINING DRY.

SATURDAY...A VERY WEAK SURFACE WAVE WILL MOVE IN FROM THE ATLANTIC
ON SATURDAY...INCREASING THE CHANCES OF SHOWERS AND THUNDERSTORMS A
BIT WITH AN SLIGHT INCREASE IN SURFACE CONVERGENCE...BUT WITH
RIDGING STILL IN PLACE ALOFT...LOW END CHANCE CATEGORY LOOKS LIKE
THE BEST FORECAST FOR NOW DUE TO LACKING SYNOPTIC SUPPORT. TEMPS
WILL AGAIN BE WITHIN A COUPLE OF DEGREES OF NORMAL FOR THE END OF
MAY.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
UPPER LEVEL RIDGING WILL EXTEND OVER THE REGION THROUGH MOST OF THE
LONG TERM PERIOD...ALTHOUGH AN UPPER LEVEL TROUGH WILL BEGIN TO
ENCROACH ON THE SOUTHEAST U.S. TOWARD THE MIDDLE OF NEXT WEEK. AT
THE SURFACE...ATLANTIC HIGH PRESSURE WILL GENERALLY PREVAIL INTO
EARLY NEXT WEEK. THERE IS THEN SOME INDICATION THAT HIGH PRESSURE
WILL TRY TO BUILD FROM THE NORTH TOWARD THE MIDDLE OF NEXT
WEEK...CAUSING A WEAK COASTAL TROUGH TO DEVELOP JUST OFFSHORE.
OVERALL...MOISTURE ADVECTION FROM A SYNOPTIC ONSHORE FLOW AND LOW
LEVEL CONVERGENCE WITH THE SEA BREEZE SHOULD SUPPORT ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS EACH DAY...WITH THE GREATEST
COVERAGE TUESDAY AND WEDNESDAY WITH THE NEARING UPPER TROUGH AND
DEVELOPMENT OF THE WEAK COASTAL TROUGH JUST OFFSHORE. TEMPERATURES
WILL BE NEAR TO SLIGHTLY ABOVE NORMAL THROUGH THE PERIOD.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
VFR IS EXPECTED TO PREVAIL.

EXTENDED AVIATION OUTLOOK...VFR CONDITIONS ARE EXPECTED TO PREVAIL
THURSDAY THROUGH THE PERIOD WITH ONLY A SMALL CHANCE OF LOWER
CIGS/VSBYS IN SHRA/TSRA THIS WEEKEND.

&&

.MARINE...
TONIGHT...AN EXTENSIVE SUB-TROPICAL RIDGE WILL MAINTAIN ITS GRIP
ON THE MARINE COMMUNITY...MAINTAINING EAST/SE WINDS AT LESS THAN
10 OR 12 KT AND SEAS OF NO MORE THAN 2 OR 3 FT. A FEW SHOWERS ARE
POSSIBLE OUT NEAR THE WARMER GULF STREAM WATERS...BUT THE RISK FOR
THUNDER/LIGHTNING IS CLOSE TO ZERO.

HIGH PRESSURE WILL CONTINUE OVER THE WATERS THROUGH EARLY
NEXT WEEK...GENERALLY MAINTAINING AN ONSHORE FLOW WITH SPEEDS OF
AROUND 15 KT OR LESS. DESPITE THE WEAK WIND SPEEDS...FAVORABLE
TRAJECTORIES WILL RESULT IN SEAS OF 2-4 FT ACROSS THE WATERS...WITH
SOME SEAS TO 5 FEET IN THE OUTER GEORGIA WATERS SATURDAY AS A WEAK
SURFACE TROUGH PASSES THROUGH THE WATERS.

&&

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

&&

$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...FWA
LONG TERM...JAQ
AVIATION...
MARINE...


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