Area Forecast Discussion
Issued by NWS Charleston, SC

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS62 KCHS 060510
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
110 AM EDT MON JUL 6 2015

.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL PREVAIL WITH AN INLAND TROUGH OF LOW
PRESSURE LINGERING THROUGH THE WEEK.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
MOSTLY DRY CONDITIONS TO PERSIST OVERNIGHT BUT SOME MODEL GUIDANCE
INDICATES ATLANTIC SHOWERS MAKING A RUN FOR THE CENTRAL SC COAST.
SOME FOG IS LIKELY WHERE HIGH CLOUDS THIN BUT DO NOT ANTICIPATE
IT TO BE WIDESPREAD AS MORE CLOUDS SPREAD NORTHWARD THROUGH
SOUTHEAST GEORGIA.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY/...
OVERVIEW: UPPER LEVEL LOW PRESSURE WILL WEAKEN AND EJECT OUT OF THE
TENNESSEE VALLEY EARLY TUESDAY. A POTENT MULTI-LAYER RIDGE WILL
BUILD WEST AND EXTEND ACROSS THE REGION THROUGH MID WEEK. THIS WILL
YIELD A RETURN TO A MORE STANDARD EARLY SUMMER CONVECTIVE REGIME
ACROSS SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA.

MONDAY: MONDAY LOOKS TO BE THE MOST ACTIVE DAY OF THE MID-RANGE
PERIOD AS UPPER LEVEL LOW PRESSURE WEAKENS AND EJECTS OUT OF THE
TENNESSEE VALLEY IN RESPONSE TO STRONG SHORTWAVE ENERGY PIVOTING
ACROSS THE WESTERN GREAT LAKES. MODELS SHOW A DEEP 500 HPA TROUGH
LINGERING ACROSS THE DEEP SOUTH IN THE WAKE OF THE DEPARTING LOW
AS A LARGE...UPPER RIDGE REMAINS POSITIONED OFFSHORE OF THE
SOUTHEAST U.S. COAST. THE COMBINATION OF SUFFICIENT LEVELS OF
MOISTURE... INSTABILITY AND LIFT WILL SUPPORT ANOTHER ROUND OF
MAINLY AFTERNOON AND EVENING SHOWERS/TSTMS. IN ADDITION...THERE
ARE SIGNALS THAT AN ENHANCED AREA OF UPPER DIFLUENCE COULD DEVELOP
OVER THE AREA DURING THE AFTERNOON AS THE RIGHT ENTRANCE REGION OF
A SUBTROPICAL JET STREAK MEANDERS EAST/NORTHEAST IN RESPONSE TO
THE EJECTION OF THE UPPER LOW. WILL HIGHLIGHT 50-60 PERCENT POPS.
FORECAST SOUNDINGS YIELD A BIT LESS IN THE WAY OF INSTABILITY
COMPARED TO THE PAST SEVERAL DAYS WITH SLIGHTLY LOWER MLCAPE AND
DCAPE...BUT LEVELS ARE STILL SUFFICIENT TO SUPPORT A FEW
STRONG/SEVERE TSTMS...MAINLY ALONG MESOSCALE BOUNDARY COLLISIONS.
CONVECTION WILL WANE DURING THE EVENING HOURS AS THE AXIS OF
STRONGEST LOW-LEVEL CONVERGENCE REDEVELOPS ALONG THE WESTERN WALL
OF THE GULF STREAM AFTER MIDNIGHT. HIGHS WILL TOP OUT IN THE LOWER
90S INLAND WITH LOWS RANGING FROM THE LOWER-MID 70S INLAND TO THE
UPPER 70S ALONG THE BEACHES AND DOWNTOWN CHARLESTON.

TUESDAY AND WEDNESDAY...MEAN RIDGING WILL BUILD WEST THROUGH THE
PERIOD WITH THE REGION REMAINING ALONG THE WESTERN FRINGE OF
ATLANTIC HIGH PRESSURE. SHOWERS AND TSTMS ARE POSSIBLE EACH
AFTERNOON AND EVENING...BUT COVERAGE WILL BE LIMITED BY WARMING
TEMPERATURES ALOFT AND SOME SYNOPTIC SUBSIDENCE ASSOCIATED WITH THE
UPPER RIDGE. INSTABILITY AND MOISTURE STILL LOOK PLENTIFUL...WHICH
SHOULD BE SUFFICIENT TO SUPPORT ISOLATED TO PERHAPS LOW-END
SCATTERED CONVECTION ALONG/AHEAD OF THE RESULTANT SEA BREEZE
CIRCULATION AS WELL AS A PERSISTENT PIEDMONT TROUGH. 20-30 PERCENT
POPS LOOK REASONABLE EACH AFTERNOON AND EVENING. HIGHS WILL WARM
INTO THE LOWER-MID 90S WITH LOWS RANGING FROM THE LOWER-MID 70S
INLAND WITH UPPER 70S AT THE BEACHES AND DOWNTOWN CHARLESTON.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
MEDIUM RANGE GUIDANCE IS IN FAIRLY GOOD AGREEMENT INDICATING HIGH
PRESSURE DOMINATING THROUGH AT LEAST FRIDAY...THEN THERE IS MORE
DISCREPANCY/FORECAST UNCERTAINTY REGARDING HOW QUICKLY THE RIDGE
BREAKS DOWN LATE WEEK AND OVER THE WEEKEND. EXPECT LOW SHOWER AND
THUNDERSTORM COVERAGE THROUGH THE PERIOD...MAINLY EACH
AFTERNOON/EVENING. TEMPERATURES WILL LIKELY BE A BIT WARMER THAN
NORMAL WITH HIGHS IN THE MID 90S AWAY FROM THE COAST AND LOWS IN THE
MID 70S INLAND AND MID TO UPPER 70S AT THE COAST. THE COMBINATION OF
SUCH TEMPS AND THE HUMIDITY LEVELS SHOULD RESULT IN HEAT INDEX
VALUES AT OR ABOVE 100 DEGREES.

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
MOSTLY VFR THROUGH 06Z TUE. CAN/T RULE OUT SOME MVFR/IFR CIGS
MAKING IT NORTHWARD TO KSAV BY DAYBREAK. ALSO SOME SHOWERS AND
TSTMS ARE FORECAST BY SEVERAL MODELS TO DEVELOP OVER THE ATLANTIC
AND AFFECT THE CENTRAL SC COAST NEAR KCHS THE REST OF THE
OVERNIGHT. CONFIDENCE THOUGH IN EITHER SITUATION IS TOO LOW TO
JUSTIFY MENTION IN THE TAFS ATTM. OTHERWISE...SHOWERS AND TSTMS
ARE EXPECTED TO DEVELOP THIS AFTERNOON AS THE SEA BREEZE KICKS IN
BUT COVERAGE SHOULD BE LESS THAN PREVIOUS DAYS AND STORMS SHOULD
NOT BE AS INTENSE GIVEN REDUCED INSTABILITY/SHEAR.

EXTENDED AVIATION OUTLOOK...BRIEF FLIGHT RESTRICTIONS ARE POSSIBLE IN
MAINLY AFTERNOON/EARLY EVENING SHOWERS AND THUNDERSTORMS.

&&

.MARINE...
OVERNIGHT...MAINLY SW WINDS 15 KT OR LESS WITH SEAS 2-3 FT.

MONDAY THROUGH FRIDAY...SOUTH TO SOUTHWEST WINDS WILL PREVAIL
THROUGH THE PERIOD AS THE REGION REMAINS ALONG THE WESTERN FRINGE
OF ATLANTIC HIGH PRESSURE CENTERED WELL OFFSHORE. WINDS WILL
GENERALLY AVERAGE 10-15 KT...POSSIBLY A BIT HIGHER AT NIGHT WITH
WEAK NOCTURNAL SURGING AND ALONG THE LAND/SEA INTERFACE WITH THE
AFTERNOON SEA BREEZE. SEAS WILL AVERAGE 2-4 FT. BOTH WINDS AND
SEAS LOOK TO REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS.

&&

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

&&

$$
SYNOPSIS...
NEAR TERM...RJB
SHORT TERM...ST
LONG TERM...RJB
AVIATION...RJB/ST
MARINE...SPR/ST


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.