AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
918 PM EDT FRI JUL 8 2011

.SYNOPSIS...
DEEPER MOISTURE WILL GRADUALLY INCREASE OVER THE REGION THROUGH
TONIGHT AS WEAK LOW PRESSURE ALONG THE GULF COAST PERSISTS. A WEAK
FRONT WILL MOVE INTO THE AREA LATE IN THE WEEKEND BEFORE DISSIPATING.
BERMUDA RIDGE WILL DOMINATE THE WEATHER ACROSS THE AREA EARLY NEXT
WEEK. ANOTHER FRONT WILL APPROACH FROM THE NORTH BY THE MIDDLE OF
NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
MOST OF THE SHOWER/TSTM ACTIVITY HAS DISSIPATED. RADAR SHOWS A
PSEUDO-ORGANIZED LINE OF TSTMS DEVELOPING FROM THE UPSTATE THROUGH
THE WESTERN MIDLANDS INTO PARTS OF CENTRAL GEORGIA. THIS LINE
SHOULD SLOWLY WEAKEN OVER THE NEXT FEW HOURS AS IT MOVES EAST INTO
AN AIRMASS THAT HAS BEEN OVERTURNED BY EARLIER TSTMS. STILL...THE
TAIL END COULD BRUSH AREAS FROM ALLENDALE UP THROUGH BERKELEY
COUNTY THROUGH MIDNIGHT.

ANOTHER SLUG OF TROPICAL MOISTURE IS FORECAST TO MOVE UP THE COAST
TONIGHT AS A 925-850MB LOW-LEVEL JET INTENSIFIES. THE MOST INTENSE
MOISTURE TRANSPORT LOOKS TO BECOME FOCUSED ALONG THE MIDDLE AND
UPPER SOUTH CAROLINA COASTS AFTER MIDNIGHT...WHICH INCLUDES MUCH
OF THE CHARLESTON TRI-COUNTY AREA. GIVEN THE TROPICAL AIRMASS THAT
IS IN PLACE...A SHOWER COULD POP JUST ABOUT ANYWHERE OVERNIGHT.
WILL MAINTAIN 20-30 PERCENT POPS ACROSS THE INTERIOR FOR THE NEXT
FEW HOURS...THEN SHOW 20 PERCENT POPS INLAND OVERNIGHT WITH 30-50
PERCENT POPS CENTERED ALONG THE COAST WITH THE HIGHEST VALUES
CLUSTERED ACROSS CHARLESTON COUNTY.

IT WILL REMAIN WARM AND MUGGY TONIGHT WITH LOWS RANGING FROM THE
MID 70S INLAND TO THE UPPER 70S AT THE COAST.

FIRE OFFICIALS...SPOTTER REPORTS AND AUTOMATED WEATHER SENSORS
INDICATE SMOKE CONTINUES TO PLAGUE PARTS OF INTERIOR SOUTHEAST
GEORGIA THIS EVENING. HYSPLIT OUTPUT FROM BOTH THE TERRELL MILL
POND WILDFIRE NEAR HINESVILLE AND THE VARIOUS WILDFIRES BURNING IN
THE OKEFENOKEE INDICATES SMOKE WILL REMAIN AN ISSUE TONIGHT. SINCE
THE ATMOSPHERE WILL REMAIN FAIRLY MIXED DUE TO ISOLATED-SCATTERED
CONVECTION AND AN INTENSIFYING LOW-LEVEL JET...WE DO NOT
ANTICIPATE THE FORMATION OF DENSE SMOKE PLUMES. HAVE ISSUED A
SPECIAL WEATHER STATEMENT FOR MUCH OF INTERIOR SOUTHEAST GEORGIA
THROUGH 8 AM SATURDAY TO ADDRESS THE SMOKE SITUATION. WILL ALSO
INCLUDE PATCHY SMOKE IN THE GRIDS AND TEXT PRODUCTS WITH AREAS OF
SMOKE NEAR AND JUST DOWNWIND OF THE TERRELL MILL POND WILDFIRE.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
UPPER TROUGH ALONG THE EAST COAST AT START OF THE PERIOD WILL LIFT
NORTHEAST AT START OF THE PERIOD. BERMUDA RIDGE AND LARGE RIDGE
ACROSS THE SOUTHERN PLAINS WILL COMBINE...WITH A LARGE RIDGE OF HIGH
PRESSURE COVERING THE SOUTHERN TWO-THIRDS OF THE NATION DURING THE
LATER HALF OF THE WEEKEND AND THROUGH EARLY NEXT WEEK. A WEAK
FRONTAL BOUNDARY AT THE SURFACE WILL STRUGGLE TO PUSH SOUTHWARD AS
UPPER TROUGH LIFTS OUT. AT THIS TIME...WILL BRING DIFFUSE FRONT INTO
FORECAST AREA SUN MORNING AND THEN DISSIPATE IT THROUGH THE DAY.

PRECIPITABLE WATER VALUES ON SAT WILL STILL BE VERY HIGH AND ON THE
ORDER OF TWO AND A THIRD INCHES. ALTHOUGH SIGNIFICANT CLOUD COVER IS
EXPECTED...THERE WILL BE ENOUGH HEATING TO INCREASE CAPE VALUES
ABOVE 2000 J/KG. DEEP MOISTURE WILL REMAIN IN PLACE...ESPECIALLY
ALONG THE COAST. WILL CARRY LIKELY POPS DURING SAT. DUE TO THE HIGH
MOISTURE CONTENT...ANY CONVECTION WILL HAVE THE CAPABILITY FOR HEAVY
DOWNPOURS. DEWPOINTS IN THE MID TO PERHAPS UPPER 70S WILL COMBINE
WITH TEMPS IN THE LOWER 90S TO PRODUCE HEAT INDICES ABOVE 100
DEG...BUT MOST LOCATIONS SHOULD REMAIN JUST BELOW HEAT ADVISORY
CRITERIA.

SUNDAY SHOULD BE A TRANSITION DAY AS COLUMN BEGINS TO DRY OUT FROM
THE TOP DOWN. WEAK FRONT WILL BE IN THE PROCESS OF DISSOLVING AND
SINCE SUBSIDENCE WILL NOT HAVE A FIRM GRIP ON THE AREA...WILL DROP
POPS AS CONVECTION SHOULD BE MORE SCATTERED WITH THE HIGHEST POPS ON
SUN EXPECTED ALONG AND INLAND FROM THE SEABREEZE. BUILDING RIDGE AND
INFLUX OF DRIER AIR WILL YIELD MORE HEAT THAN ON SAT. MAXIMUMS
MAINLY IN THE MID 90S WILL COMBINE WITH HIGH DEWPOINTS TO PUSH THE
HEAT INDEX TO NEAR ADVISORY CRITERIA...ESPECIALLY AWAY FROM THE
IMMEDIATE COAST.

MUCH DRIER AIR SHOULD BE IN PLACE ON MON WITH PRECIPITABLE WATER
VALUES DROPPING TO LESS THAN ONE AND A HALF INCHES. SUBSIDENCE WILL
BE STRONGER ON MON THAN OVER THE WEEKEND. AS CAPPING INVERSION
ERODES WITH STRONG HEATING THROUGH THE AFTERNOON...WILL CARRY SLIGHT
CHANCE TO LOW CHANCE FOR AFTERNOON AND EARLY EVE SHOWERS AND
THUNDERSTORMS...WITH SLIGHTLY HIGHER POPS INLAND AND ALONG THE
SEABREEZE. MONDAY WILL LIKELY BE THE MOST UNCOMFORTABLE DAY OF THE
PERIOD. HIGHS IN THE MID 90S TO UPPER 90S INLAND WILL RESULT IN HEAT
INDICES ABOVE 105 DEGREES ACROSS MOST OF THE AREA.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
TUESDAY LOOKS QUITE SIMILAR TO MONDAY AS WIDELY SCATTERED
AFTERNOON AND EVENING CONVECTION IS EXPECTED...BUT LOTS OF
SUNSHINE WILL ALLOW TEMPS TO RISE WELL INTO THE 90S AWAY FROM THE
COAST WITH HEAT INDICES INTO THE MID 100S.

THE SECOND HALF OF THE WEEK IS MORE COMPLICATED. GFS HAS SHIFTED
SIGNIFICANTLY FROM ITS SOLUTION 24 HOURS. NOW..INSTEAD OF HOLDING UP
THE NEXT COLD FRONT NORTH OF THE AREA...IT PLOWS IT THROUGH MID WEEK
AND BRINGS IN A SIGNIFICANTLY DRIER AIR MASS FOR THURSDAY AND
FRIDAY. I HAVE ONLY NUDGED THE FORECAST SLIGHTLY IN THAT DIRECTION
DUE TO THE LACK OF CONTINUITY...PLUS THE FACT THAT YESTERDAYS ECMWF
HAS BACKED OF ITS FRONTAL PASSAGE BY A DAY.

&&

.AVIATION /01Z SATURDAY THROUGH WEDNESDAY/...
KCHS...SHOWER ACTIVITY TO THE WEST OF KCHS IS DIMINISHING AND
SHOULD NOT POSE A DIRECT IMPACT TO THE TERMINAL. VFR CONDITIONS
WILL PREVAIL FOR THE NEXT SEVERAL HOURS ALTHOUGH VARIOUS MULTI-
LAYERED CLOUD DECKS WILL REMAIN IN PLACE. IT LOOKS LIKE ANOTHER
SURGE OF MOISTURE WILL IN FROM OFF THE ATLANTIC OVERNIGHT WITH A
GOOD CHANCE FOR SEEING ANOTHER ROUND OF MVFR AND POSSIBLY IFR CIGS
FROM TIME-TO-TIME. BEST TIME PERIOD FOR THIS TO OCCUR IS BETWEEN
07-10Z...BUT THIS MAY NEED TO BE ADJUSTED AS THE EVENING/NIGHT
PROGRESSES. SHOWERS MAY ALSO AFFECT THE TERMINAL DURING THAT
TIME...BUT HIGH RESOLUTION GUIDANCE INDICATES THE BULK OF THIS
WILL PASS TO THE EAST. SHOWER/TSTMS ARE LIKELY AGAIN FOR SATURDAY
SO A MENTION OF CB/S WILL BE MAINTAINED.


KSAV...VFR CONDITIONS WILL PREVAIL FOR MUCH OF THE NIGHT WITH THE
BETTER CHANCE FOR MVFR CIGS REMAINING EAST AND NORTH OF THE
TERMINAL. ANOTHER ROUND OF NOCTURNAL SHOWERS/TSTMS APPEAR LIKELY
WITH THE BULK OF THE ACTIVITY REMAINING OVER THE ATLANTIC AND WELL
TO THE EAST OF THE KSAV AIR SPACE. SHOWERS/TSTMS ARE LIKELY AGAIN
SATURDAY SO A MENTION OF CB/S WILL BE MAINTAINED. THE LATEST
HYSPLIT RUNS TAKES ANY SMOKE ASSOCIATED WITH WILDFIRES WELL TO
THE WEST OF THE TERMINAL.

EXTENDED AVIATION OUTLOOK...AS IS USUALLY THE CASE IN MID
SUMMER...THE BEST CHANCE FOR MVFR/IFR CIGS/VSBYS IS WITH THE
CHANCES OF AFTERNOON AND EVENING CONVECTION NEAR THE TERMINALS.
ALSO...WITH WINDS EXPECTED TO GET VERY LIGHT ON MONDAY AND TUESDAY
MORNINGS...THERE COULD BE A COUPLE OF HOURS OF BR AROUND SUNRISE
EACH DAY.

&&

.MARINE...
MODEL TRENDS...BUOY REPORTS AND OBSERVATIONS FROM THE VARIOUS PILOT
BOATS INDICATE BOTH WINDS AND SEAS HAVE LIKELY TRANSITIONED TO
SMALL CRAFT ADVISORY THRESHOLDS OVER BOTH THE GEORGIA OFFSHORE
WATERS AND THE COASTAL WATERS OFF CHARLESTON COUNTY. RECENTLY
HOISTED FLAGS FOR THE CHARLESTON COUNTY WATERS WHICH JOINS FLAGS
THAT WERE ISSUED EARLIER TODAY FOR THE GEORGIA OFFSHORE LEG.
CONDITIONS LOOK TO DROP BELOW ADVISORY THRESHOLDS BY 6 AM
SATURDAY...BUT IT WILL BE CLOSE. THE MIDNIGHT SHIFT MAY NEED TO
EXTEND THE EXPIRATION TIME INTO MID-LATE MORNING SATURDAY.

WINDS WILL BE FROM THE SW SAT AND SAT EVE AND STRONGEST WINDS ARE
EXPECTED THROUGH SAT MORNING. HOWEVER...AS NOCTURNAL JET
DISSIPATES...SW WINDS ACROSS THE WATERS WILL BE DIMINISHING. WILL
CONTINUE SCA FOR OUTER GEORGIA WATERS THROUGH ABOUT MIDDAY ON SAT
FOR LINGERING 6 FT SEAS AND WIND GUSTS TO 25 KT. ELSEWHERE...WILL
CAP WINDS AT 15 KT WITH GUSTS TO 20 KT AND SEAS AT 3 TO 5 FT. SW
WINDS WILL CONTINUE TO SLOWLY DIMINISH SAT NIGHT AND BY SUN MORNING
SHOULD BE LESS THAN 10 KT THROUGHOUT. THE WIND DIRECTION MAY BECOME
LIGHT AND VARIABLE FOR A TIME...ESPECIALLY ACROSS THE NORTHERN
WATERS DUE TO THE PROXIMITY OF A WEAK FRONT ON SUN.

GRADIENT WILL BE PRETTY SLACK MONDAY THROUGH WEDNESDAY WITH LIGHT
WINDS GENERALLY OUT OF THE SOUTH AND SOUTHWEST...TURNING ONSHORE
NEAR THE COAST IN THE AFTERNOON AND EVENING. WINDS MAY PICK UP
SOME AGAIN ON WEDNESDAY AHEAD OF THE NEXT FRONT.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT SATURDAY FOR AMZ350-374.

&&

$$