000
FXUS62 KCHS 272330
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
730 PM EDT WED AUG 27 2008
.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL BUILD OVER THE REGION THROUGH THE
WEEKEND...WHILE A TROUGH OF LOW PRESSURE PERSISTS INLAND. A WEAK
BACK DOOR COLD FRONT IS EXPECTED TO DROP ACROSS THE AREA LATE SUNDAY
INTO MONDAY...WITH HIGH PRESSURE THEN EXPECTED TO BUILD IN FROM THE
NORTH INTO THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
EARLY WEDNESDAY EVENING...ISOLATED CONVECTION HAS DISSIPATED OVER
THE FORECAST AREA. DUE TO A SHORTWAVE PUSHING OFFSHORE AND LOW
LEVEL CONVERGENCE...ADDITIONAL ISOLATED SHOWERS/THUNDERSTORMS MAY
CONTINUE TO DEVELOP OVER THE COASTAL WATERS OVERNIGHT...THUS WILL
MAINTAIN SLIGHT CHANCE POPS THERE. OVER LAND...WILL REMOVE MENTION
OF PRECIPITATION...WITH POPS LESS THAN 15 PERCENT...AND WILL
ADDRESS ANY ISOLATED SHOWERS WITHIN SHORT TERM FORECASTS. LATER
TONIGHT...LOW LEVEL MOISTURE MAY SUPPORT AREAS OF STRATUS AND
PERHAPS PATCHY FOG IS POSSIBLE...ESPECIALLY TOWARD DAYBREAK...
THUS WILL MAINTAIN THE ONGOING PARTLY CLOUDY FORECAST. MINIMUM
TEMPERATURES SHOULD REACH THE LOWER 70S...EXCEPT MID 70S/AROUND 80F
CLOSE TO THE COAST.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
ATLANTIC HIGH PRESSURE WILL CONTINUE TO BUILD OVER THE REGION
THURSDAY...WHILE A LEE SIDE TROUGH PREVAILS INLAND. ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS SHOULD DEVELOP ALONG AND AHEAD
OF THE SEA BREEZE ON THURSDAY AFTERNOON...WITH THE GREATEST
COVERAGE OVER SOUTHEAST SOUTH CAROLINA AWAY FROM THE IMMEDIATE
COAST. ANOTHER WARM DAY IS EXPECTED...WITH SLIGHTLY ABOVE NORMAL
HIGH TEMPERATURES ONCE AGAIN. MAXIMUM TEMPERATURES SHOULD BE IN
THE LOWER 90S EVERYWHERE AWAY FROM THE BEACHES.
OUTSIDE OF ANY EARLY EVENING CONVECTION...DRY CONDITIONS ARE
EXPECTED THROUGH THE NIGHT. LOWS WILL BE IN THE LOWER 70S AWAY
FROM THE IMMEDIATE COAST.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
DECENT MODEL AGREEMENT THIS PERIOD LEADS TO HIGHER THAN NORMAL
CONFIDENCE. WEAK LOW PRESSURE INLAND FRI ALONG WITH UPPER
TROUGHING WILL HELP SPARK OFF A FEW SHOWERS/TSTMS...MAINLY IN THE
AFTN. HIGH PRESSURE THEN TRIES TO GET ESTABLISHED AT THE SURFACE
AND ALOFT OVER THE WEEKEND BUT CANNOT RULE OUT ADDITIONAL DIURNAL
PRECIPITATION. A WEAK BACKDOOR COLD FRONT IS THEN SLATED TO SLIDE
AT LEAST INTO OUR AREA...IF NOT ALL THE WAY THROUGH...EARLY NEXT
WEEK. THIS PATTERN WILL HELP BRING TEMPS/HUMIDITIES DOWN A BIT AND
LESSEN OUR RAIN CHANCES AND KEEP GUSTAV WELL SOUTH OF THE AREA.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
VFR CONDITIONS ARE EXPECTED UNTIL LATER TONIGHT. AFTER 06Z-08Z...
LOW LEVEL MOISTURE WILL SUPPORT A PERIOD OF IFR CEILINGS AND MVFR
OR LOWER VISIBILITIES IN FOG/MIST AT BOTH TERMINALS. THEN...CONDITIONS
WILL GRADUALLY IMPROVE THURSDAY MORNING...WITH VFR CONDITIONS
REDEVELOPING BY 16Z. ISOLATED SHOWERS/THUNDERSTORMS SHOULD THEN
DEVELOP ALONG THE SEA BREEZE DURING THE AFTERNOON...THUS INCLUDED
CBS AT BOTH TERMINALS STARTING AT 18Z-19Z.
EXTENDED AVIATION OUTLOOK...VFR CONDITIONS EXPECTED TO PREVAIL
OUTSIDE OF AFTERNOON CONVECTION AND POSSIBLE EARLY MORNING
STRATUS/FOG.
&&
.MARINE...
THE COMBINATION OF ATLANTIC HIGH PRESSURE AND A WEAK TROUGH OF LOW
PRESSURE INLAND WILL GENERALLY KEEP A SOUTHERLY FLOW IN PLACE
THROUGH THURSDAY NIGHT. AS TYPICAL IN THIS PATTERN...A NOCTURNAL
SURGE IS EXPECTED TO DEVELOP OVER THE COASTAL WATERS THIS EVENING
AND PERSIST INTO THE EARLY MORNING HOURS THURSDAY. WIND SPEEDS
COULD REACH 15-20 KT IN THE NORTHERN NEAR SHORE WATERS AND THE
OUTER GEORGIA WATERS...WITH SPEEDS UP TO ABOUT 15 KT IN CHARLESTON
HARBOR AND THE REMAINDER OF THE NEAR SHORE COASTAL WATERS. WINDS
WILL DIMINISH AND VEER TOWARD DAYBREAK...REMAINING FAIRLY LIGHT
THROUGH THURSDAY MORNING. THE SOUTHERLY FLOW WILL BECOME BETTER
ESTABLISHED THURSDAY AFTERNOON...ESPECIALLY NEAR SHORE AND IN
CHARLESTON HARBOR DUE TO THE INFLUENCE OF THE SEA BREEZE...WITH
MORE NOCTURNAL SURGING LATE THURSDAY INTO EARLY FRIDAY MORNING.
FRIDAY THROUGH MONDAY...NO SIGNIFICANT CHANGES WERE NEEDED TO THE
FORECAST FOR THIS PERIOD. WEAK HIGH PRESSURE WILL GIVE WAY TO A WEAK
BACKDOOR COLD FRONT WHICH IS EXPECTED TO PUSH THROUGH LATE SUN INTO
MON...AS HIGH PRESSURE SETS UP OVER THE ERN GREAT LAKES AND DOWN
THE E COAST. EXPECT S/SE WINDS TO BECOME NE/E SUN INTO MON. ALTHOUGH
THE TIGHTENING PRESSURE GRADIENT WILL CAUSE AN INCREASE IN WINDS
MON...DO NOT ANTICIPATE SMALL CRAFT ADVISORY CONDITIONS AT THIS
TIME.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
