Area Forecast Discussion
Issued by NWS Charleston, SC

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000
FXUS62 KCHS 040545
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
145 AM EDT TUE AUG 4 2015

.SYNOPSIS...
A WEAK AREA OF LOW PRESSURE WILL MOVE NORTHEAST UP THE COAST
OVERNIGHT BEFORE MOVING AWAY FROM THE FORECAST AREA ON TUESDAY. HIGH
PRESSURE WILL BRIEFLY BUILD IN FROM THE NORTHWEST INTO WEDNESDAY.
AN INLAND TROUGH OF LOW PRESSURE WILL DEVELOP BY THURSDAY AND A
COLD FRONT WILL APPROACH THE AREA FRIDAY INTO SATURDAY.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
04/04Z SATELLITE...RADAR AND SURFACE ANALYSIS PLACED THE SURFACE
LOW PRESSURE OVER NEAR THE SAVANNAH RIVER ENTRANCE. THE LOW
REMAINS EMBEDDED WITHIN A BROAD SURFACE TROUGH WHICH CURVES
NORTHWEST THROUGH INTERIOR SOUTHEAST GEORGIA INTO THE SOUTHERN
SOUTH CAROLINA MIDLANDS AND SOUTHWEST INTO NORTH-CENTRAL FLORDIA.
THE LOW IS FORECAST TO MEANDER NORTHEAST ALONG THE GEORGIA AND
LOWER SOUTH CAROLINA COAST TONIGHT...BECOMING SITUATED VERY NEAR
OR JUST NORTHEAST OF THE CHARLESTON AREA BY SUNRISE.

STEADY AND OCCASIONALLY HEAVY RAINS WERE PILING UP ALONG THE
CENTRAL SOUTH CAROLINA COAST IN LOW LEVEL CYCLONIC FLOW. PWATS
ARE IN EXCESS OF 2.4 INCHES HUGGING THE COAST AND OCCASIONAL
DOWNPOURS ARE EXPECTED ALONG COASTAL AREAS OF CHARLESTON COUNTY
THROUGH AT LEAST 4 AM. LOCALIZED FLOODING IS POSSIBLE BUT THE
GOOD NEWS IS THAT THE TIDE CONTINUES TO GO OUT.

THERE ARE SIGNALS IN THE VARIOUS HIGH RESOLUTION GUIDANCE THAT
FOG/STRATUS MAY BECOME AN ISSUE ACROSS FAR INTERIOR SOUTHEAST
GEORGIA LATE TONIGHT AS WINDS DIMINISH AND SKIES CLEAR. 1000MB
CONDENSATION PRESSURE DEFICIT PROGS SUPPORT FAVORABLE FOG FORMATION
AS SKIES CLEAR FROM THE WEST...SOME OF WHICH COULD BECOME LOCALLY
DENSE WITH VSBYS 1/4 MILE OR LESS. WILL INCLUDE AREAS OF FOG ACROSS
MUCH OF INTERIOR SOUTHEAST GEORGIA.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY/...
TUESDAY AND TUESDAY NIGHT...SHORTWAVE ENERGY ALOFT WILL PULL AWAY
FROM THE AREA TO THE NORTHEAST AS THE REGION REMAINS ON THE SOUTHERN
PERIPHERY OF THE LONGWAVE TROUGH THAT ENCOMPASSES MUCH OF EASTERN
CANADA AND THE NORTHEASTERN CONUS. AT THE SURFACE...THE SLOWLY
MEANDERING WEAK AREA OF LOW PRESSURE WILL MOVE ALONG THE FORECAST
AREA COASTLINE AND EVENTUALLY BECOME AN OPEN WAVE AND LIFT OUT TO
THE NORTHEAST. IN THE MORNING...IT APPEARS THE EASTERN REACHES OF
THE FORECAST AREA WILL STILL BE DEALING WITH THE DEEP ATLANTIC
MOISTURE FEED AND CORRESPONDING SHOWER ACTIVITY. HAVE INCREASED POPS
ACROSS EASTERN PORTIONS OF CHARLESTON AND BERKELEY COUNTIES TO 40-
50. THE REST OF THE DAY...DRIER AIR WILL WORK ITS WAY INTO THE AREA
AND RAIN CHANCES WILL BE QUITE MINIMAL. OVERNIGHT...THE FORECAST IS
DRY AS HIGH PRESSURE BRIEFLY BUILDS IN. HIGHS WILL BE IN THE LOW 90S
EAST...RANGING TO THE MID/UPPER 90S FOR INTERIOR SOUTHEAST GEORGIA.
LOWS WILL FALL INTO THE MID/UPPER 70S.

WEDNESDAY THROUGH THURSDAY...WEDNESDAY LOOKS LIKE THE MOST BENIGN
DAY WITH LIMITED CONVECTIVE POTENTIAL WITH JUST A WEAK LEE TROUGH.
DRIER LOW LEVELS WILL HELP RESULT IN VERY LITTLE SURFACE BASED
INSTABILITY. JUST A SLIGHT CHANCE POP IS IN PLACE FOR DIURNAL
CONVECTION. BY THURSDAY...MOISTURE IS A BIT BETTER AND THE INLAND
TROUGH BECOMES BETTER DEFINED AS A WELL DEFINED SHORTWAVE ALOFT
APPROACHES FROM THE WEST. DIURNAL CONVECTION CHANCES WILL BE
BETTER...WITH 30 POPS IN PLACE FOR LAND AREAS. THE WARMEST DAY WILL
BE WEDNESDAY WITH HIGHS IN THE MID/UPPER 90S...AND LOW/MID 90S ON
THURSDAY.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
A PERSISTENT UPPER TROUGH THURSDAY NIGHT THROUGH SATURDAY WILL
MAINTAIN AN INLAND SURFACE TROUGH AND ABUNDANT LOW LEVEL MOISTURE
ACROSS THE FORECAST AREA. GREATER COVERAGE OF SHOWERS AND TSTMS
EXPECTED THROUGH SATURDAY. THE UPPER RIDGE MAY ATTEMPT TO REBUILD
SUNDAY INTO MONDAY WHICH COULD DECREASE CONVECTIVE COVERAGE SOMEWHAT.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
KCHS...RAINS SHOULD IMPACT THE TERMINAL THROUGH AT LEAST 08Z.
BRIEF MVFR CIGS AND MVFR/IFR VSBYS POSSIBLE IN HEAVIER RAINFALL.
AFTER THE LOW PASSES LATER THIS MORNING...LOWER CLOUDS WILL
LIFT TO VFR BUT THERE IS STILL A CHANCE FOR SHOWERS AND TSTMS
INTO THIS AFTERNOON.

KSAV...LOWER CLOUDS WERE DEVELOPING ON LATEST SATELLITE IMAGERY
AND MVFR/IFR CIGS ARE A GOOD BET OVERNIGHT INTO MID MORNING.
VFR WILL PREVAIL AFTER MORNING LOW CLOUDS LIFT WITH LESSER
CHANCES FOR AFTERNOON SHOWERS AND TSTMS.

EXTENDED AVIATION OUTLOOK...MAIN CONCERNS ARE OCCASIONAL REDUCTIONS
IN VISIBILITY AND/OR CEILING DUE TO SHOWERS AND TSTMS. ALTHOUGH
IMPACTS CANNOT BE RULED OUT ANY DAY...GREATER COVERAGE IS EXPECTED
THURSDAY AND FRIDAY.

&&

.MARINE...
OVERNIGHT...A SMALL CRAFT ADVISORY WILL REMAIN IN EFFECT THROUGH
TONIGHT FOR THE OFFSHORE GA WATERS AS LOW PRESSURE MOVES UP THE
SOUTHEAST COAST. SEAS IN THE 4-6 FT RANGE AND GUSTS OVER 25
KTS...ESPECIALLY SEAWARD OF THE GREYS REEF BUOY WHERE THE
NOCTURNAL JET WILL BE THE HIGHEST...CAN BE EXPECTED IN THIS AREA.
SHOWERS AND THUNDERSTORMS WITH HEAVY DOWNPOURS ARE POSSIBLE
THROUGHOUT THE EVENING AND INTO THE LATE NIGHT HOURS...ESPECIALLY
FOR AMZ350.

TUESDAY THROUGH SATURDAY...SOUTHWEST WINDS WILL PREVAIL ACROSS THE
LOCAL WATERS INTO THE WEEKEND. THERE WILL BE PERIODS OF ENHANCED
FLOW...PRIMARILY WITH NOCTURNAL SURGES AND THE AFTERNOON SEA BREEZE
ALONG THE LAND/SEA INTERFACE. THE SMALL CRAFT ADVISORY FOR THE OUTER
GEORGIA WATERS WILL COME DOWN TUESDAY MORNING AS SEAS SUBSIDE TO
LESS THAN 6 FT. OTHERWISE...WINDS WILL GENERALLY TOP OUT IN THE 15-
20 KT RANGE DURING THE PERIODS OF SURGING. SEAS WILL BE HIGHEST
THROUGH TUESDAY NIGHT...UP TO 5 FT AROUND 20 NM AND BEYOND. FROM
WEDNESDAY ONWARD SEAS WILL BE IN THE 2-3 FT RANGE FOR THE NEARSHORE
WATERS AND THE 3-4 FT RANGE FOR THE OUTER WATERS.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 AM EDT THIS MORNING FOR AMZ374.

&&

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


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