779
FXUS62 KCHS 140013
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
813 PM EDT SAT SEP 13 2025
SYNOPSIS
HIGH PRESSURE WILL EXTEND ACROSS THE REGION INTO NEXT WEEK.
WEAK LOW PRESSURE COULD DEVELOP OFFSHORE BY MONDAY BEFORE
MOVING FARTHER OUT INTO THE ATLANTIC BY MID NEXT WEEK.
NEAR TERM /UNTIL 6 AM SUNDAY MORNING/
THIS EVENING: WE ACTUALLY SAW A FEW LATE AFTERNOON AND EARLY
EVENING SHOWERS DEVELOP WITHIN THE LOW-LEVEL NORTHEAST FLOW
ALONG THE BERKELEY AND CHARLESTON COUNTY LINE. THESE SHOWERS
HAVE NOW PASSED THROUGH THE CHARLESTON AREA AND ARE STEADILY
DISSIPATING. THE REST OF THE OVERNIGHT IS EXPECTED TO BE QUIET
WITH CONTINUED NORTHEAST FLOW ACROSS THE FORECAST AREA.
LOWS ARE EXPECTED TO BE ABOUT 5 DEGREES BELOW NORMAL WITH UPPER
50S AND LOW 60S INLAND, RANGING TO MID TO UPPER 60S ALONG THE
COAST.
SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/
A SHARP UPPER-LEVEL TROUGH POSITIONED ALONG THE SOUTHEAST U.S.
COAST IS EXPECTED TO EVOLVE INTO A CLOSED UPPER-LEVEL LOW BY
MONDAY. AS THE LOW BECOMES MORE DEFINED, THERE IS POTENTIAL FOR
SURFACE CYCLOGENESIS TO DEVELOP A WEAK NON-TROPICAL LOW OFF THE
SOUTH CAROLINA COAST, NEAR AN EXISTING COASTAL TROUGH. HOWEVER,
THE EXACT LOCATION AND INTENSITY OF THIS SURFACE LOW REMAIN
HIGHLY UNCERTAIN. AT THE SURFACE, A WEDGE OF STRENGTHENING HIGH
PRESSURE WILL REMAIN IN PLACE ACROSS THE INTERIOR, KEEPING THE
BEST CHANCES FOR MEASURABLE RAINFALL WELL OFFSHORE.
MOSTLY SUNNY SKIES WITH A FEW CLOUDS CAN BE EXPECTED SUNDAY,
THOUGH A STRAY, LOW-TOPPED SHOWER CANNOT BE ENTIRELY RULED OUT
ALONG THE EXTREME SOUTHEAST GEORGIA COAST. OTHERWISE, DRY
CONDITIONS WILL DOMINATE ACROSS THE FORECAST AREA. MONDAY AND
TUESDAY, THE OVERALL FORECAST REMAINS LARGELY DEPENDENT ON THE
EVOLUTION OF ANY OFFSHORE SURFACE LOW. ALTHOUGH, A BRIEF
INCREASE IN MID AND UPPER-LEVEL MOISTURE WILL BRING SLIGHT RAIN
CHANCES TO THE SOUTH CAROLINA COAST ON MONDAY. EVEN SO, MOSTLY
SUNNY SKIES WITH JUST OCCASIONAL CLOUD COVER ARE EXPECTED TO
CONTINUE ACROSS MUCH OF THE AREA. POPS RANGE FROM 20-30% EAST OF
I-95 MONDAY, MAINLY ACROSS THE CHARLESTON TRI- COUNTY. TUESDAY
CURRENTLY APPEARS DRY, WITH NO MENTIONABLE RAIN CHANCES AND
CONTINUED MOSTLY SUNNY CONDITIONS.
TEMPERATURES WILL REMAIN SEASONABLE THROUGH TUESDAY, WITH HIGHS
IN THE LOW TO MID 80S ACROSS MOST LOCATIONS, AND SOME UPPER 80S
POSSIBLE ACROSS INTERIOR SOUTHEAST GEORGIA. OVERNIGHT LOWS WILL
DIP INTO THE LOW TO MID 60S INLAND, WITH UPPER 60S CLOSER TO
THE COAST.
LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/
MOSTLY QUIET CONDITIONS WILL PERSIST THROUGH THE REST OF THE
UPCOMING WEEK AS THE UPPER LOW ACROSS THE CAROLINAS GRADUALLY
WEAKENS AND EJECTS OUT TO THE NORTHEAST WEDNESDAY. THE INLAND
HIGH PRESSURE WEDGE IS FORECAST TO STRENGTHEN AS RIDGING BUILDS
IN BEHIND THE DEPARTING UPPER LOW. ANY MEANINGFUL CHANCE FOR
MEASURABLE RAINFALL WILL GENERALLY REMAIN CONFINED WELL
OFFSHORE. TEMPERATURES WILL WARM EVER SO SLIGHTLY THROUGH THE
PERIOD, PEAKING IN THE UPPER 80S/LOWER 90S THURSDAY AND FRIDAY.
AVIATION /00Z SUNDAY THROUGH THURSDAY/
THE 00Z TAF PERIOD BEGINS WITH VFR CONDITIONS AT KCHS, KJZI, AND
KSAV. A FEW SHOWERS RECENTLY PASSED NEAR KCHS AND KJZI, BUT NO
ADDITIONAL SHOWERS ARE EXPECTED. NORTH-NORTHEAST TO NORTHEAST
WINDS WILL AGAIN BE BREEZY ON SUNDAY. VFR CONDITIONS SHOULD
PREVAIL THROUGH 00Z MONDAY.
EXTENDED AVIATION FORECAST: THERE ARE NO HIGH CONFIDENCE
CONCERNS.
MARINE
TONIGHT: THE PRESSURE GRADIENT BETWEEN AN INLAND SFC RIDGE AND
A TROUGH OVER THE GULF STREAM WILL SUPPORT GUSTY NE WINDS ACROSS
THE ATLANTIC WATERS TONIGHT. THIS PATTERN SHOULD GENERALLY
YIELD NORTHEAST WINDS BETWEEN 15 TO 20 KTS WITH GUSTS TO 25 KTS
ACROSS THE ATLANTIC WATERS. THE CHARLESTON HARBOR SHOULD SEE
NORTHEAST WINDS BETWEEN 10 TO 15 KTS, WITH GUSTS TO 20 KTS
THROUGH EARLY THIS EVENING. SEAS THIS EVENING BETWEEN 5 TO 8 FT
MAY DECREASE TO 4 TO 7 FT LATE TONIGHT. SMALL CRAFT ADVISORIES
WILL REMAIN IN EFFECT FOR ALL ATLANTIC WATERS TONIGHT.
SUNDAY THROUGH THURSDAY: PINCHED GRADIENT CONDITIONS BETWEEN
INLAND HIGH PRESSURE AND A COASTAL TROUGH OFFSHORE LOOK TO HOLD
THROUGH MUCH OF THE WEEK. WEAK LOW PRESSURE COULD DEVELOP
OFFSHORE LATE SUNDAY OR MONDAY, BUT ITS STRENGTH AND TRACK ARE
UNCERTAIN. ANY LOW THAT FORMS COULD HAVE A LOCAL IMPACT, BUT TO
WHAT DEGREE REMAINS UNKNOWN. FOR NOW, NORTHEAST WINDS WILL
REMAIN AROUND THE THRESHOLD FOR SMALL CRAFT ADVISORY CONDITIONS
(25 KT) FOR ALL MARINE ZONES EXCEPT THE CHARLESTON HARBOR SUNDAY
INTO MONDAY. ADDITIONALLY, 6+ FT SEAS WILL PERSIST INTO MONDAY
WHERE SMALL CRAFT ADVISORIES CONTINUE, GRADUALLY DROPPING MONDAY
INTO MONDAY NIGHT. BY MID-WEEK CONDITIONS SHOULD IMPROVE AS
GENERAL MODEL CONSENSUS SHOWS THE WEAK SURFACE LOW LIFTING
NORTH/NORTHEASTWARD, AWAY FROM THE AREA.
RIP CURRENTS: GUSTY NORTHEAST WINDS SUNDAY WILL PERSIST WITHIN
PINCHED GRADIENT CONDITIONS. THIS COUPLED WITH 4-5 FT SWELLS
WITH AN 8 SECOND PERIOD WILL KEEP A CONTINUED HIGH RISK FOR RIP
CURRENTS ALONG THE GEORGIA BEACHES AND A MODERATE RISK FOR THE
SOUTH CAROLINA BEACHES. HEADED INTO MONDAY, NORTHEAST WINDS WILL
BE SLIGHTLY ELEVATED, AND LINGERING SWELL WILL CONTINUE A
MODERATE RISK FOR RIP CURRENTS AT ALL AREA BEACHES.
TIDES/COASTAL FLOODING
TIDE LEVELS WILL REMAIN ELEVATED THROUGH THE MIDDLE OF NEXT WEEK
DUE TO LARGE TIDAL DEPARTURES RESULTING FROM A PINCHED PRESSURE
GRADIENT WITH PERSISTENT NORTHEAST WINDS. THE POTENTIAL FOR
COASTAL FLOODING WILL EXTEND INTO MONDAY WITH THE EARLY
AFTERNOON HIGH TIDE CYCLE, ESPECIALLY FOR COASTAL PORTIONS OF
CHARLESTON AND COLLETON COUNTIES.
CHS WATCHES/WARNINGS/ADVISORIES
GA...HIGH RISK FOR RIP CURRENTS THROUGH SUNDAY EVENING FOR GAZ117-119-
139-141.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT MONDAY FOR AMZ350-352.
SMALL CRAFT ADVISORY UNTIL 2 AM EDT MONDAY FOR AMZ354.
SMALL CRAFT ADVISORY UNTIL 8 PM EDT TUESDAY FOR AMZ374.
NEAR TERM...BSH
SHORT TERM...BRS
LONG TERM...BRS
AVIATION...BRS/BSH
MARINE...BRS/NED
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