560
FXUS62 KCHS 141815
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
215 PM EDT SUN SEP 14 2025
SYNOPSIS
HIGH PRESSURE WILL EXTEND ACROSS THE REGION THIS WEEK. LOW
PRESSURE WELL OFFSHORE WILL BEGIN TO SLOWLY DRIFT TOWARD THE
NORTH CAROLINA OUTER BANKS TONIGHT AND MEANDER THROUGH THE
MIDDLE OF THE WEEK. A COLD FRONT COULD THEN APPROACH THE AREA
FROM THE NORTH NEXT WEEKEND.
NEAR TERM /THROUGH TONIGHT/
THE REGION REMAIN BETWEEN A SURFACE COASTAL LOW TO OUR EAST AND A
BUILDING SURFACE HIGH PRESSURE TO OUR NORTH, KEEPING CONDITIONS DRY
WITH MAX TEMPERATURES TODAY IN THE UPPER 70S TO MID 80S. IN REGARDS
TO THE DRY FORECAST, THIS MORNINGS 12Z SOUNDING REVEALED A PWAT
READING OF 0.78", JUST BELOW THE 10TH PERCENTILE OF OBSERVED
CLIMATOLOGY FOR THE DATE, MAKING IT DIFFICULT TO PRODUCE RAINFALL.
WINDS ARE THE BIGGEST IMPACT GIVEN THE INCREASED SURFACE PRESSURE
GRADIENT BETWEEN THE AFOREMENTIONED SURFACE LOW AND SURFACE HIGH,
WITH BREEZY NORTH-NORTHEAST WINDS CONTINUING THROUGHOUT THE
AFTERNOON. STRONGEST WINDS ARE OCCURRING ALONG THE COAST WITH
GUSTS INTO THE 20S, WHEREAS AREAS FURTHER INLAND ARE ONLY
GUSTING INTO THE TEENS IF AT ALL. EXPECT A QUIET NIGHT TONIGHT
AS WE DECOUPLE FROM THE BOUNDARY LAYER WITH ONLY A LIGHT BREEZE,
AND OVERNIGHT TEMPERATURES IN THE LOWER TO UPPER 60S, WARMEST
ALONG THE COAST.
SHORT TERM /MONDAY THROUGH WEDNESDAY/
THE UPPER LEVELS FEATURE A REX BLOCK PATTERN WITH THE UPPER LOW
MEANDERING OVER THE CAROLINAS AND THE UPPER HIGH REMAINING QUASI-
STATIONARY OVER THE GREAT LAKES. AT THE SURFACE, A WEDGE OF HIGH
PRESSURE WILL REMAIN IN PLACE ACROSS THE INTERIOR, WHILE AN OFFSHORE
LOW SLOWLY DRIFTS NORTH TOWARD THE NC OUTER BANKS. THIS WILL KEEP
THE BEST CHANCES FOR MEASURABLE RAINFALL WELL OFFSHORE. A BRIEF
INCREASE IN MID AND UPPER-LEVEL MOISTURE WILL BRING SLIGHT RAIN
CHANCES TO THE CHARLESTON TRI-COUNTY MONDAY AFTERNOON. POPS RANGE
FROM 10-20% FOR CHARLESTON, BERKELEY, AND DORCHESTER COUNTIES.
OTHERWISE, MOSTLY SUNNY SKIES ARE EXPECTED ACROSS MUCH OF THE AREA.
TUESDAY AND WEDNESDAY APPEAR RAIN-FREE, WITH NO MENTIONABLE RAIN
CHANCES AND CONTINUED MOSTLY SUNNY CONDITIONS.
TEMPERATURES WILL BE NEAR OR JUST BELOW SEASONABLE THROUGH
WEDNESDAY, WITH HIGHS IN THE LOW TO MID 80S ACROSS MOST LOCATIONS,
AND SOME UPPER 80S POSSIBLE ACROSS INTERIOR SOUTHEAST GEORGIA. THE
EXCEPTION BEING HIGH TEMPERATURES ON MONDAY ON TUESDAY WHICH MAY
ONLY TOP OUT IN THE UPPER 70S FOR PORTIONS OF THE CHARLESTON TRI-
COUNTY DUE TO A SLIGHT INCREASE IN CLOUD COVER. OVERNIGHT LOWS WILL
DIP INTO THE LOW TO MID 60S INLAND, WITH UPPER 60S ALONG THE
COAST.
LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/
THE REX BLOCK OVER THE EASTERN CONUS WILL QUICKLY BREAK DOWN LATE
WEDNESDAY WITH BROAD RIDGING FORECAST TO PREVAIL ACROSS THE
SOUTHEAST U.S. THROUGH FRIDAY NIGHT. A SOUTHERN STREAM SHORTWAVE
COULD IMPACT THE REGION THIS WEEKEND WHICH COULD RESULT IN AN UPTICK
IN RAIN CHANCES. HIGHS WILL GENERALLY MAX OUT IN MID 80S TO LOWER
90S EACH AFTERNOON (A BIT COOLER AT THE BEACHES) WITH OVERNIGHT LOWS
DROPPING INTO THE MID/UPPER 60S INLAND TO THE LOWER/MID 70S AT THE
BEACHES.
AVIATION /18Z SUNDAY THROUGH FRIDAY/
18Z TAFS: VFR CONDITIONS CONTINUE, WITH BREEZY N-NE WINDS WEAKENING
OVERNIGHT. WINDS PICK UP AGAIN IN THE MORNING, AGAIN REMAINING OUT
OF THE NORTH-NORTHEAST.
EXTENDED AVIATION FORECAST: THERE ARE NO HIGH CONFIDENCE
CONCERNS.
MARINE
IN BETWEEN A SURFACE COASTAL LOW PRESSURE TO OUR EAST AND A SURFACE
HIGH PRESSURE TO THE NORTH, BREEZY WINDS ARE OCCURRING ACROSS
OUR WATERS GIVEN THE TIGHTENED SURFACE PRESSURE GRADIENT. WINDS
HAVE BEEN UNDER-PERFORMING OVERALL COMPARED TO WHAT WAS
EXPECTED, THOUGH THEY HAVE REACHED SMALL CRAFT CRITERIA FOR A
FEW HOURS THIS AFTERNOON. SEAS ARE SETTLING DOWN EARLIER THAN
EXPECTED AS WELL, WITH THE 6 FOOT SEAS ON THE OUTER EDGES OF THE
NEAR-SHORE COASTAL WATERS, WITH 6 FOOT WAVES EXPECTED TO MOVE
OUT OF THE NEAR AND OUTER- SHORE WATERS BY THE MID-EVENING
HOURS. HAVE THUS INCLUDED NEARSHORE WATERS FROM EDISTO TO
SAVANNAH IN THE EXPIRATION TIME OF 5 PM, WHICH MATCHES UP WITH
THE EXPIRATION OF NEAR-SHORE WATERS FROM SAVANNAH TO ALTAMAHA
SOUND.
WE'LL REMAIN MARGINALLY BREEZY OVERNIGHT, WITH THE LATEST GUIDANCE
INDICATING WINDS SHOULD REMAIN BELOW SMALL CRAFT CRITERIA, THUS
ALLOWING FOR THE LAST TWO ZONES (NEARSHORE SANTEE TO EDISTO AND
OFFSHORE SAVANNAH TO ALTAMAHA SOUND) TO EXPIRE THIS EVENING. WAVES
BY DAYBREAK WILL BE 3 FOOT ALONG THE COAST, RISING TO 4-5 FEET OUT
20NM AND FURTHER.
MONDAY THROUGH FRIDAY: THE PINCHED GRADIENT ASSOCIATED WITH THE
INLAND WEDGE WILL RELAX MONDAY AS LOW PRESSURE OFFSHORE BEGINS TO
SLOWLY DRIFT NORTHWARD TOWARD THE OUTER BANKS, SHIFTING THE TIGHTEST
PRESSURE GRADIENT NORTH OF THE WATERS. OFFSHORE CONDITIONS WILL
HOVER JUST BELOW SMALL CRAFT ADVISORY CRITERIA, WITH SEAS AVERAGING
3-5 FT AND NORTH/NORTHEAST WINDS GUSTING UP TO 20-23 KT. BOTH WINDS
AND SEAS WILL GRADUALLY DECREASE TUESDAY WITH NO ADDITIONAL CONCERNS
THROUGH THE WEEK.
RIP CURRENTS: NORTHEAST WINDS WILL BE SLIGHTLY ELEVATED MONDAY AND
LINGERING SWELL WILL CONTINUE A MODERATE RISK FOR RIP CURRENTS AT
ALL AREA BEACHES.
TIDES/COASTAL FLOODING
TODAY: A COASTAL FLOOD ADVISORY WAS ISSUED FOR CHARLESTON AND
COASTAL COLLETON COUNTIES THIS MORNING DUE TO MINOR COASTAL
FLOODING FORECAST AT CHARLESTON HARBOR, WITH THE TIDE PEAKING
NEAR 7.1 FT MLLW AT THE TIME OF THIS WRITING. NOT EXPECTING
ANYMORE SIGNIFICANT RISES, AND NO COASTAL FLOODING IS FORECAST
AT FORT PULASKI.
TIDE LEVELS WILL REMAIN ELEVATED DUE TO LARGE TIDAL DEPARTURES
RESULTING FROM A PINCHED PRESSURE GRADIENT WITH PERSISTENT NORTHEAST
WINDS. THE POTENTIAL FOR MINOR 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 UNTIL 8 PM EDT THIS EVENING FOR GAZ117-
119-139-141.
SC...COASTAL FLOOD ADVISORY UNTIL 4 PM EDT THIS AFTERNOON FOR
SCZ049-050.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR AMZ350-
374.
SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR AMZ352-
354.
NEAR TERM...APT
SHORT TERM...BRS
LONG TERM...BRS
AVIATION...APT/BRS
MARINE...APT/BRS
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