147
FXUS62 KCHS 040955
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
555 AM EDT SAT OCT 4 2025
SYNOPSIS
STRONG HIGH PRESSURE WILL EXTEND ACROSS THE REGION THROUGH THE
WEEKEND AND INTO EARLY NEXT WEEK. A STRONG COLD FRONT WILL
LIKELY CROSS THE AREA LATER NEXT WEEK.
NEAR TERM /THROUGH TONIGHT/
PRIOR TO DAYBREAK: LATEST RADAR TRENDS INDICATED FEW TO SCATTERED
SHOWERS ASSOCIATED WITH A INVERTED TROUGH OFFSHORE. A FEW OF THESE
SHOWERS WILL CONTINUE TO SHIFT ONSHORE, BUT SHOULD STRUGGLE TO
SHIFT WEST OF I-95 WHILE ENCOUNTERING DRIER AIR AND BECOMING
DISPLACED FROM THE TROUGH AXIS LINGERING OFFSHORE.
TODAY: ALOFT, MID-UPPER LVL RIDGING WILL HOLD IN PLACE ACROSS MUCH
OF THE EAST CONUS WHILE WEAK/EMBEDDED LOW PRESSURE MEANDERS ACROSS
THE DEEP SOUTH/NORTHERN GULF AND ACROSS THE WESTERN ATLANTIC. AT THE
SFC, HIGH PRESSURE WILL REMAIN THE DOMINANT WEATHER FEATURE FOR MUCH
OF THE MORNING, CENTERED TO THE NORTH ACROSS THE MID-ATLANTIC AND
STRETCHING SOUTH ACROSS THE CAROLINAS INTO GEORGIA AWAY FROM THE
COAST. HOWEVER, THE HIGH LOOKS TO WEAKEN INLAND WHILE ITS CENTER
SHIFTS EAST OFF THE MID-ATLANTIC COAST, WHICH TENDS TO FAVOR COASTAL
SHOWERS ASSOCIATED WITH AN INVERTED TROUGH TO DRIFT ONSHORE DURING
PEAK HEATING HOURS. ACTIVITY COULD STRUGGLE TO MAKE SIGNIFICANT
WESTWARD PROGRESS, ENCOUNTERING DRIER AIR OVER LAND DEPICTED IN
LOCAL SOUNDINGS. HOWEVER, MOISTURE CONTENT APPEARS TO HOLD ON A BIT
LONGER ALONG COASTAL GEORGIA, WHERE NORTH-NORTHEASTLY WINDS DRIVE
MOISTURE FROM THE ATLANTIC ONSHORE. HERE, A SLIGHT CHANCE FOR
AFTERNOON SHOWERS/THUNDERSTORMS IS POSSIBLE DURING AFTERNOON INTO
EARLY EVENING HOURS. HIGH TEMPS SHOULD RANGE IN THE LOW-MID 80S,
WARMEST ACROSS INLAND AREAS OF SOUTHEAST GEORGIA.
TONIGHT: ALOFT, MID-UPPER LVL RIDGING BECOMES SLIGHTLY MORE
PRONOUNCED LOCALLY WHILE BECOMING CENTERED ACROSS THE MID-ATLANTIC
STATES. AT THE SFC, HIGH PRESSURE CONTINUES TO SHIFT SLIGHTLY
EASTWARD AND OFFSHORE NORTH OF THE REGION, WHILE AN INVERTED TROUGH
ATTEMPTS TO PERSIST OFF THE SOUTHEAST COAST. LATEST GUIDANCE
SUGGESTS A FEW SHOWERS AND/OR THUNDERSTORMS COULD LINGER DURING
EVENING HOURS AND PERHAPS INTO EARLY MORNING HOURS ACROSS COASTAL
GEORGIA WHILE THE TROUGH LINGERS AND WINDS BECOME MORE DIRECTLY
ONSHORE, VEERING TO THE EAST-NORTHEAST OVERNIGHT. LOW TEMPS SHOULD
BE SLIGHTLY MORE MILD THAN THE PREVIOUS NIGHT, RANGING IN THE MID
60S INLAND TO LOW-MID 70S NEAR THE COAST.
SHORT TERM /SUNDAY THROUGH TUESDAY/
UPPER LEVEL RIDGE HOLDS TIGHT ACROSS THE EASTERN CONUS INTO EARLY
NEXT WEEK. AT THE SURFACE, THE INVERTED TROUGH LINGERS, BUT
GRADUALLY WEAKENS, THROUGH TUESDAY. PERSISTENT LOW LEVEL SUBTROPICAL
MOISTURE ADVECTION CONTINUES IN LONG FETCH EASTERLY WINDS, BUT WITH
A CONTINUED DECREASING SIGNAL FOR ANY SIGNIFICANT FORCING MECHANISM
BEYOND COASTAL MOISTURE CONVERGENCE. RAINFALL CHANCES AND
ACCUMULATION CONTINUE TO TREND LESSER, ESPECIALLY MONDAY, AS THE VORT
ADVECTION LOOKS TO REMAIN WELL SOUTH AND WEST OF THE AREA. LIKEWISE,
THE HEAVY RAINFALL THREAT IS DECREASING, WITH THE PROB OF GREATER
THAN 1 INCH OF RAINFALL SUNDAY AND MONDAY DOWN TO 10-20% FOR THE SE
GA COAST, AND LESS THAN 10% ELSEWHERE.
TUESDAY LOOKS TO REMAIN MAINLY DRY AS THE SURFACE RIDGE AXIS SLIDES
OVERHEAD, BRINGING A MORE APPARENT RESPITE FROM THE BREEZY NE
WINDS, ESPECIALLY ALONG THE COAST. TEMPS REMAIN WITHIN A FEW DEGREES
OF NORMAL SUNDAY THROUGH TUESDAY.
LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/
H5 HEIGHTS FALL MODESTLY WEDNESDAY AS A SHORTWAVE PASSES NORTH OF
THE AREA, THEN MORE QUICKLY THURSDAY INTO FRIDAY AS STRONGER
TROUGHING DIGS ACROSS THE MISSOURI VALLEY AND A SHORTWAVE CROSSES
THE SOUTHEAST. AT THE SURFACE, STRONG HIGH PRESSURE BUILDING QUICKLY
OVER THE NORTHEAST WILL FORCE A BACKDOOR COLD FRONT DOWN THE EASTERN
SEABOARD, LIKELY CROSSING OUR AREA VERY EARLY THURSDAY. LIMITED LOW-
TO-MID LEVEL MOISTURE WILL BE IN PLACE AHEAD OF THIS FRONT, SO
LITTLE MORE THAN A FEW COASTAL SHOWERS ARE EXPECTED WITH THE FRONTAL
PASSAGE.
GUSTY NE WINDS RETURN THURSDAY INTO FRIDAY BEHIND THE FRONT - 25TH
TO 75TH PERCENTILE REFLECTING A MOST LIKELY WIND SPEED ALONG THE
COAST OF AROUND 20-30 MPH - TO END THE WORKWEEK, WHICH, IN ADDITION
TO ALREADY ELEVATED TIDE LEVELS, COULD BRING A PERIOD OF VERY
IMPACTFUL TIDAL FLOODING TO END THE WEEK. SEE COASTAL FLOODING
SECTION FOR MORE.
THE FORECAST BECOMES LESS CERTAIN AS WE MOVE INTO NEXT WEEKEND, WITH
A SPREAD OF SOLUTIONS INCLUDING THE POSSIBILITY THAT THE FRONT LIFTS
BACK NORTHWARD ACROSS THE AREA, BRINGING UNSETTLED CONDITIONS.
AVIATION /09Z SATURDAY THROUGH WEDNESDAY/
VFR CONDITIONS SHOULD PREVAIL CHS/JZI/SAV TERMINALS THROUGH 06Z
SUNDAY. HOWEVER, RECENT SATELLITE IMAGERY AND SFC OBS INDICATED
LOWER STRATUS AND LIGHT RAIN THIS MORNING. TEMPO MVFR CIGS
THROUGH 12Z TODAY HAVE BEEN INCLUDED TO ACCOUNT FOR THESE
TEMPORARY CONDITIONS AT ALL TERMINALS. OTHERWISE, NORTHEAST
WINDS SHOULD BECOME BREEZY THIS AFTERNOON, GUSTING IN THE 20-25
KT THROUGH ABOUT 23-24Z.
EXTENDED AVIATION FORECAST: THE RISK FOR RESTRICTIONS FROM
SHOWERS/TSTMS SUNDAY AND MONDAY IS DECREASING, THOUGH AT LEAST
BRIEF RESTRICTIONS REMAIN POSSIBLE, ESPECIALLY AT SAV.
OTHERWISE, NO SIGNIFICANT AVIATION IMPACTS EXPECTED.
MARINE
TODAY AND TONIGHT: HIGH PRESSURE WILL REMAIN CENTERED NORTH OF THE
REGION, MAINTAINING A PERSISTENT NORTHEAST FLOW, THEN EVENTUALLY
MORE EASTERLY FLOW WITHIN A TIGHT PRESSURE GRADIENT BETWEEN HIGH
PRESSURE INLAND AND AN INVERTED TROUGH OFF THE COAST. THE SETUP WILL
KEEP ELEVATED WINDS AND SEAS THROUGH THE DAY AND INTO THE NIGHT,
MAINLY FOR ALL WATERS OUTSIDE THE CHARLESTON HARBOR WHERE SMALL
CRAFT ADVISORIES REMAIN IN EFFECT. HOWEVER, BOTH WINDS/SEAS COULD
LOWER JUST BELOW SMALL CRAFT ADVISORY LEVEL CONDITIONS ACROSS
NEARSHORE WATERS OFF THE CHARLESTON COUNTY COAST, BUT GIVEN THE RISK
FOR 6 FT SEAS TO LINGER NEAR 15-20 NM LATER THIS AFTERNOON AND
TONIGHT A SMALL CRAFT ADVISORY WILL CONTINUE FOR THE PERIOD. IN
GENERAL, NORTHEAST WINDS SHOULD PEAK IN THE 20-25 KT, HIGHEST ACROSS
GEORGIA WATERS, WHILE SEAS RANGE BETWEEN 4-6 FT NEARSHORE AND 6-8 FT
ACROSS OUTER GEORGIA WATERS.
SUNDAY THROUGH THE MIDDLE OF NEXT WEEK: VERY LONG FETCH EASTERLY
WINDS WILL BRING PERSISTENT MEDIUM PERIOD SWELL ACROSS THE WATERS,
WITH SOME UNDERLYING, BUT MUCH SMALLER, LONGER PERIOD SWELL THROUGH
EARLY WEEK AS WELL. THE SWELL WILL PEAK SUNDAY NIGHT INTO MONDAY
WITH WAVE HEIGHTS REACHING 6-9 FT OFFSHORE, BEFORE ONLY GRADUALLY
SUBSIDING THROUGH MIDWEEK, WHEN BREEZY NE WINDS WILL BEGIN TO EASE
AS WELL.
RIP CURRENTS: A HIGH RISK OF RIP CURRENTS WILL CONTINUE THROUGH
SUNDAY IN PRIMARILY MEDIUM PERIOD E TO NE SWELLS.
TIDES/COASTAL FLOODING
EARLY MORNING: LATEST TIDE OBSERVATIONS INDICATED ~1.4 FT
DEPARTURE IN THE CHARLESTON HARBOR. GIVEN THE ONSET OF COASTAL
FLOODING FOR THE NEXT HOUR OR TWO WITH A FAVORABLE NORTHEAST
WIND PERSISTING, A COASTAL FLOOD ADVISORY HAS BEEN ISSUED FOR
CHARLESTON AND COASTAL COLLETON COUNTIES DURING THE MORNING HIGH
TIDE CYCLE THROUGH 8 AM. HIGH TIDE IS EXPECTED AROUND 5:55 AM.
HEADING INTO THIS WEEKEND AND EARLY NEXT WEEK, ASTRONOMICAL
TIDES WILL INCREASE DUE TO THE UPCOMING FULL MOON (OCT 7) AND
PERIGEE (OCT 8). THIS IN COMBINATION WITH THE ANTICIPATION OF
CONTINUED NORTHEASTERLY FLOW WILL CAUSE THE POSSIBILITY OF
COASTAL FLOODING TO BECOME MORE LIKELY ALONG THE ENTIRE
COASTLINE, INCLUDING BOTH DOWNTOWN CHARLESTON AND FORT PULASKI.
SALTWATER INUNDATION COULD THEN OCCUR DURING BOTH THE MORNING
AND EVENING HIGH TIDE CYCLES DURING THIS TIME. ALTHOUGH THERE IS
CONSIDERABLE UNCERTAINTY THIS FAR OUT, PERSISTENT FAVORABLE
WINDS HAVE THE POTENTIAL TO PRODUCE UP TO MAJOR COASTAL FLOODING
BY THE LATTER PART OF NEXT WEEK.
CHS WATCHES/WARNINGS/ADVISORIES
GA...HIGH RISK FOR RIP CURRENTS THROUGH THIS EVENING FOR GAZ117-119-139-
141.
SC...HIGH RISK FOR RIP CURRENTS THROUGH THIS EVENING FOR SCZ048>051.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 PM EDT TUESDAY FOR AMZ350-352-354.
SMALL CRAFT ADVISORY UNTIL 6 AM EDT WEDNESDAY FOR AMZ374.
NEAR TERM...DPB
SHORT TERM...CEB
LONG TERM...CEB
AVIATION...CEB/DPB
MARINE...CEB/DPB
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page