324
FXUS62 KCHS 301806
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
206 PM EDT SAT AUG 30 2025
SYNOPSIS
HIGH PRESSURE WILL EXTEND ACROSS THE AREA THROUGH EARLY NEXT
WEEK WHILE A STATIONARY FRONT LINGERS JUST OFF THE COAST. A
COLD FRONT WILL MOVE THROUGH ON THURSDAY NIGHT.
NEAR TERM /THROUGH TONIGHT/
TODAY: SHOWERS AND THUNDERSTORMS FROM THIS MORNING HAVE SINCE
TRANSLATED OFFSHORE WITH CONVECTION INCREASING IN STRENGTH AROUND 40
NM OFF OF THE GA COAST. THIS IS DUE TO WEAK VORTICITY HEADING EAST
ALONG A STALLED 850 MB FRONT. AT THE SURFACE, THIS WEAK POSITIVE
VORTICITY HAS INDUCED SURFACE CYCLOGENESIS WITH SURFACE LOW PRESSURE
NOW CLOSED OFF AROUND 40 NM EAST OF THE GA COAST. ON THE NORTHWEST
FLANK OF THE SURFACE LOW, WEAK DEFORMATION HAS DEVELOPED WITH THE
AXIS OF DILATATION EXTENDING SOUTHEAST/ NORTHWEST JUST OFF OF THE
SC/ GA COAST. AS SUCH, ONLY LIGHT PRECIPITATION REMAINS OVER THE
INLAND ZONES, WITH MOST OF THE PRECIPITATION JUST OFF OF THE SC/ GA
COAST. EXPECT HIGH TEMPERATURES IN THE MID 70S FOR MOST AREAS.
TONIGHT: SURFACE LOW PRESSURE WILL REMAIN QUASI-STATIONARY OFF OF
THE SC/ GA COAST WITH WINDS OUT OF THE NORTHEAST. SOME GUIDANCE
IS SHOWING CONVECTION REFORMING ALONG THE COAST OVERNIGHT. THIS
APPEARS TO BE DUE TO THE SURFACE LOW REMAINING WEAK WITH A LAND
BREEZE PUSHING INLAND. OTHER GUIDANCE SHOWS THE COASTAL LOW
REMAINING STRONG ENOUGH TO KEEP THE LAND BREEZE FROM FORMING.
MOST GUIDANCE KEEPS THE SURFACE LOW STRONG ENOUGH, TO PREVENT
THE QUASI- STATIONARY LAND BREEZE FROM FORMING. EXPECT LOW
TEMPERATURES IN THE MID 60S (INLAND) TO NEAR 70 AT AREA BEACHES.
SHORT TERM /SUNDAY THROUGH TUESDAY/
SUNDAY: AS A HIGH PRESSURE CONTINUES TO BUILD INTO THE REGION FROM
THE NORTH, A NEARLY STATIONARY FRONT WILL STALL JUST OFFSHORE. QUITE
A BIT OF MOISTURE AND MID-LVL SUPPORT WILL REMAIN IN THE REGION AND
WILL ALLOW SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORM TO DEVELOP
THROUGHOUT THE DAY. MAJORITY OF THE GUIDANCE CONTINUES TO AGREE THAT
THE GREATEST COVERAGE WILL LIKELY OCCUR ALONG AND SOUTH OF I-16.
ADDITIONALLY, WPC HIGHLIGHTED THE IMMEDIATE COASTLINE UNDER A
MARGINAL RISK (LEVEL 1 OF 4) FOR EXCESSIVE RAINFALL.
MONDAY AND TUESDAY: A MID-LVL LOW WILL ATTEMPT TO CUTOFF ACROSS THE
MID-ATLANTIC AND ALLOW FOR SUBTLE WAVES OF H5 VORT. ENERGY TO BE
ADVECTED ACROSS THE SOUTHEAST, WHILE THIS FRONT CONTINUES TO STALL
NEARBY. THIS SORT OF SETUP WILL PRODUCE ADDITIONAL SHOWERS AND
THUNDERSTORMS ALONG THE IMMEDIATE COASTLINE, HOWEVER COVERAGE WILL
BE LESS DUE TO THE DOWNWARD TREND OF PWATS.
TEMPERATURES WILL REMAIN BELOW NORMAL THIS WEEKEND INTO EARLY NEXT
WEEK AS EAST-NORTHEASTERLY WINDS PERSIST AND HIGH PRESSURE BUILDS
INTO THE REGION. EXPECT HIGHS IN THE LOW TO MID 80S THROUGH EARLY
NEXT WEEK. OVERNIGHT LOWS WILL RANGE IN THE MID TO UPPER 60S INLAND
AND LOW 70S NEAR THE COASTLINE.
LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/
AS THE SURFACE HIGH PRESSURE SHIFTS NORTHEASTWARD, ANOTHER WEAK LOW
PRESSURE TRIES TO FORM OFFSHORE ON WEDNESDAY AND THURSDAY.
ADDITIONALLY, DEEP MOISTURE AND ISENTROPIC ASCENT BECOMES MORE
FAVORABLE ACROSS THE REGION, AND THIS WILL AID IN HIGHER AFTERNOON
SHOWER AND THUNDERSTORMS COVERAGE IN THE MIDDLE OF THE WEEK.
THEREAFTER, A COLD FRONT APPROACHES THE REGION FROM THE NORTHWEST
AND UNSETTLED CONDITIONS COULD CONTINUE THROUGH THE END OF THE WEEK.
TEMPERATURES WILL REMAIN BELOW NORMAL THROUGH THE MIDDLE OF THE
WEEK, AND THEN NEAR NORMAL BY THE END OF THE WEEK DEPENDING ON THE
STRENGTH OF THE HIGH PRESSURE AHEAD OF THE FRONT.
AVIATION /18Z SATURDAY THROUGH THURSDAY/
TODAY: WEAK SURFACE LOW PRESSURE HAS STARTED TO FORM OFF OF OF THE
GEORGIA COAST EARLY THIS AFTERNOON WITH SHOWERS AND THUNDERSTORMS
ORGANIZING NEAR THE LOW CENTER. FOR THE TERMINALS, THIS MEANS THAT
SHOWERS AND THUNDERSTORMS FROM THIS MORNING HAVE STARTED TO COME TO
AN END, AS CONVECTION ORGANIZES OVER THE WATERS. WINDS AT THE
TERMINALS HAVE ALSO BACKED IN RESPONSE TO THE SURFACE CYCLOGENESIS
WITH SOME TRANSIENT WIND GUSTS. THE POTENTIAL FOR REDEVELOPMENT OF
CONVECTION DOES LOOK LOW THIS AFTERNOON THANKS TO WIDESPREAD CLOUD
COVER AND THE PLACEMENT OF THE SURFACE LOW (NORTH/ NORTHEAST FLOW).
TONIGHT: THE SURFACE LOW WILL MEANDER OFF OF THE GA/ SC COAST WITH
CEILINGS SLOWLY FALLING FROM VFR TO MVFR. THE LATEST ROUND OF THE
HRRR SHOWS A SLIGHTLY WEAKER SURFACE LOW WITH A WEAK LAND BREEZE
FORMING ALONG WITH ANOTHER ROUND OF CONVECTION OVERNIGHT. AT THIS
POINT, THE THINKING IS THE SURFACE LOW WILL BE STRONG ENOUGH (IT HAS
ALREADY CLOSED OFF) TO PREVENT ANOTHER LAND BREEZE SO THE TAFS ARE
DRY OVERNIGHT. AS MENTIONED THOUGH, TRENDS WILL NEED TO BE WATCHED
OVERNIGHT.
EARLY SUNDAY: WIDESPREAD MVFR CONDITIONS ARE POSSIBLE WITH SOME IFR
POSSIBLE. THE GREATEST CHANCE FOR IFR CONDITIONS WILL BE AT KSAV/
CLOSER TO THE STALLED BOUNDARY.
EXTENDED AVIATION FORECAST: OCCASIONAL MVFR CEILINGS POSSIBLE
THROUGH MONDAY AS A WEAK FRONT REMAINS STALLED ALONG THE COAST,
THEREAFTER FLIGHT RESTRICTIONS ARE POSSIBLE WITH AFTERNOON SHOWERS
AND THUNDERSTORMS.
MARINE
TODAY AND TONIGHT: COASTAL LOW PRESSURE HAS DEVELOPED AROUND 40
NM EAST OF SAVANNAH, GA WITH SHOWERS AND THUNDERSTORMS NOW
FOCUSING OVER THE COASTAL WATERS. A FEW STRONGER STORMS ARE
POSSIBLE NEAR THE SURFACE LOW WITH GUSTY WINDS AND AN ISOLATED
WATERSPOUT THE PRIMARY THREATS. WAVE HEIGHTS WILL ALSO START TO
BUILD THIS AFTERNOON TOWARDS 2 TO 4 FT.
SUNDAY THROUGH THURSDAY: AS THE PRESSURE GRADIENT STRENGTHENS, EAST-
NORTHEASTERLY WINDS WILL BECOME RATHER GUSTY ACROSS THE ATLANTIC
UNTIL THE MIDDLE OF THE WEEK (W/ GUSTS UP TO 25 TO 30 KTS POSSIBLE).
THEREFORE, SMALL CRAFT ADVISORIES WERE ISSUED FOR ALL MARINE ZONES
BEGINNING ON SUNDAY AND LASTING UNTIL AT LEAST TUESDAY. SEAS WILL
WILL RANGE FROM 5 TO 7 FT, AND THEN BACK DOWN TO 2 TO 4 FT ON
WEDNESDAY MORNING.
RIP CURRENTS: DUE TO THE INCREASING STRENGTH OF THE PRESSURE
GRADIENT AND THE HOLIDAY WEEKEND, A MODERATE RISK OF RIP CURRENTS
HAS BEEN ISSUED FOR TODAY AND TOMORROW (SUNDAY). ALSO, A HIGH RISK
OF RIP CURRENTS HAS BEEN ISSUED FOR MONDAY.
TIDES/COASTAL FLOODING
TIDAL DEPARTURES COULD BEGIN TO BUILD OVER THE WEEKEND INTO EARLY
NEXT WEEK AS LOW PRESSURE DEVELOPS OFFSHORE AND A WEDGE OF HIGH
PRESSURE LINGERS INLAND. TIDES COULD GET CLOSE TO MINOR FLOOD
THRESHOLDS IN THE CHARLESTON HARBOR BY MONDAY YIELDING A RISK FOR
COASTAL FLOODING ACROSS COASTAL AREAS OF CHARLESTON AND COLLETON
COUNTIES DURING MAINLY THE AFTERNOON HIGH TIDE CYCLE. THIS RISK MAY
EXTEND INTO THE MIDDLE OF NEXT WEEK DEPENDING ON HOW STRONG THE
PINCHED GRADIENT GETS.
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM SUNDAY TO 2 AM EDT MONDAY FOR
AMZ330.
SMALL CRAFT ADVISORY FROM 6 AM SUNDAY TO 8 AM EDT TUESDAY FOR
AMZ350-352-354.
SMALL CRAFT ADVISORY FROM 6 AM SUNDAY TO 8 PM EDT TUESDAY FOR
AMZ374.
NEAR TERM...HAINES
SHORT TERM...DENNIS
LONG TERM...DENNIS
AVIATION...DENNIS/HAINES
MARINE...DENNIS/HAINES
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