778
FXUS62 KCHS 301915
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
315 PM EDT SAT MAY 30 2026
WHAT HAS CHANGED
ALL OF THE SECTIONS WERE UPDATED.
KEY MESSAGES
- 1) LOCALLY HEAVY RAINFALL AND ISOLATED FLASH FLOODING POSSIBLE
ACROSS PORTIONS OF SOUTHEAST GEORGIA AND SOUTHEAST SOUTH
CAROLINA THROUGH THIS EVENING.
- 2) UNSETTLED WEATHER WILL PERSIST ACROSS PORTIONS OF SOUTHEAST
GEORGIA AND THE SOUTH CAROLINA LOWCOUNTRY SUNDAY THROUGH TUESDAY.
- 3) THE SUNDAY EVENING HIGH TIDE COULD BRING MINOR COASTAL
FLOODING TO THE CHARLESTON AND COLLETON COUNTY COASTLINES.
DISCUSSION
KEY MESSAGE 1: LOCALLY HEAVY RAINFALL AND ISOLATED FLASH
FLOODING POSSIBLE ACROSS PORTIONS OF SOUTHEAST GEORGIA AND
SOUTHEAST SOUTH CAROLINA THROUGH THIS EVENING.
THE MID-LEVELS CONSIST OF NORTHWEST FLOW OVERHEAD, RESULTING
FROM WEAK RIDGING TO OUR WEST AND A LONGWAVE TROUGH OFF THE EAST
COAST. AT THE SURFACE, THE SUBTLE STATIONARY BOUNDARY JUST TO
OUT SOUTH HAS DISSIPATED THIS AFTERNOON. THOUGH, A COLD FRONT
CURRENTLY SPREAD ALONG NC WILL MOVE SOUTHWARDS, REACHING OUR
AREA LATE THIS EVENING, AND SLOWLY MOVING FURTHER SOUTH
OVERNIGHT. AHEAD OF THIS FRONT IS DEEP MOISTURE ACROSS OUR AREA.
PWATS ARE IN THE 1.8-2.0" RANGE, WHICH IS ABOVE THE 90% MARK FOR
CHS ACCORDING TO SPC SOUNDING CLIMATOLOGY. TEMPERATURES IN THE
80S ARE GENERATING MODEST INSTABILITY, WITH SPC MESOSCALE
ANALYSIS SHOWING MLCAPES PEAKING IN THE 1,500-2,000 J/KG RANGE
LATE THIS AFTERNOON. ALL OF THESE PIECES ARE GENERATING
SCATTERED TO NUMEROUS CONVECTION ACROSS OUR AREA. THE SEVERE
RISK IS LOW GIVEN THE ABUNDANT MOISTURE AND MINIMAL DCAPES.
HOWEVER, THE THREAT FOR LOCALLY HEAVY RAINFALL PERSISTS.
EFFECTIVE BULK SHEAR IN THE 20-35 KT RANGE IS OFFSHORE, WHICH
COULD INTERACT WITH CONVECTION THAT TRIES TO FORM ALONG THE
PINNED SEABREEZE. THIS COULD CAUSE STORMS THERE TO MOVE SLOWER
OR BACKBUILD THROUGH EARLY THIS EVENING. ISOLATED POCKETS OF
1-3" RAINFALL AMOUNTS IN 1-3 HOURS REMAINS POSSIBLE, ESPECIALLY
CLOSER TO THE COAST. THEREFORE, WPC STILL HAS OUR ENTIRE AREA
UNDER A MARGINAL RISK FOR EXCESSIVE RAINFALL. THE THREAT FOR
LOCALLY HEAVY RAINFALL WILL DECREASE LATE THIS EVENING AND
OVERNIGHT.
KEY MESSAGE 2: UNSETTLED WEATHER WILL PERSIST ACROSS PORTIONS
OF SOUTHEAST GEORGIA AND THE SOUTH CAROLINA LOWCOUNTRY SUNDAY
THROUGH TUESDAY.
THE NBM HAS NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS ACROSS
OUR AREA AT VARIOUS TIMES SUNDAY THROUGH TUESDAY. THIS IS DUE TO
A STATIONARY FRONT ACROSS THE SOUTHEAST INTERSECTING WITH A
VERY MOIST AIRMASS. THERE IS A MARGINAL RISK (LEVEL 1 OF 4) OF
EXCESSIVE RAINFALL ON SUNDAY ACROSS MOST OF OUR AREA. ALTHOUGH
CONVECTION SHOULD REMAIN SOMEWHAT DISORGANIZED, LOCALIZED
TRAINING, BACKBUILDING, AND REPEATED ROUNDS OF RAINFALL ARE
POSSIBLE, ESPECIALLY WHERE THERE ARE BOUNDARY INTERACTIONS. AS
A RESULT, LOCALIZED FLOODING COULD BE POSSIBLE, PARTICULARLY IN
URBAN AND LOW-LYING LOCATIONS.
KEY MESSAGE 3: THE SUNDAY EVENING HIGH TIDE COULD BRING MINOR
COASTAL FLOODING TO THE CHARLESTON AND COLLETON COUNTY
COASTLINES.
GUSTY NE TO E WINDS WILL CAUSE ELEVATED TIDAL DEPARTURES TO
PERSIST WITH SUNDAY EVENING'S HIGH TIDE. THIS COULD GENERATE
MINOR COASTAL FLOODING FOR THE CHARLESTON AND COLLETON COUNTY
COASTLINES. FLOODING COULD BE EXACERBATED IF SHOWERS AND/OR
THUNDERSTORMS TRACK OVER THESE LOCATIONS AROUND THE TIME OF
HIGH TIDE (9:05 PM).
AVIATION /18Z SATURDAY THROUGH THURSDAY/
18Z TAFS: RADAR IMAGERY INDICATES NUMEROUS SHOWERS WITH SOME
EMBEDDED THUNDERSTORMS ACROSS OUR AREA THIS AFTERNOON, WITH THE
STORMS GENERALLY SHIFTING TOWARDS THE COAST. THE CAMS GENERALLY
POINT TO HIGHER PROBABILITIES OF IMPACTS AT KSAV, SO WE
MAINTAINED THE TEMPO GROUP THERE. RADAR TRENDS WILL DETERMINE IF
TEMPO GROUPS NEED TO BE AMENDED TO KCHS AND KJZI AT A LATER
TIME. THE ACTIVITY WILL DECREASE FOR KCHS AND KJZI AFTER
MIDNIGHT, BUT PERSIST AT KSAV THROUGH THE NIGHT. NE FLOW
OVERNIGHT WILL LEAD TO LOWERING CEILINGS AND MVFR. IT'LL ALSO
CAUSE GUSTY WINDS AT KCHS AND KJZI SUNDAY MORNING AND AFTERNOON.
EXTENDED AVIATION OUTLOOK: EXPECT PERIODIC FLIGHT RESTRICTIONS
EARLY NEXT WEEK DUE TO UNSETTLED WEATHER CONDITIONS. PATCHY
OVERNIGHT FOG AND/OR STRATUS ARE ALSO POSSIBLE.
MARINE
TONIGHT INTO SUNDAY: A COLD FRONT MOVING IN FROM THE NORTH WILL
REACH OUR AREA LATE THIS EVENING AND SLOWLY MOVE FURTHER SOUTH
OVERNIGHT. BEHIND THE FRONT WILL BE A SURGE IN NE TO E WINDS.
THE NEW MODEL RUNS HAVE BACKED OFF ON THE STRENGTH AND COVERAGE
OF THE WINDS. LIKEWISE, SEAS AREN'T AS HIGH. SO THIS MAKES THE
SMALL CRAFT ADVISORIES CHALLENGING. THE ADVISORIES FOR THE SC
WATERS WITHIN 20 NM SHOULD BE IN GOOD SHAPE. BUT THE ADVISORY
FOR THE GA WATERS BEYOND 20 NM IS LOOKING DOUBTFUL BECAUSE WINDS
AND SEAS MAY NOT HIT CRITERIA. WE OPTED TO KEEP THIS ADVISORY
GOING FOR NOW, AND TO MAKE SURE THE NEXT SET OF MODELS DON'T
COME IN WITH MUCH HIGHER WINDS AND SEAS. LIKEWISE, GIVEN THE
UNCERTAINTY, WE HELD OFF ON ISSUING AN ADVISORY FOR THE
CHARLESTON HARBOR LATE TONIGHT INTO SUNDAY.
MONDAY AND TUESDAY: EXPECT MODERATE NORTH-NORTHEASTERLY FLOW TO
PERSIST THROUGH MID-WEEK AS SEVERAL SUBTLE DISTURBANCES
EMBEDDED WITHIN SOUTHWESTERLY FLOW ALOFT TRAVERSES ACROSS THE
LOCAL WATERS. SEAS WILL RANGE FROM 2 TO 4 FT ON MONDAY, AND THEN
BECOME 2 TO 3 FT ON TUESDAY.
RIP CURRENTS: THE NEW MODEL RUNS REALLY BACKED OFF BOTH THE
WINDS AND WAVES ON SUNDAY. OUR INTERNAL CALCULATOR NOW HAS A
BORDERLINE LOW/MODERATE RISK, WHILE RCMOS HAS A HIGH RISK. WE
SPLIT THE DIFFERENCE AND WENT WITH A MODERATE RISK FOR ALL OF
OUR BEACHES.
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 2 AM TO 10 PM EDT SUNDAY FOR AMZ360.
SMALL CRAFT ADVISORY FROM 6 AM TO 10 PM EDT SUNDAY FOR AMZ362.
SMALL CRAFT ADVISORY FROM 6 PM SUNDAY TO 8 AM EDT MONDAY FOR
AMZ384.
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