114
FXUS62 KCHS 291856
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
256 PM EDT FRI MAY 29 2026
WHAT HAS CHANGED
ALL SECTIONS HAVE BEEN UPDATED.
KEY MESSAGES
- 1) HEAVY RAINFALL COULD PRODUCE LOCALIZED FLOODING OVER
SOUTHEAST GEORGIA TODAY.
- 2) LOCALIZED FLASH FLOODING POSSIBLE ACROSS PORTIONS OF
SOUTHEAST GEORGIA AND THE SOUTH CAROLINA LOWCOUNTRY ON
SATURDAY.
- 3) EVENING HIGH TIDES COULD BRING MINOR INUNDATION OF VERY LOW LYING
AREAS ALONG THE CHARLESTON AND COLLETON COUNTY COASTS THIS
EVENING THROUGH THIS WEEKEND.
DISCUSSION
KEY MESSAGE 1: HEAVY RAINFALL COULD PRODUCE LOCALIZED FLOODING
OVER SOUTHEAST GEORGIA TODAY.
A STALLED FRONT WILL LINGER IN THE VICINITY TODAY. ALOFT, A MID
LEVEL TROUGH WILL EXTEND OVER THE MID-ATLANTIC STATES WITH SHORTWAVE
ENERGY PROGGED TO LIFT ACROSS THE LOCAL REGION THROUGH TONIGHT.
SHOWER AND THUNDERSTORM COVERAGE WILL BE HIGHEST ACROSS SOUTHEAST
GEORGIA THIS AFTERNOON INTO THIS EVENING WHERE HIGH MOISTURE CONTENT
(NOTED BY PWATS OF OVER 2 INCHES/95TH PERCENTILE OF CLIMO) AND
VARIOUS BOUNDARIES WILL BE IN PLAY. SLOW STORM MOTIONS COULD RESULT
IN TORRENTIAL DOWNPOURS AND LOCALIZED FLOODING. 12Z HREF INDICATES A
10-30% CHANCE OF 3"/3 HR, WITH A 70-90% OF 1"/3 HR, IN THESE
LOCATIONS. FLOOD ADVISORIES, OR PERHAPS EVEN A FLASH FLOOD WARNING,
ARE POSSIBLE. CONVECTIVE COVERAGE WILL BE MORE ISOLATED TO SCATTERED
FURTHER NORTH PAST THE SAVANNAH RIVER THROUGH THE DAYTIME.
SHOWERS AND THUNDERSTORMS WILL LIKELY PERSIST TO SOME EXTENT
OVERNIGHT AS THE AFOREMENTIONED FRONT LIFTS BACK NORTHWARD AND
SHORTWAVE ENERGY PROVIDES EXTRA LIFT. HIGHER RAIN CHANCES SHOULD
TRANSITION TO SOUTHEAST SOUTH CAROLINA BY DAYBREAK. WHILE LOCALLY
HEAVY RAINFALL WILL BE POSSIBLE, THE OVERALL FLOODING THREAT SHOULD
BE LESSER DURING THE OVERNIGHT HOURS THAN EARLIER IN THE DAY.
KEY MESSAGE 2: LOCALIZED FLASH FLOODING POSSIBLE ACROSS PORTIONS OF
SOUTHEAST GEORGIA AND THE SOUTH CAROLINA LOWCOUNTRY ON SATURDAY.
THE MID-LEVELS WILL CONSIST OF A SHORTWAVE APPROACHING OUR REGION
FROM THE WEST IN THE MORNING, THEN MOVING OVERHEAD DURING THE
AFTERNOON. AT THE SURFACE, A STATIONARY FRONT WILL MEANDER ACROSS
OUR AREA. THERE WILL BE DECENT FORCING AT THE SURFACE AND ALOFT,
ALONG WITH DEEP MOISTURE. PWATS SHOULD BE AROUND 2", WHICH IS ABOUT
2 STANDARD DEVIATIONS PER NAEFS, AND ABOVE THE 90% MARK FOR CHS
SOUNDING CLIMATOLOGY PER SPC. THIS WILL SUPPORT EFFICIENT WARM-RAIN
PROCESSES AND HIGH RAINFALL RATES.
THE MAIN FORECAST CHALLENGE REMAINS THE EXACT PLACEMENT OF THE FRONT
AND THE ASSOCIATED HEAVIEST RAINFALL BAND. IF IT'S FURTHER SOUTH,
THEN THE HEAVIER RAINFALL WILL FALL ACROSS SOUTHEAST GEORGIA AND THE
SAVANNAH METRO. IF IT'S FURTHER NORTH, THEN THE HEAVIER RAINFALL
WILL FALL ACROSS THE SC LOWCOUNTRY AND THE CHARLESTON METRO.
GIVEN ALL OF THE MOISTURE, THE OVERALL SEVERE THUNDERSTORM THREAT IS
LOW. BUT THERE SHOULD BE ENOUGH INSTABILITY TO FIRE OFF SOME
EMBEDDED THUNDERSTORMS WITH LOCALLY VERY HEAVY RAINFALL. AREAS WITH
BACKBUILDING AND/OR TRAINING WILL HAVE THE HIGHEST RAINFALL AMOUNTS.
LOCALIZED RAINFALL TOTALS OF 1-3" COULD BE POSSIBLE. THE WEATHER
PREDICTION CENTER (WPC) STILL HAS OUR AREA UNDER A MARGINAL RISK
(LEVEL 1 OF 4) FOR EXCESSIVE RAINFALL ON SATURDAY. SHOWERS AND
THUNDERSTORMS WILL BEGIN TO DISSIPATE LATE SATURDAY NIGHT AS HIGH
PRESSURE STARTS TO BUILD IN FROM THE NORTH.
KEY MESSAGE 3: EVENING HIGH TIDES COULD BRING MINOR INUNDATION OF
VERY LOW LYING AREAS ALONG THE CHARLESTON AND COLLETON COUNTY COASTS
THIS EVENING THROUGH THIS WEEKEND.
A PERIOD OF MODERATE TO BREEZY NORTHEAST WINDS TODAY IN COMBINATION
WITH THE APPROACHING FULL MOON WILL BRING ELEVATED HIGH TIDE LEVELS
THIS EVENING (OCCURRING AROUND 745 PM). LATEST GUIDANCE INDICATES
TIDE LEVELS SHOULD REMAIN SHY OF MINOR COASTAL FLOOD CRITERIA, AND
LUCKILY THE THREAT FOR HEAVY RAINFALL AROUND THE TIME OF HIGH TIDE
TONIGHT IS LOW. NO COASTAL FLOOD ADVISORY IS ANTICIPATED.
ELEVATED TIDAL DEPARTURES MAY PERSIST THROUGH THIS WEEKEND. MINOR
INUNDATION OF VERY LOW LYING AREAS OF CHARLESTON AND COLLETON
COUNTIES IS POSSIBLE SATURDAY AND SUNDAY EVENINGS. HOWEVER, SHOWERS
AND THUNDERSTORMS MAY TRACK ACROSS THE CITY OF CHARLESTON DURING
HIGH TIDE SATURDAY EVENING. THE COMBINATION OF MODERATE TO HEAVY
DOWNPOURS COINCIDING WITH HIGH TIDE MAY INCREASE THE POTENTIAL FOR
FLOODING.
AVIATION /18Z FRIDAY THROUGH WEDNESDAY/
29/18Z TAF CYCLE:
KCHS/KJZI: PREVAILING VFR IS EXPECTED INITIALLY WITH AFTERNOON
SHOWERS/THUNDERSTORMS LARGELY TO STAY SOUTH OF THE TERMINALS.
LATE TONIGHT INTO SATURDAY, A STALLED FRONT WILL LIFT BACK
NORTHWARD WITH POTENTIAL IMPACTS FROM CONVECTION. OUTSIDE OF
THAT ACTIVITY, LOW CLOUDS ARE EXPECTED TO IMPACT THE TERMINALS
LATE TONIGHT INTO SATURDAY MORNING. MVFR SHOULD BE MOST
PREVALENT, BUT A BRIEF PERIOD OF IFR IS POSSIBLE.
KSAV: FLIGHT RESTRICTIONS IN SHOWERS/THUNDERSTORMS WILL BE POSSIBLE
IN THE FIRST FEW HOURS OF THE TAF CYCLE BASED ON LATEST RADAR
TRENDS. USED A TEMPO GROUP TO ADDRESS THIS. LOW CLOUDS ARE EXPECTED
TO DEVELOP LATE TONIGHT INTO SATURDAY MORNING AS A STALLED FRONT
LIFTS BACK NORTHWARD. GUIDANCE IS PRETTY CONSISTENT IN INDICATING A
PERIOD OF IFR, SO THIS WAS MAINTAINED IN THE TAF. IMPACTS FROM
CONVECTION ARE POSSIBLE AGAIN ON SATURDAY BUT CONFIDENCE WAS NOT
HIGH ENOUGH TO INTRODUCE PREVAILING CONDITIONS AT THIS TIME.
EXTENDED AVIATION OUTLOOK: PERIODIC FLIGHT RESTRICTIONS ARE EXPECTED
DUE TO NUMEROUS SHOWERS AND THUNDERSTORMS, ALONG WITH PATCHY
OVERNIGHT FOG AND/OR STRATUS.
MARINE
THROUGH TONIGHT: GUSTY EAST TO NORTHEAST WINDS THIS AFTERNOON WILL
SETTLE OVERNIGHT AS THE PRESSURE GRADIENT WEAKENS. CONDITIONS
SHOULD REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA.
EXTENDED MARINE: A COLD FRONT WILL MOVE SOUTH THROUGH OUR COASTAL
WATERS SATURDAY NIGHT INTO SUNDAY MORNING, FOLLOWED BY HIGH PRESSURE
PASSING TO OUR NORTH. THE INTERACTION BETWEEN THESE TWO SYNOPTIC
FEATURES WILL CAUSE A SURGE IN NE WINDS, WITH GUSTS AROUND 30 KT
LATE SATURDAY NIGHT THROUGH SUNDAY EVENING. THIS WILL ALSO CAUSE
SHORT-PERIOD SEAS TO BUILD. THEREFORE, SMALL CRAFT ADVISORIES WILL
BE NEEDED FOR ALL OF OUR WATERS ON SUNDAY, INCLUDING THE CHARLESTON
HARBOR. CONDITIONS WILL IMPROVE SUNDAY NIGHT INTO MONDAY.
RIP CURRENTS: A MODERATE RISK OF RIP CURRENTS IS EXPECTED FOR TODAY
ACROSS ALL BEACHES AS MODEST EASTERLY SWELL AROUND 3 TO 4 FT EVERY 8
SECONDS PERSISTS. FOR SUNDAY, OUR INTERNAL CALCULATOR HAS A
BORDERLINE MODERATE/HIGH RISK, WHILE RCMOS HAS A HIGH RISK. WE
OPTED TO START OUT WITH A HIGH RISK FOR ALL OF OUR BEACHES.
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...NONE.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page