541
FXUS62 KCHS 180934
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
534 AM EDT MON MAY 18 2026
WHAT HAS CHANGED
THE AVIATION SECTION WAS UPDATED FOR THE 18/12Z TAFS.
KEY MESSAGES
- 1) MINOR COASTAL FLOODING IS POSSIBLE ALONG COASTAL AREAS OF
CHARLESTON AND COLLETON COUNTIES WITH HIGH TIDE THIS EVENING
AND POSSIBLY TUESDAY EVENING.
- 2) MOSTLY DRY CONDITIONS EXPECTED THROUGH MIDWEEK WITH
INCREASING RAIN CHANCES TO OCCUR LATE WEEK.
DISCUSSION
KEY MESSAGE 1: MINOR COASTAL FLOODING IS POSSIBLE ALONG COASTAL
AREAS OF CHARLESTON AND COLLETON COUNTIES WITH HIGH TIDE THIS
EVENING AND POSSIBLY TUESDAY EVENING.
ASTRONOMICAL INFLUENCES ASSOCIATED WITH THE RECENT NEW MOON AND
LUNAR PERIGEE ALONG WITH A MODEST ONSHORE FLOW WILL CONTINUE TO
DRIVE ELEVATED TIDE LEVELS, LEADING TO MINOR COASTAL FLOODING
ALONG PARTS OF THE LOWER SOUTH CAROLINA COAST THIS EVENING. THE
LATEST FORECAST ADVERTISES A PEAK HIGH TIDE 7.0-7.2 FT MLLW IN
THE CHARLESTON HARBOR THIS EVENING AND 6.9-7.1 FT MLLW TUESDAY
EVENING. A COASTAL FLOOD ADVISORY FOR COASTAL COLLETON AND
CHARLESTON COUNTIES COULD BE FOR THIS EVENING'S HIGH TIDE AND
POSSIBLY AGAIN TUESDAY EVENING ALTHOUGH CONFIDENCE IN REACHING
THE 7.0 FT MLLW MINOR FLOOD STAGE IS MUCH MORE UNCERTAIN BY THEN.
ASTRONOMICAL TIDE LEVELS THEN BEGIN TO FALL AND THE POTENTIAL
FOR MINOR COASTAL FLOODING WILL DIMINISH.
KEY MESSAGE 2: MOSTLY DRY CONDITIONS EXPECTED THROUGH MIDWEEK
WITH INCREASING RAIN CHANCES TO OCCUR LATE WEEK.
SFC HIGH PRESSURE AND UPPER LEVEL RIDGING HOLDS TIGHT ACROSS
THE REGION THROUGH MID-WEEK, ALLOWING LARGELY DRY CONDITIONS TO
PREVAIL. MODEL SOUNDINGS ALSO REMAIN QUITE CAPPED, SO IN THE OFF
CHANCE THAT PRECIPITATION DOES DEVELOP, EXPECT OVERALL
ACCUMULATIONS AND SEVERE POTENTIAL TO REMAIN LOW. OTHERWISE,
LOOK FOR AFTERNOON HIGHS TO WARM INTO THE UPPER 80S TO LOWER 90S
UNDER MOSTLY SUNNY SKIES, WITH LOWS ONLY DIPPING INTO THE MID
TO UPPER 60S.
UPPER LEVEL PATTERN SHIFTS HEADING INTO THE LATTER HALF OF THE
FORECAST PERIOD, RESULTING IN CHANCES FOR UNSETTLED WEATHER. AS
NOTED IN THE PREVIOUS DISCUSSION, A DECENT AMOUNT OF MODEL
UNCERTAINTY STILL EXISTS, MAKING IT HARD TO PUT TOO MUCH
CONFIDENCE IN ANY ONE SOLUTION JUST YET. WHILE DETAILS STILL
NEED TO BE IRONED OUT, MOST GUIDANCE DOES SHOWCASE A SHORTWAVE
TROUGH DIGGING ACROSS THE CENTRAL/NORTHERN PLAINS BY THURSDAY.
MEANWHILE, AT THE SFC, WILL SEE A COLD FRONT DIVE SOUTHEASTWARD
ACROSS THE OHIO/TENNESSEE RIVER VALLEY, SENDING THE
AFOREMENTIONED HIGH PRESSURE INTO THE ATLANTIC. THERE ARE SOME
INDICATIONS THAT THIS BOUNDARY COULD STALL ACROSS OUR AREA
THROUGH SATURDAY, WHICH WOULD SUPPORT INCREASING MOISTURE AND
HIGHER RAIN CHANCES. HOWEVER, IF THE RIDGE REMAINS STRONGER, THE
FRONT AND BETTER FORCING COULD REMAIN FARTHER TO THE WEST AND
NORTH, RESULTING IN LOWER RAIN CHANCES THAN CURRENTLY FORECAST.
DO THINK IT IS WORTH NOTING THOUGH, THAT LATEST ENSEMBLE
PROBABILITIES FOR ACCUMULATED RAINFALL > 1" NOW SHOWCASE A
20-60% CHANCE (HIGHEST INLAND). CERTAINLY SOMETHING TO KEEP AN
EYE ON IN THE COMING DAYS.
AVIATION /09Z MONDAY THROUGH FRIDAY/
18/12Z TAF DISCUSSION:
KCHS/KJZI/KSAV: SHALLOW GROUND FOG AT ALL THREE TERMINALS WILL
QUICKLY DISSIPATE AT SUNRISE. VFR FOR THE PERIOD. GUSTY WINDS
WILL OCCUR WITH THE PASSAGE OF THE SEA BREEZE THIS AFTERNOON.
SHALLOW GROUND FOG WILL BE POSSIBLE AGAIN AT ALL TERMINALS EARLY
TUESDAY MORNING.
EXTENDED AVIATION OUTLOOK: THERE ARE NO HIGH CONFIDENCE
CONCERNS.
MARINE
THROUGH TONIGHT: THE SYNOPTIC FLOW REGIME WILL CHANGE LITTLE
THROUGH TONIGHT AS ATLANTIC HIGH PRESSURE REMAINS CENTERED WELL
OFFSHORE. A EASTERLY FLOW REGIME WILL PREVAIL WITH EAST TO
SOUTHEAST WINDS 15 KT OR LESS PREVAILING. SOME LOCAL ENHANCEMENT
COULD OCCUR ALONG THE LAND/SEA INTERFACE AND CHARLESTON HARBOR THIS
AFTERNOON WITH SEA BREEZE. SEAS WILL AVERAGE 2-4 FT.
MONDAY THROUGH FRIDAY: NO MARINE CONCERNS ARE EXPECTED. HIGH
PRESSURE TO THE EAST WILL DRIVE ONSHORE EAST-SOUTHEASTERLY FLOW
EACH DAY, WITH WIND SPEEDS MOSTLY TOPPING OUT IN THE 10-15 KNOT
RANGE. EACH AFTERNOON AND EVENING THERE COULD BE SOME LOCAL
ENHANCEMENT ALONG THE LAND/SEA INTERFACE WITH THE DIURNAL SEA
BREEZE. SEAS SHOULD AVERAGE 2-4 FEET THROUGH THE PERIOD.
RIP CURRENTS: INFLUENCES FROM THE NEW MOON CYCLE COMBINED WITH
PERSISTENT ONSHORE FLOW WILL PRODUCE AN ELEVATED RISK OF RIP
CURRENTS THROUGH MIDWEEK. A MODERATE RISK FOR RIP CURRENTS IS
IN PLACE FOR ALL BEACHES THROUGH TUESDAY.
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...NONE.
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