171
FXUS62 KCHS 210601
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
201 AM EDT THU MAY 21 2026
WHAT HAS CHANGED
ALL KEY MESSAGES AND SECTIONS WERE UPDATED.
KEY MESSAGES
- 1) RAIN CHANCES LIKELY TO INCREASE HEADING INTO THE WEEKEND,
THOUGH NO HAZARDOUS WEATHER IS ANTICIPATED AT THIS TIME.
DISCUSSION
KEY MESSAGE 1: RAIN CHANCES LIKELY TO INCREASE HEADING INTO THE
WEEKEND, THOUGH NO HAZARDOUS WEATHER IS ANTICIPATED AT THIS
TIME.
EXPECT SFC COLD FRONT NEAR THE TENNESSEE RIVER VALLEY TO SAG
OVER THE CAROLINAS BY FRIDAY. THIS BOUNDARY WILL BRING AN UPTICK
IN MOISTURE ALONG WITH INCREASING RAIN CHANCES THROUGH THE
WEEKEND. AS NOTED IN DAYS PAST, THE GREATEST RAIN CHANCES REMAIN
CONFINED TO AREAS INLAND NEAR THE FRONT. MEANWHILE, FOR AREAS
ALONG THE COAST, EXPECT DEVELOPMENT TO STAY FAIRLY LIMITED AS
THE UPPER LEVEL RIDGE HOLDS TIGHT OVERHEAD. IN TERMS OF SEVERE
WEATHER, THE BETTER MOISTURE AND INSTABILITY SHOULD RESIDE JUST
TO OUR WEST AND NORTH. THIS, COMBINED WITH WEAK LARGE-SCALE
FORCING AND SHEAR, IS EXPECTED TO KEEP THE OVERALL SEVERE THREAT
LOW ACROSS OUR AREA - AT LEAST THROUGH THE WEEKEND.
UNSETTLED WEATHER LOOK TO CONTINUE HEADING INTO THE NEW WEEK,
THOUGH CONFIDENCE IN LOCATION AND AMOUNTS REMAINS LOW GIVEN THE
DIURNALLY DRIVEN NATURE OF ANY SHOWER/STORM. OTHERWISE, LOOK FOR
AFTERNOON HIGHS IN UPPER 80S TO LOWER 90S TO PREVAIL, WITH
OVERNIGHT LOWS IN THE UPPER 60S TO 70S.
AVIATION /06Z THURSDAY THROUGH MONDAY/
21/06Z TAF DISCUSSION:
KCHS/KJZI/KSAV: FOG IS THE PRIMARY CONCERN THROUGH DAYBREAK. FOG
PARAMETERS ARE SIMILAR TO WEDNESDAY MORNING WHERE SHALLOW FOG
FOG LAYERS COULD SLOWLY EXPAND TO MORE MEANINGFUL FOG JUST
BEFORE DAYBREAK. CONDITIONS ARE MARGINAL FOR SIGNIFICANT FOG,
BUT 1000 HPA CONDENSATION PRESSURE DEFICITS ARE STILL SOMEWHAT
FAVORABLE. OPTED FOR A TEMPO GROUP FOR MVFR VSBYS 10-12Z AT
KCHS, BUT CONFIDENCE IN MEDIUM AT BEST. BEST FOG PARAMETERS ARE
WEST OF AT KJZI, BUT SHALLOW GROUND OF IS STILL POSSIBLE. FOG
PARAMETERS LOOK THE MOST FAVORABLE AT KSAV WHERE A PERIOD OF LOW
STRATUS COULD ALSO DEVELOP AT FOG LAYERS THICKEN. AGAIN,
CONFIDENCE IS ONLY MEDIUM AT THIS TIME AS GUIDANCE HAS BEEN
RUNNING A BIT TOO AGGRESSIVE WITH FOG/STRATUS OVER THE PAST FEW
DAYS FOR THAT TERMINAL. OPTED FOR PREVAILING MVFR VSBYS AT 08Z
WITH A TEMPO GROUP 09-12Z FOR 3SM BR BKN003 (JUST ABOVE
ALTERNATE MINIMUMS. THE FOG SHOULD QUICKLY MIX OUT AFTER
DAYBREAK AT ALL TERMINALS WITH VFR PREVAILING. GUSTY WINDS WILL
ACCOMPANY SEA BREEZE AGAIN THIS AFTERNOON WITH WINDS
DIMINISHING DURING THE MID-LATE EVENING HOURS.
EXTENDED AVIATION OUTLOOK: THERE ARE NO HIGH CONFIDENCE
CONCERNS.
MARINE
THROUGH TONIGHT: SOUTHERLY WIND REGIME WILL REMAIN PLACE THROUGH
TONIGHT WITH ATLANTIC HIGH PRESSURE CENTERED WELL OFFSHORE. SEA
BREEZE ENHANCEMENTS ALONG THE LAND/SEA INTERFACE ARE LIKELY
AGAIN TODAY THIS AFTERNOON AND EARLY EVENING NEAR THE BEACHES
AND IN THE CHARLESTON HARBOR AS THE SEA BREEZE MOVES INLAND.
SPEEDS WILL GENERALLY REMAIN LESS THAN 15 KT, EXCEPT NEAR 15 KT
AT TIMES IN THE CHARLESTON HARBOR WITH THE SEA BREEZE THIS
AFTERNOON/EVENING. SEAS WILL AVERAGE 2-4 FT.
FRIDAY THROUGH MONDAY: 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 WILL AVERAGE 2-4 FEET THROUGH THE PERIOD.
RIP CURRENTS: A MODEST EASTERLY SWELL AROUND 3FT/9S AND SEA
BREEZE INFLUENCES EACH AFTERNOON WILL KEEP THE RIP CURRENT RISK
WELL INTO THE MODERATE CATEGORY THROUGH FRIDAY.
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...NONE.
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