470
FXUS62 KCHS 241328
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
928 AM EDT WED JUN 24 2026
WHAT HAS CHANGED
UPDATE TO ISSUE A SMALL CRAFT ADVISORY FOR THE CHARLESTON COUNTY
COASTAL WATERS THROUGH 2PM.
KEY MESSAGES
- 1) ABOVE-NORMAL TEMPERATURES AND BELOW-NORMAL RAIN CHANCES
ARE EXPECTED THROUGH THE UPCOMING WEEKEND.
- 2) TEMPERATURES LIKELY TO APPROACH THE TRIPLE DIGITS THIS
WEEKEND. HEAT ADVISORIES COULD BE NEEDED.
DISCUSSION
KEY MESSAGE 1: ABOVE-NORMAL TEMPERATURES AND BELOW-NORMAL RAIN
CHANCES ARE EXPECTED THROUGH THE UPCOMING WEEKEND.
EARLY MORNING SURFACE OBSERVATIONS AND STABILITY ANALYSIS SHOWS
A BACKDOOR COLD FRONT HAS PUSHED SOUTH OF THE SANTEE RIVER AND
WILL CONTINUE TO MEANDER SOUTH THROUGH THE SOUTH CAROLINA
LOWCOUNTRY AND INTO SOUTHEAST GEORGIA THIS MORNING. THE FRONT IS
EXPECTED TO STALL OUT SOMEWHERE IN THE VICINITY OF THE ALTAMAHA
RIVER BY NOON WITH RELATIVELY COOLER AND DRIER AIR ADVECTING
INTO THE REGION. GUIDANCE IS SIMILAR IN SHOWING A MODEST PURE
SEA BREEZE CIRCULATION DEVELOPING LATER TODAY WHICH WILL
PROPAGATE STEADILY INLAND THROUGH THE AFTERNOON. WHILE MODIFIED
SOUNDINGS SHOW A PRONOUNCED CAPPING INVERSION HOLDING IN PLACE
AWAY FROM THE COAST THROUGH THE DAY, WEAK TO MODEST INSTABILITY
(MLCAPE 1000-1400 J/KG, LIFTED INDICES -2C TO -4C) IS PROGGED TO
DEVELOP BY MID-LATE AFTERNOON ALONG THE GEORGIA AND FAR
SOUTHERN SOUTH CAROLINA COAST AS DEWPOINTS SURGE WITH THE
PASSAGE OF THE SEA BREEZE. DESPITE THE DRY MID-LEVELS, THERE
LOOKS TO BE ENOUGH LOW-LEVEL THETA-E ADVECTION AND BOUNDARY
LAYER CONVERGENCE WITHIN THE SEA BREEZE CIRCULATION ITSELF TO
SUPPORT POCKETS OF ISOLATED CONVECTION, ROUGHLY ALIGNED ALONG A
BEAUFORT-SAVANNAH-HINESVILLE-LUDOWICI CORRIDOR. THE PRESENCE OF
EXTENSIVE MID-LEVEL DRY AIR WILL KEEP UPDRAFTS WEAK AND FAIRLY
TRANSIENT DUE TO DRY AIR ENTRAINMENT, BUT THERE IS A REASONABLE
SIGNAL FOR SOME MEASURABLE RAINFALL WITHIN THE NOTED CORRIDOR.
POPS 20-30% WERE INTRODUCED INTO THESE AREAS WITH POPS <10%
ELSEWHERE. TEMPERATURES THIS AFTERNOON WILL WARM INTO THE UPPER
80S/LOWER 90S AWAY FROM THE COAST WITH LOWER-MID 80S AT THE
BEACHES. QUIET, RAIN-FREE CONDITIONS WILL PREVAIL OVERNIGHT WITH
LOWS FROM THE UPPER 60S/LOWER 70S INLAND TO THE UPPER 70S AT
THE BEACHES.
ATLANTIC HIGH PRESSURE WILL EXTEND WESTWARD ACROSS THE FORECAST
AREA AND INTO THE GULF. ALOFT, A BUILDING RIDGE AND INCREASING
SUBSIDENCE WILL LIMIT CONVECTION THROUGH THE WEEKEND. RELATIVELY
DRY LOW AND MID-LEVEL AIR WILL PERSIST THROUGH THURSDAY,
FURTHER SUPPRESSING CONVECTION, WITH ONLY THE POTENTIAL FOR A
STRAY SHOWER OR TWO SOUTH OF THE SAVANNAH RIVER. OTHERWISE, NO
MORE THAN ISOLATED SHOWER OR THUNDERSTORM ACTIVITY EXPECTED
FRIDAY THROUGH SUNDAY.
KEY MESSAGE 2: TEMPERATURES LIKELY TO APPROACH THE TRIPLE
DIGITS THIS WEEKEND. HEAT ADVISORIES COULD BE NEEDED.
A GRADUAL WARMING TREND IS FORECAST THROUGH THE REMAINDER OF
THE WEEK AND INTO THE WEEKEND. HIGH TEMPERATURES IN THE LOWER
90S WEDNESDAY WILL RISE A COUPLE OF DEGREES EACH DAY, WITH UPPER
90S COMMON ACROSS MUCH OF THE AREA SATURDAY AND SUNDAY. A FEW
LOCATIONS COULD EVEN EXCEED 100 DEGREES ON SUNDAY. COMBINED WITH
DEW POINTS IN THE 70S, HEAT INDEX VALUES COULD REACH 108-113F
SUNDAY, ESPECIALLY ACROSS THE COASTAL COUNTIES. ADDITIONALLY,
BEING THAT CONVECTION IS FORECAST TO BE ISOLATED, WE DO NOT
EXPECT MUCH COOLING/RELIEF FROM SHOWERS/STORMS. WHILE CONFIDENCE
IN THE MAGNITUDE OF THE HEAT AS WELL AS THE CONVECTIVE COVERAGE
REMAINS LIMITED GIVEN THE FORECAST RANGE, THE COMBINATION OF
EXTREME HEAT, HIGH HUMIDITY, AND LIMITED COOLING COULD
NECESSITATE HEAT ADVISORIES WHERE HEAT INDICES MEET OR EXCEED
OUR LOCAL CRITERIA OF 108F DEGREES. FORECAST TRENDS WILL
CONTINUE TO BE MONITORED OVER THE COMING DAYS.
ADDITIONALLY, RECORDS WILL BE CHALLENGED THIS WEEKEND, MAINLY
THE HIGH MINIMUM TEMPERATURES. ALTHOUGH, ON SUNDAY RECORD HIGHS
COULD BE REACHED. SEE THE CLIMATE SECTION BELOW FOR DETAILS.
AVIATION /13Z WEDNESDAY THROUGH SUNDAY/
24/12Z TAF DISCUSSION:
KCHS/KJZI/KSAV: VFR THROUGH 25/12Z. THERE IS A LOW-END RISK FOR
TSTM IMPACTS AT KSAV BY LATE AFTERNOON AS ISOLATED SHOWER/TSTMS
POSSIBLY FORM NEAR/BEHIND THE INLAND MOVING SEA BREEZE. NEAR
TERM HIGH-RES RUNS OVER THE PAST 8 HOURS HAVE BEEN PRETTY
CONSISTENT IN SHOWING CONVECTION NEAR THE TERMINAL. A PROB30 FOR
TSRA WAS INCLUDED 20-00Z TO ACCOUNT FOR THIS ISOLATED ACTIVITY.
EXTENDED AVIATION OUTLOOK: NO HIGH CONFIDENCE CONCERNS.
MARINE
THROUGH TONIGHT: A COLD FRONT WILL CROSS THE WATERS TODAY,
LIKELY BECOMING STATIONARY JUST TO THE SOUTH. NORTHEAST WINDS
WITH A BIT OF POST FRONTAL SURGE WILL VEER MORE EASTERLY THIS
AFTERNOON AS THE SEA BREEZE DEVELOPS AND MOVES INLAND. THE
INITIAL SURGE BEHIND THE FRONT IS A BIT STRONGER THAN
ANTICIPATED AND THE CAPERS NEARSHORE BUOY (41029) AND THE
CHARLESTON BUOY (41066) ARE BOTH GUSTING INTO THE 25-30 KNOT
RANGE. A FEW COASTAL SITES ARE EVEN GUSTING NEAR 25 KNOTS
INCLUDING WEATHERFLOW SITES AT THE IOP PIER, FORT SUMTER, AND
FOLLY BEACH COUNTY PARK. A SMALL CRAFT ADVISORY HAS BEEN ISSUED
THROUGH 2PM. A LIGHTER SOUTHERLY FLOW WILL RETURN TONIGHT. SEAS
WILL AVERAGE 1-3 FT THROUGH THE PERIOD, HIGHEST OVER THE SOUTH
CAROLINA OFFSHORE LEGS.
THURSDAY THROUGH MONDAY: MOSTLY FAVORABLE MARINE CONDITIONS ARE
EXPECTED THROUGH THE WEEKEND AS ATLANTIC HIGH PRESSURE EXTENDS
WESTWARD ACROSS THE AREA AND INTO THE GULF. EXPECT AN INCREASE
IN WINDS ALONG THE COAST DURING THE AFTERNOON AND EVENING
PERIODS ASSOCIATED WITH THE DAILY SEA BREEZE CIRCULATION. FRIDAY
NIGHT INTO SATURDAY NIGHT THE PRESSURE GRADIENT WILL TIGHTEN AS
AN AREA OF LOW PRESSURE PASSES NORTH OF THE AREA. WINDS COULD
GUST 20-25 KT ACROSS THE CHARLESTON COUNTY WATERS. OTHERWISE, NO
MARINE HAZARDS ARE ANTICIPATED THROUGH THE FORECAST PERIOD.
CLIMATE
RECORD HIGH TEMPERATURES:
JUNE 28:
KCHS: 99/1998
KCXM: 100/1959
KSAV: 100/1998
RECORD HIGH MINIMUM TEMPERATURES:
JUNE 27:
KCHS: 77/2015
KSAV: 79/1952
JUNE 28:
KCHS: 78/2013
KCXM: 81/1998
KSAV: 80/1880
JUNE 29:
KCHS: 79/1977
KCXM: 83/1998
KSAV: 80/1885
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR AMZ360.
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