526
FXUS62 KCHS 121139
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
739 AM EDT FRI JUN 12 2026
WHAT HAS CHANGED
THE AVIATION SECTION HAS BEEN UPDATED FOR THE 12Z TAF ISSUANCE.
KEY MESSAGES
- 1) AFTERNOON HEAT INDEX VALUES COULD CLIMB INTO THE 105 TO 112 DEGREE
RANGE ACROSS THE I-95/COASTAL CORRIDOR THIS WEEKEND.
- 2) RAIN CHANCES WILL INCREASE INTO THE WEEKEND AS WE RETURN TO
A MORE TYPICAL SUMMERTIME PATTERN.
- 3) MINOR COASTAL FLOODING POSSIBLE ALONG CHARLESTON AND COLLETON
COUNTY COASTS DURING EVENING HIGH TIDES THIS WEEKEND INTO
EARLY NEXT WEEK.
DISCUSSION
KEY MESSAGE 1: AFTERNOON HEAT INDEX VALUES COULD CLIMB INTO THE 105
TO 112 DEGREE RANGE ACROSS THE I-95/COASTAL CORRIDOR THIS WEEKEND.
FOR TODAY, MID-LVL RIDGING WILL REMAIN CENTERED ACROSS THE DEEP
SOUTH WHILE SFC HIGH PRESSURE EXTENDS ACROSS THE REGION FROM THE
NEARBY ATLANTIC. LATEST GUIDANCE SUPPORTS A LIGHT WEST-SOUTHWEST
WIND DEVELOPING ACROSS THE LOCAL AREA BETWEEN THE EDGE OF THE
ATLANTIC HIGH AND WELL AHEAD OF A COLD FRONT SHIFTING ACROSS THE
APPALACHIAN MOUNTAINS THIS EVENING, WHICH WILL SUPPORT WARMING
CONDITIONS ACROSS THE SOUTHEAST WHILE LARGE SCALE SUBSIDENCE ALONG
WITH A WEST-NORTHWEST DOWNSLOPING WIND COMPONENT ALOFT PROMOTE
STRONG SFC HEATING. LATEST 1000-850MB THICKNESSES SUPPORT MAX TEMPS
IN THE MID-UPPER 90S AWAY FROM THE BEACHES THIS AFTERNOON WHILE MID
70 DEWPTS WITHIN A MARINE LAYER SLOWLY SHIFT ONSHORE THIS AFTERNOON
ALONG/BEHIND A SEA BREEZE. SOME GUIDANCE INDICATES A POTENTIAL TO
SET NEW RECORD HIGH TEMPERATURES, SEE CLIMATE SECTION BELOW. THE
COMBINATION OF HEAT AND MOISTURE IS LIKELY TO SUPPORT HEAT INDEX
VALUES AROUND 105 DEGREES ALONG THE COASTAL CORRIDOR, WITH A FEW
SPOTS POTENTIALLY REACHING 108 DEGREES EARLY AFTERNOON. HOWEVER, FEW
TO SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP
ALONG/NEAR THE SEA BREEZE WITH AT LEAST SOME CLOUDS DRIFTING BACK
TOWARD COASTAL AREAS DURING PEAK HEATING HOURS, LIKELY LIMITING THE
POTENTIAL FOR AN EXTENDED PERIOD OR LARGE COVERAGE OF HEAT ADVISORY
LEVEL CONDITIONS. GIVEN THIS EXPECTANCY, HAVE HELD OFF ON A HEAT
ADVISORY ISSUANCE THIS AFTERNOON. CONDITIONS WILL CONTINUE TO BE
MONITORED FOR A SHORT DURATION HEAT ADVISORY SHOULD CONVECTION HOLD
OFF OR COVERAGE BE LESS THAN ANTICIPATED THIS AFTERNOON.
SATURDAY: A SIMILAR PATTERN WILL BE IN PLACE AS THE PREVIOUS DAY
WITH MID-LVL RIDGING EXTENDING ACROSS THE DEEP SOUTH AND SFC HIGH
PRESSURE ATTEMPTING TO HOLD ACROSS THE WESTERN ATLANTIC. THE DAY
WILL START OFF WARM WITH A SOUTH-SOUTHWEST WIND IN ADVANCE OF A
FRONT/TROUGH WITH AFTERNOON HIGHS IN THE UPPER 90S FOR MANY AREAS
AWAY FROM THE BEACHES. MOISTURE LEVELS SHOULD BECOME HIGHER DURING
PEAK DIURNAL HEATING WITH SFC DEWPTS IN THE MID-UPPER 70S ALONG THE
COASTAL CORRIDOR, AND HEAT INDEX VALUES ARE FORECAST TO APPROACH THE
108-112 DEGREE RANGE. HOWEVER, SHOWER AND THUNDERSTORMS DEVELOPING
ACROSS THE LOCAL AREA WILL COMPLICATE THE POTENTIAL FOR HIGHER HEAT
INDEX VALUES, AND COULD VERY WELL LIMIT THE POTENTIAL FOR A HEAT
ADVISORY ISSUANCE. CONDITIONS WILL CONTINUE TO BE MONITORED FOR MAX
HEATING POTENTIAL, BUT WILL LARGELY BE DEPENDENT ON CONVECTIVE
TRENDS.
FOR SUNDAY, SHOWER/THUNDERSTORM COVERAGE ALONG WITH GREATER CLOUD
COVER IS ANTICIPATED WITH A FRONT NEARBY AND/OR JUST INLAND, WHICH
SHOULD LIMIT HEAT INDEX VALUES LOCALLY. WARM/HUMID CONDITIONS REMAIN
IN THE FORECAST WHILE THE MID-UPPER LVL RIDGE ATTEMPTS TO HOLD
ACROSS THE SOUTHEAST TO START OFF EARLY NEXT WEEK, BUT MAX TEMPS ARE
FORECAST TO BE A FEW DEGREES LOWER THAN THE WEEKEND. SHOULD PRECIP
COVERAGE BE LESS THAN ANTICIPATED AND/OR OCCUR LATE DAY, HEAT INDEX
VALUES COULD APPROACH 108 DEGREES ALONG THE COASTAL CORRIDOR.
KEY MESSAGE 2: RAIN CHANCES WILL INCREASE INTO THE WEEKEND AS WE
RETURN TO A MORE TYPICAL SUMMERTIME PATTERN.
AS A SURFACE HIGH PRESSURE CONTINUES TO WOBBLE ALONG THE FLORIDA
COASTLINE, PRECIPITABLE WATER VALUES OF 1.6-2.0" LOOK TO REMAIN
FAIRLY STEADY THROUGHOUT THE DAY, HIGHEST ALONG THE COAST. A WEAK
PRE-FRONTAL TROUGH BEGINS TO FORM BY THE LATE MORNING, WITH SBCAPE
VALUES OF 1500-2000 J/KG BUILDING INTO THE EARLY AFTERNOON. AN
AFTERNOON SEA-BREEZE IS EXPECTED PUSH ASHORE AND GIVEN THE UNCAPPED
ENVIRONMENT, SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
FORM. AMIDST THE WESTERLY SURFACE WINDS THE SEA-BREEZE MAY STRUGGLE
TO PUSH PAST THE I-95 CORRIDOR, LEADING TO HIGHEST CHANCES FOR RAIN
OCCURRING NEAR THE COASTLINE. GIVEN THE LACK OF SHEAR, ORGANIZED
CONVECTION IS NOT EXPECTED, WHICH WILL ALSO LIMIT THE RAINFALL
POTENTIAL OF THE THUNDERSTORMS AS THEY'LL LIKELY BE RATHER SHORT-
LIVED. HOWEVER, GIVEN THE WEAK FLOW ALOFT, THE SHOWERS/STORMS WILL
BE RATHER SLOW MOVING, WITH THE HREF INDICATING A NEAR 50% CHANCE
FOR AN INCH OF RAIN FOR AREAS BETWEEN THE I-95 CORRIDOR AND THE
COASTLINE ACROSS SOUTHERN SOUTHEAST SOUTH CAROLINA, DECREASING TO
NEAR 30% IN SOUTHEAST GEORGIA EAST OF THE I-95 CORRIDOR. CHANCES FOR
SHOWERS AND THUNDERSTORMS DECREASE INTO THE EVENING HOURS AS
INSTABILITY WANES.
SIMILAR CONDITIONS ARE EXPECTED FOR SATURDAY AHEAD OF AN APPROACHING
COLD FRONT, WITH AN AFTERNOON SEA-BREEZE INTERACTING WITH 1500-2000
J/KG OF CAPE LIKELY PRODUCING ANOTHER ROUND OF SCATTERED SHOWERS AND
THUNDERSTORMS. BULK SHEAR REMAINS ON THE LOWER END NEAR 20 KNOTS,
BUT WITH DCAPE VALUES NEAR 1000 J/KG AN ISOLATED STRONG-SEVERE WIND
GUST CANNOT BE RULED OUT. EXPECT SIMILAR CHANCES FOR SHOWERS AND
THUNDERSTORMS FOR SUNDAY AND MONDAY AS THE AFOREMENTIONED FRONT
LIFTS TO THE NORTH, WITH THE NEXT COLD FRONT EXPECTED TO NOW PUSH
THROUGH ON TUESDAY, PROVIDING ADDITIONAL LIFT FOR SHOWERS AND
THUNDERSTORMS.
KEY MESSAGE 3: MINOR COASTAL FLOODING POSSIBLE ALONG CHARLESTON AND
COLLETON COUNTY COASTS DURING EVENING HIGH TIDES THIS WEEKEND INTO
EARLY NEXT WEEK.
BREEZY SOUTH-SOUTHEASTERLY WINDS POST SEA BREEZE EACH DAY ALONG WITH
THE UPCOMING LUNAR PERIGEE (JUNE 14TH) AND NEW MOON (JUNE 15TH)
COULD RESULT IN ELEVATED TIDAL DEPARTURES AROUND 1/2 FT THIS WEEKEND
INTO EARLY NEXT WEEK, WHICH SETS THE STAGE FOR MINOR COASTAL
FLOODING ISSUES ALONG THE CHARLESTON AND COLLETON COUNTY COASTS
DURING EVENING HIGH TIDE CYCLES. THE LATEST TWL FORECAST CALLS FOR
7.1-7.3 FT MLLW IN THE CHARLESTON HARBOR SATURDAY EVENING, AND
SIMILAR WATER LEVELS ARE POSSIBLE DURING EVENING HIGH TIDES INTO
EARLY NEXT WEEK AS ASTRONOMICAL INFLUENCES PEAK AND BREEZY ONSHORE
WINDS PERSIST. COASTAL FLOOD ADVISORIES COULD EVENTUALLY BE
NEEDED.
AVIATION /12Z FRIDAY THROUGH TUESDAY/
VFR CONDITIONS WILL PREVAIL AT CHS/JZI/SAV TERMINALS THROUGH 12Z
SATURDAY. HOWEVER, FEW TO SCATTERED SHOWERS ALONG WITH A FEW
THUNDERSTORMS COULD IMPACT THE TERMINALS THIS AFTERNOON,
PRIMARILY AT CHS AND SAV TERMINALS WHERE A SEA BREEZE INITIATES
THIS ACTIVITY DURING PEAK HEATING HOURS. PROB30 GROUPS FOR TSRA
AND 4SM REMAIN AT CHS (18-21Z) AND SAV (18-22Z). VCTS REMAINS AT
JZI (18-21Z), BUT CONFIDENCE IN DIRECT IMPACTS FROM SHOWER OR
THUNDERSTORM ACTIVITY IS LESS CLEAR. BY SUNSET, VFR CONDITIONS
ARE EXPECTED TO PREVAIL, THEN PERSIST THROUGH 12Z SATURDAY.
EXTENDED AVIATION OUTLOOK: VFR CONDITIONS SHOULD PREVAIL AT
CHS/JZI/SAV TERMINALS THROUGH THE WEEKEND, ALTHOUGH TEMPO FLIGHT
RESTRICTIONS ARE POSSIBLE WITH AFTERNOON SHOWERS/THUNDERSTORMS
THROUGHOUT THE WEEKEND. CHANCES FOR FLIGHT RESTRICTIONS INCREASE
EARLY NEXT WEEK WITH SHOWER/THUNDERSTORM COVERAGE EXPANDING LOCALLY
AHEAD OF AN ARRIVING COLD FRONT.
MARINE
SURFACE HIGH PRESSURE WILL PREVAIL OVER THE MARINE ZONES INTO
SATURDAY. PREVAILING S TO SW WINDS GENERALLY 10 TO 15 KNOTS, WITH
GUSTS TO AROUND 20 KNOTS ALONG THE COASTLINE EACH AFTERNOON
ASSOCIATED WITH THE SEA BREEZE, WITH CONDITIONS REMAINING BELOW
SMALL CRAFT CRITERIA THROUGH SATURDAY NIGHT. A PREFRONTAL TROUGH
BEGINS TO FORM ON SUNDAY, YIELDING AN ENHANCED PRESSURE GRADIENT
LEADING TO WINDS GUSTS IN THE LOW 20 KNOT RANGE, POSSIBLY REACHING
AS HIGH AS 25 KNOTS DURING THE OVERNIGHT HOURS INTO MONDAY AND AGAIN
TUESDAY. A COLD FRONT IS EXPECTED TO MOVE THROUGH EARLY/MIDDLE OF
NEXT WEEK.
CLIMATE
RECORD HIGH TEMPERATURES:
JUNE 12:
KCHS: 97/2016
KCXM: 97/1998
KSAV: 100/1977
JUNE 13:
KCHS: 99/2011
KCXM: 96/1998
JUNE 14:
KCHS: 99/2010
KCXM: 97/1981
RECORD HIGH MINIMUM TEMPERATURES:
JUNE 11:
KCHS: 76/2020
KCXM: 79/2020
KSAV: 76/2010
JUNE 12:
KCHS: 77/1986
KCXM: 80/1998
KSAV: 78/1899
JUNE 13:
KCHS: 80/2013
KCXM: 82/1998
KSAV: 80/1880
JUNE 14:
KCHS: 79/2010
KCXM: 81/2010
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...NONE.
APT/DPB
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