525
FXUS62 KCHS 131725
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
125 PM EDT THU AUG 13 2026
WHAT HAS CHANGED
ALL KEY MESSAGES AND SECTION WERE UPDATED.
KEY MESSAGES
- 1) HEAT WILL REMAIN A CONCERN INTO EARLY NEXT WEEK.
- 2) ISOLATED SEVERE T-STORMS POSSIBLE THROUGH FRIDAY.
DISCUSSION
KEY MESSAGE 1: HEAT WILL REMAIN A CONCERN INTO NEXT WEEK.
THROUGH TONIGHT: HEAT INDICES CONTINUE TO RISE THIS AFTERNOON
AND ARE ON TARGET TO PEAK 105-112 INLAND WITH 112-118 AT THE
COAST. SURFACE OBSERVATIONS AND KCLX RADAR DATA SHOW THE
RESULTANT SEA BREEZE CONTINUES TO MATURE ALONG THE COAST AND
WILL PROPAGATE STEADILY INLAND THROUGH THIS EVENING. DEWPOINTS
ARE EXPECTED TO SURGE INTO THE UPPER 70S/LOWER 80S ALONG AND
BEHIND IT. WOULD NOT BE SURPRISED TO SEE A FEW SPOTS BRIEFLY
MAX OUT AT 119-120 BEFORE FALLING EVER SO SLOWLY. BOTH THE HEAT
ADVISORY AND EXTREME HEAT WARNING LOOK ON TARGET. THE ONLY
THING TO WATCH IS POSSIBLE CONVECTION EITHER DEVELOPING ALONG
THE SEA BREEZE OR PROPAGATING EAST/SOUTHEAST OUT CENTRAL GEORGIA
AND THE SOUTH CAROLINA MIDLANDS. RIGHT NOW, THIS ACTIVITY LOOKS
TO REMAIN FAIRLY ISOLATED, BUT ANY SHOWERS/TSTMS WILL PROVIDE
SOME TEMPORARY RELIEF FROM THE OPPRESSIVE HEAT/HUMIDITY THAT IS
PLAGUING THE LOWCOUNTRY AND SOUTHEAST GEORGIA.
FRIDAY THROUGH MONDAY: A PROMINENT RIDGE WILL CONTINUE EXPAND
ACROSS THE SOUTHEAST THROUGH EARLY NEXT WEEK. THIS WILL YIELD
WEST- SOUTHWESTERLY FLOW COMBINED WITH AFTERNOON HIGHS IN THE
MID TO UPPER 90S (WITH SOME SPOTS BRIEFLY HITTING 100F). IN
ADDITION TO THE EXTREME TEMPERATURES, IT'LL BE QUITE HUMID
OUTSIDE WITH DEWPOINTS IN THE MID TO UPPER 70S. EXPECT PWAT
VALUES TO RANGE FROM 2.0 TO 2.2 INCHES WITH THE HIGHEST MOISTURE
GENERALLY LOCATED ALONG AND EAST OF THE I-95 CORRIDOR.
AFTERNOON HEAT INDEX VALUES COULD REACH UPWARDS OF 120F TOMORROW
(FRIDAY) THROUGH MONDAY ACROSS THE COASTAL CORRIDOR (EAST OF
I-95). FOR THE REMAINING INLAND COUNTIES, HEAT INDEX VALUES WEST
OF I-95 WILL RANGE FROM 105F TO 112F THROUGH MONDAY. ALSO, THE
MAXIMUM WEB-BULB GLOBE TEMPERATURE (WBGT) WILL BE ABOVE 90F EACH
DAY THROUGH EARLY NEXT WEEK AS WELL, THIS MEANS A MAJORITY OF
THE REGION WILL BE UNDER BLACK FLAG CONDITIONS. IT WILL NOT FEEL
PLEASANT OUTSIDE AND THERE WILL BE LITTLE TO NO RELIEF FROM THE
HEAT OVERNIGHT WITH LOW TEMPERATURES RANGING FROM UPPER 70S TO
LOW 80S. THEREFORE, AN EXTREME HEAT WARNING WILL CONTINUE INTO
FRIDAY FOR THE COASTAL COUNTIES, AND A HEAT ADVISORY WILL ALSO
CONTINUE FOR THE REMAINING INLAND COUNTIES FOR THE SAME
TIMEFRAME. THEREAFTER, WE WILL LIKELY NEED TO ISSUE HEAT HAZARDS
EVERYDAY THROUGH EARLY NEXT WEEK.
KEY MESSAGE 2: ISOLATED SEVERE T-STORMS POSSIBLE THROUGH FRIDAY.
THROUGH TONIGHT: ISOLATED SHOWERS/TSTMS ARE BEGINNING TO
DEVELOP TO THE WEST, WHICH MAY MOVE INTO INLAND AREAS SOON. SOME
CONVECTION MAY ALSO POP ALONG THE SEA BREEZE AS WELL AS IT
MOVES INLAND. SLIGHT CHANCE POPS WERE MAINTAINED THROUGH MID-
EVENING. DCAPES ARE ELEVATED SO THERE IS A RISK FOR AN ISOLATED
SEVERE TSTM WITH DAMAGING WINDS AND CLOUD-TO-GROUND LIGHTNING
BEING THE PRIMARY HAZARD.
FRIDAY: AS AN UPPER-LVL RIDGE CONTINUES TO BUILD ACROSS THE
SOUTHEAST TOMORROW (FRIDAY), MULTIPLE MCVS WILL LIKELY ROUND THE
EDGE OF THE RIDGE, YIELDING THE POTENTIAL FOR STRONG
THUNDERSTORMS TO DEVELOP WITHIN A VERY HOT AND HUMID
ENVIRONMENT. SOME OF THE NEAR- TERM GUIDANCE HAS BEEN INDICATING
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS DEVELOPING
ACROSS THE MIDLANDS AND THEN TRACKING ACROSS THE SOUTH CAROLINA
LOWCOUNTRY AND SOUTHEAST GEORGIA IN THE LATE AFTERNOON AND
EVENING HOURS. THE ENVIRONMENT WILL FEATURE MODERATE AMOUNT OF
INSTABILITY (SBCAPE VALUES OF 2000-2250 J/KG WITH DCAPE VALUES
UPWARDS OF 800 J/KG) IN THE AFTERNOON, YIELDING POSSIBILITY OF
DAMAGING WIND GUSTS WITHIN THE STRONGER THUNDERSTORMS
AVIATION /18Z THURSDAY THROUGH TUESDAY/
13/18Z TAFS:
KCHS/KJZI/KSAV: VFR THROUGH 14/18Z. ISOLATED CONVECTION MAY FIRE
MID-LATE AFTERNOON, BUT CONFIDENCE FOR ANY ONE PARTICULAR CELL
IMPACTING ANY TERMINAL IS LOW. AMENDMENTS WILL BE ISSUED AS
NEEDED IF THE RISK FOR TSTM IMPACTS INCREASE.
EXTENDED AVIATION OUTLOOK: PERIODIC FLIGHT RESTRICTIONS ARE
EXPECTED IN THE AFTERNOONS WITH THE CHANCE OF SHOWERS AND
THUNDERSTORMS THROUGH EARLY NEXT WEEK.
MARINE
THROUGH TONIGHT: QUIET CONDITIONS WILL PERSIST ACROSS THE WATERS
WITH SOUTHERLY WINDS 15 KT OR LESS AND SEAS 2 FT OR LESS.
FRIDAY THROUGH MONDAY: AS A WEAK COASTAL TROUGH SITUATES ITSELF
ACROSS THE ATLANTIC, MARINE CONDITIONS WILL REMAIN ON THE QUIET
SIDE WITH SOUTH-SOUTHWESTERLY WINDS RANGING FROM 10 TO 15 KTS
WITH GUSTS UP TO 20 KTS POSSIBLE THROUGH THE PERIOD. WEAK SOUTH-
SOUTHWESTERLY SWELL WILL CONTINUE TO TAPER INTO THE WATERS
THROUGH THE WEEKEND YIELDING 2 TO 3 FT SEAS.
COASTAL FLOODING: TIDE LEVELS COULD REMAIN ELEVATED DUE TO THE
RECENT PERIGEE AND NEW MOON DURING THE EVENING HIGH TIDE CYCLE,
ALTHOUGH A SOUTH-SOUTHWESTERLY WIND SHOULD KEEP TIDAL DEPARTURES
LESS FAVORABLE FOR A COASTAL FLOOD THREAT. SHOULD ONSHORE WINDS
LINGER LONGER THAN ANTICIPATED, MINOR COASTAL FLOODING (~7.0 FT
MLLW) COULD BECOME AN ISSUE IN THE CHARLESTON HARBOR DURING THE
HIGH TIDE THIS EVENING, WHICH OCCURS AROUND 930 PM.
CLIMATE
RECORD HIGH TEMPERATURES:
AUGUST 14:
KCHS: 102/1995
KSAV: 102/1925
AUGUST 15:
KCHS: 96/2023
KCXM: 99/1918
KSAV: 100/1918
AUGUST 17:
KCHS: 102/1954
KSAV: 102/1954
AUGUST 18:
KCXM: 97/1995
KSAV: 100/1995
RECORD HIGH MINIMUM TEMPERATURES:
AUGUST 14:
KCHS: 80/2023
KCXM: 83/2023
KSAV: 80/2023
AUGUST 15:
KCHS: 78/1995
KCXM: 83/2021
KSAV: 80/1995
AUGUST 16:
KCHS: 78/2019
KCXM: 83/2016
KSAV: 78/2019
AUGUST 17:
KCHS: 80/2017
KCXM: 83/2017
KSAV: 78/2017
AUGUST 18:
KCHS: 80/2017
KCXM: 82/2017
KSAV: 78/2010
CHS WATCHES/WARNINGS/ADVISORIES
GA...HEAT ADVISORY UNTIL 8 PM EDT FRIDAY FOR GAZ087-088-099>101-114-
115-137.
EXTREME HEAT WARNING UNTIL 8 PM EDT FRIDAY FOR GAZ216>219-
238>241.
SC...HEAT ADVISORY UNTIL 8 PM EDT FRIDAY FOR SCZ040-042>044.
EXTREME HEAT WARNING UNTIL 8 PM EDT FRIDAY FOR SCZ045-147>152.
MARINE...NONE.
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