626
FXUS62 KCHS 150721
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
321 AM EDT SAT AUG 15 2026
WHAT HAS CHANGED
ALL SECTIONS HAVE BEEN UPDATED.
KEY MESSAGES
- 1) HEAT WILL REMAIN A CONCERN INTO THE MIDDLE OF NEXT WEEK.
- 2) STRONG TO SEVERE THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON
AND SUNDAY AFTERNOON.
DISCUSSION
KEY MESSAGE 1: HEAT WILL REMAIN A CONCERN INTO THE MIDDLE OF NEXT
WEEK.
TODAY THROUGH SUNDAY: A WARM PATTERN WILL REMAIN IN PLACE WITH A
LARGE-SCALE RIDGE CENTERED ACROSS THE DEEP SOUTH EXTENDING ACROSS
THE SOUTHEAST. AMPLE SUNSHINE WILL PROMOTE STRONG SFC HEATING WHILE
A WEST-NORTHWEST DOWNSLOPE FLOW PERSISTS ACROSS THE REGION. GUIDANCE
CONTINUES TO SUPPORT AFTERNOON HIGHS IN THE MID-UPPER 90S WITH A FEW
LOCATIONS POTENTIALLY TOUCHING 100 DEGREES, WHICH COULD RESULT IN
RECORD WARMTH (SEE CLIMATE SECTION BELOW). HUMID CONDITIONS WILL
ALSO PERSIST WITH SFC DEWPTS IN THE MID-UPPER 70S EACH DAY. ALTHOUGH
THE DOWNSLOPE FLOW SHOULD RESULT IN A SLIGHTLY DELAYED SEABREEZE AND
SOME MIXING OUT OF SFC DEWPTS INLAND, MOISTURE SHOULD POOL NEAR THE
BOUNDARY AS IT SHIFTS INLAND AS WELL AS BRING HIGHER MOISTURE CONTENT
ONSHORE. THIS WILL LIKELY RESULT IN THE HIGHER HEAT/MOISTURE
COMBINATION ALONG COASTAL ZONES (ALONG/EAST OF I-95) FOR THE NEXT
COUPLE DAYS, WITH HEAT INDEX VALUES UP TO THE 108-115 RANGE LATE
MORNING INTO THE AFTERNOON AND AGAIN ON SUNDAY. GIVEN TODAY'S SETUP,
AN EXTREME HEAT WARNING IS IN EFFECT FOR COASTAL COUNTIES FROM 11 AM
TO 8 PM TODAY WHILE REMAINING AREAS ARE INCLUDED IN A HEAT ADVISORY
FOR THE SAME TIME PERIOD. SUNDAY SHOULD HAVE SIMILAR RESULTS BASED
ON THE PERSISTENT PATTERN. HOWEVER, A SLIGHT UPTICK IN CONVECTIVE
COVERAGE IS POSSIBLE WITH A FRONT APPROACHING NEARBY. GIVEN SOME
UNCERTAINTY IN CONVECTION TRENDS, HAVE OPTED TO REMAIN HEAT HEADLINE
FREE ON SUNDAY. HOWEVER, HEAT ADVISORIES WILL LIKELY BE NEEDED
OVER THE AREA, AND SHOULD CONVECTION HOLD OF UNTIL LATE DAY,
ANOTHER EXTREME HEAT WARNING COULD EVENTUALLY BE REQUIRED ALONG
COASTAL COUNTIES SUNDAY AFTERNOON.
EARLY TO MIDDLE OF NEXT WEEK: HOT/HUMID CONDITIONS LIKELY REMAIN
ACROSS THE SOUTHEAST UNITED STATES WITH THE LARGE-SCALE RIDGE
EXTENDED ACROSS THE REGION FROM THE WEST-SOUTHWEST. RECORD WARMTH IS
POSSIBLE NEXT WEEK WITH LATEST GUIDANCE SUGGESTING SEVERAL AREAS OF
100+ TEMPS MONDAY/TUESDAY AND WITH LITTLE TO NO SHOWER/THUNDERSTORM
ACTIVITY. CONDITIONS STILL REMAIN HOT HEADING THROUGH MID-WEEK AS
WELL WITH HUMID CONDITIONS. ADDITIONAL HEAT HEADLINES ARE LIKELY
EARLY INTO THE MIDDLE OF NEXT WEEK.
KEY MESSAGE 2: STRONG TO SEVERE THUNDERSTORMS ARE POSSIBLE THIS
AFTERNOON AND SUNDAY AFTERNOON.
THE HEAT AND HUMIDITY (MENTIONED IN KEY MESSAGE 1) WILL PROVIDE A
MODERATE AMOUNT OF INSTABILITY ACROSS OUR AREA THIS AFTERNOON AND
AGAIN SUNDAY AFTERNOON. DEPENDING ON THE MODEL, SBCAPE VALUES PEAK
IN THE 2,000-2,500 J/KG RANGE, WITH DCAPE VALUES UPWARDS OF 800
J/KG. THERE ARE SOME MINOR DIFFERENCES AMONGST THE VARIOUS NEAR-TERM
CAMS AND EVEN THE SYNOPTIC MODELS. BUT THE GENERAL CONSENSUS IS THAT
THERE SHOULD BE ISOLATED TO SCATTERED CONVECTION BOTH AFTERNOONS.
THE STORMS ARE MOST LIKELY TO START ALONG THE SEA BREEZE AND THEN
SHIFT INLAND, WITH OUTFLOW AND BOUNDARY INTERACTIONS PLAYING A ROLE
IN STORM FORMATION AND PERSISTENCE. GIVEN THE AFOREMENTIONED
INSTABILITY, STRONG TO SEVERE THUNDERSTORMS ARE POSSIBLE. THE MAIN
THREAT WOULD BE DAMAGING WINDS. BUT HEAVY RAINFALL IS ALSO A CONCERN
DUE TO WEAK STEERING FLOW. BACKBUILDING AND/OR TRAINING OF STORMS
COULD DROP ENOUGH RAINFALL TO GENERATE VERY LOCALIZED FLOODING. THE
CONVECTION EACH AFTERNOON IS EXPECTED TO DISSIPATE EACH EVENING.
AVIATION /06Z SATURDAY THROUGH WEDNESDAY/
VFR CONDITIONS ARE EXPECTED AT CHS/JZI/SAV TERMINALS THROUGH AT
LEAST 18Z SATURDAY. THE RISK FOR ISOLATED TO SCATTERED SHOWERS
AND/OR THUNDERSTORMS INCREASES DURING AFTERNOON INTO EARLY EVENING
HOURS AT ALL TERMINALS. PROB30 GROUPS FOR THUNDERSTORMS AND MVFR
CONDITIONS REMAIN IN PLACE FOR CHS BETWEEN 20-24Z SATURDAY AND FOR
JZI/SAV BETWEEN 20-23Z SATURDAY, ALTHOUGH LATEST GUIDANCE WOULD
SUGGEST THE CHS TERMINAL HAVING THE BEST CHANCE OF DIRECT IMPACTS. A
FEW THUNDERSTORMS COULD BE STRONG WITH GUSTY WINDS. VFR CONDITIONS
ARE THEN EXPECTED TO PREVAIL AT ALL TERMINALS BETWEEN 00Z TO 06Z
SUNDAY.
EXTENDED AVIATION OUTLOOK: AFTERNOON SHOWERS AND THUNDERSTORMS WILL
BRING BRIEF FLIGHT RESTRICTIONS ON SUNDAY.
MARINE
TONIGHT AND SUNDAY: CONDITIONS ARE EXPECTED TO REMAIN QUIET
ACROSS LOCAL WATERS BETWEEN THE WESTERN PERIPHERY OF AN ATLANTIC
HIGH AND WEAK TROUGHING INLAND, ALTHOUGH THUNDERSTORMS THAT
DEVELOP OVER LAND COULD SHIFT OFFSHORE LATE AFTERNOON INTO EARLY
EVENING HOURS. A FEW THUNDERSTORMS COULD REMAIN STRONG WHEN
SHIFTING ACROSS COASTAL AREAS. OUTSIDE THUNDERSTORMS,
SOUTHWESTERLY WINDS AROUND 10 KT THIS MORNING SHOULD TURN MORE
SOUTHERLY AND GUST UP TO 15-20 KT THIS AFTERNOON, THEN PERSIST
INTO EVENING HOURS, BEFORE SLOWLY WEAKENING AND RETURNING TO A
SOUTHWESTERLY DIRECTION OVERNIGHT. SEAS SHOULD BE NO LARGER THAN
2-3 FT.
EXTENDED MARINE: THERE WILL BE AREAS OF HIGH PRESSURE IN THE WESTERN
ATLANTIC AND THE NORTHERN GULF, WHILE SURFACE TROUGHING WILL BE OVER
THE SOUTHEAST U.S. THE INTERACTION BETWEEN ALL OF THESE SYNOPTIC
FEATURES WILL GENERATE A TYPICAL SUMMERTIME WIND PATTERN. WINDS WILL
GENERALLY BE FROM THE SW, BACKING A BIT EACH DAY AND VEERING SOME
EACH NIGHT. THE STRONGEST WINDS SHOULD BE DURING THE DAY, ESPECIALLY
CLOSER TO THE COAST DUE TO THE SEA BREEZE. SEAS WILL MAINLY BE IN
THE 2-3 FT RANGE.
CLIMATE
RECORD HIGH TEMPERATURES:
AUGUST 14:
KCHS: 102/1995
KSAV: 102/1925
AUGUST 15:
KCHS: 96/2023
KCXM: 99/1918
KSAV: 100/1918
AUGUST 16:
KCHS: 99/1954
KSAV: 100/1954
AUGUST 17:
KCHS: 102/1954
KSAV: 102/1954
AUGUST 18:
KCHS: 101/1995
KCXM: 97/1995
KSAV: 100/1995
AUGUST 19:
KCHS: 98/1983
KSAV: 99/1900
AUGUST 20:
KCHS: 97/2005
KSAV: 102/1900
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
AUGUST 19:
KCHS: 79/2010
KCXM: 83/2021
KSAV: 79/1878
AUGUST 20:
KCHS: 78/2017
KCXM: 82/2017
KSAV: 82/1878
CHS WATCHES/WARNINGS/ADVISORIES
GA...HEAT ADVISORY FROM 11 AM THIS MORNING TO 8 PM EDT THIS EVENING
FOR GAZ087-088-099>101-114-115-137.
EXTREME HEAT WARNING FROM 11 AM THIS MORNING TO 8 PM EDT THIS
EVENING FOR GAZ216>219-238>241.
SC...HEAT ADVISORY FROM 11 AM THIS MORNING TO 8 PM EDT THIS EVENING
FOR SCZ040-042>044.
EXTREME HEAT WARNING FROM 11 AM THIS MORNING TO 8 PM EDT THIS
EVENING FOR SCZ045-147>152.
MARINE...NONE.
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