186
FXUS62 KCHS 092346
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
746 PM EDT THU JUL 9 2026
WHAT HAS CHANGED
ALL SECTIONS HAVE BEEN UPDATED.
KEY MESSAGES
- 1) A PROLONGED HEAT WAVE WILL MAINTAIN HOT AND HUMID
CONDITIONS THROUGH THE END OF THE WEEK AND INTO THE START OF
THE WEEKEND.
- 2) TYPICAL SUMMERTIME AFTERNOON AND EVENING THUNDERSTORMS
THIS WEEK WITH INCREASING RAIN CHANCES SUNDAY THROUGH TUESDAY.
DISCUSSION
KEY MESSAGE 1: A PROLONGED HEAT WAVE WILL MAINTAIN HOT AND
HUMID CONDITIONS THROUGH THE END OF THE WEEK AND INTO THE START
OF THE WEEKEND.
FOR FRIDAY, THE REGION WILL SOLIDLY PLACED ALONG THE NORTHERN
PERIPHERY OF THE SUBTROPICAL ANTICYCLONE ALOFT CENTERED JUST TO
THE EAST OF THE BAHAMAS. LOW-LEVEL THICKNESS AND 850 HPA
TEMPERATURES WILL CHANGE LITTLE FROM THURSDAY WITH VALUES
HOLDING 1437-1442M AND 20-22C RESPECTIVELY. THE DAY WILL START
OFF RATHER WARM WITH TEMPERATURES LIKELY TO WARM QUICKLY AFTER
DAYBREAK. SOUNDINGS AND LOW-LEVEL THICKNESS SCHEMES SUPPORT
ANOTHER DAY OF HIGHS IN THE UPPER 90S TO NEAR 100 WITH SOME
LOCATIONS LIKELY SURPASSING 100. THE RECORD HIGHS AT BOTH KCHS
AND KSAV COULD BE CHALLENGED. GUIDANCE DOES SHOW MID-LEVEL
MOISTURE DRYING OUT A BIT IN RESPONSE TO A DRY SLOT PASSING
THROUGH ALOFT. THIS COUPLED WITH VERTICAL DEEP MIXING SHOULD
HELP MIX OUT DEWPOINTS INTO THE UPPER 60S INLAND WHICH WILL
LIMIT HEAT INDICES THERE COMPARED TO THE PAST FEW DAYS. CLOSER
TO THE COAST, SOME MIXING IS ALSO LIKELY TOO OCCUR INTO THE
EARLY AFTERNOON BEFORE DEWPOINTS SURGE AGAIN WITH THE PASSAGE OF
THE SEA BREEZE. SIMILAR TO THE PAST FEW DAYS, DEWPOINTS ARE
EXPECTED TO POOL BACK INTO THE UPPER 70S/LOWER 80S NEAR/BEHIND
THE SEA BREEZE ITSELF. THE INLAND PROGRESSION OF THE BOUNDARY
DOES LOOK TO PROPAGATE INLAND A BIT LATER THAN USUAL WITH THE
BEST POOLING OF DEWPOINTS LIKELY TO OCCUR ACROSS THE LOWER SOUTH
CAROLINA COAST, ESPECIALLY THE CHARLESTON COUNTY COAST. COASTAL
HEAT INDICES ARE POISED TO PEAK IN THE 108-112 IN THE COASTAL
CORRIDOR WITH 110-115 ALONG THE CHARLESTON COUNTY COAST. FOR
THIS REASON, A HEAT ADVISORY HAS BEEN POSTED FOR THE COASTAL
COUNTIES AS WELL AS DORCHESTER AND INLAND BERKELEY WITH AN
EXTREME HEAT WARNING FOR CHARLESTON AND TIDAL BERKELEY WHERE THE
CHANCES FOR REACHING 113 HEAT INDICES FOR AT LEAST HOURS IS THE
HIGHEST. ISOLATED AFTERNOON CONVECTION COULD PROVIDE SOME
RELIEF FOR A FEW AREAS, BUT A MAJOR TO EXTREME HEAT RISK
PERSISTS ACROSS ALL OF THE LOWCOUNTRY AND SOUTHEAST GEORGIA.
OVERNIGHT, LOWS ARE ONLY FORECAST TO DIP INTO THE UPPER
70S/LOWER 80S. THESE WARM OVERNIGHT CONDITIONS COULD RESULT IN
PROLONGED HEAT STRESS, ESPECIALLY FOR MORE VULNERABLE
COMMUNITIES AND THOSE WITHOUT ADEQUATE COOLING OVERNIGHT.
FOR SATURDAY, THINGS LOOK A BIT COOLER OVERALL AS THE
SUBTROPICAL RIDGE BEGINS TO FLATTEN OUT YIELDING SLIGHTLY COOLER
TEMPERATURES AND A BIT MORE IN THE WAY OF SHOWER/TSTM ACTIVITY.
HEAT INDICES ARE STILL EXPECTED TO PEAK IN THE 105-110 RANGE
ACROSS THE COASTAL CORRIDOR WITH 100-105 FARTHER INLAND. ANOTHER
HEAT ADVISORY MAY BE NEEDED FOR THESE AREAS DEPENDING ON HOW
QUICKLY CONVECTION SPARKS, BUT LEVELS LOOK TO FALL SHORT OF
EXTREME HEAT WARNING CRITERIA.
KEY MESSAGE 2: TYPICAL SUMMERTIME AFTERNOON AND EVENING
THUNDERSTORMS THIS WEEK WITH INCREASING RAIN CHANCES SUNDAY
THROUGH TUESDAY.
FRIDAY AND SATURDAY: THIS HOT AND HUMID PATTERN WILL PERSIST
ACROSS THE REGION. HOWEVER, FORECAST SOUNDINGS INDICATE SLIGHTLY
LESS PW AND SOME POTENTIAL DEWPOINTS TO MIX A BIT LOWER. THE
FORECAST FEATURES 20-30% POPS FOR PARTS OF THE LOWCOUNTRY WITH
20-50% POPS FOR SATURDAY, HIGHEST OVER THE CHARLESTON TRI-
COUNTY.
SUNDAY THROUGH TUESDAY: THE GFS AND ECMWF INDICATES THAT A H5
TROUGH WILL RIPPLE OVER THE REGION AND PERSIST DURING EARLY NEXT
WEEK. AT THE SFC, A COLD FRONT IS FORECAST TO PUSH SOUTH OVER
THE REGION, POSSIBLY BECOMING STATIONARY. IN ADDITION, AIFS
INDICATES THAT A BROAD SFC LOW MAY DEVELOP OVER THE FORECAST
AREA SUNDAY NIGHT, PUSHING OFF THE COAST MONDAY INTO MONDAY
NIGHT. FORECAST SOUNDINGS INDICATE THE PW WILL INCREASE TO 2 TO
2.2" ACROSS THE REGION. SYNOPTIC SCALE FORCING ALONG WITH SLIGHT
TO MODERATE INSTABILITY SHOULD YIELD MUCH HIGHER SHOWER AND
THUNDERSTORM COVERAGE. THESE STORMS MAY POTENTIAL PRODUCE
POCKETS OF EXCESSIVE RAINFALL GIVEN THE DEEP MOISTURE AND
POSSIBLE CONCENTRATION OF STORM COVERAGE NEAR THE COASTAL LOW.
WPC HAS HIGHLIGHTED THE REGION WITH A MARGINAL RISK ON SUNDAY
AND SUNDAY NIGHT. THE MARGINAL RISK COULD BE EXPANDED INTO
MONDAY.
AVIATION /00Z FRIDAY THROUGH TUESDAY/
00Z TAFS: RADAR INDICATES ISOLATED CONVECTION ALONG THE SEA
BREEZE THIS EVENING, WHICH IS GENERALLY INLAND OF ALL OF THE TAF
SITES. GIVEN THE LOW PROBABILITIES OF IMPACTS, WE KEPT ALL OF
THE TAF SITES VFR AND DRY. WINDS SHOULD GRADUALLY EASE LATER
THIS EVENING. ANOTHER ROUND OF CONVECTION IS POSSIBLE FRIDAY
AFTERNOON, WITH THE HIGHEST PROBABILITIES FOR IMPACTS AT KCHS.
ALSO, GUSTY WINDS ARE EXPECTED WITH THE SEA BREEZE FRIDAY
AFTERNOON.
EXTENDED AVIATION OUTLOOK: THERE WILL BE A LOW END RISK OF
THUNDERSTORM IMPACTS EACH AFTERNOON AND EVENING THROUGH FRIDAY.
SHOWERS AND THUNDERSTORM COVERAGE AND RISK OF ASSOCIATED
RESTRICTIONS MAY INCREASE SUNDAY THROUGH TUESDAY.
MARINE
THROUGH TONIGHT: IT CONTINUES TO LOOK LIKE THE GRADIENT WILL
PINCH A BIT ACROSS THE LOCAL WATERS THROUGH THIS EVENING,
PRODUCING ENHANCED SOUTH TO SOUTHWEST FLOW. WIND SPEEDS OF 15-20
KNOTS SHOULD BE COMMON, STRONGEST ACROSS THE CHARLESTON COUNTY
WATERS AND ALONG THE CHARLESTON COUNTY COAST (AND CHARLESTON
HARBOR) WHERE SUSTAINED SPEEDS COULD REACH 20 KNOTS WITH GUSTS
PUSHING 25 KNOTS. A SMALL CRAFT ADVISORY COULD BE NEEDED IN
THESE AREAS THROUGH THE EVENING. WINDS SHOULD THEN GRADUALLY
DIMINISH THROUGH THE LATE NIGHT HOURS WHILE TURNING MORE WEST-
SOUTHWEST. HOWEVER, SPEEDS WILL REMAIN ELEVATED IN THE 15-20
KNOT RANGE. SEAS ARE EXPECTED TO BE IN THE 2-4 FT RANGE, AND UP
TO 5 FT IN PORTIONS OF THE CHARLESTON COUNTY WATERS.
FRIDAY: SURGES IN THE WAKE OF THE SEA BREEZE MAY RESULT IN
SOUTHWEST WINDS TO INCREASE DURING THE AFTERNOON AND CONTINUE
INTO FRIDAY NIGHT WITH A CLASSIC SUMMER NOCTURNAL SURGE. WIND
GUSTS MAY PEAK AROUND 25 KTS, POSSIBLY REQUIRING SMALL CRAFT
ADVISORIES. THE SHORT DURATION OF THE ELEVATED WINDS SHOULD KEEP
WAVE HEIGHTS BETWEEN 3 TO 4 FT.
SATURDAY INTO TUESDAY: THE PRESSURE PATTERN SHOULD SUPPORT
SOUTH-SOUTHWEST WINDS BETWEEN 10 TO 15 KTS, WITH OCCASIONAL
GUSTS INTO THE LOW 20 KTS. WAVE HEIGHTS ARE FORECAST TO FAVOR 2
TO 4 FT.
RIP CURRENTS: THERE IS A MODERATE RISK FOR RIP CURRENTS FOR THE
CHARLESTON COUNTY COAST ON FRIDAY, AND THEN FOR ALL OF
SOUTHEAST SC AND SOUTHEAST GA ON SATURDAY. CONDITIONS WILL
FEATURE 2-3 FT SWELL WITH WAVE PERIODS UP TO 9 SECONDS. IN
ADDITION, SSW WINDS WILL LIKELY GENERATE A MODERATE LONGSHORE
CURRENT, POSSIBLY SUPPORTING RIP CURRENTS NEAR PIERS AND
JETTIES.
CLIMATE
RECORD HIGH TEMPERATURES:
JULY 10:
KCHS: 100/1986
KCXM: 99/1986
KSAV: 102/1879
JULY 11:
KCXM: 100/2001
JULY 12:
KCXM: 97/1966
RECORD HIGH MINIMUM TEMPERATURES:
JULY 9:
KCHS: 80/1998
KCXM: 85/1998
KSAV: 80/1883
JULY 10:
KCHS: 81/1986
KCXM: 82/1986
JULY 11:
KCHS: 80/2016
KCXM: 82/2016
JULY 12:
KCHS: 79/2020
CHS WATCHES/WARNINGS/ADVISORIES
GA...HEAT ADVISORY FROM 11 AM TO 7 PM EDT FRIDAY FOR GAZ217>219-239-
241.
SC...HEAT ADVISORY FROM 11 AM TO 7 PM EDT FRIDAY FOR SCZ044-045-148-
149-151.
EXTREME HEAT WARNING FROM 11 AM TO 7 PM EDT FRIDAY FOR SCZ150-
152.
MARINE...NONE.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page