096
FXUS62 KCHS 091117
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
717 AM EDT THU JUL 9 2026
WHAT HAS CHANGED
THE AVIATION SECTION WAS UPDATED TO REFLECT THE 12Z TAFS.
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.
LITTLE CHANGE IN THE SYNOPTIC SET UP OVER THE LOCAL FORECAST AREA
WILL YIELD SIMILAR CONDITIONS TODAY THAT WERE OBSERVED YESTERDAY.
THE REGION WILL REMAIN UNDER THE INFLUENCE OF THE WESTERN PERIPHERY
OF A STRONG 594 DAM HIGH PRESSURE OVER THE ATLANTIC OCEAN. AT THE
SURFACE HIGH PRESSURE WILL DOMINATE OVER THE SOUTHEASTERN STATES
INTO THE START OF THE WEEKEND. SURFACE WINDS WILL BEGIN EACH DAY OUT
OF THE W/SW, INITIALLY LIMITING THE INLAND PROGRESSION OF THE
AFTERNOON SEA BREEZE. THIS WILL ALLOW TEMPERATURES TO SOAR INTO THE
UPPER 90S AND EVEN 100 AT SOME LOCATIONS. COMBINED WITH DEW POINTS
IN THE MID TO UPPER 70S, HEAT INDEX VALUES WILL LIKELY REACH INTO
THE 108-112 RANGE INLAND AND 113-116 RANGE ALONG THE COASTAL
COUNTIES. A HEAT ADVISORY REMAINS IN EFFECT FOR MOST INLAND ZONES
AND AN EXTREME HEAT WARNING REMAINS IN EFFECT FOR THE COASTAL
COUNTIES FOR TODAY. AFTERNOON CONVECTION TODAY IS FORECAST TO
BE ISOLATED TO SCATTERED IN COVERAGE, LIMITING ANY POTENTIAL
RELIEF FROM THE HEAT. A SIMILAR FORECAST IS IN STORE FOR FRIDAY
AND SATURDAY, ALTHOUGH CONDITIONS LOOK TO FALL JUST SHY OF
EXTREME HEAT WARNING CRITERIA. ADDITIONAL HEAT ADVISORIES ARE
LIKELY.
ADDITIONALLY, OVERNIGHT LOWS ARE ONLY FORECAST TO DIP INTO THE UPPER
70S/AROUND 80. THESE WARM OVERNIGHT CONDITIONS COULD RESULT IN
PROLONGED HEAT STRESS, ESPECIALLY FOR MORE VULNERABLE COMMUNITIES
AND THOSE WITHOUT ADEQUATE COOLING OVERNIGHT.
KEY MESSAGE 2: TYPICAL SUMMERTIME AFTERNOON AND EVENING THUNDERSTORMS
THIS WEEK.
TODAY, AN AREA OF BROAD LOW PRESSURE IS FORECAST TO REMAIN OVER THE
CENTRAL CAROLINAS THIS AFTERNOON, SUPPORTING SW WINDS ACROSS SE GA
AND SC. DUE TO THE SW WINDS, THE SEA BREEZE MAY BEGIN EARLY THIS
AFTERNOON, PUSHING INLAND THROUGH THE REST OF THE AFTERNOON INTO
EARLY THIS EVENING. AS THE SEA BREEZE PUSHES INLAND, DEWPOINTS
SHOULD RISE INTO THE UPPER 70S, WITH SOME VALUES AROUND 80. THE
ELEVATED DEWPOINTS COMBINED WITH TEMPERATURES IN THE MID TO UPPER
90S, MODERATE INSTABILITY IS FORECAST TO DEVELOP ACROSS THE COASTAL
COUNTIES OF SE GA/SC. RECENT RUNS OF THE HRRR AND HREF INDICATES
THAT SCATTERED TO ISOLATED THUNDERSTORMS DEVELOPING ALONG AND NEAR
THE SEA BREEZE THIS AFTERNOON AND EVENING. FORECAST SOUNDINGS
INDICATE THAT ONCE STORMS DEVELOP, STEERING FLOW SHOULD RESULT IN
THE STORMS TO TRACK EAST BETWEEN 15 TO 20 MPH. GIVEN SBCAPE BETWEEN
2500-3500 J/KG AND DCAPE AROUND 1000 J/KG, THE ENVIRONMENT MAY
SUPPORT SOME DAMAGING WET MICROBURSTS. MACHINE LEARNING PRODUCTS
INDICATES THAT THE GREATEST CHANCE FOR STRONG TO SEVERE
THUNDERSTORMS WILL REMAIN ALONG AND EAST OF THE I-95 CORRIDOR.
THUNDERSTORMS COVERAGE SHOULD STEADILY DECREASE THIS EVENING, LIKELY
ENDING AN HOUR OR TWO AFTER SUNSET.
FRIDAY AND SATURDAY, THE PATTERN WILL LIKELY PERSIST ACROSS THE
REGION. HOWEVER, FORECAST SOUNDINGS INDICATE SLIGHTLY LESS PW AND
SOME POTENTIAL DEWPOINTS TO MIX A BIT LOWER. THE FORECAST WILL
FEATURE AT LEAST SCHC POPS FOR SEA BREEZE CONVECTION.
SUNDAY THROUGH TUESDAY, 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 /12Z THURSDAY THROUGH MONDAY/
PREVAILING VFR THROUGH THE 12Z TAF PERIOD AT KCHS/KJZI/KSAV. S
WINDS WILL GUST INTO THE 20 KNOT RANGE IN THE AFTERNOON WITH THE
SEA BREEZE AT ALL TERMINALS. A PROB30 LINE FOR KCHS/KSAV HAS
BEEN MAINTAINED TO ACCOUNT FOR THE RISK OF TSRA IMPACTING THE
TERMINALS THIS AFTERNOON. ANY CONVECTION SHOULD DISSIPATE WITH
NIGHTFALL AND REMAIN VFR THROUGH THE REMAINDER OF THE TAF
PERIOD.
EXTENDED AVIATION OUTLOOK: MOSTLY VFR. 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
TODAY AND TONIGHT: LITTLE CHANGE IN THE PATTERN IS EXPECTED
TODAY, WITH THE AFTERNOON SEA BREEZE BRINGING WIND GUSTS
APPROACHING 25 KNOTS TO THE NEARSHORE COASTAL WATERS. OPTED FOR
NO SMALL CRAFT ADVISORY AT THIS JUNCTURE, HOWEVER IT IS POSSIBLE
THAT A SHORT DURATION SCA COULD BE NEEDED FOR THE CHARLESTON
COUNTY NEARSHORE WATERS THIS AFTERNOON AND INTO THIS EVENING.
FRIDAY INTO FRIDAY NIGHT: SURGES IN THE WAKE OF THE SEA BREEZE MAY
RESULT IN SOUTHWEST WINDS TO INCREASE DURING THE AFTERNOON AND
CONTINUE INTO FRIDAY NIGHT. 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.
THIS WEEKEND 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: A MODERATE RISK FOR RIP CURRENTS WILL REMAIN ALONG THE
CHARLESTON COUNTY COAST TODAY AND FRIDAY. 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 9:
KCXM: 99/1986
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 THIS MORNING TO 7 PM EDT THIS EVENING
FOR GAZ099>101-114-115-137-216-238-240.
EXTREME HEAT WARNING FROM 11 AM THIS MORNING TO 7 PM EDT THIS
EVENING FOR GAZ217>219-239-241.
SC...HEAT ADVISORY FROM 11 AM THIS MORNING TO 7 PM EDT THIS EVENING
FOR SCZ043>045-147.
EXTREME HEAT WARNING FROM 11 AM THIS MORNING TO 7 PM EDT THIS
EVENING FOR SCZ148>152.
MARINE...NONE.
CPM/NED
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