574  
FXUS62 KCHS 291044  
AFDCHS  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE CHARLESTON SC  
644 AM EDT TUE JUL 29 2025  
   
SYNOPSIS  
 
ATLANTIC HIGH PRESSURE WILL PREVAIL FOR MOST OF THE WEEK,  
RESULTING IN HOT AND HUMID CONDITIONS ACROSS THE REGION. A COLD  
FRONT THEN LOOKS TO DIVE ACROSS OUR AREA FRIDAY, ALLOWING  
COOLER TEMPERATURES AND INCREASED RAIN CHANCES TO RETURN OVER  
THE WEEKEND.  
 
 
   
NEAR TERM /THROUGH TONIGHT/  
 
TODAY: A STRONG AND EXPANSIVE UPPER LEVEL RIDGE (H5 598 DAM)  
WILL REMAIN IN PLACE OVER THE CENTRAL AND SOUTHEAST U.S., WHILE  
A WEAK AND SOMEWHAT BROAD AREA OF LOW PRESSURE RESIDES OVER THE  
FORECAST AREA. EMBEDDED WEAK VORTICITY IN THE NORTHWESTERLY  
UPPER-LEVEL FLOW WILL CONTINUE ROTATING AROUND THE NORTHEASTERN  
EDGE OF THE RIDGE, ADVECTING UPPER-LEVEL FORCING INTO THE  
REGION. WITH DEEP MOISTURE IN PLACE (PWATS AROUND 2.25"),  
NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP IN  
THE AFTERNOON AND CONTINUE THROUGH THE EVENING. LIGHT SURFACE  
WINDS WILL FAVOR AN INLAND MOVING SEA BREEZE, WHICH IS WHERE  
INITIAL CONVECTION IS MOST LIKELY TO DEVELOP, KEEPING MOST OF  
THE STORM ACTIVITY AWAY FROM THE IMMEDIATE COASTLINE. THERE  
COULD EVEN BE AN ISOLATED SHOWER OR THUNDERSTORM SPARK EARLY  
THIS MORNING WITH SOME INSTABILITY AND UPPER FORCING MECHANISMS  
AT PLAY. STRONG DAYTIME HEATING WILL DRIVE MLCAPE VALUES UP TO  
4000-5000 J/KG, WITH DCAPE VALUES RANGING FROM 700-900 J/KG.  
THIS ENVIRONMENT SUPPORTS THE POTENTIAL FOR A FEW STRONG STORMS  
CAPABLE OF PRODUCING DAMAGING WIND GUSTS. STORM MOTION WILL ONCE  
AGAIN BE SLOW, AROUND 5-10 KT, RAISING THE RISK OF LOCALIZED  
FLOODING DURING HEAVIER DOWNPOURS. SOME AREAS COULD SEE 1 TO 2  
INCHES OF RAIN FALL QUICKLY. HREF GUIDANCE INDICATES A 30-60%  
CHANCE OF AREAS RECEIVING 2+ INCHES OF RAIN, MAINLY FOR AREAS  
ALONG THE SEA BREEZE BOUNDARY, WITH A 10-30% CHANCE OF AMOUNTS 3  
INCHES OR GREATER.  
 
TEMPERATURES WILL BE SLIGHTLY COOLER THAN PREVIOUS DAYS BUT STILL  
UNCOMFORTABLE, WITH HIGHS REACHING THE MID TO UPPER 90S INLAND AND  
AROUND 90 DEGREES ALONG THE COAST. FORECASTING HEAT INDICES WILL  
BE CHALLENGING TODAY DUE TO THE COOLING EFFECTS OF STORMS, BUT  
MOST AREAS ARE EXPECTED TO PEAK AROUND 108-111 BEFORE CONVECTION  
DEVELOPS. A HEAT ADVISORY IS IN EFFECT FOR ALL COUNTIES IN  
SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA.  
 
TONIGHT: SHOWER AND THUNDERSTORM ACTIVITY WILL GRADUALLY TAPER OFF  
LATE IN THE EVENING AS INSTABILITY DIMINISHES, LEADING TO MOSTLY DRY  
CONDITIONS BY MIDNIGHT. HOWEVER, SOME MODEL GUIDANCE SUGGESTS  
INCREASING VORTICITY ALOFT OVERNIGHT, WHICH COMBINED WITH DEEP  
MOISTURE AND WARM TEMPERATURES COULD SPARK ISOLATED SHOWERS OR  
THUNDERSTORMS OVERNIGHT. LOWS WILL REMAIN MILD, RANGING FROM THE MID  
TO UPPER 70S INLAND TO AROUND 80 DEGREES NEAR THE COAST.  
 
 
   
SHORT TERM /WEDNESDAY THROUGH THURSDAY/  
 
HOT AND HUMID CONDITIONS CONTINUE MID-WEEK AS UPPER LEVEL RIDGE  
MAINTAINS ITS INFLUENCE OVER THE REGION. SIMILAR TO DAYS PAST, HAVE  
AFTERNOON HIGHS RISING INTO THE 90S WITH DEWPOINTS IN THE MID TO  
UPPER 70S. AS A RESULT, EXPECT HEAT INDICES TO RANGE FROM 102  
ACROSS OUR INTERIOR COUNTIES, TO 110-112 DEGREES ACROSS OUR COASTAL  
COUNTIES. WHILE AN ADVISORY WILL LIKELY BE NEEDED ACROSS PORTIONS OF  
OUR AREA WEDNESDAY, HAVE OPTED TO FORGO ANY HEADLINES WITH THIS  
FORECAST PACKAGE AFTER COLLABORATION WITH NEIGHBORS. IN TERMS OF  
PRECIPITATION, LATEST CAMS SHOW SCATTERED SHOWERS AND STORMS  
DEVELOPING DURING THE AFTERNOON AND EARLY EVENING. GIVEN THE AIRMASS  
IN PLACE, A COUPLE STRONGER STORMS WITH DAMAGING WIND GUSTS WILL BE  
POSSIBLE DESPITE RELATIVELY WEAK SHEAR, FOLLOWED BY LOCALLY HEAVY  
RAINFALL.  
 
LOOK FOR A RINSE AND REPEAT ON THURSDAY AS THE RIDGE AXIS REMAINS  
NEARBY. SFC COLD FRONT THEN LOOKS TO DIVE ACROSS THE SOUTHEASTERN  
CONUS LATE THURSDAY NIGHT INTO FRIDAY, ALLOWING THE STAGNANT UPPER  
LEVEL PATTERN TO FINALLY SHIFT. THAT BEING SAID, STILL HAVE A FEW  
TIMING DIFFERENCES TO IRON OUT WITH THE FRONT, AS THIS WILL  
ULTIMATELY AFFECT WHEN WE FINALLY SEE COOLER TEMPERATURES. FOR NOW,  
MOST GUIDANCE HINTS THAT AFTERNOON HIGHS IN THE 90S WILL CONTINUE AT  
LEAST THROUGH FRIDAY, IN ADDITION TO DIURNALLY DRIVEN SHOWERS AND  
STORMS.  
 
 
   
LONG TERM /THURSDAY NIGHT THROUGH MONDAY/  
 
A REPRIEVE FROM THE HEAT FINALLY ARRIVES OVER THE WEEKEND, AS A SFC  
COLD FRONT CONTINUES TO SAG SOUTHEASTWARD ACROSS OUR AREA. AS  
SUCH, LOOK FOR HIGHS IN THE MID 80S TO LOWER 90S TO PREVAIL  
SATURDAY, WITH HIGHS IN THE LOW TO MID 80S BECOMING COMMON  
SUNDAY INTO MONDAY. WHILE SOME TIMING FLUCTUATIONS WITH THE  
FRONT ARE STILL POSSIBLE, LATEST GUIDANCE CONTINUES TO SUGGEST  
THE BETTER CHANCES FOR SEEING MEANINGFUL RAINFALL WILL OCCUR  
LATE FRIDAY NIGHT INTO SATURDAY, AND ESPECIALLY SATURDAY  
AFTERNOON. OTHERWISE, WILL LIKELY SEE THE FRONT STALL ALONG THE  
COAST HEADING INTO THE NEW WEEK.  
 
 
   
AVIATION /12Z TUESDAY THROUGH SATURDAY/  
 
12Z TUESDAY TAF: MAINLY VFR THROUGH EARLY TUESDAY AFTERNOON AT  
ALL TERMINALS; HOWEVER, NUMEROUS SHOWERS AND THUNDERSTORMS ARE  
EXPECTED TO DEVELOP BY MID AFTERNOON. THE GREATEST COVERAGE OF  
CONVECTION IS EXPECTED INLAND, GENERALLY ALONG AND WEST OF THE  
SEA BREEZE. PREVAILING TSRA WITH MVFR VSBYS HAS BEEN INTRODUCED  
AT KSAV AND KCHS DURING THE LATE AFTERNOON AND EVENING, WHERE  
CONFIDENCE IN DIRECT IMPACTS IS GREATEST. ALSO, VCTS HAS BEEN  
INCLUDED AT KJZI TO ACCOUNT FOR NEARBY ACTIVITY, ALTHOUGH  
CONFIDENCE IN DIRECT IMPACTS IS LOW AT THIS TIME. A FEW STORMS  
COULD BECOME STRONG, PRODUCING GUSTY WINDS AND/OR TORRENTIAL  
RAINFALL THAT COULD BRIEFLY REDUCE VSBYS TO 1 MILE OR LESS.  
THESE DETAILS MAY BE REFINED IN THE 18Z TAF ISSUANCE OR HANDLED  
BY AMENDMENTS AS CONFIDENCE IN TIMING AND PLACEMENT INCREASES.  
CONVECTION IS EXPECTED TO GRADUALLY DIMINISH DURING THE LATE  
EVENING, WITH A RETURN TO VFR OVERNIGHT. WHILE MOST AREAS SHOULD  
REMAIN DRY OVERNIGHT, A FEW MODELS SUGGEST THE POTENTIAL FOR  
ISOLATED SHOWERS OR A THUNDERSTORM.  
 
EXTENDED AVIATION FORECAST: MAINLY VFR. EXPECT BRIEF FLIGHT  
RESTRICTIONS IN AFTERNOON/EVENING SHOWERS/THUNDERSTORMS.  
 
 
   
MARINE  
 
TODAY AND TONIGHT: NO MARINE CONCERNS WITH LIGHT SOUTHERLY WINDS  
AROUND 5-10 KT THROUGH TUESDAY NIGHT. SEAS WILL RANGE 1-2 FEET.  
 
EXTENDED MARINE: THE COASTAL WATERS WILL BE SANDWICHED BETWEEN  
HIGH PRESSURE IN THE ATLANTIC AND COASTAL TROUGHING INLAND MOST  
OF THIS WEEK. THIS WILL YIELD A TYPICAL SUMMERTIME WIND  
PATTERN. EACH DAY, EXPECT BACKING WINDS WITH THE FORMATION OF  
THE AFTERNOON SEA BREEZE. THE HIGHEST GUSTS WILL BE ALONG THE  
LAND/SEA INTERFACE AND ACROSS CHARLESTON HARBOR (WITH ITS  
PASSAGE). EACH NIGHT, EXPECT VEERING OF THE WINDS AS A NOCTURNAL  
JET SETS UP CLOSE TO SHORE. SEAS WILL AVERAGE 1-3 FEET. A COLD  
FRONT IS EXPECTED TO MOVE INTO THE REGION LATE THIS WEEK AND  
INTO THE WEEKEND. WINDS MAY TURN TO THE NORTH AND EVENTUALLY  
NORTHEAST, AND INCREASE. BUT THESE DETAILS WILL NEED TO BE  
IRONED OUT IN FUTURE FORECASTS.  
 
 
   
CLIMATE  
 
RECORD HIGH MINIMUM TEMPERATURES:  
 
JULY 29:  
KCHS: 80/2016  
KSAV: 82/1878  
 
JULY 30:  
KCHS: 81/2016  
KCXM: 83/2016  
KSAV: 81/1878  
 
JULY 31:  
KCHS: 80/2022  
KCXM: 84/2016  
KSAV: 80/2010  
 
AUGUST 1:  
KCHS: 81/1999  
KSAV: 79/2020  
 
AUGUST 2:  
KCHS: 79/2022  
 
 
   
CHS WATCHES/WARNINGS/ADVISORIES  
 
GA...HEAT ADVISORY FROM 11 AM THIS MORNING TO 8 PM EDT THIS EVENING  
FOR GAZ087-088-099>101-114>119-137>141.  
SC...HEAT ADVISORY FROM 11 AM THIS MORNING TO 8 PM EDT THIS EVENING  
FOR SCZ040-042>045-047>052.  
MARINE...NONE.  
 
 
 
 
 
NEAR TERM...BRS  
SHORT TERM...SST  
LONG TERM...SST  
AVIATION...BRS/SST  
MARINE...BRS/SST  
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