092  
FXUS62 KCHS 281121  
AFDCHS  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE CHARLESTON SC  
721 AM EDT MON JUL 28 2025  
   
SYNOPSIS  
 
ATLANTIC HIGH PRESSURE WILL PREVAIL EARLY THIS WEEK, WHILE A  
TROUGH OF LOW PRESSURE RESIDES INLAND. A COLD FRONT COULD  
APPROACH THE REGION LATE WEEK.  
 
 
   
NEAR TERM /THROUGH TONIGHT/  
 
TODAY: A STRONG SURFACE HIGH AND AN UNUSUALLY ROBUST 598 DAM  
UPPER-LEVEL RIDGE WILL SHIFT WESTWARD, BECOMING CENTERED OVER  
THE ARKLATEX REGION. MEANWHILE, A PERSISTENT INLAND/LEE TROUGH  
WILL REMAIN IN PLACE. WEAK VORTICITY EMBEDDED WITHIN THE  
NORTHWESTERLY FLOW ALOFT WILL ROTATE AROUND THE NORTHEASTERN  
FLANK OF THE RIDGE, HELPING TO INTRODUCE SOME UPPER-LEVEL  
SUPPORT INTO THE FORECAST AREA. LOW AND MID LEVEL MOISTURE WILL  
DEEPEN THROUGH THE DAY AS HIGHER PWATS (2+" INCHES) GRADUALLY  
MOVE SOUTHWARD FROM THE MID-ATLANTIC AND TENNESSEE VALLEY. THIS  
INCREASE IN MOISTURE, COMBINED WITH MODEST UPPER-LEVEL FORCING,  
WILL SUPPORT THE DEVELOPMENT OF ISOLATED TO SCATTERED SHOWERS  
AND THUNDERSTORMS THIS AFTERNOON AND EVENING. LIGHT, WESTERLY  
FLOW WILL RESULT IN A SEMI-PINNED SEA BREEZE, WITH SOME INLAND  
PROGRESSION LATE IN THE AFTERNOON. THE ONSET OF CONVECTION, AND  
GREATEST COVERAGE LOOK TO OCCUR NORTH OF I-16 AND AWAY FROM THE  
IMMEDIATE COAST WHERE THE GREATER MOISTURE AND FORCING IS  
FOCUSED. STRONG DAYTIME HEATING WILL BOOST MLCAPE VALUES INTO  
THE 3000–4000 J/KG RANGE, WHILE LINGERING DRY AIR ABOVE 500 MB  
WILL CONTRIBUTE TO DCAPE VALUES AROUND 1000 J/KG. THIS SETUP  
COULD SUPPORT A FEW STRONG TO MARGINALLY SEVERE STORMS CAPABLE  
OF PRODUCING DAMAGING WIND GUSTS. ADDITIONALLY, SLOW STORM  
MOTIONS (AROUND 5–10 KT) COULD LEAD TO LOCALIZED FLOODING DURING  
PERIODS OF HEAVY RAIN.  
 
ONE CAVEAT TO THE FORECAST IS THE PRESENCE OF THE STRONG RIDGE  
ALOFT. MODEL CROSS SECTIONS SHOW NOTABLE SUBSIDENCE ALOFT,  
WHICH COULD STUNT UPDRAFT STRENGTH AND POTENTIALLY LIMIT  
CONVECTIVE INTENSITY. SO WITH THAT, IT WILL BE INTERESTING TO  
SEE HOW CONVECTION EVOLVES THROUGH THE DAY.  
 
EXCESSIVE TEMPERATURES WILL CONTINUE FOR ANOTHER DAY AS HIGHS  
ARE FORECAST TO PEAK BETWEEN 98-103 DEGREES. THE BEACHES WILL  
PROVIDE LITTLE RELIEF WITH HIGHS PEAKING NEAR THE MID 90S. ALL  
THREE OF OUR LOCAL CLIMATE SITES ARE FORECAST TO COME CLOSE TO  
BREAKING OR TYING RECORD HIGHS AND/OR RECORD HIGH MINS  
TODAY/TONIGHT, SEE CLIMATE SECTION BELOW FOR DETAILS. HEAT  
INDICES WILL LIKELY PEAK BEFORE THE ONSET OF CONVECTION, BETWEEN  
112-115 ALONG THE COASTAL LOCATIONS, AND 108-112 FURTHER  
INLAND. SIMILAR TO SUNDAY, AN EXTREME HEAT WARNING IS IN EFFECT  
FOR ALL COASTAL ZONES ACROSS SOUTHEAST SOUTH CAROLINA AND  
SOUTHEAST GEORGIA INCLUDING THE FOLLOWING INLAND COUNTIES:  
BERKELEY, DORCHESTER, INLAND COLLETON, INLAND JASPER, AND INLAND  
CHATHAM, AND A HEAT ADVISORY IS IN EFFECT FOR THE REMAINING  
COUNTIES/ZONES.  
 
TONIGHT: COVERAGE OF SHOWERS AND THUNDERSTORMS SHOULD BEGIN TO  
TAPER LATER IN THE EVENING, BECOMING RAIN-FREE BY MIDNIGHT.  
WARM TEMPERATURES ARE EXPECTED OVERNIGHT DROPPING DOWN TO 75-79  
DEGREES AWAY FROM THE COAST, AND AROUND 80 DEGREES ALONG THE  
BEACHES.  
 
 
   
SHORT TERM /TUESDAY THROUGH WEDNESDAY/  
 
THE REGION WILL INITIALLY BE ON THE EASTERN PERIPHERY OF AN  
EXPANSIVE MID LEVEL RIDGE, WITH SHORTWAVE ENERGY DROPPING SOUTH  
THROUGH THE AREA. RIDGE WILL RE-BUILD OVERHEAD LATER IN THE PERIOD,  
BEFORE A LARGER SCALE TROUGH BEGINS TO SHIFT INTO THE NORTHEAST AND  
MID-ATLANTIC. THE SURFACE PATTERN WILL BE CHARACTERIZED BY TROUGHING  
INLAND AND HIGHER PRESSURE OFFSHORE.  
 
HOT AND HUMID CONDITIONS WILL PERSIST THROUGH THE PERIOD, WITH HEAT  
INDICES POTENTIALLY REACHING HEAT ADVISORY CRITERIA OF 108-112F,  
MAYBE EVEN A BRIEF TOUCH HIGHER IN SPOTS. HOWEVER, CONVECTION COULD  
DISRUPT THE TYPICAL TEMPERATURE CURVE. WENT AHEAD AND ISSUED A HEAT  
ADVISORY FOR TUESDAY PER COORDINATION WITH NEIGHBORING OFFICES.  
BEYOND THAT, IT WILL LIKELY BE A DAY-TO-DAY HEAT HEADLINE DECISION  
BASED ON LATEST CONVECTIVE MODEL TRENDS.  
 
THE MOST ACTIVE DAY OF THE SET APPEARS TO BE ON TUESDAY WITH BETTER  
FORCING IN PLAY. NUMEROUS SHOWERS AND THUNDERSTORMS FORECAST TO  
DEVELOP BY MID TO LATE AFTERNOON. THERE IS POTENTIAL FOR LOCALLY  
HEAVY RAINFALL WITH HREF 3-HR PROBS SHOWING 30-50% CHANCE OF 3  
INCHES OR GREATER. POPS FOR WEDNESDAY AND THURSDAY ARE MORE IN THE  
SCATTERED RANGE (30-50%). GIVEN THE AIRMASS IN PLACE, A COUPLE  
STRONGER STORMS WITH DAMAGING WIND GUSTS WILL BE POSSIBLE DESPITE  
RELATIVELY WEAK SHEAR.  
 
 
   
LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/  
 
THERE WILL FINALLY BE REPRIEVE FROM THE OPPRESSIVE HEAT LATE WEEK  
AND OVER THE WEEKEND AS MID LEVEL HEIGHTS FALL IN RESPONSE TO A  
TROUGH OVER THE NORTHEAST AND MID-ATLANTIC. SOME TIMING  
INCONSISTENCIES EXIST, BUT CONSENSUS SHOWS A COLD FRONT MOVING INTO  
THE AREA AS HIGH PRESSURE BUILDS FROM THE NORTH. THIS WILL BRING  
COOLER TEMPERATURES AND INCREASED RAIN CHANCES. THE FRONT COULD  
STALL IN THE VICINITY THROUGH EARLY NEXT WEEK.  
 
 
   
AVIATION /12Z MONDAY THROUGH FRIDAY/  
 
28/12Z TAFS:  
KCHS/KJZI/KSAV: VFR CONDITIONS SHOULD PERSIST THROUGH EARLY  
AFTERNOON. HOWEVER, ISOLATED TO SCATTERED THUNDERSTORMS ARE  
EXPECTED TO DEVELOP LATER THIS AFTERNOON. AS A RESULT, VCTS HAS  
BEEN INTRODUCED AT KCHS AND KJZI, WHERE STORM COVERAGE IS  
EXPECTED TO BE SOMEWHAT HIGHER. AT THIS TIME, WE HAVE HELD OFF  
ON INCLUDING PREVAILING RESTRICTIONS GIVEN THE LIMITED OVERALL  
STORM COVERAGE, BUT SHOULD A STORM DEVELOP OR MOVE DIRECTLY OVER  
A TERMINAL, REDUCTIONS IN VISIBILITY AND CEILINGS WILL BE  
LIKELY. IT IS POSSIBLE THESE DIRECT IMPACTS WILL BE BETTER  
REFINED WITH THE 18Z TAF ISSUANCE, DEPENDING ON CONFIDENCE IN  
CONVECTIVE TRENDS.  
 
EXTENDED AVIATION FORECAST: PREVAILING VFR. BRIEF FLIGHT  
RESTRICTIONS ARE POSSIBLE IN AFTERNOON SHOWERS/THUNDERSTORMS THIS  
WEEK.  
 
 
   
MARINE  
 
TODAY AND TONIGHT: WEST SOUTHWEST WINDS IN THE MORNING WILL  
SHIFT OUT OF THE SOUTH SOUTHWEST BY THE AFTERNOON WITH SPEEDS  
AROUND 5-10 KT PERSISTING THROUGH THE NIGHT. SEAS WILL AVERAGE  
1-2 FT.  
 
TUESDAY THROUGH SATURDAY: NO MARINE CONCERNS ARE ANTICIPATED THROUGH  
MUCH OF THE WEEK. GENERALLY EXPECT SOUTHERLY FLOW WITH SPEEDS LESS  
THAN 15 KNOTS. SEAS WILL AVERAGE 1-3 FEET. A COLD FRONT IS EXPECTED  
TO MOVE INTO THE REGION LATE WEEK INTO THE WEEKEND, WHICH WILL TURN  
WINDS TO THE NORTH AND EVENTUALLY NORTHEAST AND POSSIBLY INCREASE IN  
SPEED, BUT STILL SOME TIMING DISCREPANCIES SO FORECAST DETAILS ARE  
A BIT UNCERTAIN.  
 
 
   
CLIMATE  
 
RECORD HIGH TEMPERATURES:  
 
JULY 28:  
KCHS: 101/1949  
KCXM: 100/1936  
KSAV: 102/1949  
 
RECORD HIGH MINIMUM TEMPERATURES:  
 
JULY 28:  
KCHS: 80/2016  
KCXM: 83/1999  
KSAV: 81/1878  
 
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 UNTIL 8 PM EDT THIS EVENING FOR GAZ087-088-  
099>101-114>116-137-138-140.  
HEAT ADVISORY FROM 11 AM TO 8 PM EDT TUESDAY FOR GAZ087-088-  
099>101-114>119-137>141.  
EXTREME HEAT WARNING UNTIL 8 PM EDT THIS EVENING FOR  
GAZ117>119-139-141.  
SC...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR SCZ040-042.  
HEAT ADVISORY FROM 11 AM TO 8 PM EDT TUESDAY FOR SCZ040-  
042>045-047>052.  
EXTREME HEAT WARNING UNTIL 8 PM EDT THIS EVENING FOR  
SCZ043>045-047>052.  
MARINE...NONE.  
 
 
 
 
 
NEAR TERM...BRS  
SHORT TERM...ETM  
LONG TERM...ETM  
AVIATION...BRS/ETM  
MARINE...BRS/ETM  
CLICK HERE TO GO TO PREVIOUS BULLETINS.
The Nexlab SC Page
The Nexlab GA Page
Main Text Page