679  
FXUS62 KCHS 271828  
AFDCHS  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE CHARLESTON SC  
228 PM EDT SUN JUL 27 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/
 
 
REST OF THE AFTERNOON: STRONG UPPER-LEVEL RIDGING REMAINS CENTERED  
ACROSS THE SOUTHEAST TODAY, WITH 597 DAM NOTED ON 500MB ANALYSIS. AT  
THE SURFACE, HIGH PRESSURE RESIDES ACROSS THE DEEP SOUTH WITH WEAK  
TROUGHING OVER THE APPALACHIANS. AS THE KCHS SOUNDING  
INDICATES, STRONG SUBSIDENCE AND MID-LEVEL DRY AIR WILL INHIBIT  
SHOWER AND THUNDERSTORM ACTIVITY THIS AFTERNOON. LIGHT, WESTERLY  
SURFACE FLOW WILL RESULT IN A SEMI-PINNED SEABREEZE, AND WILL  
PUSH INLAND LATER IN THE AFTERNOON WHICH WILL ADVECT UPPER 70S  
TO NEAR 80 DEW POINTS INLAND. THERE IS A SMALL CHANCE OF A  
SHOWER DEVELOPING ALONG THE SEABREEZE LATER THIS AFTERNOON,  
HOWEVER DEVELOPMENT WILL BE BRIEF DUE TO STRONG DOWNWARD  
VERTICAL MOTION. THEREFORE, THE FORECAST HAS NO MENTIONABLE POPS  
THROUGH THE REST OF THE PERIOD. SKIES WILL REMAIN MOSTLY SUNNY  
WITH SOME SHALLOW CUMULUS CLOUDS MAKING AN APPEARANCE. WITH  
TEMPERATURES INTO THE UPPER 90S TO POSSIBLY HITTING LOW 100S,  
COMBINED WITH DEWPOINTS IN THE MID 70S, HEAT INDICES WILL PEAK  
THIS AFTERNOON AROUND 108 TO 115 TODAY. AS A RESULT, AN EXTREME  
HEAT WARNING IS IN EFFECT FOR ALL COASTAL ZONES ACROSS SOUTHEAST  
SOUTH CAROLINA AND SOUTHEAST GEORGIA INCLUDING BERKELEY,  
DORCHESTER, INLAND COLLETON, INLAND JASPER, AND INLAND CHATHAM  
COUNTIES, AND A HEAT ADVISORY IS IN EFFECT FOR THE REMAINING  
COUNTIES/ZONES.  
 
TONIGHT: CONDITIONS REMAIN WARM AND MUGGY OVERNIGHT, WITH  
TEMPERATURES ONLY FALLING INTO THE MID TO UPPER 70S INLAND AND  
STRUGGLING TO FALL BELOW 80 ALONG THE COASTAL CORRIDOR. ONCE AGAIN,  
HEAT ADVISORY AND EXTREME HEAT HEADLINES WILL CONTINUE THROUGH THE  
NIGHT GIVEN THE LACK OF RECOVERY FROM THE WARM OVERNIGHT  
TEMPERATURES.  
 

 
   
SHORT TERM /MONDAY THROUGH WEDNESDAY/
 
 
HOT TEMPERATURES AND HIGH HUMIDITY IS EXPECTED TO CONTINUE THROUGH  
THE PERIOD. HOWEVER, THE HIGHEST TEMPERATURES AND POTENTIAL FOR HEAT  
ADVISORIES AND/OR EXTREME HEAT WARNING CONDITIONS ARE EXPECTED TO BE  
MONDAY. THE DEEP LAYER RIDGE, CENTERED JUST WEST OF THE REGION, WILL  
HANG ON MONDAY, THEN BEGIN TO SLOWLY WEAKEN AND RETROGRADE WESTWARD  
TUESDAY AND WEDNESDAY.  
 
MONDAY: AS THE RIDGE SLOWLY WEAKENS/MOVES WESTWARD, A BAND OF DEEP  
LAYER MOISTURE WORKS IN FROM THE NORTH AND NORTHWEST. THIS MOISTURE,  
ALONG WITH INTENSE AFTERNOON HEATING, AND PRESENCE OF SEABREEZE,  
COULD PRODUCE SCATTERED SHOWERS AND THUNDERSTORMS LATE AFTERNOON,  
ESPECIALLY AROUND THE CHARLESTON TRI-COUNTY REGION. SCATTERED  
SHOWERS AND THUNDERSTORMS COULD PUSH SOUTHWARD LATER IN THE  
AFTERNOON, BEFORE DISSIPATING IN THE EVENING. GIVEN INTENSE HEATING  
HELPING TO PRODUCE AFTERNOON CAPES OF 1500 TO 2500 J/KG AND DCAPES  
AROUND 1000 J/KG, COULD SEE ISOLATED STRONG STORMS WITH GUSTY WINDS.  
TEMPERATURES AGAIN EXPECTED TO BE VERY HOT, WITH AFTERNOON HEAT  
INDICES LIKELY REACHING EXTREME HEAT WARNING LEVELS OF 113 TO 116  
DEGREES FROM THE CHARLESTON TRI-COUNTY REGION, SOUTHWARD DOWN THE  
COAST INTO OUR GA ZONES, INCLUDING THE SAVANNAH AREA. WILL LIKELY  
REPLACE THE EXTREME HEAT WATCH FURTHER INLAND TO A HEAT ADVISORY,  
SINCE WE FEEL MAX HEAT INDICES WILL LIKELY STAY BELOW 113 DEGREES.  
 
TUESDAY AND WEDNESDAY: THE DEEP LAYER RIDGE CONTINUES TO SLOWLY MOVE  
WESTWARD. THE DEEP LAYER MOISTURE THAT MOVED INTO THE AREA FROM THE  
NORTH ON MONDAY WILL NOW BE STALLED ACROSS THE ENTIRE REGION DURING  
THIS TIME FRAME. THUS, THE CHANCES FOR CONVECTION WILL INCREASE,  
WITH SCATTERED TO NUMEROUS MAINLY AFTERNOON SHOWERS AND  
THUNDERSTORMS EACH DAY. THE INCREASE IN CONVECTIVE POTENTIAL SHOULD  
HELP TO KEEP TEMPERATURES A TAD LOWER, LIKELY OUT OF THE EXTREME  
HEAT WARNING RANGE. HOWEVER STILL THINK HEAT ADVISORY CONDITIONS  
LIKELY ON TUESDAY, AND THEN LESS SO WEDNESDAY AS RIDGE CONTINUES TO  
WEAKEN.  
 

 
   
LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/
 
 
A BROAD DEEP LAYER TROUGH WILL CONTINUE TO BUILD OVER THE NORTHEAST  
AND MID ATLANTIC AND INTO THE SOUTHEAST U.S. STATES THROUGH FRIDAY,  
THEN MOVING EASTWARD INTO THE ATLANTIC SATURDAY. THIS TROUGH MAY  
ALLOW A SURFACE FRONT TO APPROACH FROM THE NORTH BY LATER FRIDAY,  
THEN POTENTIALLY PUSH SOUTH OF THE REGION BY LATE SATURDAY.  
INCREASING MOISTURE AND LOW LEVEL CONVERGENCE WITH THIS FRONT IS  
EXPECTED TO BRING INCREASING CHANCES FOR CONVECTION THROUGH THE  
PERIOD. WITH LOWER UPPER LEVEL HEIGHTS, THE THREAT FOR EXTREME HEAT  
WARNINGS SHOULD BE LOWER, BUT STILL CANNOT RULE OUT HEAT ADVISORY  
CONDITIONS DURING THIS PERIOD.  
 

 
   
AVIATION /18Z SUNDAY THROUGH FRIDAY/
 
 
27/18Z TAFS:  
KCHS/KJZI/KSAV: WITH THE UPPER-LEVEL RIDGING OVERHEAD AND MID-  
LEVEL SUBSIDENCE, VFR SHOULD REMAIN THROUGHOUT THE PERIOD.  
 
EXTENDED AVIATION FORECAST: GENERALLY VFR CONDITIONS WITH BRIEF  
FLIGHT RESTRICTIONS BECOMING MORE LIKELY THROUGH THE PERIOD AS  
CHANCES FOR AFTERNOON CONVECTION INCREASE DUE TO INCREASING DEEP  
LAYER MOISTURE AND THE POTENTIAL FOR A SURFACE FRONT TO IMPACT THE  
AREA, ESPECIALLY LATER IN THE WEEK ON THURSDAY AND FRIDAY.  
 

 
   
MARINE
 
 
THROUGH TONIGHT: EXPECT GENERALLY SOUTH-SOUTHWESTERLY FLOW AT 5  
TO 10 KT, WITH GUSTS UP TO 15 KT LATE THIS AFTERNOON. MIX OF  
SOUTHERLY WINDSWELL AND UNDERLYING EASTERLY-SOUTHEASTERLY SWELL  
WILL BE ON TAP FOR THE AFTERNOON. SEAS WILL RANGE FROM 1 TO 2 FT  
OVERNIGHT. OTHERWISE, NO MARINE CONCERNS EXPECTED.  
 
MONDAY THROUGH FRIDAY: NO HIGHLIGHTS ARE EXPECTED THROUGH THE PERIOD. A DEEP LAYER,  
ALTHOUGH WEAKENING THROUGH THE PERIOD, WILL GENERALLY STRETCH FROM  
SOUTHEAST OF THE WATERS TO THE WEST OVER THE GULF COAST STATES. THIS  
WILL MAINTAIN GENERALLY SOUTHERLY WINDS OF 15 KNOTS OR LESS WITH  
ONSHORE FLOW/SEABREEZE EACH AFTERNOON THROUGH AT LEAST THURSDAY.  
SEAS 2 TO 3 FEET. BY LATER FRIDAY, A COLD FRONT MAY APPROACH FROM  
THE NORTH, WHICH COULD VEER WINDS TO MORE SOUTHWEST.  
 

 
   
CLIMATE
 
 
RECORD HIGH TEMPERATURES:  
 
JULY 27:  
KCHS: 100/2005  
KCXM: 101/1936  
KSAV: 100/2010  
 
JULY 28:  
KSAV: 102/1949  
 
RECORD HIGH MINIMUM TEMPERATURES:  
 
JULY 27:  
KCHS: 80/2014  
KSAV: 80/1885  
 
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 10 AM EDT MONDAY FOR GAZ087-088-099>101-  
114>116-137-138-140.  
EXTREME HEAT WATCH FROM MONDAY MORNING THROUGH MONDAY EVENING  
FOR GAZ087-088-099>101-114>116-137-138-140.  
EXTREME HEAT WARNING UNTIL 8 PM EDT MONDAY FOR GAZ117>119-139-  
141.  
SC...HEAT ADVISORY UNTIL 10 AM EDT MONDAY FOR SCZ040-042.  
EXTREME HEAT WATCH FROM MONDAY MORNING THROUGH MONDAY EVENING  
FOR SCZ040-042.  
EXTREME HEAT WARNING UNTIL 8 PM EDT MONDAY FOR SCZ043>045-  
047>052.  
MARINE...NONE.  
 

 
 

 
 
NEAR TERM...DENNIS  
SHORT TERM...RFM  
LONG TERM...RFM  
AVIATION...DENNIS/RFM  
MARINE...DENNIS/RFM  
 
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