620  
FXUS62 KCHS 252228  
AFDCHS  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE CHARLESTON SC  
628 PM EDT WED JUN 25 2025  
   
SYNOPSIS
 
 
A HOT AND HUMID AIR MASS WILL REMAIN ACROSS THE REGION THROUGH  
THE REST OF THE WEEK INTO EARLY NEXT WEEK. A SLOW MOVING COLD  
FRONT MAY PUSH OVER THE REGION BY THE MIDDLE OF NEXT WEEK.  
 

 
   
NEAR TERM /UNTIL 6 AM THURSDAY MORNING/
 
 
THE ATMOSPHERE ACROSS SOUTHEAST SOUTH CAROLINA AND SOUTHEAST  
GEORGIA REMAINS QUITE UNSTABLE WITH HOT AND HUMID CONDITIONS IN  
PLACE. 25/22Z INSTABILITY PLOTS SHOW MLCAPE VALUES OF 3000-4000  
J/KG WITH DEWPOINTS HOLDING IN THE LOWER TO MID 70S. STRONG TO  
SEVERE TSTMS THAT ARE MOVING INTO THE NORTHERN MIDLANDS AND PEE  
DEE OUT OF NORTH CAROLINA ARE STEADILY CONGEALING ALONG SEVERAL  
CONVECTIVE OUTFLOW BOUNDARIES WITH SOME INTERACTIONS ALONG THE  
SEA BREEZE NOTED OVER FAR SOUTHEAST NORTH CAROLINA. THIS  
ACTIVITY WILL STEADILY DROP SOUTH THIS EVENING, POSSIBLY ZIP  
LINING TO SOME DEGREE DOWN THE SEA BREEZE, REACHING THE SANTEE  
RIVER ROUGHLY BETWEEN 8-9 PM. ACTIVITY WILL THEN STEADILY PUSH  
SOUTH THROUGH THROUGH THE REMAINDER OF THE LOWCOUNTRY AND INTO  
SOUTHEAST GEORGIA. ALTHOUGH SOME NOCTURNAL COOLING WILL OCCUR  
WITH THE LOSS OF HEATING, THERE WILL STILL BE A LOT OF FUEL FOR  
STORMS TO WORK OFF OF AS THEY INTERACT WITH A MULTITUDE OF  
CONVECTIVE OUTFLOWS.  
 
THE PRIMARY HAZARDS WITH THESE STORMS WILL BE DAMAGING WINDS UP  
TO 70 MPH (OWING TO MID-LEVEL DRY AIR AND DCAPE VALUES  
1200-1500 J/KG), FREQUENT TO CONTINUOUS CLOUD-TO-GROUND  
LIGHTNING AND POSSIBLY SOME SMALL TO MARGINALLY SEVERE HAIL.  
LOCALLY HEAVY RAINFALL COULD ALSO PRODUCE SOME MINOR FLOODING OF  
LOW-LYING AND POOR DRAINAGE AREAS, BUT FLASH FLOODING DOES NOT  
APPEAR LIKELY AT THIS TIME.  
 
SEVERE THUNDERSTORM WATCH 459 REMAINS IN EFFECT FOR THE  
CHARLESTON TRI-COUNTY AND NEARBY WATERS THROUGH MIDNIGHT, BUT  
MAY NEED TO BE EXPANDED SOUTH TO INCLUDE ADDITIONAL COUNTIES  
LATER THIS EVENING ONCE CONVECTIVE TRENDS AND BE BETTER  
ESTABLISHED.  
 
FOR THE EARLY EVENING UPDATE, POPS WERE INCREASED TO 60-70% FOR  
MOST LOCATIONS AND THE MENTION OF LARGE HAIL AND DAMAGING WINDS  
WAS EXPANDED TO INCLUDE ALL AREAS, EVEN THOSE OUTSIDE OF THE  
CURRENT SEVERE THUNDERSTORM WATCH.  
 

 
   
SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/
 
 
A WEAK REX BLOCK WILL REMAIN ACROSS THE SOUTHEAST U.S. ON  
THURSDAY. THE BLOCKING SHOULD ERODE THURSDAY NIGHT, WITH THE  
MID-LEVEL RIDGE DRIFTING OVER THE WESTERN ATLANTIC AND LOW  
SHIFTING OVER THE DEEP SOUTH. ON THURSDAY, CONDITIONS SHOULD  
START OUT A BIT COOLER THAT THE PAST COUPLE OF MORNING, IN THE  
WAKE OF OVERNIGHT CONVECTION. GIVEN THE COOLER START AND TIMING  
OF AFTERNOON SEA BREEZE, HIGH TEMPERATURES ARE FORECAST TO RANGE  
IN THE LOW TO MID 90S. GIVEN LOW TO MID 90S OVER DEWPOINTS IN  
THE 70S, MODERATE INSTABILITY SHOULD DEVELOP DURING THE  
AFTERNOON HOURS. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS  
MAY DEVELOP ON THE SEA BREEZE. GIVEN THE MODERATE INSTABILITY,  
IT IS POSSIBLE TO SEE A STRONG TO SEVERE THUNDERSTORM DURING THE  
AFTERNOON INTO EARLY EVENING. SPC HAS PLACED THE REGION IN A  
MARGINAL RISK FOR SEVERE THUNDERSTORMS ON THURSDAY.  
 
FRIDAY AND SATURDAY, THE FORECAST AREA SHOULD REMAIN BETWEEN A  
RIDGE OVER THE WESTERN ATLANTIC AND A BROAD LOW OVER THE DEEP  
SOUTH. THE REGION WILL REMAIN UNDER DEEP MOISTURE WITH PW VALUES  
RANGING BETWEEN 1.6 TO 1.8 INCHES. EACH AFTERNOON, A SEA BREEZE  
SHOULD DEVELOP AS TEMPERATURES REACH THE LOW TO MID 90S. GIVEN  
THE DEEP MOISTURE, WIDE FIELD OF INSTABILITY, AND SEA BREEZE  
SHOULD PRODUCE SCATTERED STORMS EACH AFTERNOON AND EVENING.  
SIMILAR TO THURSDAY, IT IS POSSIBLE THAT SOME OF THESE STORMS  
COULD REACH SEVERE LEVELS, WITH A PORTION OF THE CWA UNDER A SPC  
MARGINAL RISK ON FRIDAY.  
 

 
   
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/
 
 
THE H5 PATTERN WILL BE SLOW TO CHANGE THIS WEEKEND INTO EARLY  
NEXT WEEK. GENERALLY, THE REGION WILL REMAIN UNDER A BROAD  
WEAKNESS OVER THE SOUTHEAST U.S. WITH A RIDGES OVER THE SOUTHERN  
PLAINS AND WESTERN ATLANTIC. THE DEEP MOISTURE COMBINED WITH  
HIGHS IN THE LOW TO MID 90S, CAPE VALUES COULD PEAK AROUND 2000  
J/KG EACH AFTERNOON. THE FORECAST WILL FEATURE UNSETTLED  
WEATHER, WITH GRADUALLY INCREASE IN STORM ACTIVITY EACH DAY. BY  
THE MIDDLE OF NEXT WEEK, A SLOW- MOVING COLD FRONT MAY SLIDE  
OVER THE REGION. THUNDERSTORMS SHOULD EASILY DEVELOP ALONG THE  
BOUNDARY, WITH LIKELY THUNDERSTORMS POSSIBLE. THE MORE ACTIVITY  
WEATHER PATTERN SHOULD FAVOR SLIGHTLY COOLER HIGH TEMPERATURES  
IN THE LOW 90S.  
 

 
   
AVIATION /22Z WEDNESDAY THROUGH MONDAY/
 
 
26/00Z TAF DISCUSSION:  
KCHS/KJZI: PRIMARY IMPACT WILL BE TSTMS THIS EVENING. IMPACTS  
GREATEST ROUGHLY 02-04Z WHERE TEMPO FOR 2SM TSRA BR HAS BEEN  
INCLUDED FOR BOTH SITES. LOWER CONDITIONS MAY BE NEEDED AS RADAR  
TRENDS BECOME MORE APPARENT. GUSTY CONVECTIVE WINDS WERE ALSO  
INCLUDED UP TO 30 KT, BUT MAY BE HIGHER IF TSTMS CONTINUE TO  
CONSOLIDATE. THERE ARE NO MEANINGFUL CONCERNS AFTER TSTMS MOVE  
THROUGH THE SITES WITH VFR CONDITIONS RETURNING FOR THE  
REMAINDER OF THE 00Z TAF WINDOW.  
 
KSAV: PRIMARY IMPACTS WILL BE TSTMS LATE THIS EVENING INTO EARLY  
THURSDAY MORNING. IMPACTS GREATEST ROUGHLY 04-06Z WHERE TEMPO  
FOR 3SM TSRA HAS BEEN INCLUDED. LOWER CONDITIONS MAY BE NEEDED AS RADAR  
TRENDS BECOME MORE APPARENT. THERE ARE NO MEANINGFUL CONCERNS  
AFTER TSTMS MOVE THROUGH THE SITES WITH VFR CONDITIONS RETURNING  
FOR THE REMAINDER OF THE 00Z TAF WINDOW.  
 
EXTENDED AVIATION OUTLOOK: VFR WILL MAINLY PREVAIL THROUGHOUT  
THE PERIOD, HOWEVER BRIEF FLIGHT RESTRICTIONS ARE POSSIBLE  
DURING AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS.  
 

 
   
MARINE
 
 
TONIGHT: THE STRONGEST WINDS WILL OCCUR FROM THE LATE AFTERNOON  
THROUGH THE EARLY EVENING HOURS ALONG THE LAND/SEA INTERFACE  
WITH THE SEA BREEZE. SPEEDS SHOULD MOSTLY TOP OUT IN THE 10-15  
KNOT RANGE DURING THIS TIME. THEN LATE TONIGHT, WINDS WILL TURN  
MORE SOUTHWESTERLY OR EVEN WEST-SOUTHWESTERLY AND SHOULD BE 10  
KNOTS OR LESS. SEAS SHOULD MOSTLY AVERAGE AROUND 2 FEET, BUT  
COULD BE 2-3 FEET AROUND 20 NM AND BEYOND. ALSO OF NOTE, THERE  
IS POTENTIAL FOR THUNDERSTORMS TO REACH THE COAST AND MOVE OUT  
ACROSS THE COASTAL WATERS LATE THIS EVENING AND PRODUCE STRONG  
WIND GUSTS AND EVEN HAIL. THE MAIN TIME PERIOD FOR THUNDERSTORMS  
WILL BE GENERALLY BETWEEN 8PM-2AM.  
 
THURSDAY THROUGH SUNDAY: THE SFC PATTERN WILL SUPPORT SSE WINDS  
ACROSS THE MARINE ZONES BETWEEN 10 TO 15 KTS. WIND GUSTS AROUND  
20 KTS MAY OCCUR WITH THE DEVELOPMENT OF THE AFTERNOON SEA  
BREEZE. SEAS ARE GENERALLY EXPECTED TO RANGE BETWEEN 2 TO 3 FT.  
 

 
   
TIDES/COASTAL FLOODING
 
 
ASTRONOMICAL TIDES WILL PEAK AROUND 6.4 FT MLLW AT CHARLESTON  
WITH THIS EVENING'S HIGH TIDE CYCLE. LATE AFTERNOON WINDS WILL  
ONLY BE MARGINALLY SUPPORTIVE OF INCREASING TIDAL DEPARTURES.  
THIS EVENING'S HIGH TIDE WILL LIKELY PEAK AROUND 6.8-6.9 FT  
MLLW, FALLING JUST SHORT OF COASTAL FLOOD ADVISORY CRITERIA.  
 

 
   
CHS WATCHES/WARNINGS/ADVISORIES
 
 
GA...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR GAZ087-088-  
099>101-114>119.  
SC...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR SCZ040-042>045-  
047>052.  
MARINE...NONE.  
 

 
 

 
 
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