345  
FXUS62 KCHS 261008  
AFDCHS  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE CHARLESTON SC  
608 AM EDT FRI APR 26 2024  
   
SYNOPSIS
 
 
HIGH PRESSURE WILL PREVAIL THROUGH MUCH OF NEXT WEEK. A WEAK  
COLD FRONT COULD APPROACH LATE NEXT WEEK.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
DESPITE SOME OBSERVATIONS SITES REPORTING LOW VSBYS, THE FOG  
REMAINS FAIRLY SHALLOW AND PATCHY. ANY FOG AND STRATUS SHOULD  
BEGIN TO MIX OUT AFTER SUNRISE. OVERALL, ONLY MINOR CHANGES  
WERE NEEDED FOR THE SUNRISE UPDATE.  
 
TODAY: SURFACE HIGH PRESSURE NOSING SOUTH WILL BECOME BETTER  
ESTABLISHED ACROSS THE SOUTHEAST U.S. TODAY HIGH AMPLITUDE  
SUBTROPICAL RIDGING BUILDS ALOFT. AN AREA OF MIXED STRATUS AND  
STRATOCUMULUS WILL BUILD SOUTHWEST INTO PARTS OF THE CHARLESTON  
TRI-COUNTY AND FAR INTERIOR SOUTHEAST SOUTH CAROLINA PRIOR TO  
DAYBREAK. MUCH OF THIS CLOUD COVER SHOULD STEADILY MIX OUT AND  
LIFT INTO A MODEST CUMULUS FIELD ONCE THE SUN RISES AND SURFACE  
HEATING COMMENCES. EXPECT PARTLY CLOUDY SKIES TO PREVAIL FOR  
MUCH OF THE DAY. HIGHS WILL RUN A TAD COOLER THAN THURSDAY WITH  
1000-850 HPA THICKNESSES PROGGED TO PEAK ABOUT 10 M LOWER DURING  
PEAK HEATING. THIS COUPLED WITH A STRONGER INLAND PUSH TO THE  
AFTERNOON SEA BREEZE SHOULD LIMIT HIGHS TO THE UPPER 70S/LOWER  
80S INLAND WITH COOLER CONDITIONS CLOSER TO THE COAST AND ON THE  
BEACHES. GUSTY WINDS WILL ALSO OCCUR NEAR/BEHIND THE SEA BREEZE  
WITH GUSTS AS HIGH AS 25 MPH POSSIBLE.  
 
TONIGHT: THE SYNOPTIC PATTERN WILL CHANGE LITTLE TONIGHT WITH  
SPRAWLING 1035 HPA HIGH PRESSURE EXTENDING SOUTH OVER THE  
SOUTHEAST STATES AND STRONG SUBTROPICAL RIDGING ALOFT. A FAIRLY  
TIGHT SURFACE PRESSURE GRADIENT ASSOCIATED WITH THE HIGH ITSELF  
WILL HOLD THROUGH THE NIGHT WHICH SHOULD KEEP THE ATMOSPHERE  
SOMEWHAT MIXED THROUGH DAYBREAK SATURDAY. ONSHORE WINDS WILL  
LIKELY KEEP SOME DEGREE OF MARINE-BASED STRATOCUMULUS MOVING  
ONSHORE, BUT MODELS APPEAR TO BE STRUGGLING A BIT ON EXACTLY HOW  
MUCH CLOUD COVER WILL OCCUR. PARTLY CLOUDY CONDITIONS WERE  
FAVORED, BUT ADJUSTMENTS TO THIS WILL LIKELY BE NEEDED AS CLOUD  
TRENDS BECOME A BIT MORE APPARENT. LOW WILL RANGE FROM THE UPPER  
50S WELL INLAND TO THE UPPER 60S AT THE BEACHES. A FEW BEACH  
SPOTS ALONG THE GEORGIA COAST, SUCH AS TYBEE ISLAND, MAY NOT  
DROP BELOW 70.  
 

 
   
SHORT TERM /SATURDAY THROUGH MONDAY/
 
 
A STRONG UPPER RIDGE AXIS WILL REMAIN DIRECTLY OVER THE AREA  
SATURDAY INTO SUNDAY WHILE COOL SURFACE HIGH PRESSURE REMAINS TO  
THE NORTH. WEAK ENE TO E WINDS WILL PREVAIL THROUGH THE WEEKEND.  
LOW-LEVEL ONSHORE FLOW IS EXPECTED TO BRING ENOUGH MOISTURE INTO  
THE AREA TO ALLOW SCATTERED TO BROKEN STRATOCUMULUS TO DEVELOP  
DURING PEAK HEATING HOURS. HIGH TEMPS BOTH DAYS WILL BE IN THE  
UPPER 70S TO AROUND 80.  
 
THE DEEP LAYERED RIDGE SHIFTS OFF THE COAST BY MONDAY, WITH A  
SOUTHERLY FLOW SETTING UP IN LOW LEVELS. LESS CUMULUS  
DEVELOPMENT EXPECTED ON MONDAY, AND WARM ADVECTION WILL PUSH  
HIGHS INTO THE LOW TO MID 80S.  
 

 
   
LONG TERM /MONDAY NIGHT THROUGH THURSDAY/
 
 
MAINLY DRY WEATHER EXPECTED THROUGH THE EXTENDED AS A ZONAL FLOW  
DEVELOPS ALOFT AND SURFACE HIGH PRESSURE REMAINS OVER THE  
WESTERN ATLANTIC. WARM ADVECTION AND AMPLE SUNSHINE WILL YIELD A  
WARMING TREND WITH HIGHS BACK IN THE UPPER 80S TO LOWER 90S BY  
MID TO LATE WEEK.  
 

 
   
AVIATION /10Z FRIDAY THROUGH TUESDAY/
 
 
26/12Z TAF DISCUSSION:  
KCHS/KJZI: CIGS ENDED UP BEING A TAD LOWER THAN EXPECTED AND  
SOLIDLY IN IFR. THE CLOUD LAYER IS PRETTY SHALLOW AND SHOULD MIX  
OUT AS SUNRISE APPROACHES. EXPECT VFR BY 14Z AND WILL PERSIST  
THROUGH 12Z SATURDAY MORNING. GUSTY WINDS WITH GUSTS 20-22 KT  
WILL IMPACT BOTH TERMINALS AS THE SEA BREEZE MOVES INLAND THIS  
AFTERNOON.  
 
KSAV: VFR THROUGH 267/16Z SATURDAY. SHALLOW FOG WILL MIX OUT  
QUICKLY AFTER SUNRISE. NO ISSUES ARE EXPECTED. A SCATTERED CLOUD  
DECK AROUND 1200 FT COULD OOZE INTO THE TERMINAL NEAR SUNRISE,  
BUT WILL MIX OUT. WIND GUSTS NEAR 20 KT WILL BE COMMON THIS  
AFTERNOON AS THE SEA BREEZE MOVES INLAND.  
 
EXTENDED AVIATION OUTLOOK: PREVAILING VFR.  
 

 
   
MARINE
 
 
TODAY: EASTERLY WINDS WILL SLOWLY BUILD THROUGH THE DAY AS HIGH  
PRESSURE NOSES IN FROM THE NORTH. WINDS WILL REACH 15-20 KT IN  
THE SOUTH SANTEE-EDISTO BEACH NEARSHORE LEG OUT 20 NM WITH  
SLIGHTLY LOWER WINDS EXPECTED ELSEWHERE ACROSS THE LOCAL MARINE  
AREA. A ROBUST SEA BREEZE APPEARS LIKELY IN THE CHARLESTON  
HARBOR THIS AFTERNOON. WINDS SHOULD PEAK IN THE 15-20 KT RANGE  
WITH WAVES BUILDING 1-2 FT. IT WILL BE CLOSE TO SMALL CRAFT  
ADVISORY LEVELS (CHARLESTON HARBOR CRITERIA IS SUSTAINED 20 KT  
OR FREQUENT GUSTS TO 25 KT), BUT IT APPEARS THAT BOTH SUSTAINED  
WIND AND WIND GUSTS WILL FALL JUST SHY OF ADVISORY THRESHOLDS.  
SEAS WILL AVERAGE 2-4 FT.  
 
TONIGHT: EAST WINDS AROUND 15 KT WILL HOLD THROUGH THE NIGHT.  
SEA BREEZE ENHANCEMENTS IN THE CHARLESTON HARBOR WILL DIMINISH  
EARLY IN THE EVENING. SEAS WILL BUILD TO 3-5 FT AND POSSIBLY AS  
HIGH AS 6 FT IN THE GEORGIA OFFSHORE LEG OUT 20-60 NM. THERE IS  
SOME UNCERTAINTY IF 6 FT SEAS WILL REACH THE GEORGIA OFFSHORE  
WATERS BY SUNRISE SATURDAY WITH THE LATEST NWPS AND WAVEWATCH  
SHOWING SLIGHT TIMING DIFFERENCES ON THE ARRIVAL OF 6 FT SEAS. A  
SMALL CRAFT ADVISORY WILL NOT BE ISSUED JUST YET GIVEN THESE  
TIMING DIFFERENCES. THE NEED FOR AN ADVISORY WILL BE RECONSIDERED  
LATER TODAY.  
 
SATURDAY THROUGH TUESDAY: FAIRLY LONG ENE FETCH MAY BRING SOME  
6 FT SEAS INTO THE OFFSHORE GA WATERS LATE TONIGHT OR SATURDAY  
MORNING, THEN CONTINUING INTO SUNDAY BEFORE DROPPING BACK BELOW  
6 FT. A SHORT-DURATION SMALL CRAFT ADVISORY MAY BE NEEDED.  
OTHERWISE, MARINE CONDITIONS WILL REMAIN FAIRLY QUIET WITH E  
WINDS THIS WEEKEND BECOMING SE EARLY NEXT WEEK, THEN S BY MID  
NEXT WEEK.  
 
RIP CURRENTS: MODERATE ONSHORE WINDS WILL CONTINUE THROUGH  
THE WEEKEND, WHILE APPROXIMATELY 3 FT WAVES EVERY 6-7 SECONDS  
HIT THE BEACHES. LOCAL RIP CURRENT CALCULATOR INDICATES LOW RISK  
FOR SATURDAY, BUT THE RIP CURRENT MOS SHOWS MODERATE FOR THE GA  
BEACHES, SO WE ARE CARRYING LOW FOR SC AND MODERATE FOR GA.  
 

 
   
CHS WATCHES/WARNINGS/ADVISORIES
 
 
GA...NONE.  
SC...NONE.  
MARINE...NONE.  
 

 
 

 
 
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