396  
FXUS62 KCHS 210157  
AFDCHS  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE CHARLESTON SC  
857 PM EST THU FEB 20 2025  
   
SYNOPSIS  
 
COLD HIGH PRESSURE WILL BUILD INTO THE REGION THROUGH THE START  
OF THE WEEKEND. AN AREA OF LOW PRESSURE WILL DEVELOP OFF THE  
COAST ON SUNDAY, FOLLOWED BY MORE HIGH PRESSURE INTO EARLY NEXT  
WEEK.  
 
 
   
NEAR TERM /UNTIL 6 AM FRIDAY MORNING/  
 
CLEAR SKIES WILL PREVAIL OVERNIGHT AS ARCTIC HIGH PRESSURE  
BUILDS INTO THE SOUTHEAST STATES. THE LAST 3-4 HRS WORTH OF  
HIGH-RESOLUTION GUIDANCE RUNS HAVE TRENDED A TAD WARMER WITH  
OVERNIGHT LOWS, WHICH MATCHES TRENDS NOTED THE HREF GRAND  
ENSEMBLE FROM EARLIER IN THE DAY. GIVEN STEADY WARMING TREND,  
LOWS HAVE BEEN NUDGED UP A DEGREE OR TWO FOR MOST AREAS WITH THE  
LATE EVENING UPDATE, RANGING FROM THE MID-UPPER 20S INLAND TO  
AROUND 30 AT THE BEACHES. WINDS HAVE RECENTLY DIMINISHED WITH  
THE LOSS OF INSOLATION, BUT ARE FORECAST TO INCREASE AGAIN LATER  
TONIGHT AS THE PRESSURE GRADIENT TIGHTENS. MINIMUM WIND CHILLS  
ARE ON TRACK TO DROP INTO THE 15-20 DEGREE RANGE, POSSIBLY A TAD  
WARMER OVER PARTS OF THE GEORGIA COAST. A COLD WEATHER ADVISORY  
IS IN EFFECT FROM 10 PM TO 10 AM FRIDAY FOR ALL OF SOUTHEAST  
SOUTH CAROLINA AND SOUTHEAST GEORGIA, ALTHOUGH IT LOOKS MARGINAL  
ALONG PARTS OF THE GEORGIA COASTAL COUNTIES.  
 
 
   
SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY NIGHT/  
 
FRIDAY THROUGH SUNDAY: COLD AND DRY HIGH PRESSURE WILL PREVAIL  
ACROSS THE AREA ON FRIDAY. OTHER THAN SOME THIN CIRRUS SPREADING IN  
FROM THE WEST IN THE AFTERNOON, MOSTLY CLEAR SKIES ARE EXPECTED.  
DESPITE PLENTY OF SUN, TEMPERATURES WILL BE QUITE CHILLY AND ON THE  
ORDER OF 15-20 DEGREES BELOW NORMAL. HIGHS ARE EXPECTED TO TOP OUT  
IN THE MID TO UPPER 40S ACROSS SOUTHEAST SC AND NEAR 50 FOR  
SOUTHEAST GA. FRIDAY NIGHT WILL BE ANOTHER VERY COLD NIGHT, THOUGH  
NOT AS COLD AS THURSDAY NIGHT. LOWS IN THE MID TO UPPER 20S ARE  
FORECAST BUT THE LACK OF WIND WILL KEEP WIND CHILLS UP AND NO COLD  
WEATHER ADVISORY IS EXPECTED. THE HIGH WILL BRIDGE ACROSS THE  
APPALACHIANS AND EVENTUALLY OFF THE EAST COAST SATURDAY AND SATURDAY  
NIGHT. A SURFACE LOW IS EXPECTED TO DEVELOP OFF THE SOUTHEAST COAST  
SATURDAY NIGHT, BUT ANY PRECIPITATION ASSOCIATED WITH IT WILL REMAIN  
OFFSHORE. TEMPERATURES WILL START TO REBOUND, BUT REMAIN BELOW  
NORMAL, WITH HIGHS GETTING UP INTO THE UPPER 50S FOR PORTIONS OF THE  
AREA. QUIET CONDITIONS THEN CONTINUE INTO SUNDAY WARMING BACK CLOSER  
TO NORMAL. LOOK FOR HIGHS IN THE LOW TO MID 60S.  
 
 
   
LONG TERM /MONDAY THROUGH THURSDAY/  
 
A SYSTEM IS EXPECTED TO PASS BY TO THE SOUTH ACROSS THE GULF SUNDAY  
NIGHT AND MONDAY. WHILE MOST OF THE PRECIPITATION ASSOCIATED WITH IT  
WILL REMAIN DISPLACED TO THE SOUTH, THERE IS SOME MODEL SUPPORT FOR  
RAIN TO EXTEND UP TO ALONG THE GA COAST. THE FORECAST ADVERTISES 20  
PERCENT CHANCES ALONG THE GA COAST AND THE ADJACENT COASTAL  
WATERS. THEREAFTER, DRY CONDITIONS WILL PREVAIL WITH MODERATING  
TEMPERATURES. WE COULD BE BACK TO NEAR NORMAL BY MONDAY WITH LOW  
TO MID 70S POSSIBLE THROUGH MID WEEK.  
 
 
   
AVIATION /02Z FRIDAY THROUGH TUESDAY/  
 
21/00Z TAF DISCUSSION:  
KCHS/KJZI/KSAV: VFR THROUGH EARLY FRIDAY EVENING.  
 
EXTENDED AVIATION OUTLOOK: VFR CONDITIONS ARE EXPECTED TO  
PREVAIL.  
 
 
   
MARINE  
 
THE SMALL CRAFT ADVISORY HAS BEEN EXPANDED TO INCLUDE THE  
REMAINING NEARSHORE LEGS OUT 20 NM. IT WILL BE CLOSE IN THE  
CHARLESTON HARBOR, BUT THE EXPECTATION IS WINDS AND WIND GUSTS  
WILL FALL JUST SHY OF ADVISORY CRITERIA.  
 
TONIGHT: GUSTY NW WINDS WILL PERSIST ACROSS THE WATERS AS HIGH  
PRESSURE BUILDS INTO THE REGION FROM THE WEST. GUSTS ARE  
FORECAST TO RANGE BETWEEN 25 TO 30 KT. SEAS WILL RANGE BETWEEN  
3 TO 5 FT NEARSHORE WATERS AND 5-7 FT FOR THE GEORGIA OFFSHORE  
WATERS. SMALL CRAFT ADVISORIES ARE IN EFFECT.  
 
FRIDAY THROUGH TUESDAY: NORTHERLY WINDS WILL PEAK FRIDAY MORNING  
THEN STEADILY DIMINISH THROUGH THE DAY AS THE PRESSURE GRADIENT  
RELAXES. AS CONDITIONS IMPROVE, THE ONGOING SMALL CRAFT ADVISORIES  
FOR THE CHARLESTON COUNTY WATERS AND THE OUTER GA WATERS WILL COME  
TO AN END. WINDS AND SEAS WILL THEN REMAIN WELL BELOW ADVISORY  
THRESHOLDS THROUGH EARLY NEXT WEEK.  
 
 
   
CLIMATE  
 
RECORD LOW MAXIMUM TEMPERATURES:  
 
FEBRUARY 21:  
KCHS: 47/2020  
 
RECORD LOW TEMPERATURES:  
 
FEBRUARY 21:  
KCHS: 22/1958  
 
 
   
CHS WATCHES/WARNINGS/ADVISORIES  
 
GA...COLD WEATHER ADVISORY UNTIL 10 AM EST FRIDAY FOR GAZ087-088-  
099>101-114>119-137>141.  
SC...COLD WEATHER ADVISORY UNTIL 10 AM EST FRIDAY FOR SCZ040-  
042>045-047>052.  
MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EST FRIDAY FOR AMZ350-352-354.  
SMALL CRAFT ADVISORY UNTIL 5 PM EST FRIDAY FOR AMZ374.  
 
 
 
 
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