715
FXUS62 KCHS 211151
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
651 AM EST SUN DEC 21 2025
SYNOPSIS
HIGH PRESSURE CONTINUES TO PREVAIL TODAY, WITH A COLD FRONT
THEN EXPECTED TO DIVE ACROSS THE REGION TONIGHT INTO MONDAY.
HIGH PRESSURE THEN RETURNS TUESDAY, RESULTING IN ABOVE NORMAL
TEMPERATURES AND DRY CONDITIONS FOR THE REMAINDER OF THE
HOLIDAY WEEK.
NEAR TERM /THROUGH TONIGHT/
THE MID-LEVELS WILL CONSIST OF A TROUGH PASSING WELL TO OUR
NORTH TODAY, WITH SOMEWHAT ZONAL FLOW OVER OUR AREA. THE TROUGH
AMPLIFIES AS IT MOVES OFFSHORE TONIGHT, CAUSING FLOW TO TURN TO
THE NW OVERHEAD. AT THE SURFACE, HIGH PRESSURE WILL PREVAIL THIS
MORNING, THEN SHIFT AWAY INTO THE AFTERNOON. MOSTLY SUNNY SKIES
WILL YIELD ABOVE NORMAL TEMPERATURES, GENERALLY IN THE 60S, TO
NEAR 70 DEGREES ACROSS THE ALTAMAHA RIVER AND VICINITY. A DRY
COLD FRONT WILL MOVE SOUTHWARD THROUGH OUR SC COUNTIES LATE THIS
AFTERNOON OR EARLY EVENING, THEN THROUGH OUR GA COUNTIES THIS
EVENING, CAUSING A BRIEF INCREASE IN CLOUDS AND A WIND SHIFT. AS
THIS FRONT MOVES SOUTH OF OUR AREA OVERNIGHT, STRONG HIGH
PRESSURE WILL BUILD TO OUR NORTH. THE COMBINATION OF MOSTLY
CLEAR SKIES AND COLD AIR ADVECTION TONIGHT WILL CAUSE
TEMPERATURES TO DROP INTO THE 30S FAR INLAND, AND 40S AT/NEAR
THE BEACHES.
SHORT TERM /MONDAY THROUGH WEDNESDAY/
BREEZY NORTHEASTERLY WINDS WILL PERSIST ACROSS THE REGION MONDAY IN
THE WAKE OF FROPA, WITH GUSTS UP TO 20 KTS POSSIBLE THROUGH THE
AFTERNOON IN AREAS NEAR/ALONG THE COAST. GIVEN THE INFLUX OF CAA,
WILL SEE HIGHS BE A TOUCH COOLER THAN SUNDAY, AS TEMPERATURES ONLY
WARM INTO THE LOWER 60S.
SFC HIGH PRESSURE THEN SLIDES ACROSS THE REGION AGAIN TUESDAY,
ALLOWING HIGHS TO REBOUND BACK INTO THE UPPER 60S TO LOWER 70S WITH
THE AID OF SOUTHWESTERLY FLOW AND PARTLY SUNNY SKIES. WARMING TREND
CONTINUES INTO WEDNESDAY AS UPPER LEVEL RIDGING AMPLIFIES ACROSS THE
CENTRAL CONUS. AS SUCH, EXPECT AFTERNOON HIGHS IN THE LOW TO MID 70S
TO PREVAIL CHRISTMAS EVE.
LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/
UPPER LEVEL RIDGING CONTINUES TO DOMINATE INTO THE EXTENDED, WITH
ITS PLACEMENT SLIDING A BIT MORE EASTWARD OVER THE THE OHIO RIVER
VALLEY BY THURSDAY. THUS, HAVE ABOVE NORMAL TEMPERATURES (LOW TO MID
70S) AND DRY CONDITIONS CONTINUING THROUGH THE HOLIDAYS.
AVIATION /12Z SUNDAY THROUGH THURSDAY/
12Z TAFS: SATELLITE INDICATES LOW STRATUS ACROSS MUCH OF OUR
AREA. SURFACE OBSERVATIONS INDICATE IFR AT MANY LOCATIONS,
ESPECIALLY ACROSS SOUTHEAST GA. WE ADDED AN IFR TEMPO GROUP FOR
KCHS AND KJZI, AND MAINTAINED THE IFR TEMPO GROUP FOR KSAV.
CONDITIONS WILL IMPROVE AT ROUGHLY 13-14Z, WITH VFR THEN
PREVAILING. A DRY COLD FRONT WILL MOVE THROUGH DURING THE LATE
AFTERNOON AND EVENING, CAUSING A WIND SHIFT.
EXTENDED AVIATION OUTLOOK: A PERIOD OF MVFR CIGS WILL BE POSSIBLE
MONDAY MORNING IN THE WAKE OF FROPA, WITH NORTHWESTERLY GUSTS UP TO
20 KTS. OTHERWISE, EXPECT VFR CONDITIONS TO PREVAIL.
MARINE
TODAY AND TONIGHT: HIGH PRESSURE WILL PREVAIL THIS MORNING. A
DRY COLD FRONT WILL MOVE SOUTHWARD THROUGH OUR SC WATERS LATE
THIS AFTERNOON OR EARLY EVENING, THEN THROUGH OUR GA WATERS THIS
EVENING, WITH WINDS TURNING TO THE NE BEHIND THE FRONT. STRONG
HIGH PRESSURE WILL BUILD TO OUR NORTH OVERNIGHT. THE COMBINATION
OF THE SURFACE PRESSURE GRADIENT ENHANCING AND COLD AIR
ADVECTION WILL CAUSE WINDS TO INCREASE AND BECOME GUSTY THIS
EVENING AND OVERNIGHT. WE HAVE SMALL CRAFT ADVISORIES UP FOR ALL
OF THE OCEAN WATERS DUE TO WINDS AND SEAS. IT'S BORDERLINE
WHETHER WE'LL NEED A SMALL CRAFT ADVISORY FOR THE CHARLESTON
HARBOR TONIGHT.
MONDAY THROUGH TUESDAY: BREEZY NORTHWESTERLY WINDS LOOK TO PERSIST
FOR MUCH OF MONDAY MORNING, BEFORE GRADUALLY TAPERING OFF INTO THE
AFTERNOON. NONETHELESS, WILL STILL SEE SEAS RANGE BETWEEN 5-7 FT
DURING THIS TIME - KEEPING SCAS IN EFFECT THROUGH AT LEAST MONDAY
EVENING. SHOULD THEN SEE THE INNER SC/GA WATERS DROP OFF OVERNIGHT,
WITH SOME INDICATIONS THAT THE OUTER GEORGIA WATERS MAY HANG ONTO
ADVISORY LEVEL CONDITIONS UNTIL LATE TUESDAY AFTERNOON OR EVENING.
WILL CONTINUE TO MONITOR TRENDS IN THE MEANTIME.
WEDNESDAY ONWARD: NO HIGH CONFIDENCE MARINE CONCERNS AT THIS
TIME.
CHS WATCHES/WARNINGS/ADVISORIES
GA...DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR GAZ100-101-
114>119-137>141.
SC...DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR SCZ047-048-
051.
MARINE...SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO MIDNIGHT EST
MONDAY NIGHT FOR AMZ350.
SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO MIDNIGHT EST
MONDAY NIGHT FOR AMZ352-354.
SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 6 PM EST
TUESDAY FOR AMZ374.
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...
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