532
FXUS62 KCHS 201726
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
1226 PM EST SAT DEC 20 2025
SYNOPSIS
HIGH PRESSURE WILL PREVAIL OVER THE WEEKEND, WITH ANOTHER COLD
FRONT FORECAST TO IMPACT THE AREA MONDAY.
NEAR TERM /THROUGH TONIGHT/
QUIET WEATHER WILL DOMINATE ACROSS THE SC LOWCOUNTRY AND SE GA
THROUGH THIS AFTERNOON AND TONIGHT AS SURFACE HIGH PRESSURE HOLDS
STRONG.
ZONAL FLOW WILL DOMINATE IN THE MID AND UPPER LEVELS OF THE
ATMOSPHERE TODAY, WITH SLIGHT RIDGING PRESENT OVER THE SE STATES AT
850HPA ACCORDING TO THE 12Z SPC UPPER AIR ANALYSIS. SURFACE ANALYSIS
FROM 12Z SHOWS HIGH PRESSURE CENTERED OVER THE SOUTHEASTERN STATES.
AS THE AFTERNOON PROGRESSES THE CENTER OF HIGH PRESSURE WILL DRIFT
EASTWARD TOWARDS THE LOCAL FORECAST AREA. BLENDED GUIDANCE CONTINUES
TO SHOW HIGH TEMPERATURES IN THE LOW 60S, HOWEVER GIVEN THAT
LOCATIONS ACROSS THE REGION ARE ALREADY AROUND 60, TEMPERATURES WILL
LIKELY TOP OFF IN THE MID 60S WITH UPPER 60S POSSIBLE ACROSS SE GA.
TONIGHT WILL FEATURE WINDS GOING LIGHT AND VARIABLE AS THE CENTER OF
HIGH PRESSURE RESIDES OVERHEAD. GIVEN LIGHT WINDS AND CLEAR SKIES
ANOTHER RADIATIONAL COOLING NIGHT IS FORECAST, ALTHOUGH TEMPERATURES
AREN'T EXPECTED TO DIP QUITE AS LOW AS FRIDAY NIGHT/SATURDAY
MORNING. LOWS TONIGHT ARE FORECAST TO REACH INTO THE MID 30S INLAND
WITH LOW TO MID 40S ALONG THE COASTAL COUNTIES.
SHORT TERM /SUNDAY THROUGH TUESDAY/
QUASI-ZONAL UPPER LEVEL FLOW AND A WEAK SURFACE HIGH PRESSURE WILL
CONTINUE THE QUIET CONDITIONS, WITH AFTERNOON HIGHS IN THE MID 60S
TO LOWER 70S ACROSS THE AREA. A WEAK COLD FRONT PUSHES THROUGH
DURING THE AFTERNOON HOURS, THOUGH THE COLDER AIR LAGS BEHIND
OVERNIGHT INTO MONDAY. OVERNIGHT LOWS IN THE UPPER 30S TO MID 40S
EXPECTED.
UPPER LEVEL RIDGING PUSHES A SURFACE HIGH PRESSURE ONTO THE EAST
COAST NORTH OF THE AREA, INCREASING THE SURFACE PRESSURE GRADIENT.
THIS WILL RESULT IN BREEZY CONDITIONS BUILDING OVERNIGHT INTO
MONDAY, WITH GUSTS INTO THE TEENS TO LOWER 20S THROUGHOUT THE DAY.
WITH THE FRESH INFLUX OF COOLER AIR, AFTERNOON TEMPERATURES WILL BE
BELOW NORMAL IN THE UPPER 50S TO LOWER 60S.
WINDS DECREASE OVERNIGHT INTO TUESDAY AS THE SURFACE HIGH PRESSURE
WEAKENS AND MOVES INTO THE ATLANTIC. AS THEY SWING AROUND TO BECOME
OUT OF THE SOUTH-SOUTHWEST, WARMER TEMPERATURES WILL BE ADVECTED
BACK ACROSS THE REGION WITH AFTERNOON HIGHS IN THE UPPER 60S TO MID
70S EXPECTED.
LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/
THE AFOREMENTIONED UPPER LEVEL RIDGE CONTINUES INTO THE EXTENDED,
WITH ANOTHER SURFACE HIGH PRESSURE EXPECTED TO MOVE DOWN INTO THE
REGION END OF THIS HOLIDAY WEEK. THIS WILL RESULT IN ABOVE NORMAL
TEMPERATURES AND DRY CONDITIONS. AFTERNOON HIGHS LOOK TO BE IN THE
UPPER 60S TO MID 70S RANGE.
AVIATION /18Z SATURDAY THROUGH THURSDAY/
PREVAILING VFR THROUGH THE 18Z TAF PERIOD. AS THE CENTER OF HIGH
PRESSURE SHIFTS OVER THE FORECAST AREA WINDS TONIGHT ARE
FORECAST TO GO LIGHT AND VARIABLE.
EXTENDED AVIATION OUTLOOK: VFR EXPECTED TO PREVAIL THROUGH SUNDAY,
WITH A PERIOD OF MVFR CIGS POSSIBLE MONDAY MORNING IN THE WAKE OF A
FRONTAL PASSAGE. NORTHEASTERLY WINDS ARE EXPECTED TO BE BREEZY ON
MONDAY, WITH GUSTS IN THE 14-18 KT RANGE.
MARINE
TODAY AND TONIGHT: PREVAILING HIGH PRESSURE WILL YIELD
NORTHEAST WINDS 5 TO 10 KT WITH TRANSIENT GUSTS UP TO 15 KT
ACROSS ALL WATERS. SEAS 2 TO 4 FT.
SUNDAY - MONDAY: TRANQUIL CONDITIONS CONTINUE INTO SUNDAY. OVERNIGHT
INTO MONDAY, NORTH-NORTHEASTERLY WINDS STRENGTHEN WITH WAVE HEIGHTS
SIMILARLY BUILDING. CONFIDENCE FOR WIND GUSTS GREATER THAN 25 KNOTS
IS HIGH FOR ALL NEAR AND OFFSHORE WATERS, WITH BOTH THE HREF AND
REFS SHOWING 90%+ PROBABILITIES FOR WIND GUSTS GREATER THAN 25
KNOTS, THOUGH BOTH ENSEMBLES SHOW VERY LOW PROBABILITIES (<10%) FOR
GALE FORCE WINDS. FOR THE CHARLESTON HARBOR, PROBABILITIES FOR THESE
WINDS IS IN THE 60-80% RANGE, HIGHEST NEAR THE ENTRANCE AND
DECREASING INTO THE HARBOR. WAVE HEIGHTS OF 6-8 FEET ARE ALSO
EXPECTED TO BUILD INTO THE REGION OVERNIGHT INTO MONDAY. THUS, A
SMALL CRAFT ADVISORY WILL BE NEEDED FOR THE EARLY OVERNIGHT HOURS
INTO MONDAY, THOUGH UNSURE IF THE CHARLESTON HABOR WILL NEED TO BE
INCLUDED, WITH ADVISORY LEVEL WINDS AND SEAS TAPERING OFF OVERNIGHT
INTO TUESDAY. SOME INDICATIONS THAT THE SAVANNAH TO ALTAMAHA SOUND
WATER FROM 20-60NM OUT MAY HANG ONTO THE SCA CONDITIONS UNTIL LATE
TUESDAY AFTERNOON OR EVENING.
TUESDAY - WEDNESDAY: NO HIGH CONFIDENCE MARINE CONCERNS AT THIS
TIME.
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...NONE.
NEAR TERM...CPM
SHORT TERM...APT
LONG TERM...APT
AVIATION...APT/CPM
MARINE...APT/CPM
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