952
FXUS62 KCHS 141800
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
100 PM EST SUN DEC 14 2025
SYNOPSIS
AN ARCTIC COLD FRONT WILL SWEEP THROUGH TODAY. DRY HIGH
PRESSURE WILL THEN BUILD OVERHEAD FOR MUCH OF THE COMING WEEK.
NEAR TERM /THROUGH TONIGHT/
A STRONG COLD FRONT IS QUICKLY PROGRESSING THROUGH THE FORECAST
AREA THIS AFTERNOON AND AS OF 1 PM IS LOCATED ABOUT HALFWAY
THROUGH THE CWA, ORIENTED FROM NE TO SW. BEHIND THE FRONT GUSTY
NW WINDS HAVE DEVELOPED, WITH GUSTS AROUND 20 TO 25 MPH. A LAKE
WIND ADVISORY IS IN EFFECT FOR LAKE MOULTRIE BEGINNING AT 1 PM
THIS AFTERNOON AND LASTING INTO TOMORROW MORNING. A DRY
FORECAST IS IN STORE THROUGH THE REMAINDER OF THE DAY, AS ANY
SHOWERS AHEAD OF THE FRONT HAVE DISSIPATED OFFSHORE.
THE MAIN STORY THROUGH THE REMAINDER OF THIS AFTERNOON AND INTO
TONIGHT WILL BE THE STRONG COLD AIR ADVECTION (CAA) AS STRONG
HIGH PRESSURE QUICKLY BUILDS IN BEHIND THE DEPARTING COLD FRONT.
MOST LOCATIONS HAVE LIKELY REACHED THEIR HIGH TEMPERATURES FOR
THE DAY, WITH COASTAL LOCATIONS SEEING UPPER 60S TO 70 IN A FEW
SPOTS. THESE TEMPERATURES WILL QUICKLY PLUMMET AS THE CAA REGIME
TAKES OVER, DROPPING INTO THE 50S BY LATER THIS AFTERNOON AND
THE 40S THIS EVENING.
THE ARCTIC HIGH PRESSURE WILL CONTINUE TO BUILD ACROSS THE
REGION TONIGHT, SETTING UP A BITTERLY COLD OVERNIGHT.
TEMPERATURES ARE FORECAST TO DROP INTO THE LOW 20S ACROSS THE
REGION, WHICH COMBINED WITH THE GUSTY WINDS, WILL YIELD WIND
CHILL VALUES IN THE TEENS. A COLD WEATHER ADVISORY IS IN EFFECT
FROM 10 PM THIS EVENING INTO MONDAY MORNING. THERE IS A LOW END
CHANCE (~20%) THAT SOME LOCATIONS IN THE CHARLESTON TRI-COUNTY
AREA COULD SEE A BRIEF MOMENT OR TWO OF SINGLE DIGIT WIND CHILLS
IN THE EARLY MORNING HOURS.
SHORT TERM /MONDAY THROUGH WEDNESDAY/
OVERVIEW: BITTER COLD TEMPERATURES CONTINUE THROUGH TUESDAY MORNING,
THEN BEGIN TO MODERATE BY MID WEEK.
MONDAY: DEEP, COLD HIGH PRESSURE WILL BE CENTERED OVER THE REGION.
EVEN WITH FULL SUN, HIGHS NOT EXPECTED TO MAKE IT MUCH PAST 40,
WHICH ARE NEAR RECORD LOW MAX VALUES FOR THE DATE! LUCKILY, WINDS
WILL BE LIGHT AS HIGH PRESSURE BUILDS DIRECTLY OVERHEAD, REDUCING
ANY WIND CHILL EFFECTS. THE SURFACE RIDGE AXIS REMAINS DIRECTLY
OVERHEAD THROUGH MONDAY EVENING AND OVERNIGHT NIGHT, SHIFTING A BIT
FURTHER EAST CLOSER TO DAYBREAK. GIVEN NEARLY IDEAL RADIATIONAL
COOLING CONDITIONS AND DEW POINTS IN THE LOWER TEENS TO UPPER SINGLE
DIGITS, LOW TEMPERATURES INTO THE TEENS AWAY FROM THE BEACHES, ON
THE LOWER END OF THE GUIDANCE ENVELOPE, ARE REASONABLE. THIS WOULD
NECESSITATE ANOTHER COLD WEATHER ADVISORY FOR MUCH OF SE SC AND SE
GA INLAND OF THE HWY 17 CORRIDOR.
TUESDAY AND WEDNESDAY: THE SURFACE RIDGE CONTINUES TO MOVE EASTWARD
INTO THE ATLANTIC WITH ZONAL MID AND UPPER LEVEL FLOW. THIS PATTERN
IS EXPECTED TO ALLOW A MODERATION IN TEMPERATURES, REACHING TO NEAR
TO SLIGHTLY ABOVE NORMAL BY WEDNESDAY. NO PRECIPITATION IS EXPECTED
DURING THIS PERIOD.
LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/
THE GENERAL ZONAL UPPER LEVEL PATTERN IS SHOWN BY MODELS TO BRIEFLY
BE INTERRUPTED BY A FAST MOVING UPPER LEVEL TROUGH AXIS AND
ASSOCIATED WEAK COLD FRONT THURSDAY. THE MOST LIKELY SCENARIO WITH
THIS FRONT REMAINS THAT FRONTOLISIS AND WANING MOISTURE WILL LEAD TO
LIMITED RAINFALL, WITH STRONG ENSEMBLE AGREEMENT THAT RAINFALL
AMOUNTS WILL REMAIN LESS THAN AN INCH ACROSS THE AREA.
FRIDAY THROUGH SUNDAY: THE UPPER FLOW REVERTS BACK TO GENERALLY
ZONAL, WITH TEMPERATURES ABOVE NORMAL, IN THE 60S TO NEAR 70. MODELS
DIVERGE AGAIN WITH THE POTENTIAL FOR ANOTHER FRONT AND THREAT FOR
PRECIPITATION TO APPROACH THE AREA POSSIBLY BY LATE IN THE PERIOD ON
SUNDAY. CONFIDENCE WITH WHETHER OR NOT THIS FRONT WILL HAVE ANY
IMPACT IN OUR AREA IS VERY LOW AT THIS TIME.
AVIATION /18Z SUNDAY THROUGH FRIDAY/
VFR WILL DOMINATE AT KCHS/KJZI THROUGH THE 18Z TAF PERIOD, WITH
A BRIEF PERIOD OF MVFR CIGS EXPECTED AT KSAV THROUGH THE FIRST
HOUR OF THE TAF PERIOD BEFORE GOING SKC. THEREAFTER, THIS
AFTERNOON WILL FEATURE GUSTY WINDS, GENERALLY AROUND 20-25
KNOTS, AS HIGH PRESSURE BUILDS INTO THE REGION BEHIND A
DEPARTING COLD FRONT. GUSTY WINDS WILL CONTINUE INTO THE
OVERNIGHT PERIOD, WANING AROUND DAYBREAK.
EXTENDED AVIATION OUTLOOK: VFR CONDITIONS PREVAIL FOR KCHS, KJZI AND
KSAV THROUGH MID-WEEK.
MARINE
A STRONG COLD FRONT WILL QUICKLY PUSH INTO THE MARINE ZONES
THIS AFTERNOON, YIELDING A WIND SHIFT FROM THE SW TO THE N/NW.
AS HIGH PRESSURE BUILDS INTO THE REGION BEHIND THE DEPARTING
COLD FRONT WINDS ARE FORECAST TO SURGE, WITH GUSTS REACHING AS
HIGH AS 35 KNOTS OUTSIDE OF THE CHARLESTON HARBOR. A GALE
WARNING IS NOW IN EFFECT FOR ALL OFFSHORE WATERS THROUGH MONDAY
MORNING. THE CHARLESTON HARBOR WILL SEE GUSTS AROUND 25 KNOTS
AND HAS A SMALL CRAFT ADVISORY IN EFFECT THROUGH MONDAY MORNING.
IT IS WORTH NOTING THAT THE 12Z HREF SHOWS A 30-40% PROBABILITY
OF THE HARBOR SEEING WIND GUSTS GREATER THAN 30 KNOTS. IT IS NOT
OUT OF THE QUESTION THAT THE CHARLESTON HARBOR MAY NEED TO BE
UPGRADED TO A GALE WARNING AT SOME POINT THIS AFTERNOON/EVENING.
MONDAY THROUGH THURSDAY: ELEVATED SEAS AT SUNRISE MONDAY MORNING
WILL QUICKLY SUBSIDE THROUGH THE DAY AS HIGH PRESSURE PASSES
OVERHEAD. RIDGING AT THE SURFACE WILL REMAIN JUST EAST OF THE WATERS
THROUGH AT LEAST WEDNESDAY KEEPING BENIGN MARINE CONDITIONS IN
PLACE. A COASTAL TROUGH MAY DEVELOP OVER THE NEARSHORE WATERS ON
THURSDAY AS A COLD FRONT APPROACHES FROM THE WEST. WINDS LIKELY TO
INCREASE FROM THE SOUTH ON THURSDAY, BUT STILL EXPECTED TO REMAIN
BELOW HIGHLIGHT LEVELS.
CLIMATE
RECORD LOW TEMPERATURES:
DECEMBER 15:
KCHS: 15/1962
KCXM: 23/1943
KSAV: 19/1962
RECORD LOW MAXIMUM TEMPERATURES:
DECEMBER 15:
KCHS: 39/1943
KCXM: 38/1904
KSAV: 38/1904
CHS WATCHES/WARNINGS/ADVISORIES
GA...COLD WEATHER ADVISORY FROM 10 PM THIS EVENING TO 10 AM EST
MONDAY FOR GAZ087-088-099>101-114>119-137>141.
SC...COLD WEATHER ADVISORY FROM 10 PM THIS EVENING TO 10 AM EST
MONDAY FOR SCZ040-042>045-047>052.
LAKE WIND ADVISORY UNTIL 4 AM EST MONDAY FOR SCZ045.
MARINE...SMALL CRAFT ADVISORY UNTIL 9 AM EST MONDAY FOR AMZ330.
GALE WARNING UNTIL 7 AM EST MONDAY FOR AMZ350-352-354-374.
NEAR TERM...CPM
SHORT TERM...CEB
LONG TERM...CEB
AVIATION...CEB/CPM
MARINE...CEB/CPM
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