063
FXUS62 KCHS 180737
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
237 AM EST THU DEC 18 2025
SYNOPSIS
A WARM FRONT WILL SHIFT NORTH ACROSS THE AREA TODAY BEFORE A
COLD FRONT ARRIVES TONIGHT. HIGH PRESSURE WILL THEN PREVAIL
DURING THE WEEKEND. ANOTHER COLD FRONT COULD SHIFT ACROSS THE
AREA MONDAY, BEFORE HIGH PRESSURE RETURNS AND PREVAILS INTO THE
MIDDLE OF NEXT WEEK.
NEAR TERM /THROUGH TONIGHT/
PRIOR TO DAYBREAK: A WEAK COASTAL TROUGH POSITIONED OFF THE
SOUTHEAST COAST WILL BECOME BETTER DEFINED LATE, BECOMING THE
PRIMARY FOCUS FOR A FEW SHOWERS TO DEVELOP ACROSS COASTAL WATERS,
THEN SHIFT ACROSS SOUTHEAST GEORGIA BEACHES PRIOR TO DAYBREAK.
PRECIP IS EXPECTED TO REMAIN LIGHT DURING THE OVERNIGHT, BUT
COVERAGE WILL GRADUALLY INCREASE AS ACTIVITY SPREADS ONSHORE WHILE
THE SFC TROUGH BEGINS TO LIFT NORTH AS A WARM FRONT. PRECIP AMOUNTS
BETWEEN 1/10 TO 1/4 INCH ARE POSSIBLE BY DAYBREAK, MAINLY CONFINED
TO LOCATIONS ALONG AND SOUTH OF BEAUFORT, SC AND ACROSS SOUTHEAST
GEORGIA BEACHES INITIALLY, BEFORE SPREADING INLAND AND IMPACTING
MOST AREAS ALONG AND WEST OF THE I-95 CORRIDOR APPROACHING DAYBREAK.
WIDESPREAD CLOUDS AND ONSHORE FLOW WILL HELP KEEP TEMPS WARMER THAN
THE PAST SEVERAL NIGHTS. LOWS SHOULD RANGE IN THE MID-UPPER 40S
INLAND TO LOW-MID 50S NEAR THE COAST.
TODAY AND TONIGHT: ALOFT, A SOUTHWEST FLOW WILL BE IN PLACE TO START
THE DAY AHEAD OF A SOUTHERN STREAM SHORTWAVE TRACKING ACROSS THE
DEEP SOUTH AND NORTHERN GULF COAST REGION. AT THE SFC, A COASTAL
TROUGH IS ANTICIPATED TO SHIFT ONSHORE AS WARM FRONT EARLY,
EVENTUALLY LIFTING NORTH OF THE LOCAL AREA BY LATE MORNING AND
KEEPING THE REGION WARM-SECTORED THROUGH THE AFTERNOON PRIOR TO A
COLD FRONT ARRIVING TONIGHT. BREEZY SOUTH-SOUTHWEST WINDS WILL HELP
ADVECT DEEP MOISTURE INTO THE AREA (PWATS APPROACHING 1.5 TO 1.75
INCHES) AND MILD AIR (HIGH TEMPS IN THE UPPER 60S/LOWER 70S),
SETTING THE STAGE FOR NUMEROUS TO WIDESPREAD RAIN/SHOWERS AND EVEN A
FEW EMBEDDED THUNDERSTORMS. PRECIP COVERAGE APPEARS MOST WIDESPREAD
LATE AFTERNOON AND EARLY EVENING WHEN THE COMBINATION OF DEEP
MOISTURE AND FORCING (STRONG UPPER LVL JET, H5 VORT ENERGY AND
ISENTROPIC LIFT) ALIGN PRIOR TO THE COLD FRONT ARRIVING FROM THE
WEST. THE FRONT LOOKS QUITE PROGRESSIVE WITH A HIGH AMPLITUDE MID-
UPPER LVL TROUGH FORCING IT TO THE EASTERN SEABOARD AFTER MIDNIGHT
TONIGHT. EXPECT RAIN/SHOWERS AND PERHAPS A FEW EMBEDDED
THUNDERSTORMS (NON-SEVERE) TO PERSIST DURING EVENING AND EARLY
OVERNIGHT HOURS UNTIL FROPA OCCURS, ALTHOUGH THE MID-UPPER LVL
TROUGH COULD SPAWN A FEW SHOWERS POST FRONT LATE NIGHT. TOTAL
RAINFALL AMOUNTS IN THE 1/2 TO 1 INCH RANGE SHOULD BE COMMON,
HIGHEST ALONG AND EAST OF THE I-95 CORRIDOR, PARTICULARLY NEAR THE
SOUTHEAST SOUTH CAROLINA COAST LATE DAY/EVENING. OVERNIGHT LOWS
REMAIN MILD DESPITE FROPA, GENERALLY IN THE LOW-MID 50S INLAND TO
UPPER 50S NEAR THE COAST.
LAKE WIND: LOW-LVL WIND FIELDS WILL STRENGTHEN ACROSS THE AREA TODAY
AS A COLD FRONT APPROACHES THE AREA OVERNIGHT. A WARM AIR ADVECTION
REGIME COULD LIMIT MIXING OF STRONGER WINDS ACROSS THE LAKE TODAY,
BUT EVENTUALLY LEAD TO GUSTS UPWARDS TO AROUND 25 KT TONIGHT. A LAKE
WIND ADVISORY COULD EVENTUALLY BE NEEDED LATE EVENING AND OVERNIGHT.
SHORT TERM /FRIDAY THROUGH SUNDAY/
FRIDAY: BROAD MID-LVL TROUGHING WILL EXTEND FROM THE OHIO RIVER
VALLEY INTO THE DEEP SOUTH AS AN ASSOCIATED COLD FRONT MARCHES
OFFSHORE BY MID TO LATE MORNING. A BAND OF WEAKENING STRATIFORM
PRECIPITATION WILL LIKELY BE PRESENT ALONG THE FRONTAL BOUNDARY IN
THE EARLY MORNING HOURS AS IT PASSES THROUGH THE REGION. THEREAFTER,
SKIES SHOULD QUICKLY CLEAR AS POST-FRONTAL CONDITIONS SHOULD LIMIT
FORCING AT THE SURFACE AND PROMOTE SUBSIDENCE. THIS WILL YIELD
TEMPERATURES IN THE LOW TO MID 60S ACROSS THE LOWCOUNTRY. OVERNIGHT
LOWS WILL BE A BIT COOLER THAN THE PREVIOUS NIGHT WITH TEMPERATURES
DROPPING INTO THE LOW 30S ACROSS THE INTERIOR COUNTIES AND UPPER 30S
TO LOW 40S CLOSER TO THE COASTLINE.
SATURDAY AND SUNDAY: A SHALLOW UPPER-LVL TROUGH COULD PASS OVER THE
EASTERN CONUS THIS WEEKEND WITHIN THE RETURN OF QUASI-ZONAL FLOW
ALOFT. AT THE SURFACE, HIGH PRESSURE WILL BE CENTERED ACROSS THE MID-
ATLANTIC AND WILL YIELD WARM AND DRY CONDITIONS ACROSS THE
SOUTHEAST. AS SUBSIDENCE CONTINUES TO ENVELOPE THE REGION, SKIES
WILL REMAIN MOSTLY CLEAR AND TEMPERATURES WILL MODERATE BACK TO NEAR
NORMAL. THIS IS NOTHING TO WRITE HOME ABOUT, BUT IT'S POSSIBLE A
WEAK SEABREEZE COULD DEVELOP ON SATURDAY AFTERNOON. SOME OF THE
RECENT MODEL GUIDANCE CONTINUES TO SIGNAL THAT ANOTHER COLD FRONT
COULD APPROACH THE REGION ON SUNDAY NIGHT AND WINDS WILL LIKELY
BECOME A BIT BREEZY AHEAD OF IT (ESP. IN THE EVENING AND INTO
OVERNIGHT). IT'S IMPORTANT TO NOTE THAT NO PRECIPITATION IS EXPECTED
WITH THIS FRONTAL PASSAGE. CONSIDERING THE ABSENCE OF CLOUDS IN THE
SKY THIS WEEKEND, STRONG RADIATIONAL COOLING WILL LIKELY BE THE MAIN
DRIVER OF THE OVERNIGHT LOWS WITH TEMPS. FALLING INTO THE UPPER 30S
TO LOW 40S.
LAKE WIND: SOUTHWESTERLY FLOW EXPECTED TO SURGE NEAR/BEHIND A
COLD FRONT THURSDAY NIGHT INTO EARLY FRIDAY MORNING, AND THEN
BECOME MORE WESTERLY BEHIND THE FRONT ON FRIDAY MID TO LATE
MORNING. THERE COULD BE A SHORT WINDOW OF TIME WHERE GUSTS COULD
BE REACH NEAR AND ABOVE 25 KNOTS ACROSS LAKE MOULTRIE, AND A
LAKE WIND ADVISORY COULD BE NEEDED.
LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/
EXPECT QUIET AND RAIN-FREE WEATHER THROUGH THE PERIOD AS BROAD UPPER-
LVL RIDGING DOMINATES THE FORECAST THROUGH THE MIDDLE OF THE WEEK.
TEMPERATURES ON MONDAY WILL BE A BIT COOLER THAN THE REST OF THE
WEEK WITH THE PASSAGE OF THE COLD FRONT, HOWEVER TEMPERATURES WILL
QUICKLY REBOUND AND REACH NEAR TO ABOVE NORMAL VALUES THEREAFTER.
AVIATION /07Z THURSDAY THROUGH MONDAY/
AT CHS/JZI, VFR CONDITIONS SHOULD PREVAIL THROUGH LATE MORNING PRIOR
TO COASTAL SHOWERS SHIFTING ONSHORE AND IMPACTING THE TERMINALS.
TEMPO MVFR CONDITIONS ARE ANTICIPATED BETWEEN THE 17-22Z THURSDAY
RANGE AS RAIN AND/OR SHOWER ACTIVITY INCREASES THIS AFTERNOON. GUSTY
WINDS TO AROUND 20 KT COULD ALSO ACCOMPANY PRECIP ACTIVITY. THE BULK
OF RAIN/SHOWERS AND POSSIBLY A THUNDERSTORM COME BETWEEN 22Z AND 06Z
TONIGHT, WHICH COULD LEAD TO ADDITIONAL ROUNDS OF MVFR CONDITIONS
LATE DAY/EARLY EVENING, BEFORE PREVAILING MID-LATE EVENING AND
THROUGH 06Z FRIDAY.
AT SAV, LIGHT RAIN/SHOWER ACTIVITY ASSOCIATED WITH A COASTAL TROUGH
IS ALREADY SHIFTING ONSHORE ALONG THE GEORGIA COAST, LIKELY TO
IMPACT THE TERMINAL PRIOR TO 08Z TONIGHT AND POTENTIALLY LEADING TO
TEMPO MVFR CONDITIONS THROUGH ABOUT 10Z, BEFORE MVFR CONDITIONS
PREVAIL DURING A MAJORITY OF LATE MORNING AND AFTERNOON. MVFR AND
POSSIBLY LOWER CONDITIONS ARE THEN EXPECTED BY AROUND 01Z AND LIKELY
WILL PERSIST THROUGH 06Z FRIDAY.
EXTENDED AVIATION OUTLOOK: PERIODS OF MVFR POSSIBLE FRIDAY MORNING
AS LIGHT SHOWERS MIGHT RESULT IN LOWER CEILINGS AND VSBYS. HOWEVER,
CONDITIONS SHOULD RAPIDLY IMPROVE IN THE LATE MORNING AS THE FRONT
PUSHES OFFSHORE.
MARINE
PRIOR TO DAYBREAK: A WEAK COASTAL TROUGH WILL PRESS TOWARD THE
BEACHES, LEADING TO FEW/SCATTERED SHOWERS ACROSS LOCAL WATERS.
OTHERWISE, BOTH WINDS/SEAS ARE EXPECTED TO REMAIN WELL BELOW SMALL
CRAFT ADVISORY THRESHOLDS. IN GENERAL, NORTHEAST WILL PREVAIL, BUT
SHOULD BECOME MORE EAST TOWARD DAYBREAK, REMAINING AT OR BELOW 10-15
KT. SEAS WILL GENERALLY RANGE BETWEEN 2-3 FT NEARSHORE TO 3-4 FT
ACROSS OUTER GEORGIA WATERS.
TODAY AND TONIGHT: A WEAK COASTAL TROUGH WILL SHIFT ONSHORE EARLY,
THEN LIFT NORTH AS A WARM FRONT EARLY TO MID MORNING. WINDS SHOULD
BECOME MORE SOUTHERLY BEHIND THIS FEATURE, GRADUALLY INCREASING
THROUGHOUT THE DAY AS THE PRESSURE GRADIENT SLOWLY TIGHTENS WELL IN
ADVANCE OF A COLD FRONT ARRIVING DURING THE SECOND HALF OF THE
NIGHT. ALTHOUGH WIND FIELDS INCREASE THROUGHOUT THE DAY, LOW-LVL
MIXING COULD BE AN ISSUE EARLY ON WITHIN A WARM AIR ADVECTION
REGIME, BUT WIND SPEEDS SHOULD GRADUALLY TOP OUT IN THE 15-20 KT
RANGE BY LATE DAY.
SEAS WILL BUILD TODAY, POTENTIALLY REACHING 6 FT ACROSS OUTER
GEORGIA WATERS LATE AFTERNOON, BUT EVEN MORE LIKELY EARLY EVENING
(INCLUDING OFF THE CHARLESTON COUNTY COAST). GIVEN THE ARRIVAL OF
LARGER SEAS, SMALL CRAFT ADVISORIES HAVE BEEN ISSUED FOR OUTER
GEORGIA WATERS AND NORTHERN SOUTH CAROLINA WATERS OFF THE CHARLESTON
COUNTY COAST STARTING EARLY EVENING. SOUTHERN SOUTH CAROLINA
NEARSHORE WATERS ALSO FEATURES A SMALL CRAFT ADVISORY TONIGHT,
ALTHOUGH WITH A LATER START TIME BASED ON THE ARRIVAL OF LARGER
SEAS. SOUTHWEST WINDS COULD TOP OUT NEAR 25-30 KT ACROSS ZONES
ALREADY INCLUDED IN SMALL CRAFT ADVISORIES OVERNIGHT AND SHOULD
PERSIST INTO EARLY FRIDAY. SEAS SHOULD ALSO BUILD TO 6-8 FT, LARGEST
ACROSS OUTER GEORGIA WATERS AND NORTHERN SOUTH CAROLINA NEARSHORE
WATERS. A BRIEF PERIOD OF SMALL CRAFT ADVISORIES COULD EVENTUALLY BE
NEEDED ACROSS THE CHARLESTON HARBOR AND NEARSHORE GEORGIA WATERS AS
WELL, BUT THE EVENT WOULD BE BASED ON MORE MARGINAL CONDITIONS AND
WILL NEED TO BE REEVALUATED LATER TODAY.
FRIDAY THROUGH MONDAY: EXPECT A COLD FRONT TO PASS OVER THE LOCAL
WATERS MID TO LATE MORNING AND YIELD WEST-SOUTHWESTERLY WINDS AT 15
TO 20 KTS WITH GUSTS UP TO 25 KTS. ALSO, A WEAKENING BAND OF SHOWERS
ASSOCIATED WITH THE FRONT COULD PASS THROUGH AS WELL EARLY FRIDAY
MORNING. BY FRIDAY AFTERNOON, WINDS SHOULD SHIFT MORE NORTHWESTERLY
AND WIND SPEEDS SHOULD DECREASE TO 10 TO 15 KTS. EAST-SOUTHEASTERLY
SWELL CONTINUES TO MIX INTO THE WATERS WITH SEAS RANGING FROM 6 TO 8
FT ON FRIDAY MORNING, AND THEN QUICKLY TAPER BACK TO 4 TO 6 FT BY
THE AFTERNOON. THEREAFTER, EXPECT SEAS TO RANGE 2 TO 3 FT OVER THE
WEEKEND, BEFORE ANOTHER SWELL TRIES TO SETTLE INTO THE WATERS ON
MONDAY. SMALL CRAFT ADVISORIES HAVE BEEN ISSUED FOR NEARSHORE SOUTH
CAROLINA WATERS AND THE OUTER GEORGIA WATERS UNTIL FRIDAY EVENING
GIVEN THE ELEVATED MARINE CONDITIONS.
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 7 PM EST FRIDAY
FOR AMZ350-374.
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 1 PM EST
FRIDAY FOR AMZ352.
NEAR TERM...DPB
SHORT TERM...DENNIS
LONG TERM...DENNIS
AVIATION...DENNIS/DPB
MARINE...DENNIS/DPB
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