770
FXUS62 KCHS 310550
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
1250 AM EST WED DEC 31 2025
SYNOPSIS
HIGH PRESSURE WILL PREVAIL FOR THE REMAINDER OF THE WEEK. A LOW
PRESSURE SYSTEM WILL MOVE THROUGH ON SATURDAY, FOLLOWED BY A
COLD FRONT LATER THIS WEEKEND.
NEAR TERM /THROUGH TONIGHT/
THROUGH DAYBREAK: THE BOUNDARY LAYER DECOUPLED QUICKLY TUESDAY
EVENING, BUT HAS STARTED TO SHOW SIGNS TO RECOUPLING AGAIN
ACROSS PARTS OF SOUTHEAST GEORGIA INTO FAR SOUTHERN SOUTH
CAROLINA IN RESPONSE TO A TIGHTENING PRESSURE INDUCED BY THE
FORMATION OF A LEE-SIDE TROUGH EAST OF THE SOUTHERN APPALACHIANS.
TEMPERATURE FALLS HAVE SLOWED A BIT WHERE THE WIND HAS PICKED
UP, BUT ARE STILL DROPPING AT A MODEST RATE ACROSS INTERIOR
SOUTHEAST SOUTH CAROLINA UP INTO COASTAL PARTS OF BEAUFORT,
CHARLESTON AND COLLETON COUNTIES WHERE CALM WINDS PERSIST. STILL
EXPECT LOWS TO BOTTOM OUT IN THE MID-UPPER 20S INLAND WITH MID
30S AT THE BEACHES. WHERE WINDS PICK UP, WIND CHILLS COULD DROP
INTO THE LOWER-MID 20S WITH THE LOWEST VALUES OCCURRING ACROSS
FAR INTERIOR SOUTHEAST GEORGIA. INCOMING DATA SUGGEST WIND
CHILLS COULD DROP AS LOW AS 20 DEGREES IN A FEW SPOTS, BUT
DURATIONS STILL LOOK BRIEF, SIMILAR TO WHAT TRANSPIRED TUESDAY
MORNING. THE SITUATION LOOKS TOO MARGINAL TO JUSTIFY A COLD
WEATHER ADVISORY WHERE WIND CHILLS HIT 20, BUT TRENDS ARE BEING
MONITORED. THE ISSUANCE OF A SPECIAL WEATHER STATEMENT
HIGHLIGHTING BRIEF ADVISORY CONDITIONS WILL BE CONSIDERED SHOULD
WIND CHILLS APPROACH 20 DEGREES.
TODAY: A DEEP LONGWAVE TROUGH WILL REMAIN ACROSS THE EASTERN
CONUS TODAY WITH THE LOCAL AREA POSITIONED BETWEEN HIGH PRESSURE
OVER THE GULF AND A LEE-SIDE TROUGH TO THE NORTHWEST. THIS WILL
KEEP A MODEST PRESSURE GRADIENT OVER THE AREA TODAY. SOME
MOUNTAIN WAVE INDUCED CIRRUS OFF THE SOUTHERN APPALACHIANS COULD
BRUSH MAINLY THE CENTRAL AND NORTHERN COUNTIES THIS MORNING,
OTHERWISE SUNNY SKIES WILL PREVAIL. HIGHS THIS AFTERNOON WILL
RANGE FROM THE LOWER-MID 50S, CONSISTENT WITH FULL SUN LOW-LEVEL
THICKNESS SCHEMES AND 31/01Z NBM OUTPUT.
TONIGHT: A DRY COLD FRONT WILL PUSH OFFSHORE LATER THIS EVENING
USHERING IN A REINFORCING SHOT OF COOL/DRY AIR. GUIDANCE IS
SIMILAR IN SHOWING A BRIEF YET MODEST BURST OF COLD AIR
ADVECTION BEHIND THE FRONT. THE WILL KEEP THE CONDITIONS FAIRLY
WELL MIXED THROUGH THE NIGHT WITH LOWS THURSDAY MORNING DROPPING
INTO THE LOWER 30S INLAND TO THE UPPER 30S/LOWER 40S AT THE
BEACHES. WIND CHILLS WILL BOTTOM OUT IN THE 25-30 DEGREE RANGE.
ANOTHER ROUND OF MOUNTAIN WAVE INDUCED CIRRUS COULD BRUSH
NORTHERN AREAS LATE, BUT CLEAR TO MOSTLY CLEAR CONDITIONS SHOULD
PREVAIL FOR MOST AREAS.
LAKE WINDS: WINDS ARE EXPECTED TO SURGE OVER LAKE MOULTRIE LATE
THIS EVENING WITH THE PASSAGE OF A DRY COLD FRONT. RAP
SOUNDINGS SHOWING PROFILES BECOMING INCREASINGLY FAVORABLE FOR
VIGOROUS MIXING AS LOW-LEVEL LAPSE RATES STEEPEN AND LAKE WATER
TEMPERATURES HOLD IN THE MID 50S. SOUNDINGS SUPPORT FREQUENT
GUSTS AS HIGH AS 25-30 KT WITH SUSTAINED WINDS CLOSER TO 15-20
KT. A LAKE WIND ADVISORY HAS BEEN POSTED 10 PM TO 10 AM THURSDAY
PER COORDINATION WITH WFO COLUMBIA. WAVES ARE EXPECTED TO PEAK
AROUND 2 FT WITH THE HIGHEST WINDS AND THE MOST SIGNIFICANT WAVE
ACTION OCCURRING OVER THE CENTRAL AND EASTERN PARTS OF THE
LAKE.
SHORT TERM /THURSDAY THROUGH SATURDAY/
A WEAK FRONT MOVES THROUGH ON THURSDAY, BRINGING A RESURGENCE
OF WESTERLY WINDS ACROSS THE AREA WHICH BECOME MARGINALLY GUSTY
IN THE TEENS, ALONG WITH HIGH TEMPERATURES IN THE UPPER 50S TO
LOWER 60S. OVERNIGHT INTO FRIDAY, RADIATIONAL COOLING BRINGS
OVERNIGHT TEMPERATURES BACK INTO THE MID 30S INLAND AND UP TO
THE LOWER/MID 40S ALONG THE COAST. TEMPERATURES CONTINUE TO
MODERATE ON FRIDAY AS A WARM FRONT LIFTS ACROSS THE REGION, BUT
WITH CLOUD COVERAGE INCREASING, AFTERNOON TEMPERATURES WON'T
WARM TOO MUCH BUT ARE STILL EXPECTED IN THE LOWER TO MID 60S.
BEHIND THE WARM FRONT, OVERNIGHT LOWS INTO THE WEEKEND WILL BE
MUCH WARMER IN THE MID 40S TO LOWER 50S.
WEAK SHORTWAVES IN THE MID LEVELS BEGIN TO TRAVERSE THE AREA
OVERNIGHT, WITH A SURFACE LOW PRESSURE BEGINNING TO MOVE ACROSS
THE DEEP SOUTH AHEAD OF THE MAIN SHORTWAVE. THIS WILL BRING
CHANCES FOR LIGHT TO MODERATE RAIN SHOWERS ALONG WITH ISOLATED
THUNDERSTORMS STARTING EARLY SATURDAY MORNING AND ENDING
OVERNIGHT INTO SUNDAY ASH THE SURFACE LOW MOVES OFFSHORE.
ENSEMBLE CLUSTERING ANALYSIS SHOWS THAT MODEL AGREEMENT REMAINS
FAIRLY HIGH, WITH THE TWO DOMINANT CLUSTERS SHOWING 70-80%
PROBABILITIES FOR A QUARTER INCH OF RAIN NOW FOR ALL AREAS
ACROSS THE REGION. PROBABILITIES HAVE SIMILARLY RISEN FOR HALF
AN INCH, UP TO 40-50% ACROSS THE REGION, WHILE PROBABILITIES FOR
AN INCH REMAIN LOW AT ABOUT 10%. WITH CAPE VALUES LOOKING TO
REMAIN BELOW 500 J/KG, SEVERE THUNDERSTORMS ARE NOT EXPECTED.
SPC AND THE VARIOUS AI/ML OUTPUT AGREE, AND DO NOT SHOW CHANCES
FOR SEVERE WEATHER ACROSS THE AREA. DESPITE THE RAIN, AFTERNOON
TEMPERATURES IN THE LOWER TO UPPER 60S ARE EXPECTED.
LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/
NORTHWESTERLY FLOW ALOFT MOVES IN BEHIND THE EXITING SHORTWAVE,
WITH A COLD FRONT MOVING THROUGH OVERNIGHT INTO SUNDAY
RESULTING IN TEMPERATURES COOLING INTO THE MID 50S TO LOWER 60S
ON SUNDAY. FOR THE BEGINNING OF NEXT WEEK, A SURFACE HIGH
PRESSURE MOVES INTO THE NORTHEAST, WITH THE REGION WARMING UP
INTO THE LOWER TO MID 60S ON MONDAY AND MID 60S TO LOWER 70S ON
TUESDAY.
AVIATION /06Z WEDNESDAY THROUGH SUNDAY/
31/06Z TAF DISCUSSION:
KCHS/KJZI/KSAV: VFR THROUGH 01/06Z.
EXTENDED AVIATION OUTLOOK: VFR CONDITIONS EXPECTED TO PREVAIL
THROUGH THE REST OF THE WEEK. CHANCES FOR RAIN RETURN ON
SATURDAY, ALONG WITH POSSIBLE FLIGHT CATEGORY RESTRICTIONS FROM
BOTH LOWERED CIGS AND VSBYS.
MARINE
THROUGH TONIGHT: QUIET CONDITIONS WILL GIVE WAY TO INCREASING
WINDS AND SEAS TONIGHT AS A DRY COLD FRONT PUSHES OFFSHORE.
CONFIDENCE IS INCREASING THAT WINDS WILL SURGE TO SMALL CRAFT
ADVISORY LEVELS OVERNIGHT AS A PERIOD OF MODEST COLD AIR
ADVECTION PUSHES THROUGH AND STEEPENING LOW-LEVEL LAPSE RATES
BECOME INCREASING FAVORABLE FOR STRONG MIXING. WEST WINDS WILL
INCREASE TO 20-25 KT WITH GUSTS TO 30 KT ACROSS THE SOUTH
CAROLINA NEARSHORE AND GEORGIA OFFSHORE WATERS AND SMALL CRAFT
ADVISORIES HAVE BEEN POSTED TO ACCOUNT FOR THESE CONDITIONS. THE
SITUATION LOOKS A BIT MORE MARGINAL OVER THE GEORGIA NEARSHORE
WATERS AND CHARLESTON HARBOR, BUT STILL EXPECT WINDS TO REACH
15-20 KT WITH A FEW GUSTS TO 25 KT POSSIBLE. IF THE RISK FOR
HIGHER WINDS OR MORE FREQUENT GUSTS TO 25 KT INCREASES, THE
SMALL CRAFT ADVISORIES MAY HAVE TO BE EXPANDED INTO THESE ZONES.
THURSDAY THROUGH SUNDAY: WESTERLY WINDS WILL BE DECREASING TO
BELOW SMALL CRAFT CRITERIA THROUGHOUT THE MORNING HOURS, BUT
WILL REMAIN GUSTY THROUGHOUT THE DAY BEFORE WEAKENING FURTHER
OVERNIGHT INTO FRIDAY. CHANCES FOR SHOWERS AND ISOLATED
THUNDERSTORMS RETURN ON SATURDAY AS A LOW PRESSURE SYSTEM MOVES
THROUGH, WITH GUSTY SOUTHWEST WINDS NEAR SMALL CRAFT CRITERIA
POSSIBLE, PARTICULARITY IN THE OUTER GEORGIA WATERS SATURDAY
MORNING/AFTERNOON. WINDS BECOME NORTHERLY ON THE BACKSIDE OF THE
AFOREMENTIONED SURFACE LOW, REMAINING BREEZY ON SUNDAY.
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 10 AM EST
THURSDAY FOR AMZ350-352-374.
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