600
FXUS62 KCHS 031751
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
1251 PM EST WED DEC 3 2025
SYNOPSIS
HIGH PRESSURE WILL PREVAIL ACROSS THE REGION BEFORE A FRONTAL
SYSTEM IMPACTS THE AREA FRIDAY INTO THE WEEKEND. HIGH PRESSURE
WILL THEN RETURN HEADING INTO THE MIDDLE OF NEXT WEEK.
NEAR TERM /THROUGH TONIGHT/
THIS AFTERNOON: ALOFT, ZONAL FLOW WILL PREVAIL ACROSS THE SOUTHEAST
BETWEEN BROAD TROUGHING WELL NORTH AND BROAD RIDGING WELL SOUTH OF
THE REGION. AT THE SFC, A WEAK BACKDOOR COLD FRONT NOTED BY A WIND
SHIFT FROM WEST TO NORTHEAST ALONG WITH A BAND OF NOTABLE LOW CLOUDS
SHOULD BECOME STATIONARY NEAR OR JUST SOUTH OF THE SAVANNAH RIVER.
VERY DRY AIR DEPICTED ABOVE 3-4 K FT ON MODEL SOUNDINGS AND OBSERVED
DURING THE 12Z CHS SOUNDING THIS MORNING SUGGEST SOME BREAKS IN
CLOUDS AS WEAK LOW-LVL MIXING OCCURS. HOWEVER, MIXING WILL BE
SOMEWHAT LIMITED NORTH OF THE FRONT AS WIDESPREAD CLOUD COVER
PERSISTS FOR MUCH OF THE DAY. FURTHER SOUTH, BREAKS IN CLOUDS HAVE
ALREADY TAKEN PLACE, WHICH WILL PROMOTE GREATER SFC HEATING AND
ADDITIONAL MIXING OUT/ERODING OF CLOUDS ACROSS PARTS OF SOUTHEAST
GEORGIA. GIVEN THE SETUP, HIGHS SHOULD GENERALLY RANGE IN THE LOW-
MID 50S, WARMEST NEAR THE COAST. TEMPS COULD WARM TO AROUND 60
DEGREES ALONG THE GEORGIA COASTAL CORRIDOR WHERE A GREATER AMOUNT OF
SUNSHINE IS TAKING PLACE.
TONIGHT: SFC HIGH PRESSURE WILL SLOWLY BUILD ACROSS THE REGION UNDER
A ZONAL FLOW ALOFT, FAVORING DRY AND COOL WEATHER CONDITIONS THROUGH
THE NIGHT. LATEST GUIDANCE SUGGESTS CLOUD COVER TO ERODE DURING THE
OVERNIGHT PERIOD, SUPPORTING DECOUPLING WINDS AS SOME FORM OF
RADIATIONAL COOLING TAKES PLACE. GIVEN RECENT RAINFALL, THE
COMBINATION OF WET GROUNDS AND A LIGHT/CALM WIND COULD SUPPORT SOME
PATCHY FOG LATE NIGHT. HOWEVER, HIGH CLOUDS (CIRRUS) SOURCED FROM AN
UPSTREAM SYSTEM ACROSS THE SOUTHERN UNITED STATES COULD LIMIT MORE
SUBSTANTIAL FOG COVERAGE AND/OR RESULT IN MAINLY SHALLOW GROUND FOG
LOCALLY. OVERNIGHT LOWS WILL BE A BIT COLDER THAN THE PREVIOUS NIGHT
SHOULD CLOUDS ERODE SUBSTANTIALLY, WITH SOME LOCATIONS REACHING THE
FREEZING MARK WELL INLAND. LOWS SHOULD GENERALLY RANGE IN THE UPPER
30S/LOWER 40S NEAR THE COAST.
SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/
THE SURFACE HIGH PRESSURE DISSIPATES THROUGHOUT THE DAY, WITH
SCATTERED SHORTWAVES IN THE MID-LEVELS BEGINNING TO MOVE ACROSS THE
AREA BY THE AFTERNOON HOURS. DRY AIR IN THE LOW-LEVELS SHOULD KEEP
MAJORITY OF THE RAIN FROM REACHING THE GROUND IN THE EARLY
AFTERNOON, BUT TOP-DOWN SATURATION WILL EVENTUALLY SATURATE THE
LOWER-LEVELS ESPECIALLY ACROSS SOUTHEAST GEORGIA BY THE LATE
AFTERNOON HOURS. GIVEN THE MOSTLY CLOUDY SKIES AND CHANCES FOR RAIN,
EXPECT ANOTHER BELOW NORMAL TEMPERATURES TO CONTINUE, WITH HIGHS IN
THE UPPER 50S TO LOWER 60S.
OVERNIGHT INTO FRIDAY, AN INVERTED TROUGH BUILDS INTO THE REGION,
AND WITH ISENTROPIC LIFT IN THE MID-LEVELS EXPECT RAINFALL CHANCES
TO BE INCREASING BOTH PROBABILISTICALLY AND IN SPATIAL EXTENT. THIS
MARKS THE BEGINNING OF A RATHER PROLONGED PERIOD WHERE RAIN SHOWERS
ARE EXPECTED, WITH GLOBAL ENSEMBLES ALL INDICATING A 40-80+% CHANCE
FOR AT LEAST LIGHT RAINFALL DURING EACH 6 HOUR PERIOD LASTING INTO
SATURDAY NIGHT. WITH PRECIPITABLE WATER VALUES IN THE 1.25-1.5"
RANGE (AT OR ABOVE THE 90TH PERCENTILE OF CLIMATOLOGY) AND UP TO 500
J/KG OF MUCAPE, ENSEMBLES SUGGEST AT MOST 0.5-1.0 INCH OF RAIN FROM
2-7PM FRIDAY, WITH GENERALLY 0.25-0.5 INCHES DURING THE 6 HOUR
WINDOWS FRIDAY MORNING AND EVENING.
HEADING OVERNIGHT INTO SATURDAY, SCATTERED SHORTWAVES CONTINUE TO
PUSH ACROSS THE AREA RESULTING IN ADDITIONAL CHANCES FOR LIGHT
RAINFALL, WITH THE AFOREMENTIONED INVERTED TROUGH CONVERTING INTO
MORE OF A STATIONARY FRONT DRAPED FROM THE FLORIDA PANHANDLE INTO
OUR NEARSHORE WATERS. AS ADDITIONAL SCATTERED SHORTWAVES MOVE ACROSS
THE AREA, THE REGION ALSO FALLS INTO THE RIGHT ENTRANCE REGION OF
THE UPPER LEVEL JET, AND COMBINED WITH THE FRONT NEARBY WE WILL SEE
ANOTHER ROUND OF RAIN SHOWERS SATURDAY CONTINUING INTO THE OVERNIGHT
HOURS. 48 HOUR RAINFALL PROBABILITIES ENDING SATURDAY NIGHT ARE
LOWEST ALONG THE COAST, WHERE A 40-60% CHANCE FOR AN INCH EXISTS (10-
20% FOR 2 INCHES), AND HIGHEST INLAND WHERE A 70-90% CHANCE FOR AN
INCH EXISTS (50-60% FOR 2 INCHES). HIGH TEMPERATURES ON BOTH FRIDAY
AND SATURDAY EXPECTED TO REMAIN IN THE LOWER 50S INLAND TO MID 50S
TO MID 60S ALONG THE COAST, WITH OVERNIGHT LOWS IN THE LOWER 40S TO
LOWER 50S.
LONG TERM /SUNDAY THROUGH TUESDAY/
THE MID-LEVEL TROUGH THAT HAS BEEN SITTING OVER THE CENTRAL CONUS
FINALLY BEGINS TO HEAD EASTWARDS, BUT WITH THE SHORTWAVES CONTINUING
TO STREAM ACROSS THE REGION CHANCES FOR LIGHT RAINFALL CONTINUE INTO
SUNDAY. A COLD FRONT PUSH THROUGH INTO MONDAY FOLLOWED BY SURFACE
HIGH PRESSURE, WHICH WILL BRING AN END TO THE CHANCES FOR RAINFALL,
THOUGH THE BELOW NORMAL TEMPERATURES CONTINUE. THE ECMWF IS MOST
AGGRESSIVE WITH ENDING PRECIP AS DESCRIBED ABOVE, THOUGH THE GEFS AND
GEPS ARE LESS CONVINCED AND THINK THE PRECIP COULD LINGER INTO THE
EVENING HOURS. MONDAY NIGHT INTO TUESDAY HAS HIGH PROBABILITIES
(80%) FOR REACHING TEMPERATURES BELOW FREEZING FOR AREAS INLAND,
DROPPING TO 30-40% ALONG THE COAST, WITH A SIMILAR SET UP FOR
TUESDAY NIGHT INTO WEDNESDAY.
AVIATION /18Z WEDNESDAY THROUGH MONDAY/
TEMPO MVFR CIGS ARE POSSIBLE AT CHS/JZI/SAV TERMINALS DURING THE
NEXT FEW HOURS, ESPECIALLY AT SAV WHERE A WEAK FRONT LINGER NEARBY.
OTHERWISE, VFR CONDITIONS ARE EXPECTED AT ALL TERMINALS FROM 20Z
WEDNESDAY TO 18Z THURSDAY.
EXTENDED AVIATION OUTLOOK: VFR CONDITIONS EXPECTED FOR THURSDAY.
THERE ARE MODERATE PROBABILITIES (30-50%) FOR FLIGHT RESTRICTIONS
LATE THURSDAY INTO FRIDAY MORNING, DUE TO LOW CEILINGS FROM
SCATTERED SHOWERS. PROBABILITIES FOR MVFR CIGS INCREASE INTO THE 60-
90% RANGE (30-60% FOR IFR CIGS) ON FRIDAY AS MORE WIDESPREAD SHOWERS
MOVE IN, WITH NEAR 50% CHANCE FOR MVFR VSBYS AS WELL. MVFR (OR
WORSE) CONDITIONS EXPECTED TO REMAIN POSSIBLE THROUGHOUT THE DAY
ON SATURDAY, WITH CONDITIONS EXPECTED TO BEGIN TO IMPROVE ON
SUNDAY BUT ESPECIALLY ON MONDAY.
MARINE
THIS AFTERNOON AND TONIGHT: THERE ARE NO CONCERNS ACROSS LOCAL
MARINE ZONES THROUGH TONIGHT. A WEAK FRONT WILL STALL NEARBY WHILE
HIGH PRESSURE GRADUALLY SPREADS ACROSS THE REGION OVERNIGHT. THIS
WILL PLACE A WEAK PRESSURE GRADIENT ACROSS LOCAL WATERS WITH
NORTHWEST WINDS AROUND 10-15 KT DURING THE DAY SLIGHTLY WEAKENING
OVERNIGHT. SEAS WILL REMAIN BETWEEN 2-3 FT.
THURSDAY TO SUNDAY: NO MARINE HAZARDS EXPECTED. FOR THURSDAY, EXPECT
2-3 FT SEAS WITH NORTH WINDS BECOMING NORTHWEST AT 10 TO 15 KNOTS.
WINDS TURN NORTHEASTERLY OVERNIGHT INTO FRIDAY AS SCATTERED SHOWERS
BEGIN TO OVERSPREAD THE REGION, BUT WILL BECOME VARIABLE AS A
COASTAL LOW MOVES NORTHEAST, BECOMING NORTHERLY AGAIN ON SATURDAY
WITH SEAS EXPECTED TO REMAIN IN THE 2-4 FT RANGE. A COLD FRONT
CROSSES THE WATERS ON SUNDAY, KEEPING WINDS OUT OF THE NORTH AT 10
TO 15 KNOTS, WITH RAINFALL EXPECTED TO END OVERNIGHT INTO MONDAY.
TIDES/COASTAL FLOODING
ASTRONOMICAL TIDES WILL CONTINUE TO RISE WITH THE MORNING HIGH TIDE
CYCLES THROUGH FRIDAY AND REMAIN ELEVATED THROUGH THE WEEKEND.
COASTAL FLOOD ADVISORIES WILL LIKELY BE NEEDED FOR MORNING HIGH TIDE
CYCLES, PRIMARILY AT CHARLESTON HARBOR (CHARLESTON AND COASTAL
COLLETON COUNTIES) THROUGH SATURDAY MORNING.
FRIDAY, ASTRONOMICAL HIGH TIDES PEAK (6.8 FT MLLW AT CHARLESTON
HARBOR AND 8.86 FT MLLW AT FORT PULASKI) AND THIS IS WHEN WINDS ARE
FORECAST TO TURN FROM THE NORTHEAST. OVERALL, THIS TYPE OF SETUP CAN
OVER PERFORM GIVEN THE BUILDING ANOMALIES FROM THE NORTHEAST WINDS.
THE FORECAST REMAINS LARGELY UNCHANGED, WITH MODERATE COASTAL
FLOODING AT CHARLESTON HARBOR AND MINOR COASTAL FLOODING AT FORT
PULASKI.
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...NONE.
NEAR TERM...DPB
SHORT TERM...APT
LONG TERM...APT
AVIATION...APT/DPB
MARINE...APT/DPB
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