057
FXUS62 KCHS 021750
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
1250 PM EST TUE DEC 2 2025
SYNOPSIS
A STORM SYSTEM WILL SHIFT OFFSHORE THIS AFTERNOON. HIGH
PRESSURE THEN RETURNS TONIGHT THEN PREVAILS DURING THE MIDDLE
OF THIS WEEK BEFORE THE NEXT FRONTAL SYSTEM IMPACTS THE AREA
FRIDAY INTO THE WEEKEND.
NEAR TERM /THROUGH TONIGHT/
THIS AFTERNOON: ALOFT, A MID-UPPER LVL TROUGH EXTENDING ACROSS MUCH
OF THE EASTERN SEABOARD WILL ADVANCE EAST ACROSS THE WESTERN
ATLANTIC, HELPING SHIFT LOW PRESSURE OFF THE MID-ATLANTIC COAST AND A
SOUTHWARD EXTENDING COLD FRONT FURTHER OFF THE SOUTHEAST COAST. AS
THIS PROCESS UNFOLDS, DEEP MOISTURE (PWATS ~1.5 INCHES) ACROSS THE
REGION WILL DECREASE LOCALLY AS A WEST-NORTHWEST WIND DRIVES DRIER
AIR INTO THE REGION THROUGH THE REMAINDER OF THE DAY. AS A RESULT,
REMAINING SHOWERS DEPICTED ON RADAR IMAGERY WILL COME TO AN END
SHORTLY ACROSS INLAND COUNTIES, THEN WITHIN 1-2 HOURS ACROSS COASTAL
COUNTIES IN A LIGHTER/WANING STATE DUE TO DRY HIGH PRESSURE SPILLING
INTO THE LOCAL AREA. ADDITIONAL RAINFALL AMOUNTS UP TO 0.1-0.2
INCHES ARE POSSIBLE, MAINLY ACROSS SOUTH CAROLINA COASTAL COUNTIES
PRIOR TO 4 PM. HOWEVER, BROKEN TO WIDESPREAD LOW CLOUDS WILL
CONTINUE THROUGH THE DAY. CLOUDS AND PRECIP WILL LIMIT WARMER TEMPS
DURING PEAK DIURNAL HEATING HOURS, SUPPORTING HIGHS ONLY IN THE LOW-
MID 50S WELL INLAND TO LOW-MID 60S NEAR THE COAST, WARMEST IN
SOUTHEAST GEORGIA.
TONIGHT: HIGH PRESSURE CENTERED ACROSS THE OHIO RIVER VALLEY WILL
SLOWLY EXPAND EAST ACROSS THE MID-ATLANTIC AND SOUTHEAST, SUPPORTING
DRY AND COOLER AIR SPREADING ACROSS THE LOCAL AREA WITHIN A WEST-
NORTHWEST WIND THIS EVENING, THEN NORTH WIND AFTER MIDNIGHT.
COLD AIR ADVECTION WILL HELP KEEP LOW-LVL WIND FIELDS SOMEWHAT
MIXED, WHILE LINGERING LOW-LVL MOISTURE SUPPORTS SOME DEGREE OF LOW
CLOUDS ACROSS THE REGION. THE SETUP FAVORS OVERNIGHT LOWS IN THE MID
30S INLAND TO LOW-MID 40S ACROSS COASTAL COUNTIES.
SHORT TERM /WEDNESDAY THROUGH FRIDAY/
SURFACE HIGH PRESSURE WILL EXTEND INTO THE REGION ON WEDNESDAY.
QUIETER WEATHER IS EXPECTED WITH HIGHS LEANING ON THE COOLER SIDE OF
NORMAL. ON THURSDAY, HIGH PRESSURE WILL LARGELY PERSIST. MEANWHILE,
LOW PRESSURE WILL BEGIN TO TAKE SHAPE OVER THE NORTHERN GULF.
MOISTURE WILL BEGIN TO INCREASE FROM THE SOUTHWEST, AND MODELS HINT
AT WEAK SHORTWAVE ENERGY PASSING THROUGH LATER IN THE DAY. LATEST
NBM INDICATES ONLY A SMALL CHANCE (20%) OF MEASURABLE RAINFALL
(>0.01") THURSDAY AFTERNOON OVER INTERIOR SOUTHEAST GEORGIA, BUT BY
AND LARGE, MOST AREAS WILL REMAIN DRY THROUGH THE DAYLIGHT HOURS.
THE AFOREMENTIONED LOW IS EXPECTED TO LIFT NORTHEAST FROM THE GULF
AND INTO THE REGION THURSDAY NIGHT INTO FRIDAY. THE ATMOSPHERE WILL
CONTINUE TO MOISTEN WITH PWATS EXPECTED TO SURGE TO NEAR 1.5 INCHES
WHICH IS WELL ABOVE NORMAL FOR THIS TIME OF YEAR PER SPC SOUNDING
CLIMATOLOGY. THIS WILL COINCIDE WITH AN INCREASE IN ISENTROPIC
ASCENT AND LARGE SCALE FORCING WHICH WILL LEAD TO INCREASING
COVERAGE OF SHOWERS THROUGH THE DAY. LOOKING AT QPF CLUSTERS,
MAJORITY OF ENSEMBLE MEMBERS SHOW THE ENTIRE AREA RECEIVING
BENEFICIAL RAINFALL THROUGH THE DAYTIME HOURS, BUT IT'S WORTH NOTING
THAT A SMALL CONTINGENT (~20% OF MEMBERS) SHOWS THE BULK OF RAINFALL
FOCUSED MORE INLAND/OVER THE MIDLANDS THROUGH 00Z. FOR NOW, OUR QPF
INDICATES 0.25-0.75". OTHERWISE, THERE COULD BE A NOTABLE
TEMPERATURE GRADIENT BETWEEN INLAND (COOLER) AND COASTAL LOCATIONS
(WARMER) WITH A WEDGE SET-UP EVOLVING.
LONG TERM /FRIDAY NIGHT THROUGH MONDAY/
THE FIRST HALF OF THE WEEKEND WILL REMAIN ACTIVE WITH THE AXIS OF
DEEPER MOISTURE STILL ORIENTED OVER THE AREA. MODEL CONSENSUS
INDICATES THE AREA WILL REMAIN AHEAD OF A MID LEVEL TROUGH AXIS AND
THE AREA WILL ALSO BECOME POSITIONED IN THE FAVORABLE RIGHT ENTRANCE
REGION OF THE UPPER JET. THESE CONDITIONS WOULD SUPPORT ANOTHER WAVE
OF PRECIPITATION DEVELOPING ON SATURDAY INTO SATURDAY NIGHT. THERE
REMAINS UNCERTAINTY ON WHEN RAINFALL WILL END, BUT AT LEAST HALF OF
ENSEMBLE MEMBERS CURRENTLY INDICATE DRY CONDITIONS RETURNING FOR
SUNDAY AND BEYOND.
AVIATION /18Z TUESDAY THROUGH SUNDAY/
IFR CIGS WILL PREVAIL AT CHS/JZI/SAV TERMINALS THIS AFTERNOON INTO
THE EVENING, ALTHOUGH VSBYS COULD ALSO BE REDUCED TO MVFR LEVELS AT
CHS/JZI AS WELL DUE TO LINGERING SHOWERS THROUGH ABOUT 19-20Z. DRIER
AIR ARRIVES MID-LATE AFTERNOON, THEN PERSISTS THROUGH THE NIGHT,
SUGGESTING IFR CIGS TO IMPROVE TO MVFR CIGS AT ALL TERMINALS BY
AROUND 06Z WEDNESDAY. CIGS SLOWLY IMPROVE LATE NIGHT INTO DAYBREAK
WEDNESDAY MORNING, EVENTUALLY BECOMING VFR AT ALL TERMINALS STARTING
AROUND 10Z AT SAV, THEN AROUND 13Z AT CHS/JZI. VFR CONDITIONS WILL
THEN PREVAIL AT ALL TERMINALS THROUGH 18Z WEDNESDAY.
EXTENDED AVIATION OUTLOOK: FLIGHT RESTRICTIONS, POSSIBLY TO IFR OR
LOWER, ARE EXPECTED IN LOW CLOUDS AND RAIN FRIDAY INTO THE WEEKEND.
MARINE
THIS AFTERNOON AND TONIGHT: SOUTHWEST WINDS GUSTING TO AROUND 25-30
KT ACROSS A PORTION OF LOCAL WATERS WILL TURN MORE OFFSHORE MID-LATE
AFTERNOON BEHIND A FRONT ADVANCING ACROSS THE WESTERN ATLANTIC. SEAS
WILL ALSO REMAIN ELEVATED DURING THE DAY, GENERALLY 4-6 FT ACROSS
NEARSHORE SOUTH CAROLINA WATERS AND 6-9 FT ACROSS OFFSHORE GEORGIA
WATERS. SMALL CRAFT ADVISORIES REMAIN IN EFFECT ACROSS THESE WATERS
THROUGH THE DAY, BEFORE WINDS/SEAS START TO WEAKEN/SUBSIDE EARLY
EVENING, CONTINUING AN IMPROVING TREND AS HIGH PRESSURE SPILLS INTO
THE REGION OVERNIGHT. SMALL CRAFT ADVISORIES ARE THEREFORE
ANTICIPATED TO COME TO AN END EARLY EVENING ACROSS SOUTH CAROLINA
NEARSHORE WATERS, FOLLOWED BY OFFSHORE GEORGIA WATERS SHORTLY AFTER
MIDNIGHT. AFTER MIDNIGHT, NORTHWEST WINDS TURN MORE NORTHERLY,
REMAINING BETWEEN 10-15 KT WITH A FEW GUSTS UP TO 20 KT ACROSS OUTER
GEORGIA WATERS. SEAS WILL GENERALLY RANGE BETWEEN 2-4 FT.
WEDNESDAY THROUGH SUNDAY: NO MARINE CONCERNS THROUGH MID WEEK.
NORTHERLY WINDS WILL AVERAGE AROUND 10 KNOTS OR LESS WITH SEAS 2-3
FEET. LOW PRESSURE IS EXPECTED TO PASS ACROSS THE REGION FRIDAY INTO
FRIDAY NIGHT. WINDS SHOULD TURN MORE SOUTHERLY AHEAD OF IT AND
INCREASE IN SPEED, BUT CONDITIONS ARE CURRENTLY FORECAST TO STAY
BELOW SMALL CRAFT ADVISORY CRITERIA. ANOTHER WAVE OF LOW PRESSURE
COULD PASS THROUGH LATER IN THE WEEKEND.
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 LATE WEEK. THERE IS CONCERN FOR MINOR
COASTAL FLOODING TO OCCUR FROM BEAUFORT COUNTY SOUTH ACROSS THE
GEORGIA COAST WITH THE MORNING HIGH TIDE ON FRIDAY.
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 AM EST WEDNESDAY FOR AMZ350-374.
SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR AMZ352.
NEAR TERM...DPB
SHORT TERM...ETM
LONG TERM...ETM
AVIATION...DPB/ETM
MARINE...DPB/ETM
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