729
FXUS62 KCHS 302322
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
622 PM EST SUN NOV 30 2025
SYNOPSIS
HIGH PRESSURE WILL PREVAIL INTO MONDAY, AND THEN A STORM SYSTEM
WILL PASS THROUGH THE REGION LATE MONDAY INTO LATE TUESDAY.
HIGH PRESSURE THEN RETURNS FOR THE MIDDLE TO END OF THIS WEEK
AHEAD OF THE NEXT FRONTAL SYSTEM THAT COULD IMPACT THE AREA
FRIDAY INTO THE WEEKEND.
NEAR TERM /UNTIL 6 AM MONDAY MORNING/
EARLY THIS EVENING: SURFACE ANALYSIS SHOWS THAT A COLD FRONT
SITS UPSTREAM ACROSS NORTH/CENTRAL GA AND THE SC UPSTATE. RADAR
IMAGERY SHOWS A FEW SHOWERS ALONG THE FRONT, PRIMARILY IMPACTING
THE SC MIDLANDS. THIS FRONT WILL DRAW CLOSER TO THE AREA THIS
EVENING AND WILL PUSH THROUGH AS A BACKDOOR FRONT LATE TONIGHT
AS THE SURFACE HIGH SPREADS ACROSS THE GREAT LAKES AND THE OH
VALLEY. MODEL GUIDANCE IS IN GOOD AGREEMENT THAT THE SHOWER
ACTIVITY WILL DISSIPATE AS THE FRONT PROGRESSES INTO THE AREA,
KEEPING THE FORECAST DRY. THE MAIN IMPACT WILL BE THE ARRIVAL OF
STRENGTHENING NORTH-NORTHEAST FLOW LATE TONIGHT ALONG WITH
COOLER AND DRIER AIR. LOWS ARE FORECAST TO RANGE FROM THE MID
40S INLAND TO THE UPPER 40S TO LOW 50S ALONG THE COAST.
SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/
ON MONDAY, ANOTHER COLD AIR DAMMING SCENARIO UNFOLDS AS SURFACE
HIGH PRESSURE BUILDS INTO THE REGION FROM THE NORTH THROUGHOUT
THE DAY, WITH THE AFOREMENTIONED COLD FRONT BEING PUSHED OFF TO
OUR SOUTH INTO NORTHERN FLORIDA. THIS WILL DROP AFTERNOON
TEMPERATURES BACK DOWN INTO THE MID 50S TO MID 60S, WARMEST
ACROSS SOUTHEAST GEORGIA. CHANCES FOR RAINFALL REMAIN LOW
THROUGHOUT THE DAY (<20%), THOUGH MOSTLY CLOUDY SKIES REMAIN
EXPECTED WITH BREEZY CONDITIONS, ESPECIALLY ALONG THE COAST.
LATE MONDAY NIGHT, THE PRIMARY UPPER TROUGH AXIS MOVES OVER THE
EASTERN US AS DEEPENING SURFACE LOW PRESSURE OVER THE DEEP
SOUTH BEGINS TO RIDE UP THE PIEDMONT. MOISTURE ADVECTION OVER
THE STILL ENTRENCHED CAD WILL LIKELY START WIDESPREAD DRIZZLE OR
VERY LIGHT RAINFALL AROUND OR SHORTLY AFTER MIDNIGHT MONDAY
NIGHT. A LINGERING SOURCE OF UNCERTAINTY WITH THIS SYSTEM IS HOW
QUICKLY THE CAD WILL ERODE AS LOW LEVEL WAA INCREASES THROUGH
THE MORNING HOURS TUESDAY. GREATEST PRECIPITATION RATES WILL
OCCUR AFTER THE CAD ERODES, WITH WIDESPREAD MODERATE RAINFALL
PREVAILING AFTER SUNRISE TUESDAY. HOURLY RAINFALL RATES WILL
LIKELY REMAIN BELOW 0.25 IN/HR, WITH PROBS OF ANY GIVEN LOCATION
RECEIVING GREATER THAN 1 INCH OF RAINFALL WITHIN A 6 HOUR
WINDOW GENERALLY LESS THAN 20%. THIS, COMBINED WITH VERY DRY
ANTECEDENT CONDITIONS, WILL KEEP THE FLOODING THREAT VERY LOW -
WITH THE RAINFALL, WHICH SHOULD TOTAL 0.5-1.5 IN ACROSS THE
AREA, MAINLY JUST BENEFICIAL TO COMBAT THE WORSENING DROUGHT.
CHANCES FOR RAINFALL DIMINISH TUESDAY EVENING AS THE LOW
DEPARTS, A COLD FRONT CROSSES THE AREA, AND SUBSIDENCE DEVELOPS
ALOFT.
POST-FRONTAL CAA WILL BE MODEST AS HIGH PRESSURE BUILDS IN FROM
THE WEST ON WEDNESDAY, WITH TEMPS 5-10 DEGREES BELOW NORMAL
UNDER MOSTLY SUNNY SKIES.
LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/
AS THE AFOREMENTIONED SURFACE HIGH PRESSURE MOVES OFFSHORE,
TEMPERATURES WILL BEGIN TO NUDGE BACK TO NEAR NORMAL, THOUGH
LIKELY REMAINING A FEW DEGREES SHY IN THE MID 50S TO LOWER 60S
THURSDAY.
AN ACTIVE PATTERN RETURNS FRIDAY THROUGH THE WEEKEND AS A
SERIES OF SHORTWAVES CROSS THE EASTERN US. SIGNIFICANT MAGNITUDE
AND TIMING UNCERTAINTY REMAINS WITH ANY INDIVIDUAL SHORTWAVE,
BUT THE OVERALL EXPECTATION THAT A SURFACE FRONT WILL LINGER
NEAR THE AREA, WITH PERIODS OF PRECIP ENHANCEMENT/WAVES WITHIN
THE FRONT IMPACTING THE SOUTHEAST COAST THROUGH MUCH OF NEXT
WEEKEND. AT THIS TIME, THERE IS STRONG AGREEMENT WITHIN THE
LARGE ENSEMBLE SYSTEMS THAT ANY THREAT FOR WINTRY PRECIPITATION
WILL REMAIN NORTH AND WEST OF OUR AREA.
AVIATION /00Z MONDAY THROUGH FRIDAY/
VFR CONDITIONS ARE IN PLACE AT KCHS, KJZI, AND KSAV AS WE BEGIN
THE 00Z TAF PERIOD. A COLD FRONT WILL PASS THROUGH FROM THE
NORTH LATE TONIGHT AND BRING INCREASING NORTH-NORTHEAST FLOW
MONDAY MORNING WHICH WILL GRADUALLY TURN MORE NORTHEASTERLY WITH
TIME. THE MAIN FORECAST CHALLENGE WILL BE THE POTENTIAL FOR
CEILINGS TO DEVELOP AND LOWER INTO THE MVFR RANGE. MODEL
GUIDANCE SUPPORTS AN INCREASING PROBABILITY OF MVFR CONDITIONS
LATE IN THE TAF PERIOD, AND WE HAVE TIMED THESE CONDITIONS INTO
THE TAF SITES BY AROUND MIDDAY.
EXTENDED AVIATION OUTLOOK: A STORM SYSTEM WILL BRING HIGHER
PROBABILITIES (50-80%, LOWEST ALONG THE COAST) OF FLIGHT
RESTRICTIONS MONDAY NIGHT INTO TUESDAY, WITH BOTH LOW CEILINGS
AND LOWERED VSBYS POSSIBLE IN ADDITION TO RAIN SHOWERS AND
ISOLATED TO SCATTERED THUNDERSTORMS.
MARINE
TONIGHT: A WEAK COLD FRONT WILL QUICKLY MOVE FROM WEST TO EAST
THROUGH THE COASTAL WATERS THIS EVENING, SHIFTING OFFSHORE
OVERNIGHT. HIGH PRESSURE WILL THEN BUILD IN FROM THE NORTHWEST
LATE. EXPECT LIGHT WINDS AHEAD OF THE FRONT, BECOMING NNE
SUSTAINED AROUND 15 KT WITH GUSTS UP TO 20 KT JUST BEFORE
DAYBREAK MONDAY. SEAS WILL AVERAGE 3-4 FT.
MONDAY THROUGH THURSDAY: A BACKDOOR COLD FRONT WILL MODE DOWN
THE COAST ON MONDAY, BRINGING OCCASIONAL 20-25 KT WIND GUSTS
MIDDAY THROUGH THE AFTERNOON. COVERAGE AND DURATION TOO LIMITED
TO JUSTIFY SCAS GIVEN THE MARGINAL MAGNITUDE, BUT TRENDS WILL
NEED TO CONTINUE TO BE MONITORED AS SCAS POSSIBLE ACROSS ALL
COASTAL WATERS IF THE GRADIENT TIGHTENS FURTHER. SEAS MAINLY 3-5
FT MONDAY, THOUGH OCCASIONAL 6 FT SEAS POSSIBLE MAINLY BEYOND
ABOUT 15 NM OFF THE SC COAST.
MONDAY OVERNIGHT INTO TUESDAY, A SURFACE LOW PRESSURE BEGINS TO
MOVE TOWARDS THE REGION, TRAVERSING THE AREA ON TUESDAY. THIS
WILL BRING THE HIGHEST RAINFALL CHANCES TUESDAY MORNING, WITH
BOTH SHOWERS AND ISOLATED THUNDERSTORMS POSSIBLE, DECREASING
INTO THE EVENING HOURS. WINDS BECOMES S AS THE CAD ERODES VERY
EARLY TUESDAY MORNING, WITH COOLER WATERS LIMITING MIXING IN THE
WAA ENVIRONMENT, BUT BREEZY CONDITIONS STILL LIKELY. SEAS DO
BUILD AND BEGIN TO APPROACH/EXCEED 6 FEET AGAIN ON TUESDAY.
THUS, SMALL CRAFT ADVISORIES MAY BE NEEDED, ESPECIALLY IN THE
OFFSHORE GEORGIA WATERS WHERE SEAS APPROACH 8 FEET 60NM OUT.
HIGH PRESSURE RETURNS ON WEDNESDAY, WITH CONDITIONS IMPROVING
AND NO MARINE HAZARDS EXPECTED INTO THE END OF THE WEEK.
TIDES/COASTAL FLOODING
CHANCES FOR MINOR COASTAL FLOODING RETURN WITH THE TUESDAY EARLY
MORNING HIGH TIDE, ALONG THE CHARLESTON AND COLLETON COUNTY
COAST. ASTRONOMICAL TIDES WILL THEN CONTINUE TO RISE WITH THE
MORNING HIGH TIDE CYCLE THROUGH FRIDAY AND REMAIN ELEVATED
THROUGH THE WEEKEND. COASTAL FLOOD ADVISORIES WILL LIKELY BE
NEEDED, PRIMARILY FOR THE CHARLESTON HARBOR TIDE (CHARLESTON AND
COASTAL COLLETON COUNTIES).
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...NONE.
NEAR TERM...BSH
SHORT TERM...CEB
LONG TERM...CEB
AVIATION...BSH/CEB
MARINE...CEB
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