110
FXUS62 KCHS 171034
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
634 AM EDT SAT OCT 17 2026
WHAT HAS CHANGED
THE AVIATION SECTION WAS UPDATED FOR THE 17/12Z TAFS.
KEY MESSAGES
- 1) BELOW NORMAL TEMPERATURES AND GUSTY WINDS EXPECTED THIS
WEEKEND AS A POWERFUL NOR'EASTER DEVELOPS OFF THE NORTH
CAROLINA OUTER BANKS AND HIGH PRESSURE PREVAILS INLAND.
- 2) HIGH SURF AND DANGEROUS RIP CURRENTS POSSIBLE INTO EARLY NEXT
WEEK.
DISCUSSION
KEY MESSAGE 1: BELOW NORMAL TEMPERATURES AND GUSTY WINDS
EXPECTED THIS WEEKEND AS A POWERFUL NOR'EASTER DEVELOPS OFF THE
NORTH CAROLINA OUTER BANKS AND HIGH PRESSURE PREVAILS INLAND.
THROUGH TONIGHT: AS DAYBREAK APPROACHES, THE COLD FRONT IS NOW
OFFSHORE. MODEL OUTPUT AND EARLY MORNING SURFACE DATA SHOW THE
FRONT'S THERMAL AND MOISTURE PROFILES ARE CONSISTENT WITH A
BOUNDARY THAT HAS A HAD A STRONG INTERACTION WITH MOUNT MITCHELL
AND THE HIGHEST TERRAIN OF THE SOUTHERN APPALACHIANS, BUT THESE
PRESSURE AND LOW-LEVEL MOISTURE KINKS WILL CONTINUE TO SMOOTH
OUT AS THE FRONT MOVES FARTHER OFFSHORE AND STRONG POST FRONTAL
COLD AIR ADVECTION (CAA) INITIATES. A FEW SHOWERS LOOK TO OCCUR
ALONG BEHIND THE FRONT AND AHEAD OF THE APPROACHING UPPER
TROUGH OWING TO MODEST QUASI-GEOSTROPHIC FORCING WITH THE BEST
CHANCES FOR A FEW HUNDREDTHS OF AN INCH OCCURRING ACROSS FAR
INLAND AREAS ADJACENT TO THE CSRA/SOUTHERN MIDLANDS AND OVER THE
CHARLESTON TRI- COUNTY AREA. THE RISK FOR SHOWERS SHOULD END BY
MID- MORNING, POSSIBLY LINGERING TO ABOUT NOON OVER UPPER
PORTIONS OF THE CHARLESTON COUNTY COAST. THE DAY'S HIGH
TEMPERATURES HAVE LIKELY ALREADY OCCURRED WITH TEMPERATURES
POISED TO FALL INTO THE 60S LATER THIS MORNING WITH THE ONSET OF
CAA. IN FACT, THERMAL FALLS MAY BE SOMEWHAT ACCELERATED OVER
THE CHARLESTON TRI-COUNTY WHERE DIABATIC PROCESSES WILL BE
MAXIMIZED AND LOW- LEVEL CLOUD COVER WILL LINGER THE LONGEST.
WOULD NOT BE SURPRISED TO SEE A FEW SPOTS NORTH OF I-26 DROP
INTO THE UPPER 50S LATER THIS AFTERNOON.
IT WILL BECOME BREEZY BY DAYBREAK WITH WINDS 15-25 MPH WITH
GUSTS 30-35 MPH COMMON. WINDS MAY BE A BIT HIGHER OVER ELEVATED
BRIDES AND OVERPASSES, ESPECIALLY ACROSS THE CHARLESTON AND
SAVANNAH METRO AREAS. WIND GUSTS COULD APPROACH 40 MPH ACROSS
COASTAL PORTIONS OF LIBERTY AND MCINTOSH COUNTIES LATE THIS
AFTERNOON INTO TONIGHT AS THE BASE OF THE UPPER TROUGH SWINGS
THROUGH AND DIRECTIONS BECOME A BIT MORE ONSHORE RELATIVE TO THE
SHAPE OF THE GEORGIA COAST. THE SITUATION LOOKS MARGINAL FOR A
WIND ADVISORY, SO THE NEED FOR AN ADVISORY WILL BE REEVALUATED
LATER TODAY ONCE SHORTER TERM TRENDS CAN BE ESTABLISHED. WINDS
MAY ALSO GUST 35-40 MPH AT TYBEE ISLAND LATE THIS AFTERNOON INTO
TONIGHT, GIVEN THAT ISLAND'S EXPOSURE IN NORTH/NORTH-NORTHEAST
FLOW REGIMES.
A PRETTY CHILLY NIGHT IS AHEAD AS HIGH PRESSURE BUILDS IN AND
THE NOR'EASTER OFF THE NORTH CAROLINA OUTER BANKS DEEPENS. LOWS
LOOK TO BOTTOM OUT INTO THE MID 40S INLAND WITH LOWER 50S AT THE
BEACHES. WINDS WILL REMAIN ELEVATED THROUGH THE NIGHT WITH A
TIGHT GRADIENT BETWEEN THE INLAND HIGH AND THE NOR'EASTER
FORECAST TO PERSIST, ESPECIALLY AT THE COAST. WIND CHILLS ARE
EXPECTED TO DROP INTO THE UPPER 30S/LOWER 40S AWAY FROM THE
BEACHES--THE COLDEST IN QUITE SOME TIME.
SUNDAY: LOW PRESSURE WILL BE FORMING WELL OFF THE COAST OF THE
OUTER BANKS OF NC IN THE MORNING. MEANWHILE, STRONG HIGH
PRESSURE WILL BE LOCATED OVER THE MID-ATLANTIC STATES, WITH IT'S
PERIPHERY STRETCHING DOWN INTO THE SOUTHEAST U.S. THE
INTERACTION BETWEEN THESE TWO SYNOPTIC FEATURES WILL CONTINUE TO
BRING OUR AREA BREEZY NE WINDS (HIGHEST ALONG THE COAST).
ADDITIONALLY, THEY WILL USHER COLD AIR ADVECTION THROUGHOUT THE
REGION. DESPITE ABUNDANT SUNSHINE, HIGH TEMPERATURES WILL
STRUGGLE TO REACH THE MID TO UPPER 60S. LOW TEMPERATURES WILL
RANGE FROM THE 40S INLAND, TO THE LOWER/MID 50S ALONG THE
IMMEDIATE COAST.
MONDAY THROUGH WEDNESDAY: HIGH PRESSURE SHOULD PERSIST WELL TO
OUR NORTH ON MONDAY, THEN GRADUALLY RELEASE ITS HOLD ACROSS OUR
REGION THROUGH THE MIDDLE OF NEXT WEEK. THIS WILL CAUSE A
GRADUAL RISE IN TEMPERATURES. HIGHS SHOULD BE IN THE UPPER 60S
TO LOWER 70S ON MONDAY, THEN THE MID TO MAYBE UPPER 70S BY
WEDNESDAY, WHICH IS WITHIN A FEW DEGREES OF NORMAL FOR THIS TIME
OF YEAR.
LAKE WINDS: WINDS ON LAKE MOULTRIE LOOK REACH 20-25 KT WITH
GUSTS TO 30 KT LATER TODAY INTO TONIGHT WITH WAVES REACHING 2-3
FT WITH LOCALLY HIGHER SETS. SOME MINOR LAKESHORE EROSION AND
OVERWASH INDUCED BY SIGNIFICANT WAVE ACTION COULD ALONG OCCUR
ALONG THE SOUTH END OF THE LAKE, INCLUDING PINOPOLIS, LIONS
BEACH AND SHORT STAY. WINDS WILL DIMINISH AT FOR SUNDAY, BUT
WILL REMAIN ELEVATED WITH GUSTS TO 25 KT. A LAKE WIND ADVISORY
REMAINS IN EFFECT THROUGH EARLY MONDAY MORNING.
KEY MESSAGE 2: HIGH SURF AND DANGEROUS RIP CURRENTS POSSIBLE
INTO EARLY NEXT WEEK.
HIGH SURF: PROLONGED GALES AND A CONTINUOUS NORTH-NORTHEAST
FETCH WILL GENERATE LARGE BREAKING WAVES ALONG OUR BEACHES
SUNDAY INTO MONDAY. THE HIGHEST BREAKERS SHOULD BE ALONG OUR
GEORGIA BEACHES. HIGH SURF ADVISORIES ARE MOST LIKELY FOR THIS
AREA, BUT CAN'T BE RULED OUR FOR OUR SC BEACHES AS WELL.
RIP CURRENTS: INCREASING WINDS AND BUILDING WAVES WILL SUPPORT A
MODERATE RISK FOR RIP CURRENTS AT AREA BEACHES TODAY. THE
COMBINATION OF STRONG/PERSISTENT GALES AND ELEVATED SEAS WILL
GENERATE A HIGH RISK OF RIP CURRENTS AT ALL BEACHES ON SUNDAY,
WITH IT POTENTIALLY EXTENDING WELL INTO NEXT WEEK.
AVIATION /12Z SATURDAY THROUGH WEDNESDAY/
17/12Z TAFS:
KCHS/KJZI: MVFR CIGS WILL SPREAD INTO BOTH TERMINALS SOON AS A
COLD FRONT PUSHES FARTHER OFFSHORE. A FEW SHOWERS WILL OCCUR
ALONG AND BEHIND THE FRONT, BUT INTENSITIES SHOULD BE VERY
LIGHT. NO MEANINGFUL IMPACTS ARE EXPECTED. RISK FOR SHOWERS IS
HIGHEST 13-1630Z. WIDESPREAD MVFR CIGS WILL LINGER WELL INTO
THE AFTERNOON, IMPROVING TO VFR BY SUNSET WITH CLEARING
OCCURRING QUICKLY THEREAFTER. GUSTY NORTH WINDS WILL PREVAIL
BEHIND THE FRONT WITH GUSTS 22-27 KT LIKELY, DIMINISHING A BIT
BY LATE AFTERNOON/EARLY EVENING.
KSAV: MVFR CIGS WILL SPREAD INTO THE TERMINAL PRIOR TO DAYBREAK
AS A COLD FRONT PUSHES THROUGH. A FEW SHOWERS MAY OCCUR ALONG
AND BEHIND THE FRONT, BUT THE BEST CHANCES LOOK TO REMAIN NORTH
OF THE TERMINAL. VCSH WAS HIGHLIGHTED 13-15Z. MVFR CIGS SHOULD
IMPROVE TO VFR BY EARLY AFTERNOON AS CLOUDS BEHIND THE SCOUR
OUT. GUSTY NORTH WINDS WILL OCCUR WITH GUSTS 22-27 KT,
DIMINISHING A BIT BY LATE AFTERNOON/EARLY EVENING.
EXTENDED AVIATION OUTLOOK: EXPECT GUSTY WINDS SUNDAY INTO
MONDAY.
MARINE
THROUGH TONIGHT: DANGEROUS MARINE CONDITIONS WILL DEVELOP
ACROSS THE WATERS LATER THIS MORNING AS A COLD FRONT PUSHES
OFFSHORE. THE RISK FOR GALES WILL INCREASE QUICKLY THROUGH THE
DAY WITH THE ONSET OF STRONG POST FRONTAL COLD AIR ADVECTION.
NORTH/NORTHEAST GALES OF 30-35 KT WITH GUSTS TO 40-45 KT WILL
PERSIST ACROSS THE WATERS THROUGH TONIGHT AND GALE WARNINGS
REMAIN IN FORCE FOR ALL NEARSHORE AND OFFSHORE WATERS. A FEW
STORM-FORCE GUSTS COULD OCCUR BEYOND 40 NM CLOSER TO THE WEST
WALL OF THE GULF STREAM LATE THIS AFTERNOON INTO THIS EVENING AS
THE BASE OF THE UPPER TROUGH SWINGS THROUGH. THE FREQUENCY OF
SUCH GUSTS LOOK TO REMAIN PRETTY INFREQUENT WITH THE 17/01Z NBM
PROBABILITY FOR 48 KT GUSTS HOLDING INTO THE 10-30% RANGE,
HIGHEST OVER FAR OUTER PORTIONS (40-60 NM) OF THE GEORGIA AND
FAR SOUTHERN SOUTH CAROLINA OFFSHORE WATERS. THERE IS NOT ENOUGH
EVIDENCE TO SUPPORT AN UPGRADE TO A STORM WARNING AT THIS TIME.
SEAS WILL BUILD TO 4-6 FT NEARSHORE WATERS AND 6-8 FT OFFSHORE
WATERS BY THIS AFTERNOON, INCREASING TO 6-9 FT NEARSHORE WATERS
AND 9-12 FT OFFSHORE WATERS OVERNIGHT. FOR CHARLESTON HARBOR,
CONDITIONS LOOK TO REMAIN BELOW GALE-FORCE WITH WINDS 20-25 KT
WITH GUSTS TO 30 KT AND WAVES 2-4 FT. A SMALL CRAFT ADVISORY
REMAINS IN EFFECT THROUGH TONIGHT.
SUNDAY THROUGH WEDNESDAY: LOW PRESSURE WILL BE FORMING WELL OFF
THE COAST OF THE OUTER BANKS OF NC SUNDAY MORNING. MEANWHILE,
STRONG HIGH PRESSURE WILL BE LOCATED OVER THE MID-ATLANTIC
STATES, WITH IT'S PERIPHERY STRETCHING DOWN INTO THE SOUTHEAST
U.S. THE INTERACTION BETWEEN THESE TWO FEATURES WILL CONTINUE TO
GENERATE STRONG COLD AIR ADVECTION AND PRESSURE DIFFERENCES
ACROSS OUR COASTAL WATERS, GENERATING GALE TO STRONG GALE
CONDITIONS. WE HAVE GALE WARNINGS IN EFFECT FOR OUR ATLANTIC
WATERS ON SUNDAY, AND A SMALL CRAFT ADVISORY FOR THE CHARLESTON
HARBOR. EXPECT STEEP, WIND-DRIVEN WAVES CLOSE TO THE COAST.
THOUGH, THE HIGHEST WINDS AND STEEPEST/LARGEST SEAS WILL BE
FURTHER OFFSHORE. WINDS SHOULD START TO EASE LATE SUNDAY NIGHT,
GRADUALLY EASING FURTHER MONDAY AND MONDAY NIGHT. THE GALES
SHOULD END FOR OUR WATERS WITHIN 20 NM MONDAY MORNING, BUT
PERSIST FOR THE 20-60 NM WATERS, POSSIBLY INTO MONDAY EVENING.
AFTERWARDS, THERE MAY BE SEVERAL EVENING/NIGHTLY SURGES OF WINDS
THROUGH MID TO LATE NEXT WEEK. ADDITIONALLY, WAVE HEIGHTS WILL
STAY ELEVATED DURING THIS TIME FRAME. THE END RESULT COULD BE
SMALL CRAFT ADVISORIES FOR PORTIONS OF OUR WATERS FOR A
SIGNIFICANT PORTION OF NEXT WEEK.
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...LAKE WIND ADVISORY UNTIL 2 AM EDT MONDAY FOR SCZ045.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 PM EDT MONDAY FOR AMZ340.
GALE WARNING UNTIL 2 PM EDT MONDAY FOR AMZ360-362-364.
GALE WARNING UNTIL 2 AM EDT TUESDAY FOR AMZ380-382-384.
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