228
FXUS62 KCHS 022317
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
717 PM EDT FRI OCT 2 2026
WHAT HAS CHANGED
THE AVIATION SECTION HAS BEEN UPDATED.
KEY MESSAGES
- 1) UNSETTLED WEATHER WILL RETURN TODAY AND LINGER THROUGH
MONDAY.
- 2) COOLER TEMPERATURES ALONG WITH BREEZY TO WINDY CONDITIONS
ARE LIKELY NEXT WEEK.
- 3) COASTAL FLOODING IS LIKELY NEXT WEEK.
DISCUSSION
KEY MESSAGE 1: UNSETTLED WEATHER WILL RETURN TODAY AND LINGER
THROUGH MONDAY.
A MORE UNSETTLED PATTERN HAS BEGUN TO SETUP THIS AFTERNOON AS
HIGH PRESSURE BEGINS TO EAST IN RESPONSE TO OUR NEXT UPPER
TROUGH. BROADER SOUTHWESTERLY FLOW HAS BEGUN TO OVERSPREAD THE
SOUTHEAST RESULTING IN STEADY MOISTURE ADVECTION NORTHWARD. THIS
PLUME OF MOISTURE HAS BEEN NOTED BY INCREASED SHOWERS AND STORMS
ACROSS EASTERN GEORGIA AND STARTING TO DEVELOP ALONG A SLOWLY
ADVANCING SEABREEZE ACROSS SOUTHEASTERN SOUTH CAROLINA. STORMS
SHOULD SUBSIDE THIS EVENING. RAIN IS EXPECTED TO RETURN ON
SATURDAY AS COVERAGE INCREASES ACROSS SOUTH CAROLINA. PWATS ARE
EXPECTED TO CLIMB ABOVE 2.1 TO 2.2 INCHES BY SATURDAY MORNING.
STORMS WILL LIKELY DEVELOP BY MID-MORNING ACROSS THE SOUTH
CAROLINA LOW LANDS AND SLOWLY DRIFT NORTH WITH TIME. GIVEN PWATS
IN THE 98TH PERCENTILE FOR THIS TIME OF YEAR; SOME LOCALLY HEAVY
RAINFALL CANNOT BE RULED OUT WITH THE STRONGER STORMS. HOWEVER,
STORMS SHOULD MOVE NORTHWARD WITH SOME PACE AND WITHOUT A TRUE
FOCUS FOR HEAVIER RAINFALL AND STORM DEVELOPMENT A MORE FOCUSED
HEAVY RAIN THREAT DOES NOT SEEM LIKELY ON SATURDAY. NONETHELESS,
EXPECT TO BE DODGING SHOWERS AND STORMS MAINLY ACROSS SC FOR
MOST OF THE DAY SATURDAY.
BY SUNDAY AND INTO SUNDAY NIGHT, OUR REAL RAINMAKER SHALL ARRIVE
AS A UPPER TROUGH SWINGS THROUGH THE DEEP SOUTH AND A SURFACE
LOW MOVES ACROSS SOUTHERN GA AND OFF THE CAROLINA COASTLINE. A
BACKDOOR COLD FRONT IS EXPECTED TO STALL SOMEWHERE ACROSS SOUTH
CAROLINA ON SUNDAY AS THE SURFACE LOW MOVES THROUGH. PWATS WILL
CONTINUE TO BE IN THE 2.25 INCH RANGE AND COULD POSSIBLY CLIMB
TO 2.3 INCHES BY SUNDAY NIGHT. WITH INCREASING UPPER LEVEL
ASCENT AND PRESENCE OF LOW LEVEL FOCUS WITH THE STALLED
BOUNDARY AND ATTACHED SURFACE LOW, RAIN CHANCES WILL QUICKLY
INCREASE THROUGHOUT THE AFTERNOON AND INTO THE OVERNIGHT HOURS.
THE AFTERNOON SHOULD START OFF WITH SCATTERED TO NUMEROUS
SHOWERS AND THUNDERSTORMS LIKELY CONFINED TO THE AFTERNOON SEA
BREEZE; HOWEVER, AS WE GO INTO THE OVERNIGHT HOURS STORMS SHOULD
TRANSITION MORE INTO WIDESPREAD MODERATE RAIN. RAINFALL TOTALS
OF 1 TO 3 INCHES WILL BE POSSIBLE ACROSS MUCH OF THE AREA SUNDAY
INTO SUNDAY NIGHT WITH LOCALLY HIGHER AMOUNTS DEPENDING ON
WHERE THE HEAVIEST STORMS DEVELOP DURING THE AFTERNOON. RAINFALL
MAY BE DRUG OUT OVER SEVERAL HOURS WHICH MAY LIMIT FLOODING
CONCERNS; HOWEVER, WITH NEAR RECORD PWATS IT WILL NOT TAKE MUCH
TO GET STRONGER RAIN RATES THAT COULD RESULT IN LOCALIZED FLASH
FLOODING. THIS IS NOTED WITHIN SOME OF THE 95TH PERCENTILE
RAINFALL TOTALS APPROACHING 5 TO 7 INCHES FOR THE SUNDAY
THROUGH MONDAY TIMEFRAME. WHILE THESE TOTALS LIKELY WON'T
MATERIALIZE OVER THE MAJORITY OF THE AREA THEY DO DEPICT THE
UPPER END POTENTIAL THAT COULD OCCUR IN LOCALIZED SWATHS IF
STORMS TRAIN OVER THE SAME AREA.
RAIN WILL LIKELY CONTINUE INTO MONDAY AS THE SURFACE COLD FRONT
IS EXPECTED TO TAKE ITS SWEET TIME PUSHING OFFSHORE. SCATTERED
TO POSSIBLY NUMEROUS SHOWERS AND STORMS WILL LIKELY REMAIN A
THREAT THROUGH THE DAY ON MONDAY FOR MOST OF THE COASTAL AREAS
BEFORE DRIER AIR FINALLY MOVES IN BY MONDAY NIGHT. PWATS WILL
REMAIN HIGH AND DEPENDING ON HOW SUNDAY GOES SOME LOCALIZED
FLOODING THREAT COULD PERSIST INTO MONDAY AS GROUNDS BECOME MORE
SATURATED.
KEY MESSAGE 2: COOLER TEMPERATURES EARLY NEXT WEEK ALONG WITH
NORTHEASTERLY BREEZY WINDS.
AS RAINFALL CHANCES INCREASE OVER THE WEEKEND, A COLD FRONT WILL
SLIDE THROUGH THE REGION ON MONDAY MORNING. EXPECT STRONG HIGH
PRESSURE WILL BUILD INTO THE REGION BEHIND IT. THIS WILL YIELD
AFTERNOON TEMPERATURES IN THE MID TO HIGH 70S ON MONDAY WITH
NORTHEASTERLY WINDS RAMPING UP THROUGH THE AFTERNOON AND EVENING.
ADDITIONALLY, A COLD AIR DAMMING (CAD) EVENT WILL SETUP ACROSS THE
REGION IN THE MIDDLE OF THE WEEK. THIS WILL SUPPORT INCREASING CLOUD
COVER, STRONGER NORTHEASTERLY WINDS, AND COOLER TEMPERATURES ON
TUESDAY AND WEDNESDAY. EXPECT AFTERNOON TEMPERATURES TO ONLY REACH
INTO THE UPPER 60S TO LOW 70S ON TUESDAY AND WEDNESDAY. INLAND AREAS
WILL LIKELY SEE WIND GUSTS UP TO 30 MPH WITH AREAS ALONG THE
COASTLINE EXPERIENCING UP TO 40 MPH. THEREFORE, A LAKE WIND ADVISORY
FOR LAKE MOULTRIE MAY BE WARRANTED ON TUESDAY AND AGAIN ON
WEDNESDAY.
KEY MESSAGE 3: COASTAL FLOODING IS LIKELY NEXT WEEK.
BREEZY NORTHEASTERLY WINDS (THANKS TO THE STRONG COLD AIR DAMMING)
COMBINED WITH HIGH ASTRONOMICAL TIDAL LEVELS NEXT WEEK WILL LIKELY
RESULT IN COASTAL FLOODING ISSUES NEXT WEEK. MINOR TO MODERATE
FLOODING IS LIKELY WITH THE POSSIBILITY OF REACHING MAJOR LEVELS.
COASTAL FLOOD WATCHES, WARNINGS AND ADVISORIES COULD BE NEEDED.
AVIATION /00Z SATURDAY THROUGH WEDNESDAY/
PRIOR TO THE 0Z TAFS, A LARGE AREA OF STRATIFORM RAIN WAS OVER
KSAV, PRODUCING MVFR VIS RESTRICTIONS. RAINFALL RATES ACROSS
KSAV SHOULD DECREASE BETWEEN 0-2Z. CONDITIONS ACROSS THE
TERMINALS OVERNIGHT IS FORECAST TO REMAIN VFR WITH LIGHT TO
CALM WINDS. ON SATURDAY, CONDITIONS ACROSS THE REGION WILL
BECOME VERY MOIST WITH SLIGHT TO MODERATE INSTABILITY. SHOWERS
AND ISOLATED THUNDERSTORMS SHOULD BEGIN TO DEVELOP ALONG THE
SEA BREEZE DURING THE EARLY AFTERNOON. EACH TAF WILL FEATURE A
PROB30 FROM 17-22Z FOR SHOWERS.
EXTENDED AVIATION OUTLOOK: FLIGHT RESTRICTIONS ARE POSSIBLE WITH
INCREASING SHOWERS AND THUNDERSTORMS OVER THE WEEKEND INTO EARLY
NEXT WEEK. BREEZY NORTHEASTERLY WINDS ARE LIKELY ON TUESDAY AND
WEDNESDAY.
MARINE
REST OF TODAY THROUGH SUNDAY: WINDS AND SEAS WILL
REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS ACROSS ALL MARINE
ZONES. WINDS WILL SURGE A BIT EACH AFTERNOON AND EVENING, BUT
SPEEDS SHOULD MOSTLY TOP OUT IN THE 10-15 KNOT RANGE AND WILL BE
STRONGEST ALONG THE LAND/SEA INTERFACE. INCREASING SHOWERS AND
THUNDERSTORMS ARE EXPECTED OVER THE WEEKEND WITH SUNDAY
FEATURING THE HIGHEST RAIN CHANCES.
MONDAY THROUGH THURSDAY: A COLD FRONT WILL CROSS THE COASTAL WATERS
MONDAY MORNING, ACCOMPANIED BY WIDESPREAD SHOWERS AND ISOLATED
THUNDERSTORMS. NORTHERLY WINDS AROUND 10-15 KTS WILL STRENGTHEN AND
TURN MORE NORTHEASTERLY ON MONDAY AFTERNOON AS STRONG HIGH PRESSURE
BUILDS IN BEHIND THE COLD FRONT. CONDITIONS WILL DETERIORATE RAPIDLY
MONDAY NIGHT, WITH NORTHEAST WINDS INCREASING TO 20-30 KTS AND SEAS
BUILDING 4-6 FT. HAZARDOUS MARINE CONDITIONS ARE EXPECTED TUESDAY
AND WEDNESDAY AS THE PRESSURE GRADIENT STRENGTHENS. NORTHEAST WINDS
OF 25-25 KTS WITH FREQUENT GALE-FORCE GUSTS OF 35-45 KTS ARE
POSSIBLE. SEAS WILL LIKELY BUILD TO 6-9 FT IN THE NEARSHORE WATERS
AND 9-12 FT BEYOND 20 NAUTICAL MILES. SHOWERS WILL REMAIN POSSIBLE,
ESPECIALLY ACROSS THE GEORGIA WATERS ON TUESDAY. STRONG NORTHEAST
FLOW WILL LIKELY PERSIST INTO THURSDAY, ALTHOUGH WINDS COULD BEGIN
TO GRADUALLY EASE. ELEVATED SEAS WILL BE SLOWER TO SUBSIDE AND
HAZARDOUS CONDITIONS COULD CONTINUE ACROSS MUCH OF THE COASTAL
WATERS. SMALL CRAFT ADVISORIES, GALE WATCHES, AND GALE WARNINGS WILL
LIKELY BE NEEDED. THE PROLONGED NORTHEAST FLOW, COMBINED WITH HIGH
ASTRONOMICAL TIDES, COULD ALSO PRODUCE COASTAL FLOODING, HIGH SURF,
AND DANGEROUS RIP CURRENTS.
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...NONE.
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