576
FXUS62 KCHS 031047
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
647 AM EDT FRI OCT 3 2025
SYNOPSIS
A STRONG HIGH PRESSURE WILL EXTEND ACROSS THE REGION INTO THE
WEEKEND, WITH RAIN CHANCES INCREASING ON SUNDAY INTO EARLY NEXT
WEEK. A STRONG COLD FRONT WILL LIKELY CROSS THE AREA LATER NEXT
WEEK.
NEAR TERM /THROUGH TONIGHT/
AT H5, A WEAK REX BLOCK WILL REMAIN ACROSS THE SOUTHEAST U.S. TODAY
INTO MOST OF TONIGHT. AT THE SFC, THE CENTER OF HIGH PRESSURE WILL
REMAIN ACROSS THE MID-ATLANTIC STATES, RIDGING SW ALONG THE EAST
FACING SLOPES OF THE SOUTHERN APPALACHIANS. TO THE SOUTHEAST, A
BROAD AREA OF LOW PRESSURE WILL PERSIST OVER FL, GENERALLY OVER THE
GULF STREAM NORTH TO THE OFF SHORE WATERS OF SC. THIS PATTERN SHOULD
SUPPORT NORTHEAST WINDS ACROSS THE SC LOWCOUNTRY AND SE GA AND THE
ADJACENT ATLANTIC WATERS THROUGH TODAY AND TONIGHT. ISOLATED TO
SCATTERED SHOWERS WILL LIKELY REMAIN WITH THE SFC TROUGH OVER THE
ATLANTIC WATERS. ISOLATED SHOWERS MAY TRACK ONSHORE ALONG THE GA
COAST DURING THE DAYLIGHT HOURS TODAY, WITH A SLIGHT INCREASE IN
COVERAGE TONIGHT. HIGH TEMPERATURES ARE FORECAST TO GENERALLY RANGE
IN THE LOW 80S TODAY. LOW TEMPERATURES ARE FORECAST TO RANGE FROM
THE LOW 60S INLAND TO THE UPPER 60S ALONG THE COAST.
SHORT TERM /SATURDAY THROUGH MONDAY/
LOW AMPLITUDE REX BLOCK-LIKE PATTERN SETS UP OVER THE EASTERN US FOR
THE WEEKEND WITH OUR AREA BETWEEN THE H5 RIDGE TO THE NORTH AND
TROUGH TO THE SOUTH. AT THE SURFACE, THE SURFACE HIGH OVER THE
DELMARVA PENINSULA BRINGS PERSISTENT NE TO E FLOW WITH AN INVERTED
COASTAL TROUGH/WEAK BOUNDARY ALONG THE COAST SATURDAY. EXPECT SHOWER
ACTIVITY TO REMAIN FOCUSED OFFSHORE, WITH A FEW SHOWERS POSSIBLY
WORK BACK TOWARD THE SE GA COAST, BUT WITH MINIMAL IMPACT.
ELSEWHERE, LACK OF FORCING AND MID-LEVEL DRY AIR KEEP A MAINLY DRY
FORECAST IN PLACE ON SATURDAY.
SUNDAY, MID AND UPPER LEVEL HEIGHT FALLS AND INCREASING 850 MB
MOISTURE ADVECTION BRING INCREASING DEEP MOISTURE AND A MORE
UNSETTLED PATTERN INTO MONDAY. ADDITIONAL LIFT ARRIVES LATER IN THE
DAY SUNDAY AS A BAND OF VORTICITY MOVING ACROSS THE FLORIDA
PENINSULA WILL PROPAGATE INTO THE SOUTHEAST U.S. AND INTERACT WITH
THE LINGERING COASTAL TROUGH OFFSHORE TO ALSO AID IN RAIN PRODUCTION.
SCATTERED TO WIDESPREAD SHOWERS EXPECT BOTH DAYS, WITH GREATEST
COVERAGE/CONFIDENCE FROM BEAUFORT COUNTY SOUTHWARD ALONG THE SE GA
COAST. PWATS REACH 2-2.25 INCHES, OR AROUND THE 90TH PERCENTILE,
ACROSS SE GA LATER SUNDAY INTO MONDAY, WITH 500-1000 J/KG OF CAPE
SIGNALING THE POTENTIAL FOR LOCALLY HEAVY RAINFALL. TOTAL SUNDAY AND
MONDAY RAINFALL AMOUNTS OF 3 TO 5 INCHES ARE WELL WITHIN REASON FOR
COASTAL AREAS FROM BEAUFORT COUNTY SOUTHWARD, INCLUDING THE SAVANNAH
METRO AREA, WITH LOCALIZED/REASONABLE WORST CASE SCENARIO AMOUNTS
REACH UP TOWARD 6-7 INCHES.
LONG TERM /MONDAY NIGHT THROUGH THURSDAY/
UPPER RIDGING BUILDS MODESTLY TUESDAY BEFORE A SERIES OF SHORTWAVES
POTENTIALLY MOVE THROUGH MID-TO-LATE NEXT WEEK. AT THE SURFACE, HIGH
PRESSURE SHIFTS OVER BERMUDA TUESDAY, RIDGING INTO OUR AREA FROM THE
WEST INTO MIDWEEK, WITH ONLY LOW-END PRECIP CHANCES. THEN, BY LATE
WEEK, VERY STRONG HIGH PRESSURE BUILDING OVER THE NORTHEAST IS
EXPECTED TO FORCE A STRONG BACKDOOR COLD FRONT DOWN THE EASTERN
SEABOARD AS A CAD-LIKE SETUP TAKES HOLD THURSDAY INTO FRIDAY. THE
MOST IMPACTFUL ASPECT OF THIS FORECAST COULD END UP BEING THE GOOD
AGREEMENT ON NE WINDS - 25TH TO 75TH PERCENTILE REFLECTING A MOST
LIKELY WIND SPEED ALONG THE COAST OF AROUND 20-30 MPH - TO END THE
WORKWEEK, WHICH, IN ADDITION TO ALREADY ELEVATED TIDE LEVEL, COULD
BRING A PERIOD OF VERY IMPACTFUL TIDAL FLOODING. SEE COASTAL
FLOODING SECTION FOR MORE.
AVIATION /12Z FRIDAY THROUGH TUESDAY/
12Z TAFS: VFR. EXPECT GUSTY NORTHEAST WINDS TO DEVELOP THIS
MORNING AND PERSIST THROUGH THE REST OF THE DAYLIGHT HOURS. THIS
EVENING, WINDS SHOULD SETTLE TO AROUND 10 KTS AT KCHS AND KSAV,
GUSTS AROUND 15 KTS EXPECTED TO REMAIN OVERNIGHT AT KJZI.
EXTENDED AVIATION FORECAST: THE RISK FOR RESTRICTIONS FROM
SHOWERS/TSTMS WILL INCREASE THIS WEEKEND INTO EARLY NEXT WEEK
FOR ALL TERMINALS. OTHERWISE, NO SIGNIFICANT AVIATION IMPACTS
EXPECTED.
MARINE
TODAY AND TONIGHT: THE MARINE ZONES WILL REMAIN BETWEEN A RIDGE
ACROSS THE WESTERN CAROLINAS AND COASTAL TROUGH. NORTHEAST WINDS
WILL REMAIN BETWEEN 20 TO 25 KTS WITH GUSTS BETWEEN 25 TO 30 KTS.
SURGES OF WINDS GUSTS MAY ACCOMPANY SHOWERS, EXPECTED TO REMAIN
ISOLATED TO SCATTERED THROUGH THE NEAR TERM. SEAS SHOULD GENERALLY
RANGE FROM 6 TO 9 FT ACROSS ATLANTIC WATERS THROUGH TODAY AND
TONIGHT. SMALL CRAFT ADVISORIES WILL REMAIN IN EFFECT FOR ALL MARINE
ZONES OUTSIDE THE CHS HARBOR.
HIGH PRESSURE RIDGING INLAND AND INVERTED COASTAL TROUGHING OFF THE
COAST CONTINUE BREEZY N TO NE WINDS THROUGH THE WEEKEND. WINDS TREND
MORE E EARLY NEXT WEEK AS HIGH PRESSURE MOVES FURTHER OFF THE MID-
ATLANTIC COAST, BUT A VERY LONG EASTERN FETCH IS LIKELY TO KEEP
HAZARDOUS SEAS IN PLACE INTO MID-WEEK DESPITE WINDS TRENDING MORE
MODERATE.
RIP CURRENTS/HIGH SURF: A HIGH RISK RIP CURRENTS WILL CONTINUE INTO
SATURDAY IN PRIMARILY MEDIUM PERIOD E TO NE SWELL, THOUGH SOME
LONGER PERIOD COULD CONTINUE TO MIX IN THROUGH AT LEAST TONIGHT.
HIGH SURF ADVISORY HAS BEEN EXTENDED THROUGH SATURDAY, WITH LOWER
CONFIDENCE IN 6+ FT BREAKING WAVES SATURDAY NIGHT INTO SUNDAY.
TIDES/COASTAL FLOODING
MINOR COASTAL FLOODING EXPECTED FOR CHARLESTON AND COASTAL
COLLETON COUNTIES LATE THIS AFTERNOON, 5:39 PM.
HEADING INTO THIS WEEKEND AND EARLY NEXT WEEK, ASTRONOMICAL
TIDES WILL INCREASE DUE TO THE UPCOMING FULL MOON (OCT 7) AND
PERIGEE (OCT 8). THIS IN COMBINATION WITH THE ANTICIPATION OF
CONTINUED NORTHEASTERLY FLOW WILL CAUSE THE POSSIBILITY OF
COASTAL FLOODING TO BECOME MORE LIKELY ALONG THE ENTIRE
COASTLINE, INCLUDING BOTH DOWNTOWN CHARLESTON AND FORT PULASKI.
SALTWATER INUNDATION COULD THEN OCCUR DURING BOTH THE MORNING
AND EVENING HIGH TIDE CYCLES DURING THIS TIME. ALTHOUGH THERE IS
CONSIDERABLE UNCERTAINTY THIS FAR OUT, PERSISTENT FAVORABLE
WINDS HAVE THE POTENTIAL TO PRODUCE UP TO MAJOR COASTAL
FLOODING.
CHS WATCHES/WARNINGS/ADVISORIES
GA...HIGH RISK FOR RIP CURRENTS THROUGH THIS EVENING FOR GAZ117-119-139-
141.
HIGH SURF ADVISORY UNTIL 8 PM EDT SATURDAY FOR GAZ117-119-139-
141.
SC...HIGH RISK FOR RIP CURRENTS THROUGH THIS EVENING FOR SCZ048>051.
HIGH SURF ADVISORY UNTIL 8 PM EDT SATURDAY FOR SCZ048>051.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 PM EDT TUESDAY FOR AMZ350-352-354.
SMALL CRAFT ADVISORY UNTIL 6 AM EDT WEDNESDAY FOR AMZ374.
NEAR TERM...NED
SHORT TERM...CEB
LONG TERM...CEB
AVIATION...CEB/NED
MARINE...CEB/NED
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