540
FXUS62 KCHS 121149
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
749 AM EDT FRI SEP 12 2025
SYNOPSIS
HIGH PRESSURE WILL PREVAIL THROUGH THE WEEKEND.
NEAR TERM /THROUGH TONIGHT/
QUIET CONDITIONS CONTINUE TO PREVAIL ACROSS THE REGION, WITH LATEST
OBSERVATIONS SHOWING RELATIVELY LIGHT WINDS AND TEMPERATURES IN THE
60S TO LOWER 70S. SIMILAR TO DAYS PAST, COULD SEE SOME LOWER STRATUS
BUILD ACROSS OUR AREA PRIOR TO DAYBREAK - THOUGH THIS SHOULD BE
RELATIVELY SHORT LIVED.
OTHERWISE, LOOK FOR SFC HIGH PRESSURE TO REMAIN OVERHEAD, ALLOWING
DRY CONDITIONS TO PERSIST. HOWEVER, FOR THOSE WITH ANY
OUTDOOR/RECREATIONAL PLANS, DO THINK IT'S WORTH NOTING THAT ISOLATED
SHOWERS MAY STILL POSSIBLE ACROSS OUR OFFSHORE WATERS AS THE UPPER
LEVEL TROUGH NUDGES CLOSER TO THE ATLANTIC. IN REGARD TO
TEMPERATURES, HAVE AFTERNOON HIGHS WARMING INTO THE LOW TO MID 80S
UNDER MOSTLY SUNNY SKIES, WITH OVERNIGHT LOWS FALLING INTO THE
60S.
SHORT TERM /SATURDAY THROUGH SUNDAY/
SATURDAY: IN THE MID-LEVELS OF THE ATMOSPHERE STOUT RIDGING WILL
EXTEND NORTH ACROSS THE CENTRAL UNITED STATES WITH AN ELONGATED AREA
OF LOW PRESSURE EXTENDING FROM NC TO SC. AT THE SURFACE, A COLD
FRONT WILL BE LOCATED WELL OFFSHORE WITH MID 50 DEWPOINTS FILTERING
INTO MUCH OF THE REGION. PWATS WILL ALSO FALL TO LESS THAN 1" ACROSS
THE AREA. EVEN 1000/ 850 MB THICKNESSES WILL BE AROUND 1395 M, WHICH
WILL SUPPORT HIGH TEMPERATURES IN THE LOW TO MID 80S. NO
PRECIPITATION IS EXPECTED.
SUNDAY: A STRONGER MID-LEVEL LOW WILL DROP SOUTHEAST TOWARDS THE
CANADIAN MARITIMES WITH WAVE BREAKING OCCURRING ACROSS NEW ENGLAND.
ENSEMBLE GUIDANCE IS IN VERY GOOD AGREEMENT (GEFS, GEPS, AND EPS)
THAT THIS MEANS THE AREA OF LOW PRESSURE THAT WAS OVER THE REGION ON
SATURDAY WILL LIKELY BE LEFT BEHIND IN SOME CAPACITY. FOR SUNDAY,
MAINLY A REPEAT OF SATURDAY'S SENSIBLE WEATHER IS FORECAST WITH
HIGHS IN THE LOW TO MID 80S AND NO PRECIPITATION EXPECTED.
MONDAY: THE LEFT OVER AREA OF VORTICITY/ SURFACE LOW PRESSURE WILL
LIKELY RETROGRADE SLIGHTLY CAUSING THE STALLED SURFACE COLD FRONT TO
BEGIN TO UNDER GO FRONTOLYSIS. AS THIS OCCURS, HUMIDITY WILL SLOWLY
START TO RISE ACROSS COASTAL SC/ GA WITH CLOUD COVER INCREASING. THE
LATEST RUN OF THE NBM HAS SLIGHT CHANCE POPS WHICH IS PLAUSIBLE, BUT
CONFIDENCE REMAINS LOW AT THIS TIME. EXPECT HIGH TEMPERATURES IN THE
MID 80S.
LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/
ENSEMBLE GUIDANCE IS IN MODEST AGREEMENT FOR NEXT WORK WEEK. THE
MAIN ITEM OF CONCERN ON HOW THE LONG TERM PROGRESSES APPEARS TO BE
THE COLLAPSE OF THE MID-LEVEL RIDGE ACROSS THE GREAT LAKES
(ACCORDING TO THE ENSEMBLE SENSITIVITY ANALYSIS WEBPAGE). A FASTER
COLLAPSE WOULD FAVOR A LESS AMPLIFIED WAVE PATTERN, WHILE A MORE
STUBBORN RIDGING WOULD FAVOR A BLOCKING PATTERN SETTING UP.
AS OF CURRENT, THE FORMER APPEARS MORE LIKELY WHICH FAVORS
TEMPERATURES REMAINING RATHER SIMILAR EVERY AFTERNOON WITH HIGHS IN
THE MID 80S. THE MAIN CHANGE WILL BE THE INCHING UP OF HUMIDITY EACH
AFTERNOON. BY THE SECOND HALF OF THE NEXT WORK WEEK DEWPOINTS WILL
BE IN THE UPPER 60S TO LOWER 70S. THE CHANCE OF PRECIPITATION WILL
BE NEAR 20% EACH SUCCESSIVE DAY DUE TO THE LINGERING MID-LEVEL
WEAKNESS.
AVIATION /12Z FRIDAY THROUGH TUESDAY/
PRIOR TO THE 12Z TAFS, SATELLITE AND OBSERVATIONS INDICATED
PATCHES OF RESTRICTIVE CEILINGS AROUND KJZI AND KCHS. BASED ON
SATELLITE TRENDS, THE KJZI TAF WILL FEATURE A TEMPO FOR IFR
CEILINGS BETWEEN 12-14Z. OTHERWISE, EXPECTING VFR CONDITIONS
ACROSS THE TERMINALS. NORTHWEST WINDS WILL STRENGTHEN TODAY,
WITH GUSTS NEAR 20 KTS AT TIMES AT KJZI AND POSSIBLY KCHS. WINDS
SHOULD SETTLE TO AROUND 10 KTS ACROSS THE TERMINALS THIS
EVENING AND REMAIN INTO SATURDAY MORNING.
EXTENDED AVIATION FORECAST: MOSTLY VFR THROUGH THE WEEK. EXPECT SOME
BRIEF PERIODS OF RESTRICTED CEILINGS DUE TO LATE NIGHT/EARLY MORNING
STRATUS.
MARINE
TODAY AND TONIGHT: BREEZY NORTHEAST WINDS WILL PREVAIL TODAY AS
THE SFC PRESSURE GRADIENT TIGHTENS, RESULTING IN GUSTS BETWEEN
20 TO 30 KTS. SEAS BETWEEN 3 TO 4 FT WILL GRADUALLY BUILD
THROUGH THE MORNING, WITH HEIGHTS REACHING 5 TO 6 FT LATER THIS
AFTERNOON. THUS, THE CURRENT SCA HAS BEEN EXTENDED TO INCLUDE
THE INNER GEORGIA AND SOUTH CAROLINA WATERS, INCLUDING THE
CHARLESTON HARBOR.
SATURDAY: NORTHEAST WINDS WILL INCREASE IN SPEED AS A BROAD AREA OF
LOW PRESSURE FORMS ALONG A STALLED FRONT. WIND GUSTS OF 25 TO 30 KT
ARE LIKELY WITH SEAS 5 TO 7 FT. A SMALL CRAFT ADVISORY HAS BEEN
ISSUED FOR ALL WATERS ON SATURDAY.
SUNDAY: NORTHEAST WINDS WILL HOLD STEADY NEAR 25 KT AS THE PRESSURE
GRADIENT REMAINS TIGHT. SOME GUIDANCE SHOWS THE WEAK SURFACE LOW
QUICKLY LIFTING NORTHEAST EARLY SUNDAY MORNING WHILE OTHER GUIDANCE
SHOWS THE LOW MOVING AWAY FROM THE REGION SUNDAY AFTERNOON. THE
TIMING OF THE SURFACE LOW EXIT WILL DICTATE WHEN NORTHEAST WINDS
FINALLY BEGIN TO FALL (AND WHEN THE SMALL CRAFT ADVISORY CAN BE LET
GO). AS OF CURRENT, THE SMALL CRAFT IS SCHEDULED TO EXPIRE SUNDAY
MORNING.
MONDAY AND TUESDAY: NORTHEAST WINDS AROUND 15 KT WITH GUSTS UP TO 20
KT. SEAS 3 TO 5 FT.
RIP CURRENTS: THE COMBINATION OF PERSISTENT NORTHEAST WINDS,
ASTRONOMICAL FACTORS, AND ELEVATED SWELL WILL YIELD A MODERATE
RISK OF RIP CURRENTS AT ALL BEACHES TODAY. THE RISK FOR RIP
CURRENTS WILL REMAIN MODERATE FOR SOUTH CAROLINA BEACHES ON
SATURDAY. HOWEVER, A HIGH RISK OF RIP CURRENTS IS FORECAST FOR
GEORGIA BEACHES ON SATURDAY.
TIDES/COASTAL FLOODING
TOTAL WATER LEVELS WILL REMAIN HIGH FROM LARGE TIDAL DEPARTURES DUE
TO A PINCHED PRESSURE GRADIENT AND ELEVATED NORTHEAST WINDS. AS A
RESULT, A COASTAL FLOOD ADVISORY IS IN EFFECT FOR CHARLESTON AND
COASTAL COLLETON COUNTIES FOR THIS AFTERNOON. TIDAL DEPARTURES
SHOULD BE JUST LOW ENOUGH TO PREVENT THE NEED FOR COASTAL FLOOD
ADVISORIES AT FORT PULASKI. THE POTENTIAL FOR COASTAL FLOODING WILL
CONTINUE THOUGH THROUGH THE WEEKEND (ESPECIALLY AT CHARLESTON).
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...COASTAL FLOOD ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR
SCZ049-050.
MARINE...SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 11 AM EDT
SUNDAY FOR AMZ330-350.
SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 11 AM EDT
SUNDAY FOR AMZ352-354.
SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 2 AM EDT
MONDAY FOR AMZ374.
NEAR TERM...SST
SHORT TERM...HAINES
LONG TERM...HAINES
AVIATION...NED/SST
MARINE...HAINES/SST
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