066
FXUS62 KCHS 051752
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
1252 PM EST WED NOV 5 2025
SYNOPSIS
HIGH PRESSURE WILL LARGELY PREVAIL THROUGHOUT THE PERIOD,
KEEPING CONDITIONS QUIET ACROSS OUR AREA. OUTSIDE OF THIS,
EXPECT A DRY COLD FRONT ON THURSDAY WITH CONDITIONS WARMING
SATURDAY AND SUNDAY. A STRONGER COLD FRONT WILL THEN CROSS THE
REGION SUNDAY NIGHT BRINGING MUCH COLDER CONDITIONS TO THE AREA
NEXT WEEK.
NEAR TERM /THROUGH TONIGHT/
TODAY: ZONAL FLOW WILL PERSIST ACROSS THE AREA TODAY WITH A STRONG
UPPER LEVEL LOW REMAINING WELL NORTH OF THE AREA (OVER EASTERN
CANADA). AT THE SURFACE, SURFACE HIGH PRESSURE WAS ANALYZED JUST OFF
OF THE NORTH CAROLINA COAST THIS MORNING AND IS FORECAST TO CONTINUE
TO MOVE EAST THROUGH THE AFTERNOON. EXPECT HIGH TEMPERATURES IN THE
MID 70S TODAY. NO PRECIPITATION IS FORECAST.
TONIGHT: A WEAK COLD FRONT WILL APPROACH COASTAL SC/ GA LATE TONIGHT
FROM THE WEST. AHEAD OF THE COLD FRONT, WEAK WARM AIR ADVECTION WILL
COMMENCE WITH TEMPERATURES INITIALLY ONLY SLOWLY FALLING INTO THE
60S/ UPPER 50S. THEN AS THE COLD FRONT CROSSES THE ZONES,
TEMPERATURES WILL AGAIN START TO FALL INTO THE 40S. THE FRONTAL
PASSAGE WILL BE DRY WITH LITTLE IN THE OF WAY OF CLOUDS EVEN
EXPECTED.
SHORT TERM /THURSDAY THROUGH SUNDAY NIGHT/
THURSDAY: A WEAK COLD FRONT WILL MOVE OFF THE COAST IN THE
MORNING AND THEN QUICKLY HANG UP NEAR THE SC/ GA COASTLINE. THE
ZONAL FLOW MENTIONED ABOVE WILL FOSTER A QUICK EXIT OF THE HIGH
PRESSURE TO THE EAST WITH A COASTAL TROUGH MOVING ONSHORE LATE
THURSDAY. NO PRECIPITATION IS EXPECTED WITH PWATS REMAINING AT
OR BELOW 0.75". EXPECT HIGH TEMPERATURES IN THE MID TO UPPER
70S.
FRIDAY: A POTENT CLOSED UPPER LEVEL LOW WILL TAKE SHAPE OVER THE
JAMES BAY WITH THE ZONAL FLOW STARTING TO AMPLIFY. TOWARDS SC, LOW
LEVEL WINDS WILL QUICKLY TURN FROM THE SOUTHEAST WITH DEWPOINTS
RECOVERING INTO THE LOWER 60S WITH HIGHS AGAIN THE MID TO UPPER 70S.
THE MAIN NOTICEABLE DIFFERENCE ON FRIDAY WILL BE THE HIGHER
RELATIVE HUMIDITY VALUES IN THE AFTERNOON (30 - 50% THURSDAY
AFTERNOON TO 40 - 60% FRIDAY AFTERNOON). RETURN OF AFTERNOON
CUMULUS IS FORECAST FRIDAY, BUT THE AREA WILL REMAIN DRY.
SATURDAY AND SUNDAY: A SHORTWAVE OVER THE NORTHERN UNITED STATES
WILL MOVE EAST AND BEGIN TO CONSTRUCTIVELY AMPLIFY WITH THE CLOSED
LOW OVER THE JAMES BAY. THIS AMPLIFICATION PROCESS WILL SET THE
STAGE FOR THE COLDEST AIR OF THE SEASON TO DIVE SOUTHEAST
TOWARDS GA/ SC. HOWEVER, THE FRONT WILL NOT MAKE IT TO COASTAL
SC/ GA UNTIL LATE SUNDAY EARLY MONDAY THOUGH. THIS MEANS THAT
SATURDAY AND SUNDAY WILL BE WARM AND HUMID FOR THIS TIME OF YEAR
WITH LOW TEMPERATURES NEAR 60 DEGREES AND HIGH TEMPERATURES
NEAR 80. MINIMUM RELATIVE HUMIDITY VALUES WILL ONLY FALL INTO
THE UPPER 50% TO 60% RANGE, SO IT WILL FEEL NOTICEABLY HUMID
BOTH DAYS. OUT AHEAD OF THE COLD FRONT, THE APPROACHING WEDGE OF
POSITIVE VORTICITY WILL CAUSE PRESSURE FALLS OVER THE PIEDMONT
OF SC/ NC WITH A WEAK LEE SIDE TROUGH POTENTIALLY DEVELOPING.
ENSEMBLE GUIDANCE IS IN FAIRLY GOOD AGREEMENT THAT AT LEAST SOME
PRECIPITATION WILL FORM ALONG THE LEE SIDE TROUGH, BUT
CONFIDENCE IN THE EXTENT AND EXACT PLACEMENT IS LOW AT THIS
TIME.
LONG TERM /MONDAY THROUGH WEDNESDAY/
THE MAIN STORY IN THE EXTENDED REMAINS THE PASSAGE OF A STRONG COLD
FRONT LATE SUNDAY/ EARLY MONDAY. THE ENSEMBLE GUIDANCE REMAINS IN
VERY GOOD AGREEMENT WITH THE COLD FRONT BEING ABNORMALLY STRONG FOR
THIS TIME OF YEAR. THE NAEFS IS SHOWING 850 MB TEMPERATURES
AROUND -3 SD FOR THIS OF YEAR (OR NEAR THE 2ND PERCENTILE). THE
GEFS ONLY COMPONENT OF THE NAEFS IS EVEN SLIGHTLY STRONGER, OR
NEAR THE 1ST PERCENTILE FOR THIS TIME OF YEAR. THE ECMWF
EXTREME FORECAST INDEX (EFI) IS ALSO OUTPUTTING VALUES AROUND
-.80 INDICATING THAT THE TEMPERATURE DISTRIBUTION IS APPROACHING
THE TAIL OF THE M-CLIMATE ANALYSIS.
POTENTIAL FOR FREEZING TEMPERATURES
* WHEN: TUESDAY (11/11) AND WEDNESDAY (11/12) MORNINGS
* WHAT: TEMPERATURES FALLING TO 32F OR LOWER. SOME RURAL LOCATIONS
COULD OBSERVE UPPER 20S.
* PROBABILITY OF OCCURRENCE: >75% (TUESDAY) AND >55% (WEDNESDAY)
* WHERE: INTERIOR GA AND SC. CHANCES OF OBSERVING FREEZING
TEMPERATURES IN THE CITY OF CHARLESTON AND SAVANNAH ARE MUCH
LOWER.
AVIATION /18Z WEDNESDAY THROUGH MONDAY/
VFR CONDITIONS ARE EXPECTED TO PREVAIL AT KCHS, KJZI, AND KSAV
THROUGH 18Z THURSDAY.
EXTENDED AVIATION OUTLOOK: VFR CONDITIONS EXPECTED TO PREVAIL.
MARINE
TODAY THROUGH TONIGHT: OVERALL, VERY QUIET CONDITIONS ACROSS
THE LOCAL WATERS. WINDS WILL VEER FROM THE SOUTHWEST WITH SPEEDS
GENERALLY 10 KT OR LESS. OVERNIGHT, WINDS WILL SLIGHTLY INCREASE
IN SPEED AS A COLD FRONT APPROACHES. GUSTS WILL TOP OUT IN THE
15 TO 20 KT RANGE WITH SEAS 2 - 4 FEET.
THURSDAY THROUGH SUNDAY: WINDS WILL START OUT OF THE NORTHEAST
THURSDAY AFTERNOON AND THEN VEER AROUND FROM THE SOUTHWEST ON
FRIDAY. WINDS WILL REMAIN AROUND 10 KT WITH GUSTS UP TO 20 KT.
EXPECT SEAS 2 TO 4 FT.
MONDAY: A COLD FRONT WILL CROSS THE WATERS EARLY MONDAY WITH
WINDS AND SEAS PICKING UP IN ITS WAKE. AS OF CURRENT, SMALL
CRAFT ADVISORIES APPEAR LIKELY WITH WIND GUSTS IN THE 25 TO 30
KT RANGE AND SEAS 4 TO 6 FT.
TIDES/COASTAL FLOODING
WITH THE UPCOMING FULL MOON AND PERIGEE, COASTAL FLOODING IS
POSSIBLE WITH THE MORNING HIGH TIDES ALONG THE SOUTHEAST SOUTH
CAROLINA, ESPECIALLY TOWARDS THE END OF THIS WEEK WHEN THE
ASTRONOMICAL LEVELS WILL BE AT, OR NEAR MINOR FLOODING
THRESHOLDS.
CHARLESTON AND COASTAL COLLETON (CHARLESTON HARBOR TIDE GAGE):
THURSDAY AND FRIDAY MORNING HIGH TIDES WILL HAVE POTENTIAL TO
APPROACH/REACH MINOR FLOODING CRITERIA OF 7.0 FT MLLW. FRIDAY
MORNING WILL HAVE A MORE FAVORABLE WIND DIRECTION, WHILE
THURSDAY HAS A LESS FAVORABLE OFFSHORE WIND DIRECTION, BUT A
HIGHER ASTRONOMICAL LEVEL. COASTAL FLOOD ADVISORIES MIGHT NEED
TO BE ISSUED FOR THIS TIME PERIOD.
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...NONE.
NEAR TERM...HAINES
SHORT TERM...HAINES
LONG TERM...HAINES
AVIATION...HAINES
MARINE...HAINES
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