555
FXUS62 KCHS 220645
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
245 AM EDT TUE SEP 22 2026
WHAT HAS CHANGED
THE AVIATION SECTION HAS BEEN UPDATED FOR THE 00Z TAF ISSUANCE.
ADDED A KEY MESSAGE FOR COASTAL FLOODING POTENTIAL MID TO LATE
WEEK.
KEY MESSAGES
- 1) RAIN CHANCES INCREASE ON TUESDAY.
- 2) A COLD FRONT COULD BRING A THREAT OF STRONG THUNDERSTORMS
WEDNESDAY AFTERNOON, AND WILL BE FOLLOWED BY COOLER WEATHER
AND GUSTY WINDS.
- 3) THE THREAT FOR COASTAL FLOODING WILL INCREASE MID
TO LATE WEEK.
DISCUSSION
KEY MESSAGE 1: RAIN CHANCES INCREASE ON TUESDAY.
TUESDAY: RAIN CHANCES LOOK TO INCREASE TODAY AS OUR STUBBORN
UPPER LEVEL LOW THAT HAS BEEN PARKED OVER FLORIDA FOR THE PAST
FIVE DAYS WILL LIFT NORTHEAST ACROSS THE WESTERN ATLANTIC.
MOISTURE WILL CONTINUE TO STREAM IN FROM THE EAST OFF THE
ATLANTIC WITH PWATS CONTINUING TO HOVER IN AND AROUND 2 INCHES.
ONGOING SHOWERS AND STORMS ACROSS THE MARINE WATERS THIS MORNING
SHOULD PERSIST INTO THE EARLY AFTERNOON LIKELY STAYING JUST
OFFSHORE; HOWEVER, AN ISOLATED SHOWER COULD COME ASHORE. BY THIS
AFTERNOON THE SEABREEZE SHOULD BEGIN TO PUSH INLAND RESULTING IN
SCATTERED SHOWERS AND THUNDERSTORMS TO DEVELOP. GIVEN INCREASE
CLOUD COVERAGE AND RATHER DEEP MOIST PROFILES, INSTABILITY
SHOULD BE MEAGER AT BEST AROUND 1000 J/KG WHICH WHILE SHOULD
SUPPORT SOME ISOLATED THUNDERSTORMS SHOULD KEEP ANY STRONG TO
SEVERE STORMS AT A MINIMUM. WHILE PWATS REMAIN HIGH FOR THIS
TIME OF YEAR, THE OVERALL POOR CONVECTIVE ENVIRONMENT MAY NOT
SUPPORT HEAVY RAINFALL EITHER; HOWEVER, IF A STRONGER STORM SITS
OVER AN URBAN AREA LONG ENOUGH THERE IS ENOUGH ENVIRONMENTAL
SUPPORT FOR HEAVY RAIN RATE DRIVEN URBAN NUISANCE FLOODING.
STORM SHOULD SUBSIDE BY THE EARLY EVENING.
WEDNESDAY: BY LATE TUESDAY NIGHT INTO EARLY WEDNESDAY MORNING,
THE UPPER LOW WILL HAVE LIFTED NORTH OF THE AREA AND A BACKDOOR
SURFACE COLD FRONT WILL DROP SOUTH. SCATTERED SHOWERS AND STORMS
WILL LIKELY ACCOMPANY THE DROPPING FRONT. ANY STRONG STORM
THREAT LOOKS TO BE CENTERED AROUND EASTERN GA DURING THE
AFTERNOON DEPENDING ON HOW QUICKLY THE FRONT MOVES THROUGH THE
AREA. GIVEN OVERALL WEAK FORCING AND THE GENERAL SPEED OF THE
FRONT; WOULD NOT BE SURPRISED IF WE SEE POPS LOWER OVER THE NEXT
48 HOURS AND RESULT IN A COOLER AND DRIER WEDNESDAY THAN
CURRENTLY ADVERTISED.
KEY MESSAGE 2: A COLD FRONT WILL BRING GUSTY WINDS WEDNESDAY AND
THURSDAY, FOLLOWED BY COOLER WEATHER THROUGH THE END OF THE WEEK.
BEHIND THE COLD FRONT, AN INTENSIFYING PRESSURE GRADIENT WILL
PRODUCE BREEZY TO GUSTY CONDITIONS ACROSS SOUTHEAST SOUTH CAROLINA
AND SOUTHEAST GEORGIA. WINDS WILL INCREASE FROM NORTH TO SOUTH
WEDNESDAY, FOLLOWING THE PASSAGE OF THE FRONT, INITIALLY ACROSS SE
SOUTH CAROLINA BEFORE SPREADING INTO SE GEORGIA. POST-FRONTAL WIND
GUSTS ON WEDNESDAY LOOK TO PEAK AT 20-25 MPH, AND A LITTLE STRONGER
ON THURSDAY WITH WIDESPREAD GUSTS OF 25-30 MPH, AND UP TO 30-35 MPH
OVER ELEVATED BRIDGES AND OVERPASSES. WHILE WINDS ARE EXPECTED TO
REMAIN BELOW WIND ADVISORY THRESHOLDS, GUSTS OVER LAKE MOULTRIE
COULD APPROACH 25 KNOTS AT TIMES, MAINLY THURSDAY. GUSTY CONDITIONS
ARE EXPECTED TO SUBSIDE THURSDAY NIGHT.
ALONG WITH THE BREEZY CONDITIONS, THE SURFACE HIGH PRESSURE WEDGE
BUILDING SOUTH ACROSS THE CAROLINAS AND GEORGIA WILL ESTABLISH COOL,
DRY AIR FOR THE LATTER PORTION OF THE WEEK. HIGH TEMPERATURES
THURSDAY AND FRIDAY ARE FORECAST TO TOP OUT IN THE MID TO UPPER 70S
AND LOWER 80S ACROSS SOUTHEAST SOUTH CAROLINA, AND THE LOWER 80S FOR
SOUTHEAST GEORGIA, WHICH IS SEVERAL DEGREES BELOW NORMAL FOR LATE
SEPTEMBER. TEMPERATURES WILL REBOUND CLOSER TO SEASONAL NORMALS FOR
THE WEEKEND.
KEY MESSAGE 3: THE THREAT FOR COASTAL FLOODING WILL INCREASE MID
TO LATE WEEK.
AS A FULL MOON APPROACHES ON 9/26, BREEZY NORTHEAST WINDS
WEDNESDAY EVENING INTO FRIDAY MAY RESULT IN SOME COASTAL
FLOODING ISSUES AS TIDAL DEPARTURES RISE. WE WILL NEED TO KEEP
AN EYE ON THE POTENTIAL STARTING AS EARLY AS WEDNESDAY AFTERNOON
FOR COASTAL CHARLESTON AND COLLETON COUNTIES, EXPANDING
SOUTHWARDS TO INCLUDE THE REMAINDER OF THE SE SC COAST INTO SE
GA THURSDAY AFTERNOON/EVENING.
AVIATION /06Z TUESDAY THROUGH SATURDAY/
VFR CONDITIONS CONTINUE ACROSS MOST OF THE AREA; HOWEVER,
GUIDANCE HINTS THAT ANOTHER ROUND OF STRATUS AND FOG WILL BE
POSSIBLE BY THE EARLY MORNING HOURS. THE GREATER CHANCE FOR
OCCURRENCE IS AT KSAV WHERE MVFR HAS BEEN MAINTAINED, THOUGH
THERE IS POTENTIAL FOR IFR OR LOWER. VFR SHOULD RETURN MID
MORNING. BRIEF RESTRICTIONS IN SHOWERS/THUNDERSTORMS WILL BE
POSSIBLE IN THE AFTERNOON, WHICH IS CURRENTLY HIGHLIGHTED WITH
PROB30 GROUPS. WINDS WILL REMAIN LIGHT OUT OF THE NORTHEAST
THROUGHOUT THE PERIOD.
EXTENDED AVIATION OUTLOOK:FLIGHT RESTRICTIONS ARE POSSIBLE
WEDNESDAY MORNING AS LOW CEILINGS DEVELOP AHEAD OF A COLD FRONT.
ADDITIONAL BRIEF RESTRICTIONS REMAIN POSSIBLE WEDNESDAY
AFTERNOON AND EVENING DUE TO SCATTERED SHOWERS AND
THUNDERSTORMS. BEHIND THE FRONT, GUSTY NORTH TO NORTHEAST WINDS
WILL AFFECT THE TERMINALS WEDNESDAY THROUGH THURSDAY.
MARINE
THROUGH TUESDAY: A DECAYING SURFACE HIGH PRESSURE AHEAD OF A SLOWLY
APPROACHING COLD FRONT WILL CONTINUE THE BENIGN MARINE WEATHER
CONDITIONS ACROSS OUR LOCAL WATERS. PERIODIC SHOWERS AND
THUNDERSTORMS DURING THIS TIME MAY BE CAPABLE OF GUSTY WINDS AND
FREQUENT LIGHTNING.
WEDNESDAY THROUGH SUNDAY: IN THE WAKE OF A COLD FRONT, A BUILDING
INLAND WEDGE COUPLED WITH A DEEPENING SURFACE LOW OFF THE MID-
ATLANTIC COAST WILL DRIVE A STRONG NORTHEASTERLY WIND SURGE. MARINE
CONDITIONS WILL DETERIORATE WEDNESDAY EVENING, WITH WIND GUSTS
PEAKING THURSDAY EVENING. SMALL CRAFT ADVISORIES WILL LIKELY BE
NEEDED ACROSS ALL WATERS, WITH GALE WATCHES/WARNINGS POTENTIALLY
REQUIRED FOR THE OFFSHORE WATERS BEYOND 20 NM. SEAS WILL BUILD
SIGNIFICANTLY WITH THE WIND SURGE, PEAKING AT 5 TO 9 FEET THURSDAY
NIGHT. WHILE WINDS AND SEAS WILL GRADUALLY DIMINISH OVER THE WEEKEND
AS THE PRESSURE GRADIENT RELAXES, SEAS WILL REMAIN ELEVATED, WITH 6
FT WAVES PERSISTING ACROSS THE OUTER OFFSHORE ZONES POTENTIALLY INTO
SUNDAY MORNING.
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...NONE.
BLACK/BRS
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