878
FXUS62 KCHS 021834
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
234 PM EDT SAT MAY 2 2026
WHAT HAS CHANGED
A COASTAL FLOOD ADVISORY HAS BEEN ISSUED FOR CHARLESTON AND COLLETON
COUNTY FROM 7PM UNTIL 11PM EDT. THE AVIATION SECTION HAS BEEN
UPDATED FOR THE 18Z TAF ISSUANCE.
KEY MESSAGES
- 1) A WIDESPREAD RAINFALL EVENT WILL PERSIST ACROSS THE SOUTH
CAROLINA LOWCOUNTRY AND SOUTHEAST GEORGIA THROUGH THE EVENING.
- 2) MINOR COASTAL FLOODING LIKELY WITH HIGH TIDE THIS EVENING ALONG
THE SOUTH CAROLINA COASTLINE.
- 3) DRY WEATHER RETURN SUNDAY INTO THE MIDDLE OF NEXT WEEK.
DISCUSSION
KEY MESSAGE 1: A WIDESPREAD RAINFALL EVENT WILL PERSIST ACROSS THE
SOUTH CAROLINA LOWCOUNTRY AND SOUTHEAST GEORGIA THROUGH THE EVENING.
LIGHT TO MODERATE RAINFALL WILL PERSIST ACROSS THE REGION AS A FRONT
POSITIONS ITSELF TO ACROSS NORTHERN FLORIDA AND ADJACENT ATLANTIC
WATERS. SIMULTANEOUSLY, AN AREA OF LOW PRESSURE WILL DEVELOP
OFFSHORE ALONG THE FRONT. THIS SET-UP CONTINUE TO PROMOTE
STRENGTHENING ISENTROPIC LIFT NORTH OF THE FRONT COMBINED WITH A
GOOD AMOUNT OF MOISTURE SURGING INTO THE REGION (PWATS RANGING FROM
1.5 TO 1.75 INCHES). THE STORM TOTAL RAINFALL AMOUNTS OF 1 TO 2
INCHES CONTINUES TO BE ON TRACK THROUGH THE EVENING. EVEN
THOUGH THIS IS SOME MUCH NEEDED RAINFALL FOR THE SOUTHEAST
(GIVEN THE ONGOING DROUGHT CONDITIONS), LOW-LYING AND POOR
DRAINAGE AREAS RUN THE RISK OF OBSERVING MINOR FLOODING ISSUES
AS POCKETS OF PERIODIC MODERATE RAINFALL PASSES THROUGH. MULTI-
LAYERED CLOUD-DECK SHOULD SUPPORT OVERCAST SKIES AREA-WIDE
THROUGH THE EVENING, THEN CLEARING OUT OVERNIGHT AS AN AREA OF
LOW PRESSURE STRENGTHENS OFFSHORE OF THE COASTLINE. SFC
INSTABILITY REMAINS RATHER WEAK, THEREFORE THE CHANCES OF A
THUNDERSTORM DEVELOPING ARE QUITE LOW. RAINFALL COMBINED WITH
OVERCAST SKIES HAS KEPT TEMPERATURES IN THE UPPER 50S TO LOW 60S
ACROSS THE REGION, AND HAVE ADJUSTED THE FORECAST ACCORDINGLY.
EXPECT NORTHWESTERLY WINDS TO INCREASE A LITTLE BIT IN THE
AFTERNOON WITH SPEEDS 10 TO 15 MPH WITH GUSTS UP TO 20 MPH
POSSIBLE (ESP. WITHIN POCKETS OF SHOWERS). HEADING INTO THE
EVENING, RAIN CHANCES WILL QUICKLY DIMINISH AS THIS
AFOREMENTIONED AREA OF LOW PRESSURE EXITS OFFSHORE AND QUICKLY
TRACKS NORTHEASTWARD ACROSS THE ATLANTIC OVERNIGHT.
KEY MESSAGE 2: MINOR COASTAL FLOODING LIKELY WITH HIGH TIDE THIS
EVENING ALONG THE SOUTH CAROLINA COASTLINE.
TIDAL DEPARTURES HAVE STARTED TO DECREASE SLIGHTLY THIS AFTERNOON
(NEAR 1.1 FEET AS OF 18Z), BUT WITH NORTHERLY WINDS AND THE OBSERVED
RAINFALL TODAY WILL LIKELY MAINTAIN A CONSIDERABLE POSITIVE TIDAL
ANOMALY THROUGH THIS EVENING. WIND DIRECTIONS MAY BECOME SLIGHTLY
LESS FAVORABLE BY THE 9:30 PM HIGH TIDE IN CHARLESTON HARBOR, BUT IT
STILL SEEMS AS THOUGH A +1.1-1.3 FEET ANOMALY IS POSSIBLE. THIS
WOULD BRING US RIGHT TO OR ABOVE MINOR FLOOD STAGE OF 7.0 FEET MLLW,
LEADING TO MINOR COASTAL FLOODING LIKELY ALONG CHARLESTON AND
COASTAL COLLETON COUNTIES GIVEN THE UNCERTAINTIES LISTED ABOVE. AT
FORT PULASKI, WE ARE EXPECTING A CREST RIGHT BELOW ACTION STAGE OF
9.2 FEET MLLW.
KEY MESSAGE 3: DRY WEATHER RETURN SUNDAY INTO THE MIDDLE OF NEXT
WEEK.
SURFACE HIGH PRESSURE BUILDS ACROSS THE SOUTHEAST REGION ON SUNDAY,
BRINGING THE RETURN OF SUNSHINE AND DRY WEATHER TO THE REGION. AS
THE SURFACE HIGH SLIDES OFF INTO THE ATLANTIC MONDAY INTO TUESDAY,
EXPECT TEMPERATURES TO BE RISING EACH DAY, WITH HIGHS ON SUNDAY IN
THE LOWER TO MID 70S AND BY WEDNESDAY HIGHS ARE LOOKING TO BE LOWER
80S TO LOWER 90S. OUT AHEAD OF AN APPROACHING COLD FRONT THAT LOOKS
TO MOVE THROUGH LATER DURING THE DAY, THURSDAY COULD BE ANOTHER WARM
DAY IN THE 80S AND LOWER 90S, THOUGH TIMING OF THE TROUGH WHICH
INFLUENCES THE COLD FRONT REMAINS DISPUTED AMONGST THE MODELS. THE
FRONT WILL ALSO BRING OUR NEXT CHANCES FOR RAIN THURSDAY INTO
FRIDAY.
AVIATION /18Z SATURDAY THROUGH THURSDAY/
18Z TAFS: LIGHT TO MODERATE SHOWERS CONTINUE TO PASS THROUGH THE
CHS/JZI/SAV TERMINALS EARLY THIS AFTERNOON, AND HAVE BEEN SWITCHING
BETWEEN MVFR AND IFR CEILINGS THROUGH THE MAJORITY OF MORNING. THE
MENTION OF THUNDER HAS BEEN REMOVED FROM THE 18Z TAFS AS INSTABILITY
REMAINS RATHER WEAK. EXPECT SHOWERS TO TAPER OFF AFTER 00Z, AND
CONDITIONS TO GRADUALLY IMPROVE TO MVFR AT ALL TERMINALS BETWEEN 00Z-
03Z. THEREAFTER, VFR CONDITIONS WILL PREVAIL THROUGH THE NIGHT AT
ALL TERMINALS AS DRIER AIR FILTERS INTO THE REGION.
EXTENDED AVIATION OUTLOOK: EXPECT IMPROVING CONDITIONS BY EARLY
SUNDAY. OTHERWISE, THERE ARE NO CONCERNS THROUGH WEDNESDAY.
MARINE
THROUGH TONIGHT: AN AREA OF LOW PRESSURE WILL CONTINUE TO STRENGTHEN
ALONG THE STALLED FRONT SITUATED OFFSHORE AND MOVE NORTHEASTWARD
ACROSS THE LOCAL WATERS OVERNIGHT. THIS SET-UP WILL YIELD SCATTERED
TO WIDESPREAD SHOWERS OVER THE ATLANTIC UNTIL LATE THIS EVENING.
EXPECT NORTHEASTERLY WINDS TO RANGE FROM 10 TO 15 KT WITH GUSTS UP
TO 22-23 KT POSSIBLE OVERNIGHT AS THE LOW RACES FURTHER AWAY FROM
THE COASTLINE. SEAS WILL RANGE FROM 2 TO 3 FT IN THE NEARSHORE
WATERS AND 3 TO 5 FT IN THE OFFSHORE WATERS AS NORTHEASTERLY SWELLS
SURGES INTO THE WATERS OVERNIGHT.
SUNDAY THROUGH THURSDAY: SURFACE HIGH PRESSURE BUILDS ACROSS THE
SOUTHEAST REGION ON SUNDAY, BRINGING THE RETURN OF WEAKER WINDS AND
CALM SEAS. AS THE SURFACE HIGH SLIDES OFF INTO THE ATLANTIC MONDAY
INTO TUESDAY, EXPECT WINDS TO SWING AROUND TO BECOME OUT OF THE
SOUTH-SOUTHEAST. AHEAD OF AN APPROACHING COLD FRONT, THE PRESSURE
GRADIENT ALONG THE COAST DOES GET PINCHED A BIT ON TUESDAY AND
WEDNESDAY, LEADING TO SOME MARGINALLY BREEZY SOUTH-SOUTHEASTERLY
WINDS. AS THE COLD FRONT CONTINUES TO APPROACH, SMALL CRAFT
ADVISORIES MAY BE NEEDED AS WIND SPEEDS INCREASE. NBM CURRENTLY HAS
40-70% CHANCES FOR REACHING 25 KNOT GUSTS ACROSS THE COASTAL SOUTH
CAROLINA WATERS, DROPPING TO BELOW 40% ACROSS COASTAL GEORGIA
WATERS.
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...COASTAL FLOOD ADVISORY FROM 7 PM TO 11 PM EDT THIS EVENING FOR
SCZ149-150.
MARINE...NONE.
APT/DENNIS
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