188
FXUS62 KCHS 312335
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
735 PM EDT SUN MAY 31 2026
WHAT HAS CHANGED
KEY MESSAGE 1 WAS UPDATED.
KEY MESSAGES
- 1) LOCALLY HEAVY RAINFALL AND ISOLATED FLASH FLOODING REMAINS
POSSIBLE THROUGH THIS EVENING, ESPECIALLY ACROSS SOUTHEAST
GEORGIA. THE RISK FOR HEAVY RAINFALL AND FLOODING COULD SPREAD
ALONG PARTS OF THE LOWER SOUTH CAROLINA COAST, INCLUDING THE
CHARLESTON METRO AREA, EARLY MONDAY MORNING.
- 2) A LOW-END THREAT FOR LOCALIZED MINOR FLOODING CONTINUES
THROUGH TUESDAY AS A STALLED FRONT AND AN APPROACHING COLD
FRONT SUPPORT DAILY SHOWERS AND THUNDERSTORMS.
- 3) MINOR COASTAL FLOODING IS POSSIBLE ALONG THE CHARLESTON AND
COLLETON COUNTY COASTLINES THIS EVENING AND TUESDAY EVENING.
DISCUSSION
KEY MESSAGE 1: LOCALLY HEAVY RAINFALL AND ISOLATED FLASH
FLOODING REMAINS POSSIBLE THROUGH THIS EVENING, ESPECIALLY
ACROSS SOUTHEAST GEORGIA. THE RISK FOR HEAVY RAINFALL AND
FLOODING COULD SPREAD ALONG PARTS OF THE LOWER SOUTH CAROLINA
COAST, INCLUDING THE CHARLESTON METRO AREA, EARLY MONDAY
MORNING.
31/21Z SURFACE ANALYSIS SHOWED COLD AIR DAMMING HAS NOW SPREAD
SOUTH OF THE ALTAMAHA RIVER, BEING REINFORCED BY ONGOING LIGHT
TO MODERATE RAINS FALLING ACROSS MUCH OF THE SOUTH CAROLINA
LOWCOUNTRY AND SOUTHEAST GEORGIA. THERE REMAINS SOME WEAK
INSTABILITY ACROSS SOUTHEAST GEORGIA INTO FAR SOUTHERN SOUTH
CAROLINA PER THE LATEST INSTABILITY MESO PLOTS, BUT THE RISK FOR
DEEP CONVECTION HAS MOSTLY ENDED. THERE REMAINS A HEAVY
RAINFALL THREAT THROUGH THE NIGHT WITH WARM CLOUD PROCESSES
LIKELY DOMINATING WHERE POCKETS OF DEEPER MOISTURE AND SOME
INSTABILITY COULD HELP TO LOCALLY ENHANCED SOME RAINFALL RATES,
BUT ANY RISK FOR FLASH FLOODING SHOULD REMAIN FAIRLY ISOLATED.
CYCLOGENESIS IS EXPECTED TO INITIATE NEAR THE GEORGIA AND FAR
SOUTHERN SOUTH CAROLINA COAST LATER TONIGHT. THE DEVELOPING LOW
IS FORECAST TO PASS EAST OF THE CHARLESTON COUNTY COAST BY
DAYBREAK MONDAY. THE COASTAL FRONT OFFSHORE AND ITS ASSOCIATED
SURFACE-BASED INSTABILITY COULD MAKE A BRIEF RUN FOR PARTS OF
THE LOWER SOUTH CAROLINA COAST DURING THE EARLY MORNING HOURS
AS THE LOW BEGINS TO ORGANIZE, BUT SHOULD NOT MAKE TOO MUCH
PROGRESSION INLAND (LIKELY NO FARTHER INLAND THAN US-17 AT BEST).
CONVECTION IS EXPECTED TO BLOSSOM OVER PARTS OF THE SOUTH
CAROLINA COAST, INCLUDING THE PARTS OF THE CHARLESTON TRI-
COUNTY REGION, LATE TONIGHT AS THE LOW ORGANIZES AND LOW-LEVEL
CONVERGENCE NEAR THE COASTAL FRONT INCREASES. A HEAVY
RAIN/FLOODING THREAT COULD DEVELOP IN THIS REGION FOR A FEW
HOURS WITH POSSIBLY A SOMEWHAT ELEVATED RISK FOR DOWNTOWN
CHARLESTON IF HOURLY RAINFALL RATES ARE HIGH ENOUGH.
GRIDS AND TEXT PRODUCTS WERE UPDATED TO REFLECT NEAR TERM TRENDS
AND BETTER RESOLVE THE COASTAL FRONT AND TRACK OF THE LOW
OVERNIGHT.
KEY MESSAGE 2: A LOW-END THREAT FOR LOCALIZED MINOR FLOODING
CONTINUES THROUGH TUESDAY AS A STALLED FRONT AND AN APPROACHING
COLD FRONT SUPPORT DAILY SHOWERS AND THUNDERSTORMS.
A STALLED FRONT WILL LINGER ACROSS THE FORECAST AREA THROUGH
MONDAY, INTERACTING WITH A MOIST AIRMASS CHARACTERIZED BY PWAT
VALUES OF 1.6-1.9 INCHES. THIS WILL MAINTAIN AN UNSETTLED
PATTERN WITH SCATTERED TO NUMEROUS SHOWERS AND A FEW EMBEDDED
THUNDERSTORMS. THE MEANDERING FRONT DRAPED ALONG THE SC COAST
AND SOUTHERN GEORGIA ALONG WITH A WEAK AREA OF LOW PRESSURE
DEVELOPING OFF THE SC COAST WILL FOCUS THE GREATEST RAINFALL
POTENTIAL ACROSS COASTAL AREAS OF SOUTHEAST SOUTH CAROLINA.
TUESDAY, AN APPROACHING COLD FRONT FROM THE NORTH WILL SLOWLY
DROP THROUGH THE AREA, PROVIDING CONTINUED SUPPORT FOR SCATTERED
CONVECTION. AS A RESULT, SHOWER AND THUNDERSTORM COVERAGE
SHOULD BEGIN TO DECREASE FROM NORTH TO SOUTH TUESDAY EVENING,
WITH THE GREATEST RAINFALL POTENTIAL SHIFTING TOWARD SOUTHEAST
GEORGIA AND AREAS ALONG AND SOUTH OF I-16 AHEAD OF THE FRONT.
ALTHOUGH CONVECTION WILL REMAIN SOMEWHAT DISORGANIZED, SLOW
STORM MOTIONS AND LOCALIZED TRAINING COULD RESULT IN POCKETS OF
REPEATED RAINFALL. GIVEN THE MODEST RAINFALL AMOUNTS, THE
OVERALL FLOOD THREAT REMAINS ON THE LOWER END. FOR MONDAY, THE
LATEST NBM INDICATES A 30-60% CHANCE OF EXCEEDING 1 INCH WITH
THE GREATER CHANCES OCCURRING ACROSS COASTAL SOUTH CAROLINA.
ADDITIONALLY, THERE IS A 15-30% CHANCE OF RAINFALL EXCEEDING 1
INCH ACROSS PORTIONS OF THE AREA FOR TUESDAY. URBAN AND LOW-
LYING AREAS, AND THOSE LOCATIONS THAT RECEIVED 5+ INCHES OF RAIN
OVER THE WEEKEND, MAY BE MORE SUSCEPTIBLE TO MINOR FLOODING IF
ADDITIONAL SHOWERS SET UP OVER THE AREA.
KEY MESSAGE 3: MINOR COASTAL FLOODING IS POSSIBLE ALONG THE
CHARLESTON AND COLLETON COUNTY COASTLINES THIS EVENING AND
TUESDAY EVENING.
TIDES IN THE CHARLESTON HARBOR ARE EXPECTED TO PEAK 7.0-7.1 FT
MLLW THIS EVENING. A COASTAL FLOOD ADVISORY HAS BEEN ISSUED
UNTIL 11 AM FOR CHARLESTON AND COASTAL COLLETON.
GUSTY EAST-NORTHEASTERLY WINDS ARE CAUSING ELEVATED TIDAL
DEPARTURES FOR THIS EVENING'S HIGH TIDE (9:05 PM). THE TWL
FORECAST IS 7.0 FT MLLW, WHICH WOULD RESULT IN BRIEF, MINOR
COASTAL FLOODING IN THE USUAL FLOOD PRONE AREAS ACROSS
CHARLESTON AND COASTAL COLLETON COUNTIES. ALSO, IF SHOWERS AND
THUNDERSTORMS TRACK OVER THE REGION AROUND THE TIME OF HIGH
TIDE, THEN FLOODING COULD BE EXACERBATED.
ANOTHER SURGE OF NORTHEASTERLY WINDS COULD GENERATE MINOR
COASTAL FLOODING FOR THESE SAME LOCATIONS TUESDAY EVENING.
AVIATION /00Z MONDAY THROUGH FRIDAY/
01/00Z TAF DISCUSSION:
KCHS/KJZI: SHOWERS WILL LINGER AT BOTH TERMINALS THIS EVENING
BEFORE PICKING UP IN COVERAGE AND INTENSITY OVERNIGHT AS WEAK
LOW PRESSURE DEVELOP AND PASSES JUST OFFSHORE. THE COASTAL FRONT
MAY MOVE CLOSE ENOUGH TO KJZI TO ALLOW FOR A FEW TSTMS TO
DEVELOP, SO TSRA WAS INTRODUCED ROUGHLY 05-08Z TO ACCOUNT FOR
THIS. NO TSTMS WERE INCLUDED AT KCHS FOR NOW. ACTIVITY SHOULD
GRADUALLY WIND DOWN AFTER DAYBREAK AS LOW PRESSURE MOVES FARTHER
OFFSHORE, ALTHOUGH SOME WRAP AROUND SHOWER ACTIVITY MAY LINGER
THROUGH MID-MORNING. IFR CIGS ARE EXPECTED TO DEVELOP
OVERNIGHT, BUT BASES SHOULD REMAIN JUST ABOVE ALTERNATE
MINIMUMS, ALTHOUGH IT COULD BE CLOSE AT TIMES. CLOUDS SHOULD
LIFT AND SCATTER OUT DURING THE DAY WITH VFR RETURNING BY EARLY
AFTERNOON.
KSAV: SHOWER ACTIVITY SHOULD DIMINISH BY MID-EVENING.
WIDESPREAD IFR AND LIFR CIGS ARE EXPECTED TO EXPAND ACROSS MUCH
OF THE REGION TONIGHT, IMPACTING THE TERMINAL FOR MUCH OF THE
OVERNIGHT PERIOD. CIGS ARE EXPECTED TO BOTTOM OUT BELOW
ALTERNATE MINIMUMS, BUT STAY ABOVE AIRFIELD MINIMUMS 07-11Z.
SOME OF THE STRATUS COULD BUILD-DOWN TO PRODUCT SOME LIGHT FOG,
BUT VSBYS WERE LIMITED TO 5SM FOR NOW. CLOUDS SHOULD LIFT AND
SCATTER OUT DURING THE DAY WITH VFR RETURNING BY EARLY
AFTERNOON.
EXTENDED AVIATION OUTLOOK: PERIODIC FLIGHT RESTRICTIONS ARE
POSSIBLE THROUGH TUESDAY DUE TO SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS. PATCHY OVERNIGHT FOG AND/OR LOW STRATUS ARE ALSO
POSSIBLE.
MARINE
TONIGHT: THE SMALL CRAFT ADVISORIES FOR THE SOUTH CAROLINA
NEARSHORE WATERS WILL BE ALLOWED TO EXPIRE.
MONDAY THROUGH FRIDAY: TRANSIENT BENIGN MARINE CONDITIONS ON MONDAY
WILL BEGIN TO DETERIORATE TUESDAY MORNING. A WEAK AREA OF LOW
PRESSURE COULD DEVELOP OFFSHORE ON MONDAY BEFORE MOVING FARTHER INTO
THE ATLANTIC. MEANWHILE, STRENGTHENING HIGH PRESSURE TO THE NORTH
WILL CAUSE NORTHEASTERLY WINDS TO SURGE TUESDAY THROUGH WEDNESDAY
NIGHT. WINDS ARE EXPECTED TO RANGE FROM 20 TO 25 KT WITH GUSTS
AROUND 30 KT ACROSS THE WATERS. A BRIEF PERIOD OF GUSTS UP TO 35 KT
IS POSSIBLE WEDNESDAY MORNING ACROSS THE WATERS 20 TO 60 NM
OFFSHORE. SMALL CRAFT ADVISORY CONDITIONS APPEAR LIKELY, WITH A LOW-
END CHANCE FOR GALE CONDITIONS. STRONG EAST-NORTHEASTERLY SWELL WILL
ALSO BUILD INTO THE LOCAL WATERS TUESDAY EVENING, WITH SEAS PEAKING
WEDNESDAY AT 5 TO 7 FT IN THE NEARSHORE WATERS AND 7 TO 9 FT IN THE
OFFSHORE WATERS.
MARINE CONDITIONS ARE EXPECTED TO GRADUALLY IMPROVE WEDNESDAY NIGHT
INTO THURSDAY AS THE LOW MOVES FARTHER OUT INTO THE ATLANTIC. NO
ADDITIONAL MARINE CONCERNS ARE ANTICIPATED THROUGH THE REMAINDER OF
THE PERIOD.
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...COASTAL FLOOD ADVISORY UNTIL 11 PM EDT THIS EVENING FOR SCZ149-
150.
MARINE...NONE.
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