417
FXUS62 KCHS 011106
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
706 AM EDT MON JUN 1 2026
WHAT HAS CHANGED
THE AVIATION SECTION HAS BEEN UPDATED FOR THE 12Z TAF ISSUANCE.
KEY MESSAGES
- 1) LOCALLY HEAVY RAINFALL WILL REMAIN A THREAT FOR PORTIONS
OF SOUTHEAST GEORGIA AND SOUTHEAST SOUTH CAROLINA THROUGH
TUESDAY.
- 2) MINOR COASTAL FLOODING IS POSSIBLE ALONG THE CHARLESTON
AND COLLETON COUNTY COASTLINE WITH THE TUESDAY EVENING HIGH
TIDE.
DISCUSSION
KEY MESSAGE 1: LOCALLY HEAVY RAINFALL WILL REMAIN A THREAT FOR
PORTIONS OF SOUTHEAST GEORGIA AND SOUTHEAST SOUTH CAROLINA
THROUGH TUESDAY.
THROUGH TONIGHT: THE MAIN CONCERN FOR LOCALLY HEAVY RAINFALL
AND PERHAPS AN ISOLATED FLASH FLOOD THREAT WILL COME PRIMARILY
DURING THE EARLY MORNING HOURS. SURFACE ANALYSIS SHOWS A SURFACE
LOW TAKING SHAPE JUST OFF THE GA/SC COAST WHICH WILL THEN
GRADUALLY TRACK TO THE EAST THROUGH DAYBREAK. AS IT DOES, BANDS
OF CONVERGENCE WILL FEED BACK INTO THE COAST WITHIN A VERY MOIST
ENVIRONMENT DEFINED BY PRECIPITABLE WATER VALUES IN EXCESS OF 2
INCHES. HI-RES MODEL GUIDANCE HAS DISPLAYED SOME RUN-TO-RUN
INCONSISTENCY, BUT STILL SEEMS TO FAVOR THE SC COAST AND
SPECIFICALLY THE CHARLESTON COUNTY COAST FOR THE HEAVIEST RAIN
THROUGH SUNRISE. STORM MOTION IS QUITE SLOW AND WHEN COMBINED
WITH WARM CLOUD PROCESSES, RAINFALL EFFICIENCY IS QUITE HIGH.
THE MAIN CONCERN WILL BE FOR URBANIZED AREAS ALONG THE SC COAST,
SPECIFICALLY BEAUFORT AND CHARLESTON. THE THREAT FOR LOCALLY
HEAVY RAINFALL AND FLOODING SHOULD PERSIST THROUGH DAYBREAK AND
THEN COME TO AN END AS THE SURFACE LOW PULLS AWAY TO THE EAST.
FOR THE REST OF THE DAY, GUIDANCE WOULD SUGGEST THAT THERE WON'T
BE TOO MUCH CONVECTIVE COVERAGE AS THE FLOW TURNS OFFSHORE. THE
NEXT BEST CHANCE OF CONVECTION WILL COME DURING THE LATE
EVENING HOURS AS UPSTREAM THUNDERSTORMS ALONG THE COLD FRONT
APPROACHING FROM THE NORTH SHIFT INTO THE AREA. THESE STORMS
SHOULD HAVE ENOUGH MOTION TO PREVENT MUCH OF A FLOOD THREAT.
TUESDAY: THE COLD FRONT SHOULD START THE DAY HAVING CLEARED
SOUTHEAST SC AND CONTINUE TO SINK SOUTHWARD. THIS SHOULD PUT THE
FOCUS FOR AFTERNOON CONVECTIVE COVERAGE ACROSS SOUTHEAST
GEORGIA. FORTUNATELY THIS KEEPS MOST OF THE FORECAST AREA DRY,
BUT WE WILL HAVE TO WATCH THE PROGRESSION OF THE FRONT WITH TIME
AND CONTINUE TO ASSESS THE HEAVY RAIN POTENTIAL ACROSS
SOUTHEAST GEORGIA.
KEY MESSAGE 2: MINOR COASTAL FLOODING IS POSSIBLE ALONG THE
CHARLESTON AND COLLETON COUNTY COASTLINE WITH THE TUESDAY
EVENING HIGH TIDE.
A STRONG SURGE OF NORTHEAST FLOW WILL OCCUR ALONG THE SOUTHEAST
SC COAST ON TUESDAY BEHIND A PASSING COLD FRONT. THIS NORTHEAST
FLOW WILL PRODUCE A SURGE IN TIDE LEVELS, ESPECIALLY AROUND THE
TIME OF THE TUESDAY EVENING HIGH TIDE. THE ASTRONOMICAL TIDE
LEVEL IS 5.5 FT MLLW, SO IT WOULD REQUIRE A RATHER ANOMALOUS 1.5
FT DEPARTURE TO REACH THE MINOR COASTAL FLOOD THRESHOLD OF 7 FT
MLLW. FOR CONTEXT, HISTORICAL ANALYSIS SHOWS THAT A DEPARTURE OF
1.5 FT OR HIGHER HAS ONLY OCCURRED WITH ~7% OF ALL MINOR COASTAL
FLOOD EVENTS ON RECORD. STILL, MINOR COASTAL FLOODING IS
POSSIBLE AND A COASTAL FLOOD ADVISORY COULD BE NEEDED.
AVIATION /12Z MONDAY THROUGH FRIDAY/
KCHS AND KJZI: IFR CEILINGS HAVE ALREADY STARTED TO SCATTER OUT
BUT WE COULD STILL SEE AT LEAST BRIEF PERIODS OF IFR THROUGH
ABOUT MID MORNING. WE SHOULD SEE VFR CONDITIONS RETURN BY AROUND
MIDDAY. THUNDERSTORM COVERAGE THIS AFTERNOON IS EXPECTED TO BE
ISOLATED TO SCATTERED AND CONFIDENCE IN DIRECT IMPACTS IS LOW.
INSTEAD THERE IS A BETTER CHANCE FOR STORMS TO PASS THROUGH FROM
THE NORTH LATE THIS EVENING AS A COLD FRONT APPROACHES THE
AREA. FOR NOW, WE HAVE JUST INCLUDED VCSH FOR THIS EVENING
PERIOD. FINALLY, THERE IS SOME POTENTIAL FOR MVFR OR IFR STRATUS
TO DEVELOP IN THE EARLY TUESDAY MORNING HOURS. CONFIDENCE IS
LOW IN THIS POTENTIAL, BUT CERTAINLY SOMETHING TO CONSIDER WITH
SUBSEQUENT TAF PACKAGES.
KSAV: IFR CEILINGS AND FOG HAVE SETTLED IN THIS MORNING AND
WILL LIKELY TAKE UNTIL MID MORNING TO SCATTER OUT AND IMPROVE.
VFR CONDITIONS AREN'T EXPECTED TO RETURN UNTIL AROUND MIDDAY.
THUNDERSTORM COVERAGE THIS AFTERNOON IS EXPECTED TO BE ISOLATED
TO SCATTERED AND CONFIDENCE IN DIRECT IMPACTS IS LOW. THERE IS
AGAIN POTENTIAL FOR MVFR OR IFR STRATUS TO DEVELOP IN THE EARLY
TUESDAY MORNING HOURS, THOUGH CONFIDENCE IS TOO LOW TO INCLUDE
IN THE FORECAST AT THIS POINT.
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
TODAY THROUGH FRIDAY: NO SIGNIFICANT CONCERNS THROUGH MONDAY
NIGHT. THEN ON TUESDAY A SURGE OF NORTHEAST FLOW WILL SPREAD
ACROSS THE LOCAL WATERS, PEAKING TUESDAY NIGHT. THIS WILL BRING
SOLID SMALL CRAFT ADVISORY CONDITIONS TO ALL WATERS (OUTSIDE
CHARLESTON HARBOR) WITH FREQUENT GUSTS. FURTHERMORE, GUIDANCE
SUGGESTS THERE IS A WINDOW OF TIME EARLY WEDNESDAY MORNING WHEN
GALE FORCE GUSTS WILL BE POSSIBLE AS WELL. NORTHEAST WINDS WILL
REMAIN ELEVATED WEDNESDAY BEFORE TAPERING OFF INTO THURSDAY.
OVERALL, SMALL CRAFT ADVISORIES WILL LIKELY BE NEEDED FOR A TIME
PERIOD FROM TUESDAY MORNING THROUGH THURSDAY MORNING FOR BOTH
WINDS AND SEAS.
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...NONE.
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