955
FXUS62 KCHS 312024
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
424 PM EDT MON MAR 31 2025
SYNOPSIS
SHOWERS AND THUNDERSTORM WILL OCCUR THIS EVENING AHEAD OF A
COLD FRONT. THE FRONT LINGERS NEARBY MID-WEEK, BEFORE STRONGER
HIGH PRESSURE PREVAILS LATE THIS WEEK. ANOTHER COLD FRONT COULD
APPROACH LATER THIS WEEKEND.
NEAR TERM /UNTIL 6 AM TUESDAY MORNING/
LATE AFTERNOON INTO EARLY EVENING: ALOFT, H5 SHORTWAVE ENERGY WILL
QUICKLY MOVE INTO GEORGIA BY MID-AFTERNOON, REACHING SOUTHERN SOUTH
CAROLINA BY EARLY EVENING. AT THE SFC, A STRONG COLD FRONT WILL
CROSS THE APPALACHIAN MOUNTAINS, APPROACHING THE REGION DURING THE
EVENING AND OVERNIGHT, KEEPING THE LOCAL AREA SOLIDLY WITHIN A MOIST
WARM-SECTOR THROUGH EVENING HOURS. WARM AIR ADVECTION ALONG WITH
SUBSTANTIAL BREAKS IN CLOUD COVER HAVE ALREADY ALLOWED TEMPS TO
REACH THE LOW-MID 80S AWAY FROM THE COAST. A SEA BREEZE WILL HELP
MAINTAIN SLIGHTLY COOLER ONSHORE WIND ACROSS COASTAL COMMUNITIES,
WITH TEMPS GENERALLY IN THE LOW-MID 70S.
ENVIRONMENTAL MOISTURE LEVELS AND INSTABILITY HAVE INCREASED LATE
THIS AFTERNOON, WITH PWATS NEAR 1.60-1.80 INCHES AND WARMER SFC
TEMPS LEADING TO AN AXIS OF SBCAPE STRETCHED ACROSS THE LOCAL AREA,
GENERALLY IN THE 2000-3500 J/KG RANGE. THIS COINCIDES WITH 0-6 KM
BULK SHEAR NEAR 20-30 KT, MAINLY SUPPORTIVE OF LOOSELY ORGANIZED
CONVECTIVE ACTIVITY THAT DEVELOPS AN HOUR OR SO PRIOR TO A SQUALL
LINE CURRENTLY MAKING ENTERING SOUTHEAST GEORGIA LATE THIS AFTERNOON
AFTERNOON. MOST GUIDANCE SUGGESTS ACTIVITY AHEAD OF THE MAIN LINE OF
THUNDERSTORMS TO REMAIN SUB-SEVERE. THE BULK OF SHOWERS AND
THUNDERSTORM ACTIVITY IS MORE LIKELY TO OCCUR/CONTINUE IN A SLIGHTLY
MORE SHEARED ENVIRONMENT JUST UPSTREAM (WEST) OF THE LOCAL AREA IN
THE FORM OF A SQUALL LINE, PROGRESSING EAST WITH TIME. BASED ON
LATEST RADAR TRENDS, THIS LINE WILL TRAVERSE INLAND ZONES DURING THE
NEXT FEW HOURS, QUICKLY PROGRESSING TOWARD THE COAST INTO EARLY
EVENING, THEN SHIFTING OFFSHORE BY AROUND 8-9 PM. THUNDERSTORMS
ALONG AND/OR NEAR THE PASSING SQUALL LINE WILL BE CAPABLE OF
BECOMING STRONG AND/OR SEVERE, WITH GREATEST IMPACTS LIKELY TO OCCUR
AWAY FROM THE COAST WHERE INSTABILITY REMAINS STRONGER BEFORE
SUNSET.
THE OVERALL ENVIRONMENT REMAINS MOST CONDUCIVE FOR DAMAGING WIND AS
THE LINE OF THUNDERSTORMS MAKES A FASTER PUSH TOWARD THE COAST
WITHIN AN ENVIRONMENT INDICATING STRONG LOW-LVL WIND FIELDS (AT LEAST
40 KT) AND MODEST DCAPE AND LOW-LVL LAPSE RATES. THE TORNADO RISK
REMAINS LOW WITH SOUNDINGS DISPLAYING UNIDIRECTIONAL WIND PROFILES,
BUT A BRIEF SPIN-UP CANNOT BE RULED OUT INLAND IF ANY REAR-INFLOW
JETS DEVELOP NEAR CONVECTION, ORIENTING PARTS OF THE QLCS IN A MORE
NORTHWEST TO SOUTHEAST FASHION (LINE NORMAL BULK SHEAR). THE LATEST
HREF ENSEMBLE HAS NOTICEABLY DECREASED 2-5 UPDRAFT HELICITIES ACROSS
THE AREA, SUGGESTING A VERY LIMITED TORNADO RISK AS WELL. THE RISK
FOR HAIL REMAINS LOW AS WELL, WITH PERHAPS A FEW STORMS CAPABLE OF
MARGINALLY SEVERE HAIL (1 INCH), BUT OVERALL THE ENVIRONMENT IS NOT
CONDUCIVE FOR SOMETHING MORE SIGNIFICANT. A SEVERE THUNDERSTORM
WATCH IS NOW IN EFFECT FOR ALL AREAS UNTIL 9 PM, INCLUDING FOR
NEARSHORE COASTAL WATERS.
GIVEN THE PROGRESSIVE NATURE OF THE SQUALL LINE, RAINFALL
AMOUNTS WILL BE ON THE ORDER OF 1/3 TO 2/3 INCHES, BUT WITH
LOCALLY HIGHER AMOUNTS APPROACHING 1 INCH OVER A SHORT PERIOD OF
TIME DURING THUNDERSTORMS. FORTUNATELY THE HIGH TIDE OCCURS
AFTER THE SQUALL LINE PASSES OFFSHORE.
LATE EVENING AND OVERNIGHT: THE TRAILING COLD FRONT IS NOT EXPECTED
TO REACH THE LOCAL AREA UNTIL LATE NIGHT, ALLOWING A FEW ADDITIONAL
SHOWERS TO PERSIST ACROSS THE LOCAL AREA UNTIL FROPA OCCURS.
SKIES SHOULD ALSO BEGIN TO CLEAR OUT LATE AND WITH RECENT RAINS/WET
GROUNDS, PATCHY FOG REMAINS A POSSIBILITY UNTIL AROUND DAYBREAK.
LOW TEMPS SHOULD GENERALLY RANGE IN THE MID 50S INLAND TO LOWER
60S CLOSER TO THE COAST.
SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/
AS A COLD FRONT DEPARTS OFFSHORE, CANADIAN HIGH PRESSURE SPREADING
SOUTH INTO THE MIDWEST WILL GRADUALLY FILTER INTO THE SOUTHEAST
TUESDAY. SURFACE HIGH PRESSURE WILL THEN CONTINUE TO BUILD ACROSS
THE FORECAST AREA THROUGH THE PERIOD AS THE CENTER SHIFTS OVER THE
NEW ENGLAND REGION AND EVENTUALLY OVER THE CENTRAL ATLANTIC.
SIMULTANEOUSLY, AN UPPER RIDGE WILL SET UP EAST OF THE FLORIDA
PENINSULA ALLOWING FOR WARMING TEMPERATURES EACH DAY. SKIES WILL
BECOME MOSTLY CLEAR TUESDAY AFTERNOON BEHIND THE FROPA WITH SOME
ADDITIONAL CLOUDS DEVELOPING FOR WEDNESDAY AND THURSDAY. VERY WEAK
SIGNALS OF SHORTWAVE ACTIVITY ALOFT COMBINED WITH MOISTURE PRESENT
WEDNESDAY COULD RESULT IN AN ISOLATED SHOWER OR THUNDERSTORM, MAINLY
FOR INLAND COUNTIES. OTHERWISE, THE FORECAST WILL BE RAIN-FREE
THROUGH THE PERIOD.
THE HIGHLIGHT OF THE FORECAST THIS WEEK WILL BE THE ABOVE NORMAL,
POSSIBLY RECORD-BREAKING TEMPERATURES (SEE CLIMATE SECTION BELOW).
NO REAL SEMBLANCE OF ANY COLD AIR ADVECTION IN THE WAKE OF THE FRONT
WILL QUICKLY SHIFT TO WAA AS FLOW SHIFTS OUT OF THE SOUTH TUESDAY
NIGHT. ALSO, TRENDS SHOW A CONTINUED PATTERN OF HIGHER THAN "NORMAL"
GEOPOTENTIAL HEIGHTS AS WE NEAR THE LATTER HALF OF THE WEEK. HIGHS
WILL REACH THE UPPER 70S TO LOW 80S ACROSS SOUTHEAST SOUTH CAROLINA
AND LOW TO MID 80S ACROSS SOUTHEAST GEORGIA TUESDAY AND A COUPLE OF
DEGREES WARMER FORECAST FOR WEDNESDAY. BY THURSDAY, MID TO UPPER 80S
ARE FORECAST EVERYWHERE WITHIN THE FORECAST AREA WITH THE EXCEPTION
OF THE IMMEDIATE COAST WHERE UPPER 70S ARE EXPECTED. IT IS POSSIBLE
SOME LOCATIONS, ESPECIALLY ACROSS INTERIOR SOUTHEAST GEORGIA, COULD
HIT THE 90 DEGREE MARK. ONSHORE FLOW WILL HELP PROMOTE A PROGRESSIVE
SEA BREEZE EACH DAY WHICH WILL AID IN COOLING AT LEAST THE COASTAL
COMMUNITIES PRIOR TO SUNSET. LOWS IN THE UPPER 50S TUESDAY NIGHT
WILL JUMP TO THE MID 60S FOR WEDNESDAY NIGHT.
LONG TERM /THURSDAY NIGHT THROUGH MONDAY/
THE LONG TERM CONTINUES TO REMAIN LARGELY WARM AND DRY AS A STRONG
UPPER LEVEL RIDGE REMAINS IN PLACE JUST OFF TO OUR SOUTH. HIGHS IN
THE MID TO UPPER 80S WILL BE COMMON THROUGH THE WEEKEND, WITH
ISOLATED LOCATIONS PEAKING IN THE LOWER 90S. A STRONG UPPER LEVEL
WAVE MOVING OUT OF THE ONTARIO PROVIDENCE SUNDAY INTO MONDAY
ACCOMPANIED BY A SURFACE HIGH PRESSURE MOVING INTO THE CENTRAL
PLAINS WILL SEND A COLD FRONT TOWARDS THE REGION LATER THIS WEEKEND
INTO EARLY NEXT WEEK. SCATTERED SHOWERS ARE EXPECTED PRIOR TO THE
FRONTAL PASSAGE, WITH COOLER TEMPERATURES FORECAST FOR MONDAY IN THE
LOWER/MID 70S.
AVIATION /20Z MONDAY THROUGH SATURDAY/
MVFR CIGS ARE POSSIBLE AT CHS/JZI THROUGH ABOUT 19Z MONDAY, BUT
EXPECT A FEW HOURS OF VFR AT CHS/JZI AND SAV TERMINALS PRIOR TO
SHOWER AND THUNDERSTORMS ARRIVING FROM THE WEST LATE AFTERNOON.
TEMPO MVFR CIGS/VSBYS (AND PERHAPS LOWER) REMAIN IN THE FORECAST
FROM ROUGHLY 22Z TO 01-02Z THIS EVENING WITH A LINE OF THUNDERSTORMS
IMPACTING ALL TERMINALS. GUSTY WINDS UPWARDS TO 25-30 KT ARE
ALSO POSSIBLE WITH THUNDERSTORMS. CIGS WILL LOWER TO MINIMUM
MVFR (AND POSSIBLY IFR) LEVELS AT ALL TERMINALS BETWEEN 07-15Z
TUESDAY, BEFORE IMPROVING BY AROUND DAYBREAK POST FROPA, AND
EVENTUALLY TO VFR BY MID-LATE MORNING TUESDAY.
EXTENDED AVIATION OUTLOOK: ASIDE FROM POSSIBLE LOW CEILINGS WITH ANY
ISOLATED SHOWER ACTIVITY ON WEDNESDAY, GENERALLY NO CONCERNS FOR
FLIGHT RESTRICTIONS THROUGH THE WEEK.
MARINE
LATE AFTERNOON AND TONIGHT: THE LOCAL AREA WILL REMAIN POSITIONED
ALONG THE WESTERN PERIPHERY OF HIGH PRESSURE CENTERED EAST OF
BERMUDA WHILE A STRONG COLD FRONT MOVES INTO THE SOUTHEAST THIS
EVENING, AND MOVES ACROSS THE LOCAL WATERS LATE NIGHT. SOUTH/SOUTHWEST
WINDS AROUND 10-15 KT WITH SOME GUSTS UP TO 20 KT ARE POSSIBLE
ACROSS THE CHARLESTON HARBOR AND NEARBY COASTAL WATERS. SEAS WILL
GENERALLY RANGE BETWEEN 3-5 FT, LARGEST NEAR 20 NM AND FARTHER
OFFSHORE ACROSS OUTER GEORGIA WATERS.
THE BIGGEST CONCERN FOR MARINERS WILL BE STRONG AND SEVERE T-STORMS
THAT OCCUR WITH A LINE OF THUNDERSTORMS PUSHING OFFSHORE EARLY THIS
EVENING, GENERALLY IMPACTING LOCAL WATERS AROUND 6-10 PM. DAMAGING
WIND GUSTS IN EXCESS OF 40 OR EVEN 50 KT CAN OCCUR, ALONG WITH
FREQUENT LIGHTNING STRIKES AND BRIEF VERY HEAVY RAINS THAT REDUCE
VISIBILITIES UNDER 1 NM AT TIMES. A SEVERE THUNDERSTORM WATCH IS
CURRENTLY IN PLACE FOR ALL NEARSHORE WATERS, INCLUDING THE
CHARLESTON HARBOR, AND SPECIAL MARINE WARNINGS WILL LIKELY BE NEEDED
DURING THIS TIME.
TUESDAY THROUGH SATURDAY: SURFACE HIGH PRESSURE WILL BUILD IN FROM
THE NORTH AS A COLD FRONT PUSHES OFFSHORE TUESDAY, WITH GENERALLY NO
MARINE CONCERNS EXPECTED THROUGH THE END OF THE WEEK. THERE IS A
SMALL CHANCE SOME PATCHY FOG OVER THE COASTAL NEARSHORE WATERS COULD
REMAIN/DEVELOP BEHIND ANY LINGERING SHOWERS EARLY TUESDAY
MORNING.
CLIMATE
RECORD HIGH TEMPERATURES:
APRIL 4:
KSAV: 91/1963
APRIL 5:
KCHS: 89/1978
KSAV: 90/1988
APRIL 6:
KCHS: 90/1967
KSAV: 90/1967
RECORD HIGH MINIMUM TEMPERATURES:
MARCH 31:
KCXM: 68/1938
APRIL 2:
KCHS: 65/2012
APRIL 3:
KCHS: 67/2012
KCXM: 68/2012
KSAV: 68/2012
APRIL 4:
KCHS: 70/1974
KCXM: 69/1974
KSAV: 69/1974
APRIL 5:
KCHS: 65/2017
KCXM: 67/2023
KSAV: 66/1957
APRIL 6:
KSAV: 68/2023
EQUIPMENT
THE KCLX RADAR REMAINS OFFLINE FOR DOME MAINTENANCE THROUGH
APRIL 1, 2025. RADAR DATA WILL NOT BE AVAILABLE DURING THIS
TIME. USERS ARE URGED TO USE ADJACENT WSR-88D SITES WHICH ALSO
COVER MUCH OF SOUTHEAST SOUTH CAROLINA, SOUTHEAST GEORGIA AND
THE ADJACENT COASTAL WATERS. THESE INCLUDE:
KCAE - COLUMBIA, SC
KLTX - WILMINGTON, NC
KJAX - JACKSONVILLE, FL
KJGX - ROBBINS AFB, GA
KVAX - MOODY AFB, GA (MAY ALSO BE UNAVAILABLE DUE TO
MAINTENANCE)
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...NONE.
NEAR TERM...DPB
SHORT TERM...BRS
LONG TERM...BRS
AVIATION...BRS/DPB
MARINE...BRS/DPB
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