121
FXUS62 KCHS 311835
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
235 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 /THROUGH TONIGHT/
THIS 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 LATE DAY, APPROACHING THE REGION
DURING THE EVENING AND OVERNIGHT, KEEPING THE LOCAL AREA SOLIDLY
WITHIN A MOIST WARM-SECTOR THROUGHOUT THE DAY AND EARLY EVENING
HOURS. WARM AIR ADVECTION ALONG WITH SUBSTANTIAL BREAKS IN CLOUD
COVER HAVE ALREADY ALLOWED TEMPS TO REACH THE UPPER 70S/AROUND 80
ACROSS MANY PARTS OF THE AREA, AND SHOULD WARM A FEW MORE DEGREES
LEADING TO HIGHS IN THE LOW-MID 80S AWAY FROM THE COAST. NEAR
COASTAL COMMUNITIES, A SEA BREEZE WILL HELP PRODUCE AN ONSHORE FLOW
OFF COOLER WATERS, LIMITING HIGH TEMPS TO THE LOW-MID 70S.
ENVIRONMENTAL MOISTURE LEVELS AND INSTABILITY WILL CONTINUE TO
INCREASE HEADING INTO MID AFTERNOON, WITH PWATS APPROACHING 1.60-
1.80 INCHES AND WARMER SFC TEMPS LEADING TO AN AXIS OF SBCAPE
STRETCHED ACROSS THE LOCAL AREA, GENERALLY IN THE 2000-3000 J/KG
RANGE. THIS COINCIDES WITH 0-6 KM BULK SHEAR NEAR 25-30 KT, MAINLY
SUPPORTIVE OF LOOSELY ORGANIZED CONVECTIVE ACTIVITY THAT DEVELOPS A
FEW HOURS PRIOR OF A SQUALL LINE CURRENTLY MAKING WAY ACROSS GEORGIA
EARLY THIS AFTERNOON. HOWEVER, MOST GUIDANCE SUGGESTS THIS TO BE A
VERY LIMITED IN REGARDS TO SEVERE WEATHER POTENTIAL THROUGH ABOUT 4
PM. 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 SHOULD
ARRIVE ACROSS WESTERN MOST ZONES AROUND 4 PM AND QUICKLY PROGRESS
TOWARD THE COAST LATE AFTERNOON INTO EARLY EVENING, 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 HEADING INTO EVENING
HOURS.
THE OVERALL ENVIRONMENT REMAINS MOST CONDUCIVE FOR DAMAGING WIND AS
THE LINE OF THUNDERSTORMS MAKES A FASTER PUSH TOWARD THE COAST
WITHIN AN ENVIRONMENT DISPLAYING 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, BUT THE OVERALL THE ENVIRONMENT IS NOT CONDUCIVE FOR
SOMETHING MORE SIGNIFICANT. A CONVECTIVE WATCH COULD EVENTUALLY
BE NEEDED LATER THIS AFTERNOON.
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. FORTUNATELY THE HIGH TIDE OCCURS AFTER
THE SQUALL LINE PASSES OFFSHORE.
FOR THE REST OF THE NIGHT, SINCE THE TRAILING COLD FRONT DOESN'T
MOVE IN UNTIL OVERNIGHT, A FEW MORE SHOWERS WILL BE POSSIBLE. PATCHY
FOG WILL LIKELY FORM DUE TO SOME CLEARING OF THE SKIES, LIGHT WINDS,
AND THE WET GROUNDS. LOWS WILL GENERALLY BE ONLY DOWN INTO THE UPPER
50S AND LOWER 60S.
SHORT TERM /TUESDAY THROUGH THURSDAY/
TUESDAY: PATCHY FOG ERODES AFTER SUNRISE, THOUGH IT MAY LINGER
A TOUCH LONGER FOR THOSE ALONG THE COAST. A SURFACE HIGH
PRESSURE BUILDS IN FROM THE NORTH THROUGHOUT THE DAY, WITH UPPER
LEVEL RIDGING TAKING PLACE ALOFT. THIS WILL RESULT IN HIGHS
ONLY A COUPLE DEGREES COOLER DESPITE THE RECENT FROPA, WITH
AFTERNOON HIGHS IN THE UPPER 70S TO LOWER 80S.
WEDNESDAY: UPPER LEVEL RIDGING STARTS TO STRENGTHEN THROUGHOUT THE
DAY, WHICH IN COMBINATION WITH WARM AIR ADVECTION (WAA) IN THE MID-
LEVELS WILL RESULT IN AFTERNOON HIGHS IN THE LOWER TO UPPER 80S
ACROSS THE REGION, CLOSER TO THE MID/UPPER 70S ALONG THE COAST. THE
WAA AND MOISTURE IN THE MID-LEVELS WILL RESULT IN PARTLY TO MOSTLY
CLOUDY SKIES THROUGHOUT THE DAY. CAN'T RULE OUT A FEW SCATTERED
SHOWERS AS WELL, THOUGH RAINFALL AMOUNTS WILL REMAIN ON THE LOW SIDE
(< 0.05").
THURSDAY: AS UPPER LEVEL RIDGING CONTINUES ON THURSDAY, WITH
SITUATIONAL AWARENESS TABLES SHOWING RECORD HIGH 500 HPA
GEOPOTENTIAL HEIGHTS OCCURRING IN RELATION TO 30-YEAR NORMALS,
WARM/HOT TEMPERATURES ARE EXPECTED. THE NBM CONTINUES TO WARM-UP
TOWARDS THE 50TH PERCENTILE, AND WITH THE AFOREMENTIONED
SIGNALS IN THE ENSEMBLES, DID MIX IN SOME TEMPERATURES NEAR THE
75TH PERCENTILE OF GUIDANCE, RESULTING IN AFTERNOON HIGHS IN THE
LOWER TO UPPER 80S FOR INLAND AREAS, AND MID 70S TO LOWER 80S
ALONG THE COAST. CAN'T RULE OUT SOME 90 DEGREE TEMPERATURES, AS
NBM PROBABILITIES SHOW 40-60% CHANCES ACROSS INLAND SC COUNTIES,
REACHING UP INTO THE 60-80% RANGE FOR INLAND GA COUNTIES. THE
GOOD NEWS IS THE AFTERNOON SEA-BREEZE WILL BE COMING ASHORE IN
THE MID/LATE AFTERNOON HOURS, WHICH WILL HELP COOL THE REGION
BACK DOWN AGAIN.
LONG TERM /THURSDAY NIGHT THROUGH MONDAY/
THE LONG TERM CONTINUES TO REMAIN LARGELY WARM AND DRY AS A STRONG
UPPER LEVEL RIDGE SETS UP JUST OFF TO OUR SOUTH. ACCORDING TO THE
SITUATIONAL AWARENESS DISPLAYS, 1000 HPA TEMPERATURE ARE ALL IN THE
90+ PERCENTILE COMPARED TO 30-YEAR NORMALS, WITH 850 HPA
TEMPERATURES AT THE MAX OF 30-YEAR NORMALS AT TIMES...FROM BOTH THE
NAEFS AND ECMWF. THE EURO EFI IS ALSO COMING IN WARM, WITH A COUPLE
SHIFT OF TAILS BEING NOTED AS WELL. SO, EXPECT WELL ABOVE NORMAL
TEMPERATURES THURSDAY THROUGH SATURDAY, WITH DAILY CHANCES FOR
REACHING 90+ DEGREES HIGHEST (70-90% CHANCES) FOR AREAS WELL WEST OF
THE I-95 CORRIDOR, WHILE ALSO INCLUDING THE NORTHERN HALF OF
BERKELEY AND DORCHESTER COUNTIES IN SC. RECORD HIGH DAILY MAXIMUMS
MAY OCCUR, THOUGH THE CURRENT FORECAST FALLS ABOUT 1-2 DEGREES SHY
FRIDAY-SUNDAY AT THE CLIMATE SITES. RECORD HIGH DAILY MINIMUMS ALSO
MAY OCCUR, WITH THE CURRENT FORECAST WITHIN 2-3 DEGREES THURSDAY-
SATURDAY, AND IS GOING TO BE LARGELY DEPENDENT ON THE STRENGTH OF
THE AFTERNOON SEA-BREEZE.
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
SOMETIME SUNDAY/MONDAY. SCATTERED SHOWERS ARE EXPECTED PRIOR TO THE
FRONTAL PASSAGE, WITH CURRENT FORECASTED HIGHS ON MONDAY IN THE
LOWER/MID 70S.
AVIATION /19Z 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 THUNDERTORMS
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: FLIGHT RESTRICTIONS CONTINUE TO REMAIN
POSSIBLE TUESDAY MORNING DUE TO BOTH SEA AND LAND FOG, WITH MVFR/IFR
VSBYS POSSIBLE. AFTER THAT, ASIDE FROM POSSIBLE LOW CEILINGS
WITH ANY ISOLATED SHOWER ACTIVITY ON WEDNESDAY, GENERALLY QUIET
AVIATION CONDITIONS ARE EXPECTED.
MARINE
THIS 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 INTO OR NEAR THE LOCAL WATERS
DURING THE NIGHT. SOUTH/SOUTHWEST WINDS AROUND 15 KT OR LESS
WILL OCCUR DURING THIS TIME, WITH SOME GUSTS UP TO 20 KT ACROSS
THE CHARLESTON HARBOR THIS AFTERNOON AS A SEA BREEZE OCCURS.
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 THE SQUALL LINE, AS IT IMPACTS THE 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. SPECIAL
MARINE WARNINGS WILL LIKELY BE NEEDED DURING THIS TIME.
TUESDAY: PATCHY FOG WILL LIKELY LINGER/DEVELOP BEHIND THE EXITING
SHOWERS, WITH PERIODS OF WEAK AND VARIABLE WINDS ALLOWING FOR
CONVERGENCE OF HIGHER SURFACE MOISTURE.
WEDNESDAY-FRIDAY: SURFACE HIGH PRESSURE BUILDS IN FROM THE NORTH,
WITH GENERALLY QUIET MARINE CONDITIONS FORECASTED THROUGH THE END OF
THE WEEK, WITH WINDS AROUND 10 KNOTS AND SEAS AVERAGING 3 TO 4 FT.
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...
LONG TERM...
AVIATION...DPB
MARINE...DPB
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