447
FXUS62 KCHS 302027
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
427 PM EDT SUN MAR 30 2025
SYNOPSIS
RAIN AND THUNDERSTORM CHANCES CONTINUE THIS AFTERNOON AND AGAIN
MONDAY AHEAD OF AN APPROACHING COLD FRONT. THE FRONT COULD
LINGER NEARBY MID-WEEK, BEFORE STRONGER HIGH PRESSURE PREVAILS
LATE THIS WEEK.
NEAR TERM /UNTIL 6 AM MONDAY MORNING/
LATE AFTERNOON INTO EARLY EVENING: ALOFT, H5 SHORTWAVE ENERGY WILL
CONTINUE TO TRAVERSE THE LOCAL AREA WITHIN A WEST/SOUTHWEST FLOW. AT
THE SFC, WEAK COASTAL TROUGHING WILL SLIDE ALONG THE WESTERN
PERIPHERY OF AN ATLANTIC HIGH CENTERED WELL OFFSHORE. FORCING
ASSOCIATED WITH THE H5 SHORTWAVE, ISENTROPIC LIFT, AND THE COASTAL
TROUGH JUST OFFSHORE WILL CONTINUE TO SUPPORT LATE AFTERNOON INTO
EARLY EVENING SHOWERS AND THUNDERSTORMS, SOME OF WHICH HAVE ALREADY
PRODUCED 1-2 INCHES OF RAINFALL IN LOCALIZED AREAS ACROSS INLAND
ZONES OF SOUTHEAST GEORGIA AND ALONG THE IMMEDIATE GEORGIA
COASTLINE. ANOTHER 1/4 TO 1/2 INCH OF RAINFALL IS POSSIBLE NEAR
THESE AREAS DURING THIS TIME-FRAME. THERE ARE QUESTIONS AS TO HOW
FAR NORTH CONVECTION TRACKS, BEFORE INSTABILITY WANES DURING EVENING
HOURS, BUT RAINFALL AMOUNTS ARE LIKELY TO BE CONSIDERABLY LESS THAN
EXPERIENCED THIS AFTERNOON. AT THIS POINT, CHANCES OF ANY
THUNDERSTORMS TO BECOME SEVERE ARE NEAR ZERO. ALTHOUGH A STRONGER
THUNDERSTORM CAN NOT BE RULED OUT, MUCH OF THE AREA WITH LARGEST
INSTABILITY (SBCAPE AROUND 1000-1500 J/KG) AND BULK SHEAR NEAR
20-25 KT HAS BEEN WORKED OVER FROM PREVIOUS ACTIVITY. THUS, SHOWER
AND THUNDERSTORM ACTIVITY IS LIKELY TO REMAIN LOOSELY ORGANIZED
AT BEST. TEMPS WILL REMAIN MILD INTO EARLY EVENING HOURS, GENERALLY
RANGING IN THE LOW-MID 70S.
AFTER MIDNIGHT: THE MAIN CONCERN FOR THE NIGHT WILL CONTINUE TO
BE THE POSSIBILITY FOR FOG ACROSS THE AREA. AS THE CONVECTION
COMES TO AN END, LOW STRATUS/STRATOCUMULUS WILL DEVELOP, AS A
WARM FRONT LIFTS NORTH-NORTHEAST THROUGH THE AREA. THIS ALONG
WITH THE WET GROUNDS WILL LEAD TO AT LEAST SOME FOG FORMATION.
LATEST TRENDS CONTINUE TO INDICATE AT LEAST PATCHY FOG DEVELOPING
ACROSS THE ENTIRE AREA. DENSE FOG IS POSSIBLE LATE, BUT 10-15 KT
GEOSTROPHIC WINDS AT 1000 MB SUGGEST SOME LIMITATION TO OVERALL
COVERAGE AND PERHAPS MORE OF A LOW-STRATUS SCENARIO LATE. TEMPS
WILL REMAIN MILD THROUGH THE NIGHT, WITH LOWS ONLY DIPPING INTO
THE LOW-MID 60S.
SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/
THE MOST ACTIVE PERIOD OF THE FORECAST WILL BE MONDAY AS A MID-
LEVEL TROUGH, INITIALLY CENTERED NEAR THE MISSISSIPPI RIVER
VALLEY, SWINGS EASTWARD TOWARDS THE EAST COAST. AT THE SURFACE
AN ASSOCIATED COLD FRONT WILL APPROACH THE LOCAL FORECAST AREA
FROM THE WEST. AHEAD OF THE COLD FRONT A LINE OF SHOWERS AND
THUNDERSTORMS IS FORECAST TO PUSH THROUGH THE REGION, BRINGING
THE THREAT FOR SEVERE WEATHER. MORE DETAILS ON THAT BELOW. WITH
SOUTHWESTERLY FLOW ALOFT SOLID WAA WILL IMPACT THE REGION,
LEADING TO ANOTHER ABOVE NORMAL DAY IN REGARDS TO HIGH
TEMPERATURES. HIGHS ARE FORECAST TO REACH INTO THE LOW TO MID
80S ACROSS THE REGION. ADDITIONALLY, DEW POINTS ARE EXPECTED TO
SURGE INTO THE UPPER 60S, PROVIDING A MOIST ENVIRONMENT FOR
SHOWER AND TSTORM FORMATION. THE TIMING FOR THE LINE OF SHOWERS
AND STORMS HAS NOT CHANGED SIGNIFICANTLY FROM THE PREVIOUS
FORECAST. THE LINE WILL LIKELY MOVE INTO THE WESTERN PARTS OF
THE FORECAST AREA IN THE MID-AFTERNOON, PUSHING EASTWARD AND
REACHING THE COAST BY EARLY EVENING.
REGARDING THE SEVERE WEATHER POTENTIAL ON MONDAY: THE STORM
PREDICTION CENTER CONTINUES TO HIGHLIGHT THE FORECAST AREA IN AN
ENHANCED RISK (LEVEL 3 OUT OF 5). THE MAIN THREAT IS SEVERE DAMAGING
WIND GUSTS, HOWEVER HAIL AND ISOLATED TORNADOES CANNOT BE RULED OUT.
CAMS INDICATE THAT THERE WILL BE BETWEEN 1000-1500 J/KG OF ML CAPE
MONDAY AFTERNOON, WHICH COMBINED WITH THE FORECAST ARRIVAL TIME OF
MID-AFTERNOON, THE SHOWERS AND THUNDERSTORMS SHOULD BE ABLE TO
UTILIZE THE INSTABILITY. ADDITIONALLY, SHEAR VALUES RANGE BETWEEN 30-
40 KNOTS AND FORECAST SOUNDINGS SHOW DCAPE VALUES UPWARDS OF 800
J/KG. THEREFORE, STRONG, DAMAGING WIND GUSTS ARE THE MAIN HAZARD
WITH THE LINE OF SHOWERS AND THUNDERSTORMS. WHILE LARGE HAIL AND
TORNADOES CANNOT BE RULED OUT, 0-3KM SRH VALUES OF >100 M2/S2 AND
LOW-LEVEL LAPSE RATES BETWEEN 5-6 C/KM INDICATE THAT THE RISK FOR
LARGE HAIL AND TORNADOES IS LOW. GENERALLY RAINFALL AMOUNTS ARE
FORECAST TO BE BETWEEN 0.5 AND 1 INCH, HOWEVER HIGHER RAINFALL
AMOUNTS ARE CERTAINLY POSSIBLE WITH THUNDERSTORMS.
THE COLD FRONT WILL PUSH OFF THE COASTLINE OVERNIGHT MONDAY, LIKELY
STALLING IN THE VICINITY OF THE LOCAL OFFSHORE WATERS. LITTLE CHANGE
IN AIRMASS IS EXPECTED WITH OVERNIGHT TEMPERATURES IN THE UPPER 50S
TO LOW 60S. TEMPERATURES ON TUESDAY AND WEDNESDAY WILL REMAIN ABOVE
NORMAL, REACHING INTO THE LOW TO MID 80S EACH DAY. WITH THE FRONT
LINGERING IN THE VICINITY, MOISTURE WILL REMAIN ELEVATED ACROSS THE
REGION AND ISOLATED SHOWERS WILL BE POSSIBLE OVERNIGHT TUESDAY INTO
WEDNESDAY AFTERNOON.
LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/
THE REMAINDER OF THE WEEK WILL FEATURE HIGH PRESSURE BOTH ALOFT AND
AT THE SURFACE, YIELDING A DRY AND WARM FORECAST. THE MAIN FORECAST
HIGHLIGHT THROUGH THE WEEK WILL BE THE WARM TEMPERATURES. HIGHS ON
THURSDAY AND FRIDAY COULD APPROACH 90 DEGREES IN SOME LOCATIONS,
WITH MID TO UPPER 80S ELSEWHERE. THESE VALUES COULD CHALLENGE THE
RECORD HIGH TEMPERATURES AT OUR THREE CLIMATE SITES THURSDAY THROUGH
SATURDAY. OVERNIGHT LOWS WILL SIMILARLY BE ABOVE NORMAL, ONLY
DIPPING INTO THE MID 60S, POSSIBLY CHALLENGING SOME RECORD HIGH
MINIMUM TEMPERATURES AS WELL.
AVIATION /20Z SUNDAY THROUGH FRIDAY/
KCHS/KJZI: VFR CONDITIONS WILL PREVAIL INTO THE AFTERNOON WITH WINDS
GUSTING UPWARDS TO 15-20 KT RANGE. THERE REMAINS SOME RISK FOR MVFR
CIG/VSBYS WITH SHOWER ACTIVITY NEAR THE TERMINALS THIS AFTERNOON,
BUT PROBABILITIES REMAIN TOO LOW TO INCLUDE IN THE LATEST TAF
ISSUANCE. HEADING INTO THE NIGHT, CIGS WILL LOWER TO AT LEAST MVFR
BETWEEN 23-03Z, AND POSSIBLY IFR BETWEEN 08-14Z MONDAY, BEFORE
GRADUALLY IMPROVING IN THE MVFR RANGE LATE MORNING. AT THIS TIME,
ADDITIONAL SHOWER AND THUNDERSTORM ACTIVITY LIKELY HOLDS OFF UNTIL
AFTER 18Z MONDAY, BUT WILL LIKELY NEED TO BE INTRODUCED IN LATER TAF
ISSUANCES.
KSAV: SHOWERS/THUNDERSTORMS ARE LIKELY TO IMPACT THE TERMINAL DURING
THE NEXT FEW HOURS, RESULTING IN AT LEAST TEMPO MVFR CIGS/VSBYS
BETWEEN 18-21Z. WINDS WILL ALSO BE SLIGHTLY GUSTY AT TIMES,
GENERALLY PEAKING IN THE 15-20 KT RANGE THIS AFTERNOON. SHOWER
AND THUNDERSTORM ACTIVITY LIKELY ENDS HEADING INTO EARLY EVENING
HOURS, BUT CIGS WILL BE LOWERING WITH TIME. AT LEAST MVFR
CONDITIONS ARE EXPECTED BY AROUND 22Z SUNDAY, FOLLOWED BY A
PERIOD OF IFR CIGS BETWEEN 03-15Z MONDAY. FOG IS ALSO A POSSIBILITY
OVERNIGHT. CONDITIONS SHOULD BE SLOWLY TO IMPROVE HEADING INTO
EARLY AFTERNOON HOURS, BUT ADDITIONAL SHOWERS/THUNDERSTORMS
LIKELY ARRIVE AFTER 18Z MONDAY. REDUCED FLIGHT RESTRICTIONS WILL
LIKELY BE INTRODUCED AFTER 18Z MONDAY IN LATER TAF ISSUANCES.
EXTENDED AVIATION OUTLOOK: REDUCTIONS IN VISIBILITY AND CEILING ARE
LIKELY MONDAY AFTERNOON INT THE EVENING AS A LINE OF SHOWERS AND
THUNDERSTORMS PUSHES THROUGH THE REGION. LOW CEILINGS ARE POSSIBLE
AGAIN ON WEDNESDAY ALONG WITH SOME ISOLATED SHOWERS.
MARINE
THIS AFTERNOON INTO EARLY EVENING: HIGH PRESSURE CENTERED EAST OF
BERMUDA WILL EXTEND ACROSS THE IMMEDIATE WATERS, WITH THE ASSOCIATED
RIDGE AXIS JUST TO THE NORTH EARLY ON SAGGING SOUTH LATE DAY. THE
PRESSURE GRADIENT REMAINS RATHER WEAK ACROSS LOCAL WATERS, BUT
SUFFICIENT TO GENERATE SE WINDS UP TO 10-15 KT. SEAS WILL BE A MIX
OF SWELLS AND WIND DRIVEN WAVE, RESULTING IN SIGNIFICANT WAVE
HEIGHTS OF 3-5 FT ACROSS LOCAL WATERS, LARGEST ACROSS OUTER GEORGIA
WATERS. MARINERS COULD EXPERIENCE SOME THUNDERSTORMS LATE AFTERNOON
INTO EARLY EVENING, MAINLY SOUTH OF EDISTO. INSTABILITY AND SHEAR
REMAIN ON THE LOWER SIDE, LIMITING THE RISK TO NEAR ZERO FOR STRONG
AND/OR SEVERE THUNDERSTORMS. KEEP IN MIND THOUGH THAT LIGHTNING
STRIKES WILL OCCUR.
AFTER MIDNIGHT: THE ATLANTIC HIGH WILL SHIFT FARTHER EAST AS A COLD
FRONT APPROACHES THE REGION WELL AFTER DAYBREAK SUNDAY. WINDS
WILL TURN MORE SOUTHERLY, BUT REMAIN WELL BELOW SMALL CRAFT ADVISORY
LEVELS THROUGH THE NIGHT (10-15 KT). SEAS WILL GENERALLY RANGE
BETWEEN 3-5 FT. THE MAIN CONCERN WILL BE THE POSSIBILITY FOR SEAFOG
TO DEVELOP LATE, WITHIN A WARM AND MOISTURE AIRMASS ATOP SOMEWHAT
COOLER WATERS. AT THIS TIME, PATCHY FOG REMAINS IN THE FORECAST
ACROSS NEARSHORE WATERS, INCLUDING THE CHARLESTON HARBOR LATE.
TUESDAY THROUGH THURSDAY: THE AFOREMENTIONED COLD FRONT WILL LINGER
IN THE VICINITY OF THE MARINE WATERS THROUGH MID-WEEK, WITH HIGH
PRESSURE BUILDING IN THEREAFTER. GENERALLY QUIET MARINE CONDITIONS
ARE FORECAST THROUGH THE END OF THE WEEK, WITH WINDS AROUND 10 KNOTS
AND SEAS AVERAGING 3 TO 4 FT.
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
KVAX - MOODY AFB, GA
KJGX - ROBBINS AFB, GA
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...NONE.
NEAR TERM...DPB
SHORT TERM...CPM
LONG TERM...CPM
AVIATION...CPM/DPB
MARINE...CPM/DPB
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