425
FXUS62 KCHS 291834
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
234 PM EDT THU MAY 29 2025
SYNOPSIS
A STRONG UPPER DISTURBANCE WILL MOVE THROUGH THIS EVENING, THEN
A COLD FRONT WILL SWEEP THROUGH LATE FRIDAY. HIGH PRESSURE WILL
BUILD IN OVER THE WEEKEND INTO EARLY NEXT WEEK.
NEAR TERM /THROUGH TONIGHT/
SO FAR THIS AFTERNOON, CLUSTERS OF THUNDERSTORMS HAVE SPREAD
ACROSS THE SC LOWCOUNTRY, WITH NUMEROUS OUTFLOW BOUNDARIES. THIS
ACTIVITY SHOULD CONTINUE TO EXPAND THROUGH THE REST OF THIS
AFTERNOON, LARGELY TRIGGERED ALONG THE LEADING EDGE OF THE COLD
POOLS. TO THE WEST, RADAR SHOWS A LARGE OUTFLOW PUSHING AHEAD OF
AN OLD MCS. THIS FEATURE SHOULD SERVE A FOCUS FOR STORMS LATER
THIS AFTERNOON AND EVENING.
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL DEVELOP
ALONG AND INLAND OF THE SEA BREEZE AND COLD POOL(S) SOURCED FROM
THE MCS. THE ENVIRONMENT APPEARS VERY SUPPORTIVE FOR STRONG TO
DAMAGING WET MICROBURST, WITH DCAPE VALUES BETWEEN 500-1000 J/KG
AND MLCAPE AROUND 2000 J/KG. A SEVERE THUNDERSTORM WATCH
APPEARS POSSIBLE FOR THIS AFTERNOON AND EVENING.
TONIGHT: CONVECTION WILL LIKELY BE ONGOING TO START THE
OVERNIGHT PERIOD, PUSHING OFF THE COASTLINE BY MIDNIGHT.
OVERNIGHT LOWS ARE FORECAST TO DIP INTO THE MID TO UPPER 60S,
WITH AROUND 70 ALONG THE COASTLINE.
SHORT TERM /FRIDAY THROUGH SUNDAY/
A POTENT SHORTWAVE WILL PASS WELL NORTH OF THE REGION ON FRIDAY,
PUSHING A COLD FRONT INTO THE AREA DURING THE AFTERNOON. LOW AND
MID LEVEL FLOW WILL VEER AHEAD OF THE FRONT. THIS WILL RESULT IN
SOME SUBSIDENCE WHICH COULD LEAD TO A DECREASE IN OVERALL
CONVECTIVE COVERAGE ALONG AND AHEAD OF THE FRONT. HOWEVER, WITH
PWS REMAINING ABOVE 1.75", IT SHOULDN'T BE DIFFICULT TO MAINTAIN
AT LEAST SCATTERED SHOWERS AND TSTMS AHEAD OF THE FRONT. WIND
FIELDS WILL BE FAIRLY STRONG SO SOME CONVECTIVE ORGANIZATION IS
POSSIBLE. DAMAGING WINDS WOULD BE THE MAIN THREAT. THE LATEST
SPC DAY 2 CONVECTIVE OUTLOOK SEEMS REASONABLE WITH THE GREATEST
SEVERE THREAT ACROSS THE WESTERN HALF OF OUR AREA. THE LINE
COULD BE DECAYING BY THE TIME IT REACHES THE COAST.
DRY HIGH PRESSURE WILL BUILD OVER THE AREA FRIDAY NIGHT THROUGH
SUNDAY. THE 50S DEWPOINTS WILL MARK A NOTICEABLE AIRMASS CHANGE.
OVERNIGHT LOWS COULD DIP INTO THE UPPER 50S INLAND, WITH DAYTIME
HIGHS IN MOST SPOTS IN THE LOW/MID 80S.
LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/
MAINLY DRY WEATHER EXPECTED DURING THE EXTENDED AS A DEEP
LAYERED RIDGE BUILDS OVER THE AREA. WE'LL SEE A WARMING TREND
INTO THE MIDDLE OF NEXT WEEK WITH HIGHS PUSHING BACK INTO THE
UPPER 80S.
AVIATION /18Z THURSDAY THROUGH TUESDAY/
PRIOR TO THE 18Z TAFS, A CLUSTER OF THUNDERSTORMS WAS LOCATED
JUST INLAND OF KCHS, DRIFTING TO THE ENE. THE KCHS TAF WILL
INITIALIZE WITH TS, THEN OUTFLOW BOUNDARY DEVELOPMENT SHOULD
PUSH THE STORM ACTIVITY CLOSER TO THE KCHS AND KJZI TERMINALS
BETWEEN 19 TO 23Z, HIGHLIGHTED WITH TEMPOS. THE REMNANT COLD
POOL ASSOCIATED WITH AN UPSTREAM MCS WILL LIKELY TRIGGER MORE
STORMS AS IT ARRIVES LATE THIS AFTERNOON AND EVENING. KSAV TAF
WILL MENTION TSRA WITH A TEMPO FROM 20 TO 24Z. SHOWERS AND
THUNDERSTORMS WILL GRADUALLY DECREASE IN COVERAGE THIS EVENING
AS OUTFLOWS SPREAD ACROSS THE FORECAST AREA. THUNDERSTORM
PROBS SHOULD RAMP DOWN AROUND MIDNIGHT.
EXTENDED AVIATION OUTLOOK: OCCASIONAL VISIBILITY REDUCTIONS
EXPECTED THROUGH FRIDAY EVENING, MAINLY IN SHOWERS AND
THUNDERSTORMS.
MARINE
TODAY: THE FORECAST TODAY WILL FEATURE SOUTHERLY WINDS AROUND 10
KNOTS, WITH SEAS AVERAGING 2 TO 3 FT. A DISTURBANCE ALOFT WILL
PASS OVER THE REGION THIS AFTERNOON WITH SHOWERS AND
THUNDERSTORMS PUSHING THROUGH THE FORECAST AREA AND INTO THE
MARINE WATERS. SOME STORMS MAY PRODUCE GUSTY WINDS, POSSIBLY
NECESSITATING SPECIAL MARINE WARNINGS INTO THE EVENING.
TONIGHT: SHOWERS AND THUNDERSTORMS WILL LIKELY BE ONGOING TO
START THE OVERNIGHT PERIOD, PUSHING FURTHER INTO THE ATLANTIC
WATERS BY AROUND MIDNIGHT. THERE AFTER WINDS WILL BEGIN TO
INCREASE HEADED TOWARDS SUNRISE AS A COLD FRONT APPROACHES FROM
THE WEST. BY THE EARLY MORNING HOURS SOUTHWESTERLY WINDS 10 TO
15 KNOTS ARE FORECAST, WITH SEAS AVERAGING 2 TO 3 FT.
LOW-LEVEL WINDS WILL INCREASE ON FRIDAY AHEAD OF THE COLD FRONT.
WARMING AFTERNOON TEMPS WILL PRODUCE RELATIVELY DEEP MIXING,
WITH SOME 25 KT WIND GUSTS POSSIBLE IN CHARLESTON HARBOR. IT
CURRENTLY LOOKS TOO MARGINAL TO PULL THE TRIGGER ON A SMALL
CRAFT ADVISORY. WINDS/SEAS COULD BE CLOSE TO SCA CRITERIA ACROSS
THE CHARLESTON NEARSHORE AND GA OFFSHORE WATERS FRIDAY NIGHT
AFTER THE FRONT PASSES THROUGH, BUT AGAIN IT LOOKS PRETTY
MARGINAL.
MODERATE NW WINDS SATURDAY MORNING WILL SUBSIDE DURING THE DAY.
QUIET CONDITIONS THEN EXPECTED THROUGH EARLY NEXT WEEK.
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...NONE.
NEAR TERM...CPM/NED
SHORT TERM...JRL
LONG TERM...JRL
AVIATION...NED
MARINE...CPM/JRL
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