272
FXUS62 KCHS 290000
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
800 PM EDT WED MAY 28 2025
SYNOPSIS
A SERIES OF DISTURBANCES WILL AFFECT THE AREA THROUGH THURSDAY,
THEN A COLD FRONT WILL SWEEP THROUGH LATE FRIDAY. HIGH PRESSURE
WILL BUILD IN OVER THE WEEKEND INTO EARLY NEXT WEEK.
NEAR TERM /UNTIL 6 AM THURSDAY MORNING/
EARLY THIS EVENING: OVER THE LAST FEW HOURS, CONVECTION
INITIATION ACROSS SOUTHEAST GA ALONG THE COAST AND THEN
PROPAGATED TO THE NORTHEAST WITH OUTFLOW ACROSS CHATHAM COUNTY
AND BEAUFORT COUNTY. THIS ACTIVITY HAS WEAKENED SIGNIFICANTLY IN
THE LAST HALF HOUR, AND SHOULD CONTINUE TO DO SO WITH THE LOSS
OF SURFACE HEATING. THE SEA BREEZE CONTINUES TO SLOWLY WORK
INLAND, AND WE COULD STILL SEE AN ISOLATED SHOWER OR
THUNDERSTORM THROUGH THE EARLY MORNING HOURS AS BOUNDARIES
MEANDER ABOUT. OVERALL, THE FORECAST IS DRY FOR THE BULK OF THE
OVERNIGHT. LATE TONIGHT, THERE ARE INDICATIONS IN THE SETUP AND
IN MODEL GUIDANCE THAT WE COULD SEE SOME LOW STRATUS AND FOG. WE
AREN'T ANTICIPATING ANYTHING NEAR WHAT WE SAW TUESDAY NIGHT AND
WEDNESDAY MORNING, BUT THERE COULD AT LEAST BE SOME PATCHY FOG
AROUND WITH LOW CLOUDS. WE HAVE KEPT JUST A MENTION OF PATCHY
FOG IN THE FORECAST, THOUGH MOST OF THE GUIDANCE IS HINTING THAT
THE CHARLESTON TRI-COUNTY REGION HAS THE BEST CHANCE. WE WILL
CONTINUE TO EVALUATE THIS EVENING AND WE COULD EVENTUALLY NEED
TO ADD IN SOME PATCHY DENSE FOG OR EVEN SOME AREAS OF FOG.
SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/
THURSDAY: THE 500 MB PATTERN BEGINS TO AMPLIFY ON THURSDAY WITH
A SHORTWAVE LIFTING THROUGH THE AREA IN THE EVENING. DEEP
TROPICAL MOISTURE WILL ADVECT INTO THE AREA WHILE MLCAPE VALUES
TOP OUT JUST BELOW 1000 J/KG LATER IN THE DAY. SCATTERED
COVERAGE OF SHOWERS AND THUNDERSTORMS EXPECTED, WITH SOME AREAS
PICKING UP TO 1-2" OF RAINFALL. CANNOT RULE OUT AN ISOLATED
STRONG TO SEVERE THUNDERSTORM WITH PLENTIFUL INSTABILITY AND
MARGINAL SHEAR VALUES. CONVECTION SHOULD TAPER TO SOME EXTENT IN
THE LATE EVENING, BUT COULD CONTINUE INTO THE EARLY OVERNIGHT
PERIOD WITH ONGOING SHORTWAVE ACTIVITY AND FORCING ALOFT
PRESENT. TEMPERATURES WILL PEAK IN THE MID TO UPPER 80S WITH A
FEW PLACES REACHING 90 DEGREES, AND MIN TEMPS IN THE MID TO
UPPER 60S TO LOWER 70S ALONG THE BEACHES.
FRIDAY: A LONGWAVE UPPER TROUGH WITH AN EMBEDDED SHORTWAVE WILL
APPROACH THE SOUTHERN MID-ATLANTIC, PUSHING A COLD FRONT
THROUGH THE AREA LATE FRIDAY. PWATS WILL HOLD STEADY ABOVE 1.75"
AHEAD OF THE FRONT, AND MLCAPE VALUES ARE EXPECTED REACH
1000-1300 J/KG. WIND FIELDS ARE DECENT WITH 0-6 KM BULK SHEAR OF
30-45 KT LATER IN THE AFTERNOON. WE SHOULD SEE A FAIRLY
CONTIGUOUS BAND OF SHOWERS AND THUNDERSTORMS WITH SOME
ORGANIZATION SWEEP THROUGH THE AREA FRIDAY AFTERNOON/EVENING. A
FEW SEVERE THUNDERSTORMS ARE POSSIBLE, WITH DAMAGING WINDS AND
LARGE HAIL THE MAIN HAZARDS. MODELS SIGNAL THE POSSIBILITY FOR
THE DEVELOPMENT OF CONVECTION IN THE MORNING/EARLY AFTERNOON
HOURS OR PRECEDING THE FRONT IN GENERAL WHICH COULD AID IN SOME
STABILIZATION, THEREBY LIMITING THE SEVERE POTENTIAL LATER IN
THE DAY. CONVECTION WILL HELP LIMIT MAX TEMPERATURES TO THE LOW
TO MID 80S WITH ISOLATED AREAS CLOSER TO THE COAST REACHING THE
UPPER 80S. TEMPERATURES WILL BECOME RELATIVELY COOL OVERNIGHT,
DROPPING INTO THE UPPER 50S FAR INLAND AND LOW TO MID 60S
ELSEWHERE.
SATURDAY: A MUCH DRIER AIR MASS WILL RAPIDLY MOVE INTO THE AREA
IN THE WAKE OF THE FRONT. MOSTLY SUNNY SKIES ARE EXPECTED IN
ADDITION TO DEW POINTS DIPPING INTO THE 50S DURING PRIME
AFTERNOON MIXING HOURS. HIGHS POST FROPA WILL PEAK IN THE LOW TO
MID 80S.
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/
WEAK HIGH PRESSURE WILL BUILD IN FROM THE WEST SUNDAY
CONTINUING DRY/RAIN-FREE CONDITIONS. A SECONDARY, REINFORCING
COLD FRONT COULD MOVE THROUGH ON MONDAY, POTENTIALLY ACCOMPANIED
BY A POTENT UPPER SHORTWAVE. THIS COULD BRING A ROUND OF
CONVECTION, HOWEVER MOISTURE WILL BE LIMITED WITH WEAK SURFACE
HIGH PRESSURE STILL IN PLACE. SLIGHT CHANCE POPS ARE IN PLACE
DURING THE AFTERNOON HOURS MONDAY AND WILL CONTINUE INTO THE
MIDDLE OF NEXT WEEK DUE TO THE POTENTIAL RETURN OF DIURNAL
CONVECTION. TEMPERATURES SHOULD REBOUND TO NEAR NORMAL FOR THE
REST OF THE PERIOD.
AVIATION /00Z THURSDAY THROUGH MONDAY/
THE 00Z TAF PERIOD BEGINS WITH VFR CONDITIONS AT KCHS, KJZI, AND
KSAV. THE FIRST FORECAST CONCERN IS FOR FOG AND LOW STRATUS
CLOSER TO SUNRISE AT ALL 3 SITES. IT DOES NOT APPEAR THAT WE
WILL HAVE TO DEAL WITH WIDESPREAD DENSE FOG LIKE WE DID LAST
NIGHT, WITH FOG AND STRATUS BEING A BIT MORE PATCHY IN COVERAGE.
ALSO, THE FOG AND STRATUS POTENTIAL SEEMS TO BE HIGHEST AROUND
KCHS AND KJZI. THEREFORE, WE ADVERTISE A TEMPO GROUP FOR IFR
CEILINGS AND MVFR VISIBILITY AT KCHS AND KJZI FROM 11-13Z. WE
HAVE KEPT THE FORECAST VFR AT KSAV.
THE SECOND FORECAST CONCERN IS FOR AFTERNOON/EVENING
THUNDERSTORMS NEAR THE END OF THE 00Z TAF PERIOD AT ALL 3 SITES.
HI-RES MODEL GUIDANCE PROVIDES SEVERAL DIFFERENT SOLUTIONS FOR
THE ONSET AND COVERAGE OF THUNDERSTORMS SO CONFIDENCE IS QUITE
LOW THIS FAR OUT. HOWEVER, THERE SEEMS TO BE SOME REASONABLE
AGREEMENT THAT THE BEST THUNDERSTORM POTENTIAL WILL BE LATE IN
THE TAF PERIOD, PERHAPS FROM A CLUSTER OF STORMS APPROACHING
FROM THE WEST. FOR NOW, WE HAVE ADDED IN VCTS AT ALL 3 TAF SITES
BEGINNING AROUND 21-22Z.
EXTENDED AVIATION OUTLOOK: OCCASIONAL VISIBILITY REDUCTIONS
EXPECTED THROUGH FRIDAY EVENING, MAINLY IN SHOWERS AND
THUNDERSTORMS.
MARINE
TONIGHT: THE WEATHER PATTERN WILL SUPPORT SOUTHERLY WINDS
BETWEEN 5 TO 10 KTS. SEAS ARE FORECAST TO RANGE BETWEEN 2 TO 4
FT, THEN 2 TO 3 FT AFTER MIDNIGHT.
THURSDAY THROUGH MONDAY: SOUTH TO SOUTHWEST WINDS AND SEAS
SHOULD BE WELL BELOW ADVISORY THRESHOLDS THROUGH THURSDAY NIGHT.
SW WINDS WILL BEGIN TO INCREASE FRIDAY AHEAD OF A STRONG COLD
FRONT. GUSTS COULD REACH 25 KT AS EARLY AS FRIDAY AFTERNOON AND
CONTINUE INTO THE OVERNIGHT PERIOD. SMALL CRAFT ADVISORIES COULD
BE NEEDED FOR THE CHARLESTON COUNTY NEARSHORE WATERS, INCLUDING
THE CHARLESTON HARBOR, AND THE OUTER GEORGIA WATERS FROM 20-60
NM. RAPID IMPROVEMENT WILL OCCUR SATURDAY WITH NO ADDITIONAL
MARINE CONCERNS THROUGH THE PERIOD.
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...NONE.
NEAR TERM...BSH
SHORT TERM...BRS
LONG TERM...BRS
AVIATION...BRS/BSH
MARINE...BRS/NED
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