378
FXUS62 KCHS 290523
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
123 AM EDT THU MAY 29 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 THIS MORNING/
NO MAJOR CHANGES WERE MADE TO THE OVERNIGHT PERIOD WITH THE
OVERNIGHT UPDATE.
LATE THIS EVENING: WE HAVE SEEN ISOLATED SHOWERS DEVELOP OVER
THE LAST FEW HOURS AS THE SEA BREEZE HAS PUSHED INLAND. THIS
ACTIVITY SHOULD REMAIN WEAK AND COME TO AN END OVER THE NEXT
HOUR OR TWO, BUT WITH SUBTLE MESOSCALE BOUNDARY FLOATING AROUND
IN A WARM/MOIST ENVIRONMENT, WE CAN'T COMPLETELY RULE OUT AN
ISOLATED SHOWER JUST ABOUT ANYWHERE THROUGH THE OVERNIGHT. ONE
THING TO WATCH IS MORE SCATTERED ACTIVITY MAKING SLOW EASTWARD
PROGRESS SOUTHEAST OF MACON. IF THIS ACTIVITY HOLDS TOGETHER OR
CAN PUT DOWN AN OUTFLOW BOUNDARY, WE COULD SEE SOME ACTIVITY
THROUGH THE OVERNIGHT ACROSS INTERIOR SOUTHEAST GA. LATE
TONIGHT, THERE CONTINUE TO BE 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 THIS 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 /05Z THURSDAY THROUGH MONDAY/
KCHS/KJZI/KSAV WILL INITIALIZE WITH VFR CONDITIONS FOR THE 06Z
TAFS. FOG IS FORECAST TO DEVELOP EARLY THIS MORNING, POSSIBLY
BRINGING RESTRICTIONS TO KCHS AND KJZI. A TEMPO GROUP HAS BEEN
INCLUDED FROM 11Z TO 13Z TO ACCOUNT FOR THIS. THEREAFTER VFR
WILL PREVAIL AT ALL TAF SITES UNTIL THIS AFTERNOON WHEN SHOWERS
AND THUNDERSTORMS ARE EXPECTED TO PUSH THROUGH THE REGION. EXACT
TIMING OF IMPACTS IS STILL UNCERTAIN AT THIS JUNCTURE, SO HAVE
ONLY INCLUDED MENTION OF VCTS STARTING AT 21Z AT KCHS AND 22Z AT
KJZI AND KSAV. SHOWERS AND STORMS ARE EXPECTED TO CLEAR THE
TERMINALS IN THE EVENING HOURS, WITH A LOW END CHANCE OF MVFR
CIGS RETURNING OVERNIGHT.
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/CPM
SHORT TERM...BRS
LONG TERM...BRS
AVIATION...BRS/CPM
MARINE...BRS/NED
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