592
FXUS62 KCHS 040617
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
217 AM EDT SUN MAY 4 2025
SYNOPSIS
A COLD FRONT WILL LINGER NEARBY BEFORE SHIFTING OFFSHORE ON
MONDAY. THEREAFTER, HIGH PRESSURE WILL BUILD IN AGAIN FROM THE
WEST. ANOTHER COLD FRONT COULD IMPACT THE REGION LATER NEXT
WEEK.
NEAR TERM /UNTIL 6 AM THIS MORNING/
EARLY THIS MORNING: RADAR IMAGERY HAS CHANGED SIGNIFICANTLY OVER
THE LAST 1-2 HOURS AS UPSTREAM CONVECTION AHEAD OF THE
APPROACHING FRONT HAS MOVED IN AS WELL AS LIGHT RAIN AND
EMBEDDED CONVECTION HAS BROKEN OUT ALONG THE COAST. THE INBOUND
CONVECTION ASSOCIATED WITH THE FRONT HAS BEEN ON A DEFINITIVE
WEAKENING TREND AS IT HAS ENCOUNTERED A MORE STABLE ENVIRONMENT.
HOWEVER, WE ARE SEEING BLOSSOMING CONVECTION ALONG THE SC COAST
AND UP THROUGH THE CHARLESTON AREA WHERE MLCAPE VALUES ARE STILL
AROUND 1,000 J/KG. THERE ISN'T ANY REAL SEVERE WEATHER RISK, BUT
WE COULD SEE SOME MUCH NEEDED LOCALLY HEAVY RAINFALL FOR SHORT
PERIODS OF TIME. RAIN CHANCES WILL CERTAINLY MAXIMIZE OVER THE
NEXT FEW HOURS, ESPECIALLY ALONG THE COAST AS WE SEE THE FOCUS
FOR CONVECTION SHIFT TO THE COAST AND THE ADJACENT WATERS WHERE
THE BEST INSTABILITY WILL RESIDE. BY SUNRISE, THE AXIS OF BEST
INSTABILITY IS EXPECTED TO SHIFT OFF TO THE EAST AND NORTHEAST
AND WE SHOULD SEE MOST AREAS RAIN-FREE BY THAT TIME. VERY MILD
TEMPERATURES WILL CONTINUE THROUGH THE REST OF THE NIGHT. AREAS
FURTHER INLAND SHOULD REACH THE LOW 60S BUT LOCATIONS ALONG THE
COASTAL CORRIDOR WILL LIKELY REMAIN IN THE UPPER 60S TO LOW 70S.
SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY/
SUNDAY: AN OMEGA BLOCK PATTERN WILL REMAIN OVER THE CONUS, WITH
A CLOSED LOW POSITIONED OVER THE OHIO RIVER VALLEY. AT THE
SURFACE A COLD FRONT WILL LINGER IN THE VICINITY. THIS STALLED
COLD FRONT WILL BE THE FOCUS OF SHOWERS AND THUNDERSTORMS IN THE
MORNING AND INTO THE AFTERNOON HOURS. THE COLD FRONT WILL BEGIN
TO PULL AWAY FROM THE REGION LATE SUNDAY, BRINGING AN END TO
THE SHOWERS AND THUNDERSTORMS OVERNIGHT. GIVEN THE LINGERING
COLD FRONT AND MOSTLY CLOUDY SKIES, TEMPERATURES ON SUNDAY WILL
ONLY REACH INTO THE LOW 80S. OVERNIGHT LOWS WILL BE COOLER THAN
PREVIOUS NIGHTS, POST FROPA, WITH LOW 50S INLAND AND AROUND 60
ALONG THE COASTLINE.
MONDAY AND TUESDAY: A DRY FORECAST RETURNS FOR MONDAY AND
TUESDAY, WITH HIGH PRESSURE BUILDING IN AT THE SURFACE FROM THE
WEST. ALOFT THE OMEGA BLOCK PATTERN WILL REMAIN THE DOMINANT
SYNOPTIC FEATURE. TEMPERATURES EACH DAY WILL REACH INTO THE 80S
WITH OVERNIGHT LOWS GENERALLY IN THE 60S.
LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/
THE OMEGA BLOCK PATTERN BEGINS TO BREAK DOWN ON WEDNESDAY AS
THE CLOSED LOW OVER THE OHIO RIVER VALLEY PUSHES NORTHEASTWARD
AND EXITS THE CONUS OFF THE NEW ENGLAND COASTLINE. AT THE
SURFACE A COLD FRONT WILL APPROACH THE REGION LATE WEEK, WITH
RAIN CHANCES INCREASING INTO FRIDAY. TEMPERATURES WILL BE NEAR
NORMAL THROUGH THE WEEK.
AVIATION /06Z SUNDAY THROUGH THURSDAY/
KCHS AND KJZI: FOR THE NEXT FEW HOURS, SHOWERS AND A
THUNDERSTORM OR TWO WILL IMPACT THE TERMINALS. BRIEF PERIODS OF
HEAVY RAIN COULD YIELD BRIEF MVFR OR EVEN IFR CONDITIONS, BUT
OVERALL VFR WILL PREVAIL. THIS SHOWER ACTIVITY WILL MAXIMIZE
OVER THE NEXT 3-4 HOURS, BUT SHOULD DWINDLE BY AROUND 12Z.
LOOKING INTO THE MIDDAY AND AFTERNOON TIME PERIOD, ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE. IT IS
UNCLEAR JUST HOW MUCH COVERAGE THERE WILL BE AT THIS TIME, AND
IT IS ENTIRELY PLAUSIBLE THAT THERE IS LITTLE TO NO SHOWER AND
THUNDERSTORM COVERAGE AT ALL. FOR NOW, WE HAVE INTRODUCED A
PROB30 FOR TSRA BETWEEN 16-19Z. WINDS WILL LIKELY BE BREEZY
AGAIN, BUT NOT AS GUSTY AS SATURDAY.
KSAV: LIGHT RAIN WITH EMBEDDED HEAVIER SHOWERS WILL CONTINUE TO
MOVE THROUGH FOR THE NEXT 2-3 HOURS. CONDITIONS SHOULD MOSTLY BE
VFR, BUT THERE COULD BE BRIEF PERIODS OF MVFR CEILINGS OR
VISIBILITIES. WE SHOULD SEE THE RAIN COME TO AN END BY 12Z.
LOOKING AHEAD TO THE MIDDY AND AFTERNOON PERIOD, WE COULD SEE
ISOLATED SHOWERS AND THUNDERSTORMS, BUT CHANCES APPEAR TO LOW TO
INCLUDE IN THE TAF AT THIS POINT.
EXTENDED AVIATION OUTLOOK: ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO IMPACT CHS/JZI/SAV THROUGH EARLY
MONDAY MORNING AS A COLD FRONT PASSES THROUGH THE REGION.
MARINE
TONIGHT: A COLD FRONT WILL APPROACH FROM THE WEST OVERNIGHT
KEEPING SOUTHERLY WINDS ELEVATED THROUGH THE NIGHT. GUSTS COULD
GET CLOSE TO 25 KT, BUT SHOULD REMAIN SHY THROUGH THE PERIOD.
SEAS WILL BUILD TO 3-5 FT, AND PERHAPS A BRIEF PERIOD OF 6 FT
SEAS COULD ENTER WITHIN 20NM OF THE COAST. WE DID NOT ISSUE ANY
SMALL CRAFT ADVISORIES WITH MARGINAL CONDITIONS THAT SHOULD
REMAIN BRIEF. LASTLY, SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS COULD IMPACT THE WATERS OVERNIGHT AHEAD OF THE
FRONT, WHICH COULD PRODUCE GUSTY WINDS.
SUNDAY THROUGH THURSDAY: A LINGERING COLD FRONT WILL EXIT THE
REGION SUNDAY NIGHT, WITH HIGH PRESSURE PREVAILING THROUGH MID
WEEK. ANOTHER COLD FRONT COULD APPROACH THE REGION LATE IN THE
WEEK. CONDITIONS WILL REMAIN BELOW SMALL CRAFT ADVISORY
CRITERIA, WITH SOUTHERLY WINDS GENERALLY 10 TO 15 KNOTS. GUSTS
ALONG THE COASTLINE AND IN THE CHARLESTON HARBOR COULD REACH 20
KNOTS EACH AFTERNOON WITH THE SEA BREEZE. SEAS SHOULD AVERAGE 2
TO 3 FT.
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...NONE.
NEAR TERM...BSH
SHORT TERM...CPM
LONG TERM...CPM
AVIATION...BSH
MARINE...BRS/CPM
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