268
FXUS62 KCHS 051730
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
130 PM EDT MON MAY 5 2025
SYNOPSIS
A COLD FRONT WILL STALL JUST OFFSHORE AS HIGH PRESSURE BEGINS
TO BUILD INTO THE REGION. A COLD FRONT AND AN UPPER-LEVEL LOW
WILL APPROACH FROM THE WEST THURSDAY AND CAUSE AN UNSETTLED
WEATHER PATTERN TO PERSIST INTO THE WEEKEND.
NEAR TERM /THROUGH TONIGHT/
LATE-MORNING UPDATE: FORECAST REMAINS ON TRACK, ONLY MINOR
ADJUSTMENTS WERE MADE.
TODAY: EARLY AFTERNOON WATER VAPOR IMAGERY SHOWS A CLOSED OFF UPPER LEVEL
LOW CENTERED ALONG THE KENTUCKY/INDIANA/OHIO BORDER, WITH SURFACE
ANALYSIS SHOWING A STUBBORN FRONT REMAINING BARELY ON THE SC
COAST FROM JAMES ISLAND UP TO SANTEE. SCATTERED CUMULUS HAS
DEVELOPED ACROSS THE REGION, THOUGH CONTINUE TO EXPECT A DRY
FORECAST GIVEN WARM AND DRY SOUNDING PROFILES ALONG WITH A WEAK
INVERSION AT THE TOP OF THE MIXED LAYER. SURFACE WINDS REMAIN
OUT OF THE WEST, WITH AFTERNOON HIGHS IN THE LOWER TO MID 80S.
EXPECT THE SEA-BREEZE TO FORM A TOUCH LATER THAN USUAL (AROUND
3-4PM) AND BE A LITTLE WEAKER GIVEN THE PROMINENT WESTERLY
FLOW.
TONIGHT: HIGH PRESSURE WILL REMAIN IN CONTROL AND A QUIET NIGHT
IS EXPECTED. LOWS ARE FORECAST TO BE RIGHT AROUND NORMAL WITH
MOSTLY MID 50S INLAND RANGING TO THE LOW 60S ALONG THE COAST.
SHORT TERM /TUESDAY THROUGH THURSDAY/
TUESDAY: THIS OMEGA BLOCKING PATTERN WILL BEGIN TO FINALLY
BREAK DOWN AS THE CLOSED UPPER-LVL LOW BEGINS TO MOVE SLIGHTLY
FURTHER AWAY TOWARDS NEW ENGLAND. A WEAK MID-LVL RIDGE AXIS WILL
MOVE OVERHEAD WITH DRY CONDITIONS PERSISTING INTO THE OVERNIGHT
DESPITE THE ONSET OF MODEST HEIGHT FALLS ALOFT. THE DOMINATE
FEATURE TODAY WILL BE THE SEA BREEZE WITH TEMPERATURES CLIMBING
INTO THE MID TO UPPER 80S AHEAD OF THE SEA BREEZE FRONT.
TUESDAY NIGHT: EXPECT WINDS TO DECOUPLE AND CLOUDS TO BEGIN
FILLING IN. WITH A GOOD AMOUNT OF WAA PRESENT, LOWS WILL RETURN
TO NEAR-NORMAL.
WEDNESDAY AND THURSDAY: AS THE CLOSED UPPER-LVL LOW APPROACHES
THE REGION, WEST-SOUTHWESTERLY FLOW WILL ALLOW MOISTURE TO SURGE
INTO TO THE REGION FROM THE GULF. A WEAK ASSOCIATED COLD FRONT
WILL POSSIBLY LINGER NEARBY ALLOWING FOR SOME SHOWERS AND
THUNDERSTORMS TO DEVELOP THROUGHOUT THE PERIOD. WITH THIS, HIGHS
WILL BE A TAD COOLER THAN NORMAL. TEMPERATURES OVERNIGHT STAY
WARM BOTH NIGHTS WITH LOWS IN THE UPPER 50S TO LOW 60S INLAND
AND MID TO UPPER 60S CLOSER TO THE COASTLINE.
LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/
THIS OMEGA BLOCKING PATTERN WILL CONTINUE TO DECAY ON FRIDAY AS
AN UPPER-LVL LOW SITUATED OVER NEW ENGLAND CONTINUES TO DRIFT
NORTHEASTWARD AND ANOTHER SECONDARY UPPER-LVL LOW LOCATED OVER
THE SOUTHERN PLAINS INCHES CLOSER AND CLOSER THE REGION. THE
SECONDARY LOW MIGHT DEVELOP A WEAK REX BLOCK PATTERN AS IT MOVES
ACROSS THE CENTRAL CONUS. AN ASSOCIATED COLD FRONT WILL
POSSIBLY LINGER NEARBY BEFORE PASSING THROUGH THE REGION ON
FRIDAY AFTERNOON. THERE ARE MANY SOLUTIONS TO HOW THIS PATTERN
MIGHT PLAY OUT, DEPENDING ON THE SPEED THESE UPPER-LVL LOWS
CHOOSE TO PROGRESS. HOWEVER, THE MAJORITY OF THESE SOLUTIONS
POINT TO THE DEVELOPMENT OF SEVERAL ROUNDS OF SHOWERS AND
THUNDERSTORMS THROUGH THE WEEKEND. TEMPERATURES WILL COOL TO
AROUND NORMAL THROUGH THE PERIOD.
AVIATION /18Z MONDAY THROUGH SATURDAY/
VFR CONDITIONS PERSIST THROUGH 18Z TUESDAY, THOUGH THE REGION WILL
SEE A SCATTERED CUMULUS FIELD FOR THE REST OF THE AFTERNOON HOURS
AND AGAIN TOMORROW BY LATE MORNING. WINDS REMAIN OUT OF THE
WEST TODAY, THOUGH AREAS NEAR THE COAST MAY BRIEFLY SEE A SWITCH
TOWARDS SOUTHEASTERLY WINDS LATER THIS AFTERNOON AS THE SEA-
BREEZE ATTEMPS TO PUSH INLAND.
EXTENDED AVIATION OUTLOOK: WITH THE COLD FRONT OFFSHORE, VFR
CONDITIONS SHOULD RETURN AT CHS/JZI/SAV ON TUESDAY. THEREAFTER,
MULTIPLE ROUNDS OF SCATTERED SHOWERS AND THUNDERSTORMS COULD
POSSIBLY IMPACT ALL TERMINALS THROUGH THE PERIOD AS AN UPPER-LVL
LOW APPROACHES FROM THE WEST. SIMULTANEOUSLY, A FRONT MIGHT
LINGER NEAR THE REGION THURSDAY INTO SATURDAY. PERIODS OF
MVFR/IFR CONDITIONS ARE POSSIBLE AT ALL TERMINALS.
MARINE
TODAY THROUGH TONIGHT: MODEST SOUTHERLY FLOW IS EXPECTED TODAY,
WITH SPEEDS MOSTLY IN THE 10-15 KNOT RANGE. OVERNIGHT, WINDS
WILL TURN OFFSHORE OUT OF THE NORTHWEST WITH SPEEDS ONLY IN THE
5-10 KNOT RANGE. SEAS SHOULD AVERAGE 2-3 FEET THROUGH THE
PERIOD.
TUESDAY: WITH HIGH PRESSURE CONTINUING TO BUILD INTO THE
REGION, WINDS WILL BRIEFLY TURN NORTH-NORTHWESTERLY ON TUESDAY,
BUT WILL QUICKLY SPIN BACK AROUND TO THE SOUTHEAST BY THE
EVENING. SEAS WILL BE 2 TO 3 FT.
WEDNESDAY THROUGH SATURDAY: MULTIPLE ROUNDS OF SHOWERS AND
THUNDERSTORMS ARE EXPECTED THROUGH THIS PERIOD AS AN UPPER-LVL
LOW APPROACHES THE REGION. WITH SOME ONSHORE FLOW ALONG THE
BEACHES, WAVES WILL BE A BIT CHOPPY AND TEXTURED. CONDITIONS
SHOULD REMAIN BELOW SCAS CRITERIA THROUGH SATURDAY MORNING. AS A
COLD FRONT ASSOCIATED WITH THE UPPER-LVL LOW APPROACHES ON
FRIDAY, NORTHEASTERLY WINDS WILL SURGE (10 TO 15 KT WITH GUSTS
UP TO 20 KT) AND SEAS WILL BUILD FROM 3 TO 5 FT. ON SATURDAY
AFTERNOON, THE NEARSHORE GEORGIA WATERS (AMZ354) AND OUTER
GEORGIA WATERS (AMZ374) WILL POSSIBLY SEE SOME 6 TO 7 FOOTERS
AND A SCA WILL LIKELY BE NEEDED BEGINNING AROUND MID-DAY ON
SATURDAY.
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...NONE.
NEAR TERM...APT/BSH
SHORT TERM...DENNIS
LONG TERM...DENNIS
AVIATION...APT/DENNIS
MARINE...BSH/DENNIS
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