065
FXUS62 KCHS 202255
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
555 PM EST THU FEB 20 2025
SYNOPSIS
COLD HIGH PRESSURE WILL BUILD INTO THE REGION THROUGH THE START
OF THE WEEKEND. AN AREA OF LOW PRESSURE WILL DEVELOP OFF THE
COAST ON SUNDAY, FOLLOWED BY MORE HIGH PRESSURE INTO EARLY NEXT
WEEK.
NEAR TERM /UNTIL 6 AM FRIDAY MORNING/
THE LAST SET OF USABLE GOES-E VISIBLE SATELLITE IMAGES SHOW
CLOUDS ARE FINALLY ERODING ACROSS THE CHARLESTON TRI-COUNTY
AREA AFTER HOLDING FIRM FOR MUCH OF THE DAY. THE RISK FOR PATCHY
DRIZZLE AND FLURRIES HAS ENDED. CLEAR SKIES WILL PREVAIL
OVERNIGHT AS ARCTIC HIGH PRESSURE BUILDS INTO THE SOUTHEAST
STATES. INCOMING HIGH RESOLUTION GUIDANCE HAS TRENDED A TAD
WARMER WITH OVERNIGHT LOWS WHICH MATCHES TRENDS NOTED IN THE
LATEST HREF GRAND ENSEMBLE. HOWEVER, THE 20/18Z BOTH THE NAM AND
GFS-BASED STATISTICAL GUIDANCE PACKAGES HAVE COME IN A TAD
COOLER. SUFFICE TO SAY, THERE REALLY IS NOT ENOUGH EVIDENCE TO
MAKE ANY CHANGES EITHER WAY AT THIS POINT AND WILL NEED TO SEE
HOW TEMPERATURES THIS EVENING TREND BEFORE MAKING ANY MEANINGFUL
ADJUSTMENTS. LOWS WERE HELD IN THE LOWER-MID 20S INLAND WITH
UPPER 20S/NEAR 30 AT THE BEACHES FOR THE EARLY EVENING UPDATE.
GUSTY NORTHERLY WINDS WILL DIMINISH A BIT OVERNIGHT, BUT SHOULD
HOLD IN THE 5-10 MPH RANGE DURING THE DIURNAL MINIMUM. THIS WILL
RESULT IN MINIMUM WIND CHILL VALUES OF 13-19 DEGREES. A COLD
WEATHER ADVISORY REMAINS IN EFFECT FOR ALL AREAS FROM 10 PM
TONIGHT TO 10 AM FRIDAY MORNING.
SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY NIGHT/
FRIDAY THROUGH SUNDAY: COLD AND DRY HIGH PRESSURE WILL PREVAIL
ACROSS THE AREA ON FRIDAY. OTHER THAN SOME THIN CIRRUS SPREADING IN
FROM THE WEST IN THE AFTERNOON, MOSTLY CLEAR SKIES ARE EXPECTED.
DESPITE PLENTY OF SUN, TEMPERATURES WILL BE QUITE CHILLY AND ON THE
ORDER OF 15-20 DEGREES BELOW NORMAL. HIGHS ARE EXPECTED TO TOP OUT
IN THE MID TO UPPER 40S ACROSS SOUTHEAST SC AND NEAR 50 FOR
SOUTHEAST GA. FRIDAY NIGHT WILL BE ANOTHER VERY COLD NIGHT, THOUGH
NOT AS COLD AS THURSDAY NIGHT. LOWS IN THE MID TO UPPER 20S ARE
FORECAST BUT THE LACK OF WIND WILL KEEP WIND CHILLS UP AND NO COLD
WEATHER ADVISORY IS EXPECTED. THE HIGH WILL BRIDGE ACROSS THE
APPALACHIANS AND EVENTUALLY OFF THE EAST COAST SATURDAY AND SATURDAY
NIGHT. A SURFACE LOW IS EXPECTED TO DEVELOP OFF THE SOUTHEAST COAST
SATURDAY NIGHT, BUT ANY PRECIPITATION ASSOCIATED WITH IT WILL REMAIN
OFFSHORE. TEMPERATURES WILL START TO REBOUND, BUT REMAIN BELOW
NORMAL, WITH HIGHS GETTING UP INTO THE UPPER 50S FOR PORTIONS OF THE
AREA. QUIET CONDITIONS THEN CONTINUE INTO SUNDAY WARMING BACK CLOSER
TO NORMAL. LOOK FOR HIGHS IN THE LOW TO MID 60S.
LONG TERM /MONDAY THROUGH THURSDAY/
A SYSTEM IS EXPECTED TO PASS BY TO THE SOUTH ACROSS THE GULF SUNDAY
NIGHT AND MONDAY. WHILE MOST OF THE PRECIPITATION ASSOCIATED WITH IT
WILL REMAIN DISPLACED TO THE SOUTH, THERE IS SOME MODEL SUPPORT FOR
RAIN TO EXTEND UP TO ALONG THE GA COAST. THE FORECAST ADVERTISES 20
PERCENT CHANCES ALONG THE GA COAST AND THE ADJACENT COASTAL
WATERS. THEREAFTER, DRY CONDITIONS WILL PREVAIL WITH MODERATING
TEMPERATURES. WE COULD BE BACK TO NEAR NORMAL BY MONDAY WITH LOW
TO MID 70S POSSIBLE THROUGH MID WEEK.
AVIATION /00Z FRIDAY THROUGH TUESDAY/
21/00Z TAF DISCUSSION:
KCHS/KJZI/KSAV: VFR THROUGH EARLY FRIDAY EVENING.
EXTENDED AVIATION OUTLOOK: VFR CONDITIONS ARE EXPECTED TO
PREVAIL.
MARINE
THE SMALL CRAFT ADVISORY HAS BEEN EXPANDED TO INCLUDE THE
REMAINING NEARSHORE LEGS OUT 20 NM. IT WILL BE CLOSE IN THE
CHARLESTON HARBOR, BUT THE EXPECTATION IS WINDS AND WIND GUSTS
WILL FALL JUST SHY OF ADVISORY CRITERIA.
TONIGHT: GUSTY NW WINDS WILL PERSIST ACROSS THE WATERS AS HIGH
PRESSURE BUILDS INTO THE REGION FROM THE WEST. GUSTS ARE
FORECAST TO RANGE BETWEEN 25 TO 30 KT. SEAS WILL RANGE BETWEEN
3 TO 5 FT NEARSHORE WATERS AND 5-7 FT FOR THE GEORGIA OFFSHORE
WATERS. SMALL CRAFT ADVISORIES ARE IN EFFECT.
FRIDAY THROUGH TUESDAY: NORTHERLY WINDS WILL PEAK FRIDAY MORNING
THEN STEADILY DIMINISH THROUGH THE DAY AS THE PRESSURE GRADIENT
RELAXES. AS CONDITIONS IMPROVE, THE ONGOING SMALL CRAFT ADVISORIES
FOR THE CHARLESTON COUNTY WATERS AND THE OUTER GA WATERS WILL COME
TO AN END. WINDS AND SEAS WILL THEN REMAIN WELL BELOW ADVISORY
THRESHOLDS THROUGH EARLY NEXT WEEK.
CLIMATE
RECORD LOW MAXIMUM TEMPERATURES:
FEBRUARY 21:
KCHS: 47/2020
RECORD LOW TEMPERATURES:
FEBRUARY 21:
KCHS: 22/1958
CHS WATCHES/WARNINGS/ADVISORIES
GA...COLD WEATHER ADVISORY FROM 10 PM THIS EVENING TO 10 AM EST
FRIDAY FOR GAZ087-088-099>101-114>119-137>141.
SC...COLD WEATHER ADVISORY FROM 10 PM THIS EVENING TO 10 AM EST
FRIDAY FOR SCZ040-042>045-047>052.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EST FRIDAY FOR AMZ350-352-354.
SMALL CRAFT ADVISORY UNTIL 5 PM EST FRIDAY FOR AMZ374.
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