088
FXUS62 KCHS 170858
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
358 AM EST MON FEB 17 2025
SYNOPSIS
HIGH PRESSURE WILL BUILD INTO THE AREA TODAY INTO TUESDAY. A
LOW PRESSURE SYSTEM WILL MOVE ACROSS THE REGION ON WEDNESDAY,
WITH HIGH PRESSURE RETURNING AT THE END OF THE WEEK.
NEAR TERM /THROUGH TONIGHT/
HIGH PRESSURE WILL BUILD ACROSS THE FORECAST AREA THROUGH TODAY AND
TONIGHT. WINDS SHOULD REMAIN FROM THE NORTH-NORTHWEST THROUGH MUCH
OF THE DAY, WITH GUSTS NEAR 20 MPH POSSIBLE AT TIMES THIS MORNING.
THE COMBINATION OF SUNNY CONDITIONS, STEADY NNW WINDS, AND COOL LLVL
THICKNESSES, TEMPERATURES SHOULD REMAIN BELOW NORMAL TODAY. USING A
BLEND OF MOS, HIGH TEMPERATURES ARE FORECAST TO RANGE IN THE MID
50S, SOME UPPER 50S EXPECTED ACROSS EXTREME SE GA. DEWPOINTS SHOULD
DROP INTO THE MID TO UPPER 20S, WITH RH VALUES FALLING INTO 30S THIS
AFTERNOON.
A LOBE OF HIGH PRESSURE WILL SETTLE OVER THE CWA THIS EVENING AND
WILL REMAIN THROUGH TONIGHT. WINDS SHOULD DECOUPLE BY SUNSET, WITH
LITTLE TO NO WINDS THROUGH THE NIGHT. GIVEN ONLY THIN HIGH CLOUDS,
DEEP DRY AIR, AND CALM CONDITIONS, SEVERAL HOURS OF GOOD RADIATIONAL
COOLING CONDITIONS SHOULD OCCUR TONIGHT. LOW TEMPERATURES ARE
FORECAST TO RANGE FROM AROUND 30 DEGREES INLAND TO THE UPPER 30S
ALONG THE COAST.
SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/
NOT A WHOLE LOT GOING ON TUESDAY AS A WEAK AREA OF LOW PRESSURE
TRIES TO DEVELOP OFF THE SOUTHEAST COAST, WITH AFTERNOON HIGHS IN
THE UPPER 50S TO LOWER 60S. CLOUD COVERAGE STARTS TO INCREASE INTO
THE EVENING HOURS AS OUR NEXT SYSTEM GETS ORGANIZED OVER TEXAS, WITH
OVERNIGHT LOWS IN THE LOWER TO UPPER 40S EXPECTED.
BY WEDNESDAY MORNING, THE PREFRONTAL TROUGH JUST ALONG THE COAST MAY
RESULT IN SOME WEAK SHOWERS, THOUGH THE BULK OF THE PRECIPITATION
WILL ARRIVE AS THE MID-LEVEL SHORTWAVES AND SURFACE LOW MOVE ACROSS
THE REGION. THIS LOOKS TO OCCUR DURING THE LATE MORNING INTO THE
AFTERNOON HOURS, WITH RAINFALL ENDING OVERNIGHT INTO THURSDAY AS WE
QUICKLY TRANSITION FROM THE RIGHT ENTRANCE REGION OF ONE UPPER LEVEL
JET INTO THE RIGHT EXIT REGION OF THE NEXT JET STREAK.
PRECIPITABLE WATER VALUES (PWATS) BY MIDDAY LOOK TO BE SITTING
NEAR THE 1.25" MARK, WHICH ACCORDING TO THE ENSEMBLE SITUATIONAL
AWARENESS TABLES (ESATS) IS JUST ABOVE THE 90TH PERCENTILE OF
CLIMATOLOGY . SO, DESPITE NOT HAVING MUCH (OR ANY) CAPE TO WORK
WITH, THE SHOWERS WILL BE EFFICIENT RAINFALL MAKERS GIVEN THE
AMPLE PWATS AND DEPTHS OF THE WARM CLOUD PROCESSES EXCEEDING
2000-3500 METERS, WITH TOTAL RAINFALL AMOUNTS GENERALLY IN THE
1-1.5" RANGE. NOT EXPECTING ANY FLOODING RISKS WITH THESE
RAINFALL AMOUNTS.
WILL HAVE A BIT OF A RANGE OF MAX TEMPERATURES ON WEDNESDAY, AS
PORTIONS OF THE AREA LOOK TO START THE DAY JUST BEHIND A QUASI-COLD
FRONT, IMPACTING AREAS FURTHER INLAND WITH HIGHS IN THE 40S WHILE
THOSE CLOSER TO THE COAST LOOK TO REACH INTO THE UPPER 50S.
OVERNIGHT INTO THURSDAY, MUCH COLDER AIR FILTERS DOWN INTO THE
LOWCOUNTRY, WITH EARLY MORNING TEMPERATURES IN THE LOWER TO MID 30S
EXPECTED. THROUGHOUT THE REST OF THE DAY, SURFACE HIGH PRESSURE
BUILDS ACROSS THE CENTRAL US SENDING COOLER AND DRY AIR ACROSS THE
REGION. AFTERNOON HIGHS IN THE UPPER 40S TO MID 50S EXPECTED.
LONG TERM /FRIDAY THROUGH SUNDAY/
FRIDAY WILL SEE THE AFOREMENTIONED SURFACE HIGH PRESSURE OVER THE
CENTRAL US CONTINUE TO SLOWLY DRIFT EASTWARDS, WHICH WILL CONTINUE
THE COLD AIR ADVECTION ACROSS THE AREA THROUGH AT LEAST THE MORNING
HOURS. TAKING A LOOK AT THE ESATS, BOTH SETS SHOW TEMPERATURES NEAR
THE SURFACE ARE IN THE BOTTOM 0.5 PERCENTILE OF CLIMATOLOGY. USING
THE EXTREME FORECAST INDEX, TEMPERATURES DON'T LOOK TO BREAK ANY
RECORDS, AS ONLY ONE SHIFT OF TAILS (SOT) IS BEING POPULATED, WHICH
INDICATES THAT AT LEAST 10% OF THE ENSEMBLE MEMBERS ARE FORECASTING
BELOW MODEL CLIMATE. SO, IT SHOULD BE NO SURPRISE THAT WE ARE NOT
GOING TO BE QUITE COLD ENOUGH TO BREAK ANY RECORDS, THROUGH EARLY
MORNING TEMPERATURES IN THE 20S WILL CERTAINLY FEEL CRISP. GIVEN
SOME LIGHT BREEZES, WIND CHILLS IN THE 20S AND UPPER TEENS ARE ALSO
EXPECTED, WHICH MAY REQUIRE A COLD WEATHER ADVISORY FOR A FEW HOURS.
CLEAR SKIES WILL ALLOW FOR TEMPERATURES TO RISE BACK UP INTO THE
UPPER 40S TO LOWER 50S FOR FRIDAY AFTERNOON, WITH TEMPERATURES
RISING INTO THE LOWER TO MID 60S BY MONDAY.
AVIATION /09Z MONDAY THROUGH FRIDAY/
KCHS/KJZI/KSAV: VFR WILL PREVAIL WITH THE 06Z TAFS. GUSTY
NORTHWEST WINDS EXPECT THROUGH LATE TONIGHT AS COLDER AIR MOVES
IN, WINDS WILL EASE OFF DURING THE PRE-DAWN HOURS. WINDS SHOULD
DECOUPLE THIS EVENING WITH CALM WINDS EXPECTED UNTIL DAYBREAK
TUESDAY.
EXTENDED AVIATION OUTLOOK: VFR WILL PREVAIL THROUGH TUESDAY. FLIGHT
RESTRICTIONS ARE POSSIBLE WEDNESDAY INTO WEDNESDAY NIGHT AS LOW
PRESSURE PASSES ACROSS THE REGION. VFR IS EXPECTED TO RETURN
THEREAFTER.
MARINE
TODAY, HIGH PRESSURE WILL GRADUALLY INCREASE ACROSS THE MARINE ZONES
TODAY. GUSTY NNW WINDS SHOULD OCCUR THIS MORNING, THEN SHIFTING FROM
THE NE THIS AFTERNOON WITH SPEEDS FALLING BELOW 10 KTS. SMALL CRAFT
ADVISORIES (SCA) HIGHLIGHTING GUSTY WINDS AND ELEVATED WAVE HEIGHTS
WILL REMAIN IN EFFECT OUTSIDE THE CHS HARBOR THIS MORNING. ACROSS
THE OUTER GA WATERS, SEAS MAY REMAIN AROUND 6 FT THROUGH MID-DAY,
SCA SHOULD END EARLY THIS AFTERNOON. BY LATE THIS AFTERNOON, SEAS
ACROSS THE MARINE ZONES ARE FORECAST TO SUBSIDE TO 2 TO 3 FT.
TONIGHT, A LOBE OF HIGH PRESSURE WILL PUSH OVER THE REGION AND
SHOULD RELAX THE PRESSURE GRADIENT. NORTHEAST WINDS ARE FORECAST TO
REMAIN BETWEEN 5 TO 10 KTS WITH SEAS BETWEEN 2 TO 3 FT.
TUESDAY THROUGH SATURDAY: NORTHEAST WINDS ARE FORECAST TO INCREASE
BETWEEN 10 TO 15 KTS ON TUESDAY. SEAS SHOULD REMAIN BETWEEN 2 TO 3
FT ON TUESDAY. ON WEDNESDAY, AN INVERTED TROUGH OR A COASTAL LOW IS
EXPECTED TO DEEPEN ACROSS THE MARINE ZONES. WINDS SHOULD STRENGTHEN
ON WEDNESDAY INTO THURSDAY NIGHT, WITH GUSTS AROUND 25 KTS POSSIBLE
OUTSIDE THE CHS HARBOR. IN ADDITION, SEAS SHOULD BUILD DURING THE
MID-WEEK, GENERALLY BETWEEN 3 TO 5 FT WITH PERIODS OF 6 FT SEAS
ACROSS THE OUTER GA AND CHARLESTON COUNTY NEARSHORE WATERS. SCAS
WILL BE POSSIBLE FOR PORTIONS OF THE ATLANTIC WATERS WEDNESDAY INTO
THURSDAY NIGHT. HIGH PRESSURE WILL RETURN TO THE REGION FRIDAY
THROUGH SATURDAY. WINDS AND SEAS SHOULD REMAIN BELOW SCA
CRITERIA.
TIDES/COASTAL FLOODING
AS WINDS TURN FROM THE NORTHWEST TIDAL DEPARTURES WILL CONTINUE
TO DECREASE AND APPROACH A FOOT BELOW NORMAL MLLW. THE NEXT LOW
TIDE FORECAST DURING THE PRE-DAWN HOURS MONDAY AT CHARLESTON
HARBOR AND FORT PULASKI WILL BE BETWEEN -0.5 AND -1.0 FT MLLW.
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR
AMZ330.
SMALL CRAFT ADVISORY UNTIL 10 AM EST THIS MORNING FOR AMZ350-
352-354.
SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR AMZ374.
NEAR TERM...NED
SHORT TERM...APT
LONG TERM...APT
AVIATION...NED
MARINE...NED
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