647
FXUS62 KCHS 162017
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
317 PM EST SUN FEB 16 2025
SYNOPSIS
HIGH PRESSURE WILL BUILD INTO THE AREA TONIGHT THROUGH TUESDAY.
A LOW PRESSURE SYSTEM WILL MOVE ACROSS THE REGION DURING THE
MIDDLE OF THE WEEK. HIGH PRESSURE WILL THEN RETURN LATE WEEK.
NEAR TERM /UNTIL 6 AM MONDAY MORNING/
TODAY: ALL PRECIPITATION HAS EXITED THE REGION THIS AFTERNOON
WITH A SURFACE COLD FRONT APPROACHING THE SC/ GA COAST. WINDS
BEHIND THE COLD FRONT ARE GENERALLY GUSTING 20 TO 30 KT.
TONIGHT: SURFACE HIGH PRESSURE WILL BEGIN TO SLOWLY BUILD INTO
THE AREA WITH THE PRESSURE GRADIENT WEAKENING. WINDS WILL BE
GUSTY AT TIMES (UP TO 25 KT) INITIALLY WITH GUSTS BECOMING MORE
AND MORE TRANSIENT. THE PBL DOESN'T FULLY DECOUPLE THOUGH, SO
WINDS WILL NOT GO CALM TONIGHT (DUE TO THE CAA). EXPECT LOW
TEMPERATURES GENERALLY IN THE MID 30S.
SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY NIGHT/
HIGH PRESSURE WILL EXPAND ACROSS THE REGION MONDAY INTO TUESDAY.
DEEP DRY AIR WILL BE IN PLACE, MAINTAINING A RAIN-FREE FORECAST.
PLENTY OF SUNSHINE IS EXPECTED FOR MONDAY THEN THERE WILL BE AN
INCREASE IN CLOUD COVER ON TUESDAY AHEAD OF THE NEXT WEATHER SYSTEM.
SOME SHOWER ACTIVITY COULD START TO DEVELOP LATE TUESDAY NIGHT, BUT
THE BULK OF PRECIPITATION IS EXPECTED BEYOND DAYBREAK WEDNESDAY.
COOLER HIGHS IN THE MID 50S MONDAY WILL MODERATE CLOSER TO NORMAL
FOR TUESDAY. SOLID RADIATIONAL COOLING CONDITIONS MONDAY NIGHT WILL
BRING LOWS DOWN TO THE 30-35F RANGE MOST LOCATIONS INLAND OF THE
COAST, THEN MORE MILD IN THE 40S TUESDAY NIGHT UNDER CLOUDY SKIES.
WEDNESDAY WILL BE THE MOST ACTIVE DAY OF THE SET. LOW PRESSURE IS
EXPECTED TO ORGANIZE OVER THE NORTHERN GULF REGION THEN TRACK
NORTHEAST NEAR OR ALONG THE SOUTHEAST COAST ON WEDNESDAY, BEFORE
PULLING AWAY FROM THE LOCAL AREA WEDNESDAY NIGHT. THERE IS AMPLE
LARGE SCALE FORCING FOR ASCENT WITH THE AREA LOCATED IN THE
FAVORABLE RIGHT REAR QUADRANT OF THE UPPER JET AND MID LEVEL ENERGY
PASSING ACROSS THE REGION. PWATS SURGE WELL ABOVE CLIMATOLOGICAL
NORMS FOR THIS TIME OF YEAR, WITH MODELS PROGS SHOWING VALUES
APPROACHING OR EVEN EXCEEDING 1.3 INCHES. THIS SET-UP WILL ALLOW
WIDESPREAD SHOWERS TO OVERSPREAD THE AREA. AREA-WIDE RAINFALL
AMOUNTS LOOK TO AVERAGE IN THE 1-1.5 INCH RANGE, WHICH SHOULD NOT
POSE MUCH OF A FLOODING RISK. THERE IS SOME DEPENDENCY ON TRACK OF
THE LOW AS TO THE AMOUNT OF INSTABILITY (OR LACK THEREOF) THAT WILL
DEVELOP, BUT CURRENTLY MODEL PROGS ARE RATHER UNIMPRESSIVE SO NO
MENTION OF THUNDER IS IN THE FORECAST AT THIS TIME. TEMPERATURES
WILL LIKELY BE A CHALLENGE WITH A POTENTIALLY NOTABLE GRADIENT
ACROSS THE AREA. FAR INLAND LOCATIONS COULD REMAIN ON THE COOL SIDE,
TOPPING OUT IN THE UPPER 40S, WHILE CLOSER TO THE COAST MAY REACH
THE UPPER 50S, TO PERHAPS LOWER 60S IN COASTAL SOUTHEAST GEORGIA.
COLDER AND DRIER AIR WILL ADVECT INTO THE AREA WEDNESDAY NIGHT AS
THE LOW LIFTS AWAY. AT THIS POINT, THE THREAT FOR ANY NON-LIQUID
PRECIPITATION LOOKS PRETTY LOW AS IT APPEARS TO BE THE CLASSIC CASE
OF COLDER TEMPERATURES CHASING THE DEEPER MOISTURE.
LONG TERM /THURSDAY THROUGH SUNDAY/
CHILLY AND DRY HIGH PRESSURE IS EXPECTED TO BUILD IN FOR LATE WEEK.
TEMPERATURES WILL BE WELL BELOW CLIMATOLOGY - BY AROUND 10-15
DEGREES. IT WILL BE COLDEST THURSDAY NIGHT WHEN LOWS DIP WELL INTO
THE 20S ACROSS MOST LOCATIONS AWAY FROM THE IMMEDIATE COAST, AND
THERE REMAINS POTENTIAL FOR SOME AREAS TO REACH COLD WEATHER
ADVISORY CRITERIA (WIND CHILL 20F OR COLDER). OTHERWISE, RAIN-FREE
CONDITIONS ARE EXPECTED THROUGH FRIDAY. THERE ARE HINTS THAT A WEAK
COASTAL TROUGH COULD DEVELOP ON SATURDAY AND PERHAPS BRING A
FEW SHOWERS. POPS ARE NO HIGHER THAN 20%.
AVIATION /20Z SUNDAY THROUGH FRIDAY/
THIS AFTERNOON: ALL TAF SITES ARE VFR THIS AFTERNOON AS THE LINE
OF SHOWERS (AND ISOLATED RUMBLES OF THUNDER) HAVE EXITED THE
COAST. STRATIFORM RAIN REMAINS ACROSS COASTAL SC/ GA AND IS
FORECAST TO EXIT THE COAST OVER THE NEXT HOUR OR TWO. A COLD
FRONT WILL THEN SWEEP ACROSS THE TAF SITES WITH WINDS TURNING
FROM THE WEST WITH GUSTS UP TO 30 KT.
TONIGHT: VFR. HIGH PRESSURE WILL SLOWLY BUILD INTO THE REGION
FROM THE NORTHWEST WITH WIND GUSTS BECOMING MORE INFREQUENT
THROUGH THE NIGHT. TAKING A LOOK AT FORECAST SOUNDINGS, SHOWS A
PBL NOT FULL DECOUPLING THOUGH THANKS TO THE STRONG CAA. SO TAF
SITES WILL LIKELY NOT LOSE THE WIND GUSTS COMPLETELY THOUGH THE
NIGHT.
MONDAY: VFR. WEAK HIGH PRESSURE WILL BUILD OVERHEAD WITH WINDS
SLACKENING TO BELOW 10 KT. NO CLOUDS ARE EXPECTED.
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
THIS AFTERNOON: WINDS HAVE FALLEN BELOW GALE CRITERIA FOR THE
GA WATERS AS WELL AS AMZ352 AS THE LINE OF SHOWERS HAS SINCE
EXITED THE REGION. THESE ZONES HAVE BEEN TRANSITIONED TO A SMALL
CRAFT ADVISORY (ALONG WITH THE CHARLESTON HARBOR). THE
CHARLESTON ADJACENT WATERS IS THE ONLY ZONE LEFT WITH A GALE
WARNING. THIS WILL LIKELY BE ABLE TO BE TRANSITIONED TO A SMALL
CRAFT BY THIS EVENING.
TONIGHT: A SURFACE COLD FRONT WILL SWEEP ACROSS THE WATERS WITH
WINDS VEERING FROM THE NORTHWEST 20 TO 25 KT WITH GUSTS UP TO 30
KT AND SEAS 6 TO 9 FT. SURFACE HIGH PRESSURE WILL BUILD IN FROM
THE NORTHWEST WITH THE GRADIENT STARTING TO SLOWLY RELAX. AS
THIS OCCURS WINDS WILL SLOWLY FALL, BUT REMAIN ABOVE SMALL CRAFT
ADVISORY CRITERIA.
MONDAY THROUGH FRIDAY: WINDS AND SEAS WILL SUBSIDE THROUGH THE DAY
ON MONDAY, WITH ALL SMALL CRAFT ADVISORIES EXPECTED TO BE DOWN BY
EARLY AFTERNOON. WINDS GRADUALLY TURN FROM THE NORTH TO NORTHEAST BY
TUESDAY, WITH SPEEDS SETTLING BELOW 15 KNOTS AND SEAS 2-3 FEET. THE
NEXT TIME PERIOD OF CONCERN IS WEDNESDAY INTO WEDNESDAY NIGHT AS LOW
PRESSURE PASSES ACROSS THE REGION, THOUGH THERE IS SOME UNCERTAINTY
ON THE EXACT TRACK OF THE LOW. REGARDLESS, SMALL CRAFT ADVISORIES
WILL BE POSSIBLE. THE LOW WILL PULL AWAY ON THURSDAY, BUT MARINE
CONDITIONS COULD STAY ELEVATED INTO FRIDAY BEFORE THE PRESSURE
GRADIENT EASES. HIGH SURF: GIVEN THAT SEAS ARE 6-10 FEET ON
THE NEARSHORE WATERS, A HIGH SURF ADVISORY FOR CHARLESTON COUNTY
REMAINS IN EFFECT. ELSEWHERE, THE FLOW IS MORE PARALLEL TO THE
COAST.
TIDES/COASTAL FLOODING
AS WINDS TURN FROM THE NORTHWEST TIDAL DEPARTURES WILL CONTINUE
TO DECREASE AND APPROACH A FOOT BELOW NORMAL MLLW. THE OVERALL
LOW TIDE FORECAST AT CHARLESTON HARBOR AND FORT PULASKI WILL BE
BEWTEEN -0.5 TO -1.0 FT MLLW.
CHS WATCHES/WARNINGS/ADVISORIES
GA...WIND ADVISORY UNTIL 6 PM EST THIS EVENING FOR GAZ087-088.
SC...WIND ADVISORY UNTIL 6 PM EST THIS EVENING FOR SCZ040-042>045-
049-050-052.
HIGH SURF ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR SCZ050.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST MONDAY FOR AMZ330.
GALE WARNING UNTIL 6 PM EST THIS EVENING FOR AMZ350.
SMALL CRAFT ADVISORY UNTIL 10 AM EST MONDAY FOR AMZ352-354.
SMALL CRAFT ADVISORY UNTIL 1 PM EST MONDAY FOR AMZ374.
NEAR TERM...HAINES
SHORT TERM...ETM
LONG TERM...ETM
AVIATION...ETM/HAINES
MARINE...ETM/HAINES
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