115
FXUS62 KCHS 160920
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
520 AM EDT TUE SEP 16 2025
SYNOPSIS
HIGH PRESSURE WILL EXTEND ACROSS THE REGION. LOW PRESSURE WILL
MEANDER NEAR THE NORTH CAROLINA OUTER BANKS THROUGH THE MIDDLE
OF THE WEEK. A COLD FRONT COULD APPROACH FROM THE NORTH EARLY
IN THE WEEKEND.
NEAR TERM /THROUGH TONIGHT/
THE SYNOPTIC PATTERN HAS CHANGED LITTLE OVER THE PAST 24 HOURS
WITH A PSEUDO REX BLOCK IN PLACE ACROSS THE EASTERN CONUS AND
~1008 MB NON-TROPICAL LOW PRESSURE LOCATED ABOUT 100 MI EAST OF
CAPE HATTERAS. THE REX BLOCK WILL BEGIN TO BREAK DOWN TODAY AS
THE LARGE, UPPER-LEVEL ANTICYCLONE OVER THE GREAT LAKES WEAKENS
IN RESPONSE TO A SHARP SHORTWAVE THAT IS DIGGING ACROSS THE
CANADIAN PRAIRIES. THIS WILL ALLOW THE UPPER LOW POSITIONED OVER
THE CAROLINAS TO MEANDER NORTH INTO THE VIRGINIA TIDEWATER
TONIGHT. LOCALLY, A WEDGE OF HIGH PRESSURE WILL MAINTAIN ITS
INFLUENCE ON THE REGION TODAY AS THE SLOWLY DEEPENING SURFACE
LOW OFF THE NORTH CAROLINA OUTER BANKS PROPAGATES NORTHWEST AND
APPROACHES THE PAMLICO AND ALBEMARLE SOUNDS.
CONDITIONS WILL REMAIN RAIN-FREE ACROSS THE LOWCOUNTRY AND
SOUTHEAST GEORGIA THROUGH TONIGHT. HIGHS WILL WARM INTO THE MID-
UPPER 80 WEST OF I-95 WITH LOWER-MID 80S ACROSS THE COASTAL
CORRIDOR. THE BEACHES WILL REMAIN A TAD COOLER IN THE LOWER 80S.
THE BOUNDARY LAYER WILL DECOUPLE AGAIN AFTER SUNSET WITH SOLID
RADIATIONAL CONDITIONS EXPECTED TO PREVAIL OVERNIGHT. SOME THIN
HIGH CLOUDS MAY BEGIN TO INCREASE FROM THE SOUTHWEST LATE, BUT
THESE SHOULD NOT HAVE TOO MUCH OF AN IMPACT ON THE RADIATIONAL
SET UP. LOWS WILL RANGE FROM THE UPPER 50S/LOWER 60S INLAND TO
THE UPPER 60S/NEAR 70 AT THE BEACHES. SOME OF THE NORMALLY
COLDER, MORE SHELTERED SPOTS ACROSS THE INTERIOR COULD DIP INTO
THE MID 50S JUST BEFORE DAYBREAK WEDNESDAY.
SHORT TERM /WEDNESDAY THROUGH FRIDAY/
HIGH PRESSURE WILL BE THE PRIMARY SURFACE FEATURE OVER THE
LOCAL AREA THROUGH FRIDAY. AN AREA OF LOW PRESSURE NEAR THE
NC/VA COAST AT THE START OF THE PERIOD WILL TRACK NORTHEAST AND
AWAY FROM THE REGION WITH TIME. ALOFT, A MID LEVEL LOW AND
ASSOCIATED TROUGH AXIS EXTENDING OVER THE AREA WILL LIFT,
ALLOWING HEIGHTS TO BUILD. QUIET AND DRY WEATHER IS FORECAST TO
PERSIST THROUGH THE PERIOD, ALTHOUGH ITS WORTH NOTING SOME
GUIDANCE HINTS AT A FEW SHOWERS ON THURSDAY WITH SHORTWAVE
ENERGY ROTATING THROUGH ALONG THE BASE OF THE TROUGH. POPS
REMAIN SILENT AT THIS POINT. TEMPERATURES WILL GRADUALLY WARM
AND BY FRIDAY, HIGHS WILL BE PEAKING IN THE UPPER 80S TO AROUND
90 AWAY FROM THE IMMEDIATE COAST. LOWS WILL BE SEASONABLE.
LONG TERM /FRIDAY NIGHT THROUGH MONDAY/
MID LEVEL RIDGING LOOKS TO GIVE WAY TO AN INCOMING TROUGH EARLY
NEXT WEEK. AT THE SURFACE, A RIDGE OF HIGH PRESSURE WILL EXTEND
SOUTH INTO THE REGION FOR MUCH OF THE PERIOD. LOW-END RAIN
CHANCES (GENERALLY 20-40%) RETURN, ESPECIALLY NEAR THE COAST,
WITH AN INCREASE IN DEEP MOISTURE AND CONVERGENCE WITH A
DEVELOPING COASTAL TROUGH. TEMPERATURES WILL TREND NEAR OR
SLIGHTLY ON THE COOLER SIDE OF NORMAL.
AVIATION /09Z TUESDAY THROUGH SATURDAY/
16/12Z TAF DISCUSSION:
KCHS/KJZI/KSAV: VFR WILL PREVAIL THROUGH 17/12Z.
EXTENDED AVIATION FORECAST: VFR.
MARINE
THROUGH TONIGHT: QUIET CONDITIONS WILL PERSIST ACROSS THE WATERS
TODAY INTO TONIGHT. WINDS WILL REMAIN LESS THAN 10 KT WITH SEAS
2-4 FT.
WEDNESDAY THROUGH SUNDAY: NO MARINE CONCERNS ARE EXPECTED
THROUGH LATE WEEK WITH WIND SPEEDS GENERALLY 15 KNOTS OR LESS
AND SEAS 1-3 FEET. THE PRESSURE GRADIENT WILL TIGHTEN OVER THE
WEEKEND AS HIGH PRESSURE RIDGES SOUTH INTO THE REGION AND A
COASTAL TROUGH DEVELOPS OFFSHORE. THIS WILL LEAD TO INCREASING
SEAS AND GUSTY NORTHEAST WINDS. CONDITIONS COULD APPROACH SMALL
CRAFT ADVISORY CRITERIA.
EQUIPMENT
THE KCLX RADAR WILL BE DOWN FOR MAINTENANCE FROM SEPTEMBER
16-18TH FOR COMPONENT UPGRADES. USERS ARE ENCOURAGED TO USE
ADJACENT WSR-88D RADAR SITES. THESE RADARS INCLUDE:
KCAE: COLUMBIA, SC
KLTX: WILMINGTON, NC
KJAX: JACKSONVILLE, FL
KVAX: MOODY AIR FORCE BASE, GA
KJGX: ROBBINS AIR FORCE BASE, GA:
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...NONE.
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