113
FXUS62 KCHS 270627
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
227 AM EDT MON OCT 27 2025
SYNOPSIS
A COASTAL LOW PRESSURE SYSTEM WILL IMPACT THE REGION TODAY INTO
TONIGHT. HIGH PRESSURE WILL THEN BUILD INTO THE REGION BEFORE A
COLD FRONT MOVES THROUGH LATE WEEK.
NEAR TERM /THROUGH TONIGHT/
SATELLITE WATER VAPOR SHOWED A CLOSED LOW OVER THE MISSISSIPPI RIVER
VALLEY AND A PLUME OF DEEP MOISTURE ACROSS THE SOUTHEAST U.S. THE
SFC PATTERN WILL FEATURE A WEDGED AREA OF HIGH PRESSURE ACROSS THE
CAROLINAS AND GA AND LOW PRESSURE OVER THE NEARSHORE WATERS. THIS
PATTERN WILL SUPPORT A PROLONGED PERIOD OF LLVL ISENTROPIC LIFT.
RECENT RUNS OF THE HRRR AND HREF INDICATES THAT SHOWERS WILL
GRADUALLY INCREASE IN COVERAGE ACROSS SE GA AND THE SC LOWCOUNTRY
THROUGH TODAY. THE RAINFALL SHOULD DEVELOP INTO A BROAD BAND AS THE
COASTAL LOW DEVELOPS THIS AFTERNOON. THIS BAND SHOULD RESULT IN
NEARLY 100 POPS ACROSS THE SC LOWCOUNTRY THIS AFTERNOON. ROUNDS OF
RAINFALL, THICK CLOUD COVER, AND GUSTY NORTHEAST WINDS SHOULD LIMIT
HIGHS TO THE 60S, POSSIBLY REACHING 70 DEGREES ACROSS EXTREME SE
GA. THESE TEMPERATURES MAY NEED TO BE ADJUSTED COOLER, BASED ON
UPCOMING TEMPERATURE TRENDS DURING RAINFALL.
THIS EVENING, THE COASTAL LOW SHOULD TRACK NE OFF THE SC COAST.
ROUNDS OF MODERATE RAINFALL, POSSIBLY WITH EMBEDDED ISOLATED
THUNDERSTORMS, MAY REMAIN THROUGH THE EVENING HOURS. RAINFALL RATES
SHOULD DECREASE SHARPLY AFTER MIDNIGHT. RAINFALL AMOUNTS FROM TODAY
THROUGH TONIGHT MAY RANGE FROM NEAR ONE INCH INLAND TO 2-2.5 INCHES
ACROSS THE COASTAL COUNTIES. LOW TEMPERATURES SHOULD FAVOR VALUES IN
THE 50S.
LAKE WINDS: WIND GUSTS ACROSS LAKE MOULTRIE MAY APPROACH 25 KTS LATE
THIS AFTERNOON INTO THIS EVENING. IT IS POSSIBLE A LAKE WIND
ADVISORY COULD BE ISSUED LATER TODAY.
SHORT TERM /TUESDAY THROUGH THURSDAY/
TUESDAY: WEAK TROUGHING WILL PREVAIL ALOFT, WHILE AT THE SURFACE LOW
PRESSURE OFF THE SOUTHEASTERN COASTLINE WILL PROGRESS NORTHEASTWARD.
HIGH PRESSURE WILL BUILD IN AT THE SURFACE SETTING UP A COLD AIR
DAMMING (CAD) SCENARIO. RAINFALL ASSOCIATED WITH THE DEPARTING LOW
PRESSURE SYSTEM WILL WANE IN THE MORNING HOURS, WITH CLOUDINESS
LINGERING THROUGH THE REMAINDER OF THE DAY. WHILE THE NBM FEATURES
HIGH TEMPERATURES IN THE UPPER 50S TO MID 60S, WITH STRONG CAD IN
PLACE, TEMPERATURES WILL LIKELY STRUGGLE TO GET OUT OF THE 50S
ACROSS MOST LOCATIONS.
WEDNESDAY: THE UPPER LEVELS WILL FEATURE A TROUGH OVER ARKLATEX,
WITH THE LOCAL FORECAST AREA POSITIONED ON THE DOWNSTREAM SIDE OF
THIS TROUGH. AT THE SURFACE, NOT MUCH CHANGE IN THE PATTERN IS
EXPECTED, WITH CAD PRESENT DUE TO HIGH PRESSURE BUILDING IN FROM THE
NORTH. A COLD FRONT WILL APPROACH FROM THE WEST LATER IN THE DAY,
CAUSING THE CAD TO BREAK DOWN. THIS WILL ALLOW TEMPERATURES TO REACH
INTO THE UPPER 60S TO AROUND 70. AS THE COLD FRONT APPROACHES
MOISTURE WILL ALSO INCREASE, WITH PWATS FORECAST TO EXCEED 1" BY THE
AFTERNOON HOURS. ISOLATED TO SCATTERED SHOWERS ARE POSSIBLE IN THE
AFTERNOON AND INTO THE OVERNIGHT HOURS.
THURSDAY: THE UPPER LEVEL TROUGH WILL PROGRESS TOWARDS NEW ENGLAND,
WITH AN ASSOCIATED SURFACE COLD FRONT PUSHING THROUGH THE REGION. AS
HIGH PRESSURE BUILDS IN FROM THE WEST, TEMPERATURES WILL BE BELOW
NORMAL, ONLY REACHING INTO THE LOW TO MID 60S. A RAIN-FREE FORECAST
HAS BEEN MAINTAINED.
LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/
HIGH PRESSURE WILL DOMINATE AT THE SURFACE INTO THE WEEKEND, WHILE
ZONAL FLOW PREVAILS ALOFT. A COOLER AIRMASS WILL BE IN PLACE INTO
THE WEEKEND, WITH TEMPERATURES SEVERAL DEGREES BELOW NORMAL. FRIDAY
NIGHT IS FORECAST TO BE THE COOLEST OF THE PERIOD, WITH LOWS IN THE
UPPER 30S INLAND AND MID 40S ALONG THE COASTAL COUNTIES (AROUND 50
AT THE BEACHES). FROST CANNOT BE RULED OUT FAR INLAND ON FRIDAY
NIGHT. ANOTHER UPPER LEVEL TROUGH COULD IMPACT THE REGION LATE IN
THE WEEKEND, BRINGING THE REGION THE NEXT CHANCE OF RAINFALL.
AVIATION /06Z MONDAY THROUGH FRIDAY/
6Z TAFS: THE SFC PATTERN WILL FEATURE A WEDGED AREA OF HIGH
PRESSURE ACROSS THE CAROLINAS AND GA AND LOW PRESSURE OVER THE
NEARSHORE WATERS. THIS PATTERN WILL SUPPORT A PROLONGED PERIOD
OF LLVL ISENTROPIC LIFT. AS A RESULT, CLOUD BASES SHOULD
GRADUALLY LOWER THROUGH THE TAF PERIOD, REACHING IFR THIS
MORNING. THE RESTRICTIVE CEILINGS WILL LIKELY PERSIST THROUGH
THE REST OF THE PERIOD. RAINFALL RATES SHOULD PEAK THIS
AFTERNOON AND EVENING, WITH SOME RISK OF TSRA. THE TAFS WILL
FEATURE AT LEAST MVFR VISIBILITY DURING RAINFALL WITH PROB30S
FROM 0-6Z FOR TSRA. NORTHEAST WINDS SHOULD FAVOR SPEEDS AROUND
15 KTS WITH GUSTS BETWEEN 20 TO 25 KTS.
EXTENDED AVIATION OUTLOOK: LOW CIGS ARE POSSIBLE TUESDAY AND
WEDNESDAY AS A WEDGE OF HIGH PRESSURE BUILDS INTO THE REGION.
ANOTHER COLD FRONT PUSHING THROUGH THE REGION WEDNESDAY INTO
THURSDAY COULD BRING ISOLATED SHOWERS TO THE TERMINALS. VFR WILL
RETURN LATE WEEK.
MARINE
TODAY AND TONIGHT: THE SFC PATTERN SHOULD YIELD GUSTY ENE WINDS
BETWEEN 15 TO 20 KTS WITH GUSTS BETWEEN 25 TO 30 KTS. AS THE COASTAL
LOW TRACKS OVER THE COASTAL WATERS OF GA/SC THIS EVENING, GUSTS
ACROSS THE CHARLESTON COUNTY NEARSHORE WATERS COULD APPROACH GALES.
SMALL CRAFT ADVISORIES WILL REMAIN IN EFFECT FOR ALL MARINE ZONES
THROUGH THE NEAR TERM PERIOD. WAVE HEIGHTS SHOULD PEAK THIS EVENING,
RANGING BETWEEN 5 TO 10 FT.
TUESDAY THROUGH FRIDAY: HIGH PRESSURE WILL BUILD OVER THE REGION
TUESDAY AND INTO WEDNESDAY, YIELDING NE WINDS WITH GUSTS UPWARDS OF
30 KNOTS. THERE IS A CHANCE THAT SOME GUSTS IN THE CHARLESTON COUNTY
NEARSHORE WATERS COULD APPROACH GALE FORCE. A SMALL CRAFT ADVISORY
IS IN EFFECT FOR ALL MARINE ZONES, INCLUDING THE CHARLESTON HARBOR.
A COLD FRONT WILL PUSH THROUGH THE REGION WEDNESDAY INTO THURSDAY,
CAUSING ANOTHER BATCH OF WIND GUSTS UP TO 30 KNOTS. THE SMALL CRAFT
ADVISORIES WILL REMAIN IN EFFECT THROUGH THE PERIOD. SEAS WILL
INCREASE THROUGH THE PERIOD, WITH 5-6 FT BY THURSDAY ACROSS THE
NEARSHORE WATERS AND 7-8 FT IN THE 20-60 NM OFFSHORE GA WATERS.
RIP CURRENTS: A COMBINATION OF INCREASING SWELL AND STRONG NE WINDS
WILL YIELD A HIGH RISK OF RIP CURRENTS AT ALL AREA BEACHES TODAY AND
TUESDAY. AN ENHANCED RISK OF RIP CURRENTS WILL LIKELY PERSIST INTO
MID-WEEK.
TIDES/COASTAL FLOODING
CHARLESTON TIDE GAGE: DUE TO INCREASING NE FLOW THERE IS A RISK OF
MINOR COASTAL FLOODING WITH THE LATE MORNING/EARLY AFTERNOON HIGH
TIDES THROUGH MID-WEEK. THE CURRENT FORECAST FEATURES A FORECAST OF
6.9 FT MLLW FOR TODAY AND TUESDAY, WITH 7.1 FT MLLW ON WEDNESDAY.
COASTAL FLOOD ADVISORIES WILL LIKELY BE REQUIRED.
CLIMATE
RECORD PRECIPITATION:
OCTOBER 27:
KCHS: 1.07/2006
KCXM: 1.49/1985
KSAV: 2.22/1888
CHS WATCHES/WARNINGS/ADVISORIES
GA...HIGH RISK FOR RIP CURRENTS THROUGH THIS EVENING FOR GAZ117-119-139-
141.
SC...HIGH RISK FOR RIP CURRENTS THROUGH THIS EVENING FOR SCZ048>051.
MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TUESDAY NIGHT FOR
AMZ330.
SMALL CRAFT ADVISORY UNTIL 6 AM EDT FRIDAY FOR AMZ350.
SMALL CRAFT ADVISORY UNTIL 11 PM EDT THURSDAY FOR AMZ352.
SMALL CRAFT ADVISORY UNTIL 2 PM EDT THURSDAY FOR AMZ354.
SMALL CRAFT ADVISORY UNTIL 8 PM EDT FRIDAY FOR AMZ374.
NEAR TERM...NED
SHORT TERM...CPM
LONG TERM...CPM
AVIATION...CPM/NED
MARINE...CPM/NED
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