436
FXUS62 KCHS 310002
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
802 PM EDT THU OCT 30 2025
SYNOPSIS
COOL AND DRY HIGH PRESSURE WILL BUILD ACROSS THE REGION TONIGHT
AND WILL LINGER THROUGH THIS WEEKEND. A LOW PRESSURE SYSTEM
COULD IMPACT THE AREA EARLY NEXT WEEK.
NEAR TERM /UNTIL 6 AM FRIDAY MORNING/
STRONG HIGH PRESSURE WILL EXPAND OVER THE AREA THROUGH TONIGHT.
THE DEPARTING SURFACE LOW IS NOW WELL NORTHEAST OF THE AREA,
HOWEVER BROKEN STRATOCUMULUS ASSOCIATED WITH ITS COMMA HEAD HAS
BEEN EXPANDING INTO THE AREA FROM THE WEST. ALL GUIDANCE
INDICATES THIS CLOUD COVER SHOULD DISSIPATE BY LATE THIS
EVENING, RESULTING IN CLEAR SKIES OVERNIGHT. DECENT WEST WINDS
WILL CONTINUE THROUGH THE EARLY OVERNIGHT HOURS, THEN DIMINISH
LATE. THE DECREASING SURFACE WINDS IN CONCERT WITH CLEARING
SKIES WILL ALLOW SURFACE TEMPS TO RAPIDLY DROP OFF LATER
TONIGHT. FRIDAY MORNING LOWS COULD DIP INTO THE LOWER 40S
INLAND.
1000 MB GEOSTROPHIC WINDS WILL CONTINUE 25-30 KT THROUGH THIS
EVENING SO WE MAINTAINED A LAKE WIND ADVISORY FOR LAKE MOULTRIE
UNTIL 11 PM.
SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/
AN AREA OF SURFACE HIGH PRESSURE WILL BE MEANDERING AROUND THE
SOUTHEAST, THE COOL AND DRY CONDITIONS WILL CONTINUE INTO AND
THROUGHOUT MOST OF THE WEEKEND. EXPECT THE HIGHS ON FRIDAY TO BE IN
THE MID TO UPPER 60S. AS THE SURFACE PRESSURE GRADIENT RELAXES
THROUGHOUT THE DAY ON FRIDAY, EXPECT THE BREEZY WEST-NORTHWEST WINDS
TO SUBSIDE, SETTING THE STAGE FOR A STRONG RADIATIONAL COOLING SETUP
AS SKIES REMAIN CLEAR AND A MODEST TEMPERATURE INVERSION OCCURS.
OVERNIGHT LOW TEMPERATURES FROM THE DETERMINISTIC NBM CONTINUE TO
RUN A COUPLE DEGREES TOO WARM, WHILE AT THE SAME TIME PROVIDING 50
PERCENT OR GREATER PROBABILITIES OF REACHING TEMPERATURES AT OR
BELOW 38, PARTICULARLY FOR INLAND SOUTHEAST SOUTH CAROLINA AND
SOUTHEAST GEORGIA. SO, IN COORDINATION WITH SURROUNDING OFFICES,
DID MIX IN SOME COOLER GUIDANCE TO ACCOUNT FOR THOSE
PROBABILITIES, WHICH THEN ALSO ALLOWS/CONTINUES PATCHY FROST TO
BE REPRESENTED IN THE FORECAST. DOES NOT LOOK LIKE WE'LL SEE
TEMPERATURES DIP BELOW 36, AS PROBABILITIES SIMILARLY DROP INTO
THE 30 PERCENT RANGE FOR TEMPERATURES AT OR BELOW 36 DEGREES, SO
NOT ANTICIPATING A FROST ADVISORY AT THIS TIME. FOR AREAS ALONG
THE COAST, OVERNIGHT LOWS
OTHERWISE, EXPECT DAILY HIGH TEMPERATURES THIS WEEKEND IN THE MID
60S TO LOWER 70S. OVERNIGHT TEMPERATURES SATURDAY INTO SUNDAY RISE
INTO THE LOWER 40S INLAND AND MID 50S ALONG THE COAST. AN UPPER
LEVEL TROUGH BEGINS TO MOVE TOWARDS THE REGION FROM THE DEEP SOUTH
ON SUNDAY, INCREASING CLOUD COVERAGE AS MID/UPPER LEVEL MOISTURE
LEVELS RISE.
LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/
SUNDAY NIGHT INTO MONDAY, THE AFOREMENTIONED TROUGH CONTINUES TO
APPROACH THE AREA FROM THE WEST, WITH THE NORTHERN PART OF ENERGY
LIKELY MOVING THROUGH THE REGION BY MONDAY AFTERNOON, WHILE THE
SOUTHERN PART MAY BREAK OFF INTO A CLOSED OFF UPPER LEVEL LOW. THAT
ALONE INTRODUCES A GREAT DEAL OF UNCERTAINTY AS MODEL AGREEMENT, IN
BOTH THE DETERMINISTIC AND ENSEMBLE SPACE, REGARDING THE
PLACEMENT/TIMING/STRENGTH OF THE TROUGH IS LOW/MODERATE. IN
ADDITION, DETERMINISTIC AND ENSEMBLE GUIDANCE THUS ARE HAVING
TROUBLE AGREEING ON WHERE SURFACE CYCLOGENESIS TAKES PLACE, AND THUS
WHERE THE BULK OF THE RAIN WILL FALL. THE TWO LEADING QPF ENSEMBLE
CLUSTERS WOULD SUGGEST THE BULK OF THE RAIN WILL FALL EITHER ACROSS
EASTER NORTH CAROLINA, OR WELL OFF TO SEA, WHILE THE TRAILING THIRD
SOLUTION (ONLY REPRESENTING 15% OF ENSEMBLES) GIVES THE BULK OF THE
PRECIPITATION OVER EASTERN SOUTH CAROLINA, AND LOWER AMOUNTS IN
SOUTHEAST GEORGIA. THE NBM COVERS THIS UNCERTAINTY WELL ONLY
CARRYING A 20-30% CHANCE FOR SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS, STARTING LATE SUNDAY EVENING AND ENDING LATE MONDAY
EVENING, THOUGH BASED ON THE PREVIOUS CLUSTERING ANALYSIS WE
MAY BE SEEING A DECREASING TREND IN PRECIPITATION POTENTIAL.
TEMPERATURES THROUGHOUT THE TIME PERIOD LOOK TO REMAIN IN THE
MID 60S TO LOWER 70S, WITH OVERNIGHT LOWS IN THE MID 40S TO MID
50S.
SURFACE HIGH PRESSURE BUILDS INTO THE REGION INTO TUESDAY,
CONTINUING THE COOLER TEMPERATURES, WHILE ALSO BRINGING
MARGINALLY-BREEZY CONDITIONS ALONG WITH IT.
AVIATION /00Z FRIDAY THROUGH TUESDAY/
VFR CONDITIONS WILL PREVAIL AT CHS/JZI/SAV TERMINALS THROUGH 00Z
SATURDAY.
EXTENDED AVIATION OUTLOOK: PREVAILING VFR THROUGH SUNDAY. MVFR
CEILINGS POSSIBLE SUNDAY NIGHT AND MONDAY AS LOW PRESSURE AFFECTS
THE AREA.
MARINE
THE NW FLOW WILL CONTINUE TO SLOWLY SUBSIDE THROUGH TONIGHT,
WITH SEAS ALSO STARTING TO COME DOWN. GUSTS IN CHARLESTON HARBOR
COULD GET CLOSE TO 20 KT THROUGH EARLY EVENING. SMALL CRAFT
ADVISORIES CONTINUE FOR ALL OTHER WATERS, THOUGH THEY SHOULD
DROP OFF AROUND MIDNIGHT FOR THE NEARSHORE WATERS FROM BEAUFORT
COUNTY SOUTHWARD.
FRIDAY THROUGH MONDAY: HIGH PRESSURE WILL BUILD OVER THE MARINE
ZONES ON FRIDAY, WINDS DECREASING TO AROUND 10 KTS. WAVE HEIGHTS
SHOULD SUBSIDE DURING THE DAY, FALLING BELOW 6 FT FRIDAY MORNING.
SMALL CRAFT ADVISORIES WILL BE EXPIRING THROUGHOUT THE DAY ON
FRIDAY. HIGH PRESSURE WILL PROVIDE BENIGN CONDITIONS THROUGH THIS
WEEKEND. LOW PRESSURE WILL BEGIN TO DEVELOP EAST OF THE REGION ON
MONDAY, REMAINING NEAR THE REGION INTO WEDNESDAY. AS A RESULT, WINDS
AND WAVE HEIGHTS SHOULD INCREASE ON MONDAY AND TUESDAY. GUSTY WINDS
AND BUILDING SEAS MAY REQUIRE SMALL CRAFT ADVISORIES STARTING OVER
PORTIONS OF THE WATERS ON MONDAY.
RIP CURRENTS: MODEST SWELL ENERGY WILL CONTINUE A MODERATE RIP
CURRENT RISK ON FRIDAY FOR ALL BEACHES. FOR SATURDAY, A LOW RIP
CURRENT RISK IS EXPECTED AT ALL BEACHES.
TIDES/COASTAL FLOODING
KING TIDES RETURN EARLY NEXT WEEK. COASTAL FLOODING IMPACTS ARE
POSSIBLE, BUT DETAILS ARE UNCERTAIN.
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...LAKE WIND ADVISORY UNTIL 11 PM EDT THIS EVENING FOR SCZ045.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EDT FRIDAY FOR AMZ350-374.
SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR AMZ352-
354.
NEAR TERM...JRL
SHORT TERM...APT
LONG TERM...APT
AVIATION...APT/DPB
MARINE...APT/JRL
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