635
FXUS62 KCHS 231156
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
656 AM EST FRI JAN 23 2026
WHAT HAS CHANGED
THE AVIATION SECTION HAS BEEN UPDATED FOR THE 12Z FRIDAY TAF
ISSUANCE.
KEY MESSAGES
- 1) WIDESPREAD PRECIPITATION IS EXPECTED SATURDAY THROUGH
SUNDAY NIGHT, WITH FREEZING RAIN POSSIBLE SATURDAY NIGHT
ACROSS INLAND PORTIONS OF THE SC LOWCOUNTRY.
- 2) VERY COLD TEMPERATURES WILL OCCUR EARLY NEXT WEEK, WITH
LOWS IN THE UPPER TEENS TO LOWER 20S AWAY FROM THE COASTLINE.
DISCUSSION
KEY MESSAGE 1: WIDESPREAD PRECIPITATION IS EXPECTED SATURDAY
THROUGH SUNDAY NIGHT, WITH FREEZING RAIN POSSIBLE SATURDAY
NIGHT ACROSS INLAND PORTIONS OF THE SC LOWCOUNTRY.
A CLOSED UPPER LOW OFF THE SW CALIFORNIA COAST THIS MORNING WILL
MOVE EAST TOWARD SOUTHERN TX THROUGH SATURDAY NIGHT WHILE A
NORTHERN STREAM SHORTWAVE DROPS INTO THE UPPER MIDWEST. AN
UNSEASONABLY STRONG ARCTIC AIRMASS WILL OVERSPREAD THE EASTERN
HALF OF THE CONUS THROUGH SATURDAY. THE INTERACTION BETWEEN THE
COLD AIRMASS AND THE STRONG UPPER LEVEL DYNAMICS IS EXPECTED TO
PRODUCE A LARGE-SCALE WINTER STORM OVER PARTS OF THE COUNTRY.
AS THE ARCTIC HIGH SHIFTS EAST TOWARD NEW ENGLAND ON SATURDAY,
IT WILL OOZE DOWN THE LEE SIDE OF THE APPALACHIANS, CREATING A
TYPICAL COLD AIR DAMMING REGIME. THE COLD AIR WEDGE WILL BECOME
FURTHER ENTRENCHED SATURDAY NIGHT OVER INLAND PORTIONS OF THE
CAROLINAS AS A SURFACE LOW DEVELOPS OFF THE SC COAST.
FURTHERMORE, EXTENSIVE LIGHT TO MODERATE PRECIPITATION FALLING
INTO THE BOUNDARY LAYER WILL REDUCE TEMPERATURES DUE TO
EVAPORATIONAL COOLING. THE BIG QUESTION MARK IS IF AND/OR WHERE
TEMPERATURES ARE ABLE TO DROP TO OR BELOW FREEZING. GUIDANCE HAS
BEEN SURPRISINGLY CONSISTENT OVER THE LAST 48 HOURS THAT THE
MOST LIKELY AREA FOR THIS TO OCCUR WOULD BE ALONG AND NORTH OF A
LINE FROM MILLEN, GA TO ALLENDALE-WALTERBORO-SUMMERVILLE-MONCKS
CORNER, SC. MID-SATURDAY EVENING THROUGH DAYBREAK SUNDAY STANDS
THE GREATEST CHANCE OF SUB-FREEZING TEMPERATURES IN THESE AREAS.
MODEL SOUNDINGS CONTINUE TO SHOW A VERY STRONG WARM NOSE
CENTERED AROUND 900 MB, WITH THE SUB-FREEZING TEMPERATURES ONLY
OCCURRING IN A SHALLOW SURFACE LAYER. THIS IS A SOLIDLY
FREEZING RAIN PATTERN SINCE ANY SNOW OR SLEET WOULD EASILY MELT
WHEN PASSING THROUGH THE ROBUST WARM LAYER ALOFT.
FORTUNATELY, THE QUANTITATIVE PRECIPITATION FORECAST (QPF)
SATURDAY EVENING IS QUITE LOW, AND WE'RE FORECASTING LESS THAN A
TENTH OF AN INCH OF ICE ACCUMULATION IN THE INLAND SC AREAS.
IT'S WORTH NOTING THAT SMALL ERRORS IN THE TEMPERATURE FORECAST
OR QPF COULD HAVE A SIGNIFICANT IMPACT ON LOCATION AND IMPACT OF
ANY FREEZING RAIN.
ON SUNDAY, A PATTERN SHIFT IS EXPECTED, THOUGH THE TIMING OF
THAT SHIFT IS SOMEWHAT UNCERTAIN. A SECONDARY SURFACE LOW
ASSOCIATED WITH THE SOUTHERN STREAM SHORTWAVE (FORMERLY THE
UPPER LOW OFF THE CA COAST) WILL MOVE ACROSS THE NORTHERN GULF
AND THEN UP THE SPINE OF THE APPALACHIANS LATE SUNDAY. A WARM
FRONT WILL LIFT NORTH THROUGH THE AREA AT SOME POINT ON SUNDAY.
OUR NORTHWEST TIER WILL PROBABLY REMAIN COLD-SECTORED MOST OF
THE DAY, WHILE SOUTHEAST GA SEES TEMPERATURES RISE INTO THE
UPPER 60S TO LOWER 70S. ANOTHER POINT OF UNCERTAINTY IS HOW
QUICKLY OUR FAR INLAND SC AREAS RISE ABOVE FREEZING SUNDAY
MORNING. IT'S NOT OUT OF THE QUESTION THAT TEMPS COULD REMAIN AT
OR SLIGHTLY BELOW FREEZING THROUGH MUCH OF THE MORNING, IN WHICH
CASE ANOTHER 0.05" OF ICE ACCUMULATION COULD OCCUR. AT THE
MOMENT WE ARE SHOWING TEMPS JUST ABOVE FREEZING BY 9AM SUNDAY.
A STRONG COLD FRONT WILL APPROACH SUNDAY EVENING, BY WHICH POINT
ALL AREAS SHOULD BE IN THE WARM SECTOR. A FAIRLY ROBUST BAND OF
PRECIPITATION WILL ACCOMPANY THE FRONT, WITH AREAL AVERAGE QPF
AROUND 0.5". THERE COULD BE ENOUGH ELEVATED INSTABILITY TO
SUPPORT ISOLATED THUNDERSTORMS SUNDAY EVENING. COLDER AIR WILL
FILTER IN BEHIND THE FRONT, BUT THE PRECIP SHOULD BE OFF THE
COAST BY DAYBREAK MONDAY AND THERMAL PROFILES ONLY SUPPORT RAIN.
KEY MESSAGE 2: VERY COLD TEMPERATURES WILL OCCUR EARLY NEXT
WEEK, WITH LOWS IN THE UPPER TEENS TO LOWER 20S AWAY FROM THE
COASTLINE.
STRONG HIGH PRESSURE BUILDING IN WAKE OF A DEPARTING COLD FRONT WILL
USHER ARCTIC AIR INTO THE REGION MONDAY NIGHT INTO TUESDAY MORNING,
WHICH SHOULD THEN LINGER INTO EARLY WEDNESDAY PRIOR TO THE AIRMASS
MODIFYING/WARMING UNDER A MORE ZONAL FLOW TYPE PATTERN WELL IN
ADVANCE OF ANOTHER FRONT APPROACHING DURING THE LATER HALF OF THE
WEEK. AS A RESULT, LOW TEMPS ARE FORECAST TO DIP INTO THE TEENS WEST
OF I-95 AND ACROSS MUCH OF THE FRANCIS MARION FOREST WHILE LOW TO
MID 20S ARE ANTICIPATED ALONG THE COAST TUESDAY MORNING. THESE TEMPS
IN COMBINATION WITH A NORTH/NORTHEAST WIND GENERALLY IN THE 5-10 MPH
RANGE SHOULD RESULT IN WIDESPREAD WIND CHILL VALUES IN THE MID-UPPER
TEENS. A COLD WEATHER ADVISORY SHOULD EVENTUALLY BE NEEDED FOR THE
ENTIRE AREA ACROSS SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA.
LATEST GUIDANCE HAS TRENDED SLIGHTLY COOLER HEADING INTO EARLY
WEDNESDAY, SUFFICIENTLY TO PRODUCE ANOTHER ROUND OF COLD SFC TEMPS
WITH LIGHT WESTERLY WINDS SUPPORTIVE OF WIND CHILL VALUES DIPPING
INTO THE UPPER TEENS/LOWER 20S, LOWEST INLAND FROM COASTAL COUNTIES.
A COLD WEATHER ADVISORY COULD EVENTUALLY BE NEEDED FOR AREAS INLAND
TUESDAY NIGHT INTO EARLY WEDNESDAY.
AVIATION /12Z FRIDAY THROUGH TUESDAY/
VFR CONDITIONS WILL PREVAIL AT CHS/JZI/SAV TERMINALS THROUGH 12Z
FRIDAY. HOWEVER, NORTHERLY WINDS COULD BECOME BREEZY BEHIND A
COLD FRONT (15-20 KT) AT CHS/JZI TERMINALS BY AROUND 10Z SATURDAY.
EXTENDED AVIATION FORECAST: PERIODS OF MVFR AND/OR IFR CONDITIONS
ARE LIKELY AT ALL TERMINALS THIS WEEKEND AS A STORM SYSTEM IMPACTS
THE AREA. THERE IS A LOW-END THREAT FOR FREEZING RAIN LATE SATURDAY
NIGHT INTO SUNDAY, MAINLY AT THE CHS TERMINAL, BUT TRENDS SUGGEST
THIS ACTIVITY TO STAY INLAND. VFR CONDITIONS SHOULD PREVAIL AT ALL
TERMINALS ONCE A COLD FRONT SHIFTS OFFSHORE EARLY MONDAY.
MARINE
TODAY AND TONIGHT: WEAK HIGH PRESSURE WILL PREVAIL FOR MUCH OF THE
DAY, FAVORING MARINE CONDITIONS WELL BELOW SMALL CRAFT ADVISORY
LEVEL THRESHOLDS. THE PRESSURE GRADIENT IS THEN EXPECTED TO
TIGHTEN ACROSS LOCAL WATERS OVERNIGHT, WITH COLD AIR ADVECTION
STRENGTHENING AND SUPPORTIVE OF DETERIORATING MARINE CONDITIONS
ACROSS ALL WATERS. SMALL CRAFT ADVISORIES WILL FOLLOW THE TREND,
STARTING ACROSS NORTHERN SOUTH CAROLINA AT MIDNIGHT TONIGHT,
THEN REMAINING COASTAL WATERS LATE NIGHT (EXCEPT IN THE CHARLESTON
HARBOR).
SATURDAY THROUGH WEDNESDAY: STRONG COLD AIR ADVECTION AND AN
ENHANCED PRESSURE GRADIENT ACROSS LOCAL WATERS CONTINUES TO SUPPORT
DETERIORATING CONDITIONS ACROSS ALL LOCAL WATERS SATURDAY AS LOW
PRESSURE ATTEMPTS TO DEVELOP/STRENGTHEN NEAR A COLD FRONT OFFSHORE
WHILE SOME ELEMENT OF WEDGING ATTEMPTS TO SPREAD ACROSS THE REGION
TO THE NORTH/NORTHWEST. GUIDANCE CONTINUES TO INDICATE SOLID SMALL
CRAFT ADVISORY CONDITIONS ACROSS ALL NEARSHORE AND OUTER WATERS
SATURDAY AND SUNDAY WITH A POTENTIAL OF LOW-END GALE FORCE GUSTS
ACROSS NORTHERN SOUTH CAROLINA WATERS SATURDAY AFTERNOON AND NIGHT.
SMALL CRAFT ADVISORIES SHOULD EVENTUALLY BE NEEDED AT SOME POINT FOR
THE CHARLESTON HARBOR AS WELL SATURDAY/SATURDAY NIGHT. NORTHEAST
WINDS GUSTING UP TO 25-30 KT APPEAR COMMON ACROSS MOST WATERS WHILE
SEAS BUILD UPWARDS TO 7-10 FT (LARGEST AWAY FROM THE COAST). HIGH
SEAS SHOULD LINGER ACROSS MOST WATERS INTO MONDAY, WHILE ANOTHER
BURST OF COLD AIR ADVECTION TAKES PLACE NEAR/POST COLD FROPA. SMALL
CRAFT ADVISORIES WILL REMAIN IN PLACE FOR MOST IF NOT ALL COASTAL
WATERS INTO MONDAY NIGHT AS A RESULT, WITH AGAIN ANOTHER LOW-END
CHANCE FOR GALE FORCE WIND GUSTS TO OCCUR ACROSS OUTER GEORGIA
WATERS AND NORTHERN SOUTH CAROLINA WATERS DURING THE PEAK OF THE
EVENT.
EQUIPMENT
THE KCLX RADAR WILL REMAIN OUT OF SERVICE UNTIL AT LEAST
SATURDAY. CRITICAL PARTS ARE ON ORDER. USERS SHOULD USE ADJACENT
WSR-88D SITES, INCLUDING KCAE, KLTX, KJAX, KVAX AND KJGX.
THE BEAUFORT/GREEN POND NOAA WEATHER RADIO TRANSMITTER (WXJ-23)
IS OPERATING AT LOW POWER WITH DIMINISHED SERVICE. REPAIRS ARE
SCHEDULED TO BE MADE TODAY TO RESTORE FULL SERVICE.
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 10 AM EST
TUESDAY FOR AMZ350.
SMALL CRAFT ADVISORY FROM 3 AM SATURDAY TO 10 AM EST TUESDAY
FOR AMZ352-354.
SMALL CRAFT ADVISORY FROM 3 AM SATURDAY TO 1 PM EST TUESDAY
FOR AMZ374.
DPB/JRL
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