661
FXUS62 KCHS 221738
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
1238 PM EST THU JAN 22 2026
WHAT HAS CHANGED
THE AVIATION SECTION HAS BEEN UPDATED FOR THE 18Z TAF ISSUANCE.
KEY MESSAGES
- 1) WIDESPREAD PRECIPITATION IS EXPECTED THIS WEEKEND,
BRINGING THE POTENTIAL FOR A WINTER WEATHER EVENT ACROSS
PORTIONS OF THE REGION.
- 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 THIS
WEEKEND, BRINGING THE POTENTIAL FOR A WINTER WEATHER EVENT
ACROSS PORTIONS OF THE REGION.
AS THIS BAJA LOW SWIFTLY EXITS AND MOVES ACROSS THE SOUTHERN
HALF OF THE CONUS, A NORTHERN STREAM SHORTWAVE WILL DIVE INTO
THE MID-WEST ON SATURDAY USHERING COLD, ARCTIC AIR ALONG WITH
IT. AT THE SURFACE, A REMARKABLE HIGH PRESSURE WILL WEDGE ITSELF
ACROSS THE REGION SAT. INTO SAT. NIGHT CREATING A STRONG COLD-
AIR DAMMING (CAD) EVENT TO SET-UP. THERE HAS BEEN A DECENT SHIFT
IN THE FORECAST OVER THE LAST 36 HOURS AS THE TRACK OF THE
AFOREMENTIONED LOW HAS SHIFTED A TAD TO THE NORTH. TAKING A LOOK
AT THE 22.00Z WPC CLUSTER ANALYSIS (E.G., 50% OF THE GEFS
CONTAINED IN CLUSTER 1), IT APPEARS ENSEMBLE GUIDANCE HAS NOW
BECOME LESS DISPERSIVE OVER THE LAST 36 HOURS. THIS REVEALS THAT
THIS RECENT NORTHERLY, WARM TREND SEEMS LEGITIMATE. ALSO, THE
AIRCRAFT RECON DATA THAT WAS IMPLEMENTED IN THE 22.00Z DATA HAS
CERTAINLY HELPED INCREASE CONFIDENCE IN THIS FORECAST. THIS
RECENT TREND CAN BE COMMENDED TO THE SWIFT EJECTION OF THE BAJA
LOW AS THIS THE PATTERN DOWNSTREAM AND ALLOW FOR AN IMPRESSIVE
WARM-AIR ADVECTION TO PUSH ACROSS THE SOUTHEAST. THE 22.12Z GFS
STILL STAYS A BIT TO THE SOUTH, HOWEVER THIS SEEMS TO BE THE
OUTLIER OUT OF ALL THE MODELS.
IT'S IMPORTANT TO NOTE THAT THERE IS SOME CONCERN THAT THE
MODELS COULD BE UNDER-PLAYING THE CAD, AND THIS IS SOMETHING
THAT WE WILL NEED TO PAY CLOSE ATTENTION TO OVER THE NEXT COUPLE
DAYS AS COLDER TEMPS. COULD RESULT IN HIGHER CHANCE OF FREEZING
RAIN OVER PORTIONS OF THE AREA. IT'S VALUABLE TO TAKE A LOOK AT
THE NAM 22.12Z REGARDING THIS CONCERN OVER THE WEEKEND, AS THIS
IS A GOOD EXAMPLE OF MODEL FAVORING A STRONG CAD SET-UP, AND
HAS TEMPS. HOLDING ONTO THE MID 20S TO LOW 30S ON SUNDAY
MORNING. HOWEVER, A LARGE PORTION OF THE GUIDANCE SHOWS A MUCH
WEAKER CAD SET-UP AND EFFECTIVELY PUTS THE REGION IN A WARM-
SECTOR ON SUNDAY, THEREFORE WE'VE BEEN STICKING WITH THE WEAKER
CAD SOLUTION FOR THE MOMENT.
RECENT MODEL SOUNDINGS CONTINUE TO INDICATE A PROMINENT WARM
NOSE ALOFT THIS WEEKEND, THEREFORE THE LARGEST THREAT WITH THIS
SYSTEM REMAINS TO BE FREEZING RAIN. IN REGARDS TO TIMING, THE
PERIOD OF GREATEST CONCERN REMAINS TO BE SAT. EVENING INTO SUN.
MORNING, WITH THE HIGHEST PROBABILITIES OF ACCUMULATING ICE
ALONG AND WEST OF A LINE FROM MONCKS CORNER TO WALTERBORO TO
HAMPTON AND MILLEN. LATEST NBM PROBABILITIES INDICATE A 20-40%
OF FREEZING RAIN >0.01", WITH A NEAR ZERO PERCENT CHANCE FOR
>0.25". ELSEWHERE, PROBABILITIES OF FREEZING REMAIN TO EXTREMELY
LOW, AND IMPACTS REMAIN NEGLIGIBLE AT THIS TIME. TO MATCH UP
WITH THIS THINKING, THE PROBABILISTIC WINTER STORM SEVERITY
INDEX (WSSI-P) SHOWS A 5-10% CHANCE ACROSS THE NORTHERN TIER
COUNTIES FOR THIS WEEKEND.
A RATHER IMPRESSIVE TEMP. GRADIENT IS APPARENT ON SUNDAY WITH
MID 60S TO LOW 70S ACROSS SOUTHEAST GA AND UPPER 50S TO LOW 60S
ACROSS SOUTHEAST SC. HENCE, IT'S NOT OUT OF THE QUESTION TO SEE
A COUPLE THUNDERSTORMS DEVELOP IN THE AFTERNOON/EVENING ON
SUNDAY. NEVERTHELESS, PRECIPITATION SHOULD COME TO AN END ON
SUNDAY NIGHT INTO EARLY MONDAY AS THE COLD FRONT PASSES THROUGH
THE REGION. IT'S IMPORTANT TO NOTE THAT THERE MIGHT BE AN
OVERLAP WITH PRECIP. AND COLDER TEMPS. ON SUNDAY, RESULTING IN
SOME LINGERING P-TYPE CONCERNS INTO THE EVENING.
THERE IS STILL SOME UNCERTAINTY WITH THIS SYSTEM AND IT'S
IMPORTANT TO REMEMBER TO EXERCISE CAUTION HERE AS THE FORECAST
CAN CHANGE, AND WILL LIKELY CHANGE OVER THE NEXT COUPLE DAYS.
KEY MESSAGE 2: VERY COLD TEMPERATURES WILL OCCUR EARLY NEXT
WEEK, WITH LOWS IN THE UPPER TEENS TO LOWER 20S AWAY FROM THE
COASTLINE.
AS A STRONG ARCTIC HIGH PRESSURE USHERS COLD, DRY AIR INTO THE
REGION ON MONDAY NIGHT, LOW TEMP. ARE FORECAST TO DROP 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 MONDAY
NIGHT/TUESDAY MORNING. THERE CONDITIONS COMBINED WITH A LIGHT
NORTH- NORTHEASTERLY WIND COULD RESULT IN WIDESPREAD WIND CHILLS
IN THE MID TO UPPER TEENS. THEREFORE, A COLD WEATHER ADVISORY
APPEARS LIKELY AS PROBABILITY FOR TEMPS. < 20 RANGE FROM 50-75%.
FORECAST HAS IS A BIT WARMER ON TUESDAY NIGHT/WEDNESDAY MORNING
AS TEMPS RANGE IN THE LOW TO MID 20S ACROSS THE INTERIOR
COUNTIES WITH LOW 30S ALONG THE COASTLINE. THUS, CONFIDENCE WITH
NEEDING A COLD WEATHER ADVISORY SEEM LESS LIKELY FOR THIS TIME
PERIOD WITH PROBABILITIES FOR TEMPS. < 20 RANGE FROM 20-40%.
IT'S IMPORTANT TO NOTE THAT MODEL CONFIDENCE CONTINUES TO BE
FAIRLY HIGH AS THE IQR SHOWS A 2 TO 3 DEGREE SPREAD FOR LOWS
TUESDAY AND WEDNESDAY MORNING. HOWEVER, IN REGARD TO THE SYSTEM
THIS WEEKEND, IT'S POSSIBLE THE COLD AIR COULD STICK AROUND INTO
MID-WEEK AND YIELD COLDER TEMPERATURES.
AVIATION /18Z THURSDAY THROUGH TUESDAY/
VFR CONDITIONS ARE EXPECTED TO PREVAIL AT KCHS, KJZI, AND KSAV
THROUGH 18Z FRIDAY.
EXTENDED AVIATION FORECAST: MVFR OR IFR CONDITIONS WILL BE
POSSIBLE AT ALL TERMINALS THIS WEEKEND AS A STORM SYSTEM IMPACTS
THE AREA. THE THREAT FOR FREEZING/FROZEN PRECIPITATION
CONTINUES TO DIMINISH AND SHOULD REMAIN NORTH OF THE KCHS AND
KJZI TERMINALS.
MARINE
TONIGHT THROUGH FRIDAY: QUIET CONDITIONS ARE EXPECTED TO
PREVAIL ACROSS THE LOCAL WATERS THROUGH FRIDAY. WINDS WILL TURN
MORE NORTHEASTERLY WITH TIME AND INCREASE TO AROUND 10 KT OR UP
TO 10-15 KT BY LATE FRIDAY. SEAS SHOULD AVERAGE 2-4 FEET THROUGH
THE PERIOD.
FRIDAY NIGHT THROUGH TUESDAY: A STRONG COLD FRONT WILL MOVE
ACROSS THE WATERS FRIDAY NIGHT AND BRING A PERIOD OF HAZARDOUS
MARINE CONDITIONS. NORTHEAST WINDS WILL BEGIN TO SURGE FRIDAY
NIGHT AND CONTINUE THROUGH SATURDAY. SUSTAINED WINDS ARE
FORECAST TO INCREASE INTO THE 20-25 KT RANGE WITH FREQUENT GUSTS
INTO THE 25-30 KT RANGE. THERE ALSO REMAINS A WINDOW OF TIME
LATER IN THE DAY ON SATURDAY WHEN GALE FORCE GUSTS COULD OCCUR,
PRIMARILY IN THE CHARLESTON COUNTY WATERS. WINDS WILL LIKELY
THEN DIMINISH SATURDAY NIGHT INTO SUNDAY AS AN AREA OF LOW
PRESSURE MOVES AWAY FROM THE REGION. HOWEVER, CONDITIONS ARE
EXPECTED TO RAMP BACK UP SUNDAY NIGHT THROUGH MONDAY AS THE MAIN
COLD FRONT PASSES THROUGH FROM THE WEST WITH GUSTS UP TO 30
KNOTS OCCURRING AGAIN INTO MONDAY NIGHT. CONDITIONS SHOULD THEN
IMPROVE TUESDAY AS HIGH PRESSURE RETURNS AND THE GRADIENT
RELAXES.
IN SUMMARY, SMALL CRAFT ADVISORIES HAVE BEEN INITIATED FOR ALL
WATERS FOR BOTH WINDS AND SEAS STARTING AROUND OR JUST AFTER
MIDNIGHT SATURDAY AND CONTINUING INTO TUESDAY MORNING. A SMALL
CRAFT ADVISORY COULD EVENTUALLY BE NEEDED FOR CHARLESTON HARBOR
AS WELL. THERE REMAINS A LOW CHANCE THAT A GALE WATCH COULD BE
NEEDED FOR THE CHARLESTON COUNTY WATERS ON SATURDAY.
EQUIPMENT
THE BEAUFORT/GREEN POND NOAA WEATHER RADIO TRANSMITTER (WXJ-23)
IS OPERATING AT LOW POWER WITH DIMINISHED SERVICE. REPAIRS ARE
SCHEDULED TO BE MADE FRIDAY TO RESTORE FULL SERVICE.
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM MIDNIGHT FRIDAY NIGHT 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.
BSH/DENNIS
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