226
FXUS62 KCHS 201135
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
635 AM EST TUE JAN 20 2026
WHAT HAS CHANGED
THE AVIATION SECTION HAS BEEN UPDATED FOR THE 12Z TAF ISSUANCE.
COLD TEMPERATURES ARE LIKELY THIS MORNING AND WEDNESDAY MORNING
AND REMAIN IN KEY MESSAGE 1. THE POTENTIAL FOR A WINTER WEATHER
EVENT REMAINS ADDRESSED IN KEY MESSAGE 2.
KEY MESSAGES
- 1) COLD TEMPERATURES IN THE LOW TO MID 20S (UPPER 20S TO LOWER
30S ALONG THE COAST) LIKELY THIS MORNING AND WEDNESDAY MORNING.
- 2) WIDESPREAD PRECIPITATION IS EXPECTED TO OCCUR THIS WEEKEND,
BRINGING INCREASING POTENTIAL FOR A WINTER WEATHER EVENT TO
IMPACT THE REGION.
DISCUSSION
KEY MESSAGE 1: COLD TEMPERATURES IN THE LOW TO MID 20S (UPPER 20S
TO LOWER 30S ALONG THE COAST) LIKELY THIS MORNING AND WEDNESDAY
MORNING.
DRY HIGH PRESSURE CENTERED ACROSS THE CENTRAL UNITED STATES WILL
CONTINUE TO BUILD/SPREAD EAST INTO THE REGION TONIGHT, BEFORE
PASSING TO THE NORTH LATE TUESDAY INTO WEDNESDAY. THE HIGH WILL
BRING COLDER THAN NORMAL TEMPERATURES TO THE LOCAL AREA AS A LIGHT
WIND UNDER CLEAR SKIES FAVORS STRONG RADIATIONAL COOLING. LATEST
GUIDANCE SUPPORTS LOW TEMPERATURES IN THE LOW-MID 20S LATE TONIGHT
INTO DAYBREAK AND AGAIN EARLY WEDNESDAY, EXCEPT NEAR THE COAST WHERE
TEMPS REMAIN IN THE LOW-MID 30S. ADDITIONALLY, OVERNIGHT LOWS EARLY
WEDNESDAY APPEAR TO BE 1-2 DEGREES WARMER THAN WHAT IS LIKELY TO
OCCUR PRIOR TO DAYBREAK THIS MORNING. GIVEN A LIGHT WIND ASSOCIATED
WITH HIGH PRESSURE, WIND CHILL IS LIKELY TO BE LIMITED EACH MORNING.
COLD WEATHER ADVISORIES ARE NOT EXPECTED FOR EITHER MORNING AT THIS
TIME.
KEY MESSAGE 2: WIDESPREAD PRECIPITATION IS EXPECTED TO OCCUR THIS
WEEKEND, BRINGING INCREASING POTENTIAL FOR A WINTER WEATHER EVENT TO
IMPACT THE REGION.
MODELS CONTINUE TO SUPPORT POTENTIAL FOR A WINTER WEATHER EVENT
IMPACTING AT LEAST PORTIONS OF SOUTHEAST SOUTH CAROLINA AND
SOUTHEAST GEORGIA THIS WEEKEND. THE SYNOPTIC PATTERN WILL FEATURE
STRONG, COLD HIGH PRESSURE WEDGING DOWN THE EASTERN SEABOARD THROUGH
THE WEEKEND, WITH AN AREA OF LOW PRESSURE FAVORED TO DEVELOP OFF THE
SOUTHEAST COAST. BROAD MID LEVEL TROUGHING WILL LARGELY BE IN PLACE
TO START, WITH A STRONGER WAVE DIVING INTO THE REGION LATER IN THE
WEEKEND. FURTHER ALOFT, WE CAN FIND AN IMPRESSIVE UPPER LEVEL JET
POSSIBLY ON THE ORDER OF 160+ KNOTS. THE CONDITIONS WILL CERTAINLY
BE IN PLACE TO SUPPORT PRECIPITATION SPREADING ACROSS THE AREA, WITH
INCREASING CONFIDENCE OF SOME OVERLAP WITH COLDER TEMPERATURES.
ATTENTION THEN TURNS TO PRECIPITATION TYPE AS COLD AIR SETTLES INTO
THE REGION. WHILE FORECAST DETAILS ON TIMING, AMOUNTS, AND P-TYPES
WILL CONTINUE TO BE REFINED IN THE COMING DAYS, A PERUSAL OF MODEL
SOUNDINGS INDICATE A NOTABLE WARM NOSE CENTERED AROUND 850 MB WITH
SURFACE TEMPS DROPPING TO NEAR OR BELOW FREEZING SATURDAY NIGHT INTO
SUNDAY MORNING. THIS WOULD SUGGEST FREEZING RAIN AS A PRIMARY
THREAT, WHICH ALSO JIVES WITH THE LATEST NBM PRECIP PROBABILITIES.
THE PROBABILISTIC WINTER STORM SEVERITY INDEX (WSSI-P) SHOWS CHANCES
OF MINOR WINTER STORM IMPACTS ACROSS THE ENTIRE AREA, WITH EVEN A 20-
40% CHANCE OF MODERATE IMPACTS ESPECIALLY NORTH OF I-16.
THE COLUMN BEGINS TO DRY OUT LATER SUNDAY INTO MONDAY, BUT IF
PRECIPITATION LINGERS, THE THREAT FOR WINTER WEATHER COULD CONTINUE
INTO EARLY MONDAY AS ENSEMBLE GUIDANCE SHOWS HIGH LIKELIHOOD FOR SUB-
FREEZING TEMPERATURES AGAIN SUNDAY NIGHT. WE WILL ALSO NEED TO BE ON
THE LOOKOUT FOR TEMPS/WIND CHILLS APPROACHING COLD WEATHER ADVISORY
CRITERIA SUNDAY NIGHT AND BEYOND.
AVIATION /12Z TUESDAY THROUGH SATURDAY/
VFR CONDITIONS WILL PREVAIL AT CHS/JZI/SAV TERMINALS THROUGH 12Z
WEDNESDAY.
EXTENDED AVIATION FORECAST: VFR THROUGH FRIDAY. PERIODS OF MVFR
AND/OR IFR CONDITIONS POSSIBLE WITH A RAIN AND/OR MIX OF FROZEN
PRECIP OVER THE WEEKEND.
MARINE
TODAY AND TONIGHT: HIGH PRESSURE WILL SPREAD ACROSS THE SOUTHEAST,
LEADING TO A WEAKER PRESSURE GRADIENT ACROSS LOCAL WATERS. THIS WILL
RESULT IN A WEST-NORTHWEST WIND BETWEEN 10-20 KT TO SLIGHTLY WEAKEN
AND TURN NORTH LATE DAY AND OVERNIGHT. SEAS WILL GENERALLY RANGE
BETWEEN 2-3 FT NEARSHORE AND 3-4 FT ACROSS OUTER GEORGIA WATERS.
SMALL CRAFT ADVISORIES ARE NOT EXPECTED DURING THIS TIMEFRAME.
WEDNESDAY THROUGH FRIDAY: QUIET MARINE CONDITIONS PREVAIL MID WEEK
WHILE HIGH PRESSURE CENTERED NORTH OF THE REGION SHIFTS ACROSS THE
WESTERN ATLANTIC. A COLD FRONT WILL APPROACH THE SOUTHEAST LATE
WEEK, LIKELY SHIFTING ACROSS THE REGION FRIDAY. NORTHEAST WINDS WILL
INCREASE POST FROPA, GENERALLY TO THE 15-20 KT RANGE WHILE SEAS
BUILD UP TO 3-6 FT FRIDAY NIGHT. IT IS POSSIBLE A SMALL CRAFT
ADVISORY COULD BE NEEDED ACROSS NEARSHORE WATERS OFF THE CHARLESTON
COUNTY COAST PRIOR TO DAYBREAK SATURDAY.
SATURDAY AND SUNDAY: THIS IS THE PERIOD OF GREATEST CONCERN IN
REGARDS TO DETERIORATING WIND AND SEA CONDITIONS ACROSS LOCAL
WATERS. LOW PRESSURE COULD DEVELOP ALONG A COLD FRONT POSITIONED
OFFSHORE, FAVORING A STRONG PRESSURE GRADIENT ACROSS LOCAL WATERS
WHILE COLD AIR ADVECTION PROMOTES AMPLE MIXING INTO ENHANCED LOW-LVL
WIND FIELDS. CONDITIONS LOOK TO SUPPORT SMALL CRAFT ADVISORY LEVEL
CONDITIONS ACROSS A MAJORITY OF LOCAL WATERS WITH EVEN A LOW-END
RISK FOR GALE FORCE WIND GUSTS ACROSS NORTHERN SOUTH CAROLINA
NEARSHORE WATERS DURING THE PEAK OF THE EVENT 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).
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...NONE.
DPB/ETM
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