867
FXUS62 KCHS 152323
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
623 PM EST THU JAN 15 2026
WHAT HAS CHANGED
THE AVIATION SECTION HAS BEEN UPDATED FOR THE 00Z TAF ISSUANCE.
EXPANDED THE COLD WEATHER ADVISORY TO NOW INCLUDE BERKELEY
COUNTY. OTHERWISE, CONFIDENCE REMAINS LOW IN REGARD TO FROZEN
PRECIPITATION ON SUNDAY.
KEY MESSAGES
- 1) DRY CONDITIONS AND LOW RELATIVE HUMIDITY VALUES EXPECTED
FRIDAY.
- 2) VERY COLD TEMPERATURES WILL OCCUR FRIDAY MORNING, WITH LOWS
IN THE UPPER TEENS TO LOWER 20S AWAY FROM THE BEACHES.
- 3) POTENTIAL FOR SNOW MIXING WITH RAIN SATURDAY NIGHT INTO
SUNDAY MORNING AS COASTAL LOW TRIES TO DEVELOP ON SUNDAY.
DISCUSSION
KEY MESSAGE 1: DRY CONDITIONS AND LOW RELATIVE HUMIDITY VALUES
EXPECTED FRIDAY.
THE CENTER OF THE DRY AIR MASS WILL BUILD ACROSS THE SOUTHEAST
U.S. ON FRIDAY. RH VALUES SHOULD FALL TO THE UPPER TEENS TO
AROUND 20 PERCENT VERY FAR INLAND, AND AROUND 25 PERCENT CLOSER
TO THE COAST. FORTUNATELY, HIGH PRESSURE OVERHEAD SHOULD ONLY
SUPPORT WINDS BETWEEN 5-10 MPH. NO FIRE DANGER STATEMENTS ARE
EXPECTED.
KEY MESSAGE 2: VERY COLD TEMPERATURES WILL OCCUR FRIDAY
MORNING, WITH LOWS IN THE UPPER TEENS TO LOWER 20S AWAY FROM THE
BEACHES.
A COLD WEATHER ADVISORY REMAINS IN EFFECT FROM 8 PM THIS
EVENING TO 9 AM EST FRIDAY MORNING. IT WAS EXPANDED TO INCLUDE
BERKELEY COUNTY. SURFACE HIGH PRESSURE OVER THE SOUTHERN MS
VALLEY LATE THIS AFTERNOON WILL QUICKLY MOVE EAST AND BECOME
LOCATED OVER THE SOUTHEAST U.S. BY FRIDAY MORNING. THIS WILL
CAUSE WINDS ACROSS OUR AREA TO BECOME VERY LIGHT OR GO CALM LATE
TONIGHT INTO EARLY FRIDAY MORNING. ADDITIONALLY, THE HIGH WILL
USHER IN VERY COLD TEMPERATURES AND DRY CONDITIONS. THE
COMBINATION OF CLEAR SKIES, LIGHT TO CALM WINDS, AND DRY
CONDITIONS WILL LEAD TO NEAR IDEAL RADIATIONAL COOLING. EXPECT
LOW TEMPERATURES IN THE UPPER TEENS WEST OF I-95 AND IN THE
TYPICAL COLDER SPOTS. ALONG AND EAST OF I-95 TO ABOUT US HIGHWAY
17, EXPECT LOW TEMPERATURES IN THE LOWER TO MID 20S. ALONG THE
BEACHES, EXPECT LOW TEMPERATURES IN THE MID TO UPPER 20S
(INCLUDING THE CHARLESTON PENINSULA). TEMPERATURES WILL BE BELOW
FREEZING FOR 8 TO 12 HOURS.
KEY MESSAGE 3: POTENTIAL FOR SNOW MIXING WITH RAIN SATURDAY
NIGHT INTO SUNDAY MORNING AS COASTAL LOW TRIES TO DEVELOP ON
SUNDAY.
A REX BLOCK WILL GRADUALLY TO LOOSE COHESION AS A WAVE SITUATED
OVER THE EASTERN PACIFIC APPROACHES FROM THE WEST. IN RESPONSE
TO THIS DOWNSTREAM EFFECT, A SUBSTANTIAL SHORTWAVE TROUGH WILL
DIVE SOUTHEAST OUT OF MANITOBA AND APPROACH THE REGION SUNDAY
MORNING. THIS SHORTWAVE COULD POTENTIALLY TAKE ON A MORE
NEGATIVE TILT AS IT APPROACHES THE COASTLINE. AS THIS STORY
UNFOLDS, A COASTAL LOW MAY DEVELOP OFFSHORE OF THE CAROLINAS,
AND ITS EXACT POSITION WILL BE EXTREMELY IMPORTANT TO HOW
CONDITIONS EVOLVE FROM SATURDAY NIGHT INTO SUNDAY MORNING.
THERE'S A COUPLE DIFFERENT SCENARIOS AT PLAY, LET'S WALK THROUGH
THEM.
(1) COASTAL LOW FORMS OFFSHORE OF THE CAROLINAS
*THIS APPEARS TO BE THE MOST LIKELY SCENARIO AT THE MOMENT,
WITH SUPPORT FROM CMC, GEFS (GFS ENSEMBLE), AND 06Z EPS (ECMWF
ENSEMBLE). THIS WOULD FAVOR A RAIN/SNOW MIX SOLUTION AWAY FROM
THE COASTLINE WITH RAIN ALONG THE COASTLINE AS THE PLACEMENT OF
THE LOW WOULD YIELD WARMER TEMPERATURES. THERE IS A CHANCE OF
BRIEF SNOW (NOT A MIX) FOR THE INLAND COUNTIES IN THE MORNING.
(2) COASTAL LOW FORMS FAR EAST/NORTHEAST OF SC/GA
*SOME SUPPORT WITH THIS SOLUTION AS 06Z/12Z GFS (DETERMINISTIC)
AND EC-AIFS SUPPORTING THIS SCENARIO. THIS WOULD FAVOR A WARM
AND WET (MOSTLY RAIN) SOLUTION AS THE LOW WOULD BE FORMING FAR
OFFSHORE AWAY FROM THE CAROLINAS.
(3) COASTAL LOW FORMS ALONG THE SC/NC COASTLINE
*NOT MUCH SUPPORT WITH THIS SCENARIO WITH THE LATEST GUIDANCE,
HOWEVER SOME OF THE ENSEMBLES STILL INDICATING THIS AS A
POSSIBILITY. THIS WOULD AGAIN FAVOR A WARM AND WET (MOSTLY
RAIN) SOLUTION.
THERE REMAINS A CONSIDERABLE AMOUNT OF UNCERTAINTY WITH THIS
SYSTEM, AS IT HINGES ON A MULTITUDE OF FACTORS: THE PLACEMENT OF
THIS COASTAL LOW, HOW FAR SOUTH THIS TROUGH SHIFTS, AND HOW
QUICKLY IT DEVELOPS A NEGATIVE TILT. TAKING A LOOK AT THE 15.00Z
WPC CLUSTER ANALYSIS (E.G., 50% OF THE GEFS BEING CONTAINED IN
CLUSTER 1), IT APPEARS THE ENSEMBLE GUIDANCE IS BECOMING LESS
DISPERSIVE AS TIME GOES ON. THIS REVEALS THAT THE MAJORITY OF
THE UNCERTAINTY REMAINS WITH THE DUELING SHORTWAVES ON THE
WESTERN AND EASTERN FLANKS OF THE REX BLOCK (E.G., CLUSTER 3 AND
4). ALSO, THE COMBINATION OF WARM GROUND TEMPERATURES AND
MARGINALLY COLD AIR PRESENT ON SUNDAY IS REALLY THE MAIN FACTOR
WORKING AGAINST THIS SYSTEM. NEVERTHELESS, THE PROBABILISTIC
WINTER STORM SEVERITY INDEX (WSSI-P) CONTINUES TO SHOW A 5-10%
CHANCE OF EXPERIENCING MINOR IMPACTS FROM WINTER WEATHER ON
SUNDAY. THEREFORE, WITH THIS IN MIND, IT'S IMPORTANT TO REMEMBER
TO EXERCISE CAUTION HERE AS THE FORECAST CAN CHANGE, AND WILL
LIKELY CHANGE.
BEHIND THIS COLD FRONT, TEMPERATURES WILL AGAIN BE SEASONABLY
COLD ON MONDAY MORNING WITH LOW TO MID 20S (WITH UPPER 20S NEAR
THE COASTLINE). OUT AHEAD OF THE HIGH PRESSURE SETTLING INTO THE
REGION, WIND SPEEDS REMAIN ON THE LIGHT SIDE (NEAR 5 KTS). THIS
WILL BE ENOUGH TO KICK WIND CHILLS INTO THE UPPER TEENS TO LOW
20S ACROSS THE REGION, WITH THE HIGHEST PROBABILITIES (40-50%)
ACROSS THE THE FURTHEST INLAND COUNTIES. THEREFORE, A COLD
WEATHER ADVISORY MIGHT BE NEEDED FOR MONDAY MORNING. HIGHS ON
MONDAY REMAIN BELOW NORMAL AS TEMPS. ONLY REACHING INTO THE
UPPER 40S TO LOW 50S.
AVIATION /00Z FRIDAY THROUGH TUESDAY/
VFR CONDITIONS WILL PREVAIL AT KCHS, KJZI, AND KSAV THROUGH 00Z
SATURDAY.
EXTENDED AVIATION OUTLOOK: VFR CONDITIONS WILL CONTINUE FOR
KCHS, KJZI AND KSAV THROUGH THE MAJORITY OF SATURDAY, BEFORE
ANOTHER SYSTEM COULD IMPACT THE REGION LATE SATURDAY NIGHT.
MARINE
TONIGHT: WINDS WILL REMAIN ELEVATED AND GUSTY ACROSS THE LOCAL
WATERS AS HIGH PRESSURE CONTINUES TO BUILD IN FROM THE WEST THIS
EVENING. WINDS WILL CONTINUE TO GUST INTO THE 25-30 KNOT RANGE,
ESPECIALLY EARLY IN THE EVENING, SUPPORTING THE ONGOING SMALL
CRAFT ADVISORIES IN EFFECT FOR ALL WATERS OUTSIDE CHARLESTON
HARBOR. BEGINNING EARLY FRIDAY MORNING, WINDS AND SEAS WILL
QUICKLY IMPROVE AS THE PRESSURE GRADIENT RELAXES. ALL SMALL
CRAFT ADVISORIES SHOULD BE DOWN BY SUNRISE.
THE CENTER OF A LARGE AREA OF HIGH PRESSURE WILL ARRIVE ON
FRIDAY AND MAY LINGER INTO SATURDAY, SUPPORTING SOUTHWESTERLY
WINDS AT 10 TO 15 KTS WITH GUSTS UP TO 20 KTS. SEAS WILL EASE
BACK FROM FRIDAY WITH THE 2 TO 3 FT EXPECTED. THERE IS POTENTIAL
FOR AN AREA OF LOW PRESSURE TO DEVELOP OFFSHORE OF THE
CAROLINAS ON SUNDAY, YIELDING GUSTY WINDS AND BUILDING SEAS YET
AGAIN. IT'S POSSIBLE THAT SMALL CRAFT ADVISORIES MIGHT BE NEEDED
ACROSS A PORTION OF THE WATERS ON SUNDAY. THEREAFTER, HIGH
PRESSURE SHOULD SETTLE OVER THE REGION EARLY NEXT WEEK, ALLOWING
CONDITIONS TO REMAIN LESS THAN SMALL CRAFT ADVISORY CRITERIA.
CHS WATCHES/WARNINGS/ADVISORIES
GA...COLD WEATHER ADVISORY UNTIL 9 AM EST FRIDAY FOR GAZ087-088-
099>101-114-115.
SC...COLD WEATHER ADVISORY UNTIL 9 AM EST FRIDAY FOR SCZ040-042>045-
047.
MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR AMZ350-352-
354.
SMALL CRAFT ADVISORY UNTIL 4 AM EST FRIDAY FOR AMZ374.
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