415
FXUS62 KCHS 210622
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
122 AM EST WED JAN 21 2026
WHAT HAS CHANGED
THE AVIATION SECTION HAS BEEN UPDATED FOR THE 00Z TAF ISSUANCE.
KEY MESSAGES
- 1) COLD TEMPERATURES IN THE MID TO UPPER 20S ACROSS INLAND
AREAS WEDNESDAY MORNING.
- 2) WIDESPREAD PRECIPITATION IS EXPECTED TO OCCUR THIS
WEEKEND, BRINGING INCREASING POTENTIAL FOR A MULTI-DAY WINTER
WEATHER EVENT ACROSS PORTIONS OF THE REGION.
- 3) VERY COLD TEMPERATURES WILL OCCUR EARLY NEXT WEEK.
DISCUSSION
KEY MESSAGE 1: COLD TEMPERATURES IN THE MID TO UPPER 20S ACROSS
INLAND AREAS THIS MORNING.
DRY HIGH PRESSURE CENTERED ACROSS THE MID-ATLANTIC STATES TONIGHT
WILL SLOWLY SLIP OFFSHORE ACROSS THE WESTERN ATLANTIC MID-LATE
MORNING, SUPPORTING A LIGHT NORTHERLY WIND TONIGHT TO TIP MORE NORTH-
NORTHEAST APPROACHING DAYBREAK. STRONG RADIATIONAL COOLING UNDER
CLEAR SKIES WILL SUPPORT LOW TEMPS IN THE MID 20S, COLDEST ALONG AND
WEST OF I-95 AND NORTH OF I-16 WHERE LITTLE TO NO CIRRUS IMPACTS
MAXIMUM RADIATIONAL COOLING FOR THE NIGHT. WINDS WILL REMAIN
LIGHT/CALM IN THESE AREAS LATE NIGHT, INDICATING LITTLE IN THE WAY
OF WIND CHILL VALUES BELOW THESE FORECASTED LOW TEMPERATURES. A COLD
WEATHER ADVISORY IS NOT EXPECTED AT THIS TIME.
KEY MESSAGE 2: WIDESPREAD PRECIPITATION IS EXPECTED TO OCCUR THIS
WEEKEND, BRINGING INCREASING POTENTIAL FOR A MULTI-DAY WINTER
WEATHER EVENT ACROSS PORTIONS OF THE REGION.
FOCUS FOR THE WEEK WILL CONTINUE BE ON THE POTENTIAL WINTER WEATHER
EVENT IMPACTING AT LEAST PORTIONS OF SOUTHEAST SOUTH CAROLINA AND
SOUTHEAST GEORGIA THIS WEEKEND INTO EARLY NEXT WEEK. STRONG, COLD
HIGH PRESSURE WILL WEDGE DOWN INTO THE REGION THROUGH THE WEEKEND,
WITH LOW PRESSURE EXPECTED TO DEVELOP OFF THE SOUTHEAST COAST.
INCREASING ISENTROPIC ASCENT WILL LEAD TO RAIN SPREADING INTO THE
AREA ON SATURDAY, THEN CONCERN INCREASES LATER SATURDAY INTO
SATURDAY NIGHT FOR WINTRY WEATHER OVER PARTS OF THE AREA AS COLD AIR
SETTLES IN. MODEL SOUNDINGS REMAIN CONSISTENT IN INDICATING A
PROMINENT WARM NOSE CENTERED AROUND 850 MB WITH AROUND FREEZING/SUB-
FREEZING TEMPS DEVELOPING CLOSER TO THE SURFACE. THIS WOULD SUGGEST
FREEZING RAIN COULD BECOME THE MORE DOMINANT P-TYPE, ESPECIALLY
INLAND, WITH LITTLE CHANCE FOR SNOW WHICH JIVES WITH MOST MODEL
GUIDANCE AND PROBABILITIES. THERE IS QUESTION IN HOW CLOSE TO THE
COAST AND SOUTH THE FREEZING TEMPERATURES WILL REACH.
TEMPERATURES WILL REMAIN VERY CHILLY THROUGH THE DAY SUNDAY, BUT
THERE IS STILL QUITE A SPREAD IN GUIDANCE REGARDING HOW COLD IT
COULD STAY. MOST AREAS SHOULD "WARM" ENOUGH DURING THE DAYTIME HOURS
TO TRANSITION MOST PRECIPITATION BACK OVER TO RAIN. OVER THE FAR
INTERIOR, P-TYPE CONCERNS COULD LINGER LONGER.
THERE REMAINS UNCERTAINTY REGARDING THE END OF THE PRECIPITATION.
THERE IS A PRETTY EVEN SPLIT AMONG ENSEMBLE MEMBERS PER CLUSTER
ANALYSIS ON SCENARIOS. ONE CLUSTER, COMPRISED OF MOSTLY GFS AND
CANADIAN MEMBERS, WOULD INDICATE A SLOWER EXIT TO THE UPPER WAVE,
WHICH IN TURN COULD KEEP PRECIP AROUND A BIT LONGER INTO MONDAY.
WHILE ANOTHER CLUSTER, MAJORITY EURO MEMBERS, HINTS AT A FASTER EXIT
AND END TO THE PRECIP. ANY LINGERING PRECIPITATION SUNDAY NIGHT AND
MONDAY MORNING COULD BE IN THE FORM OF FREEZING RAIN, ESPECIALLY
NORTH OF I-16, GIVEN HIGH LIKELIHOOD OF SUB-FREEZING TEMPERATURES
AND TEMPERATURE PROFILES.
THIS EVENT HAS POTENTIAL TO BRING ACCUMULATING ICE TO THE AREA.
LATEST NBM SHOWS THE PROBABILITY FOR 48 HOUR FREEZING RAIN
ACCUMULATION >0.01" IN THE 50-80% RANGE LARGELY NORTH OF I-16.
LOOKING AT THE PROBABILITIES FOR >0.25" PEAKS AROUND 30-40% ROUGHLY
ALONG AND WEST OF A LINE FROM MONCKS CORNER TO WALTERBORO TO
SYLVANIA AND MILLEN. WINTER WEATHER WATCHES AND/OR ADVISORIES
WILL BE POSSIBLE IN THE COMING DAYS.
THE PROBABILISTIC WINTER STORM SEVERITY INDEX (WSSI-P) CONTINUES TO
SHOW CHANCES OF MINOR WINTER STORM IMPACTS ACROSS THE ENTIRE AREA,
WITH EVEN A 20-40% CHANCE OF MODERATE IMPACTS ESPECIALLY NORTH OF I-
16.
KEY MESSAGE 3: VERY COLD TEMPERATURES WILL OCCUR EARLY NEXT WEEK.
STRONG HIGH PRESSURE WILL USHER ARCTIC AIR INTO THE REGION MONDAY
NIGHT INTO TUESDAY MORNING, WHICH THEN LINGERS THROUGH EARLY WEEK
BEFORE THE AIRMASS MODIFIES/WARMS DURING THE SECOND HALF OF THE
WEEK. AS A RESULT, LOW TEMPS ARE FORECAST TO DIP INTO THE TEENS WEST
OF I-95 WITH LOW TO MID 20S ALONG THE COAST TUESDAY MORNING AND
WEDNESDAY MORNING. THESE TEMPS IN COMBINATION WITH A NORTH/NORTHEAST
WIND AROUND 10 MPH ACROSS THE REGION COULD RESULT IN WIDESPREAD WIND
CHILL VALUES IN THE TEENS. COLD WEATHER ADVISORIES COULD EVENTUALLY
BE NEEDED.
AVIATION /06Z WEDNESDAY THROUGH SUNDAY/
VFR CONDITIONS WILL PREVAIL AT CHS/JZI/SAV TERMINALS THROUGH 06Z
THURSDAY.
EXTENDED AVIATION FORECAST: VFR CONDITIONS ARE EXPECTED AT
CHS/JZI/SAV TERMINALS 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 CENTERED ACROSS THE MID-ATLANTIC
STATES EARLY MORNING WILL GRADUALLY SLIDE EAST ACROSS THE WESTERN
ATLANTIC THIS AFTERNOON AND OVERNIGHT. THE SETUP WILL FAVOR QUIET
MARINE CONDITIONS ACROSS LOCAL WATERS WITH NORTHEAST WINDS UP TO 10-
15 KT EARLY DAY TRENDING WEAKER DURING THE AFTERNOON AND NIGHT WHILE
TIPPING BACK TO THE NORTH-NORTHWEST. SEAS WILL GENERALLY RANGE
BETWEEN 1-3 FT NEARSHORE TO 3-4 FT ACROSS OUTER GEORGIA WATERS.
THURSDAY AND FRIDAY: QUIET MARINE CONDITIONS WILL PERSIST INTO LATE
WEEK WHILE WEAK HIGH PRESSURE LINGERS ACROSS THE SOUTHEAST AHEAD OF
A FRONT APPROACHING INLAND. IN GENERAL, A NORTH/NORTHEAST WIND UP TO
AROUND 10 KT WILL BE COMMON ACROSS MOST WATERS. SEAS SHOULD RANGE
BETWEEN 2-3 FT NEARSHORE TO 3-4 FT ACROSS OUTER GEORGIA WATERS.
FRIDAY NIGHT THROUGH MONDAY: THIS IS PERIOD OF GREATEST CONCERN IN
REGARDS TO DETERIORATING WIND/SEA CONDITIONS. A COLD FRONT WILL
APPROACH THE SOUTHEAST BY THE WEEKEND, LIKELY SHIFTING OFFSHORE BY
FRIDAY EVENING WITH STRONG COLD AIR ADVECTION IN ITS WAKE.
CONDITIONS WILL BEGIN TO DETERIORATE ACROSS LOCAL WATERS AS A RESULT
FRIDAY NIGHT, POSSIBLY REACHING SMALL CRAFT ADVISORY LEVELS ACROSS
SOUTH CAROLINA WATERS AFTER MIDNIGHT FRIDAY NIGHT AND ACROSS GEORGIA
WATERS BY AROUND DAYBREAK SATURDAY. CONDITIONS SHOULD CONTINUE TO
DETERIORATE DURING THE WEEKEND AS LOW PRESSURE ATTEMPTS TO DEVELOP
NEAR THE COLD FRONT POSITIONED OFFSHORE, WITH GUIDANCE SUGGESTING A
SOLID SMALL CRAFT ADVISORY EVENT ACROSS ALL WATERS THIS WEEKEND AND
THE POSSIBILITY OF LOW-END GUSTS TO GALE FORCE AS COLD AIR ADVECTION
PROMOTES AMPLE MIXING INTO ENHANCED LOW-LVL WIND FIELDS DURING THE
PEAK OF THE EVENT SATURDAY NIGHT INTO SUNDAY MORNING. 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 COULD LINGER ACROSS OUTER GEORGIA WATERS INTO MONDAY,
SUPPORTING A LONGER DURATION SMALL CRAFT ADVISORY INTO EARLY NEXT
WEEK.
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 TODAY OR THURSDAY TO RESTORE FULL SERVICE.
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...NONE.
DPB/ETM
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