027
FXUS62 KCHS 211709
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
1209 PM EST SUN DEC 21 2025
SYNOPSIS
HIGH PRESSURE CONTINUES TO PREVAIL TODAY, WITH A COLD FRONT
THEN EXPECTED TO DIVE ACROSS THE REGION TONIGHT INTO MONDAY.
HIGH PRESSURE THEN RETURNS TUESDAY, RESULTING IN ABOVE NORMAL
TEMPERATURES AND DRY CONDITIONS FOR THE REMAINDER OF THE
HOLIDAY WEEK.
NEAR TERM /THROUGH TONIGHT/
EXPECT PLEASANT CONDITIONS THIS AFTERNOON AS A SURFACE HIGH PRESSURE
BUILDS INTO THE REGION, WITH RIDGING OCCURRING ALOFT RESULTING IN
HIGH TEMPERATURES IN THE MID 60S TO LOWER 70S. AS THE AFOREMENTIONED
SURFACE HIGH PRESSURE MOVES IN, A COLD FRONT MOVES THROUGH LATER
THIS AFTERNOON. THE COLDER AIR LAGS BEHIND THE FRONT A COUPLE HOURS,
BUT AS IT MOVES IN THIS EVENING GUSTY CONDITIONS DEVELOP DUE TO A
COMBINATION OF PRESSURE RISES AND COLD AIR ADVECTION. GUSTS INTO THE
15 TO 25 MPH RANGE ARE EXPECTED AND WITH TEMPERATURES IN THE MID 30S
TO LOWER 40S, THE WIND CHILLS DIP DOWN INTO THE 30S OVERNIGHT AND
EARLY MONDAY MORNING.
LAKE WINDS: GIVEN THE UNFAVORABLE NORTHEASTERLY WIND DIRECTION,
EXPECTING WINDS TO REMAIN BELOW CRITICAL THRESHOLDS, WITH WINDS
SUSTAINED IN THE 15 TO 19 KT RANGE AND GUSTS IN THE 20 TO 24 KT
RANGE. THIS WILL CONTINUE TO BE MONITORED, AND UPDATED AS NEEDED.
SHORT TERM /MONDAY THROUGH THURSDAY/
MONDAY: SURFACE HIGH PRESSURE WILL BE CENTERED OVER THE PIEDMONT OF
NORTH CAROLINA WITH HIGH CLOUDS STREAMING OVERHEAD. LOW LEVEL WINDS
WILL BE GUSTY AT TIMES IN THE MORNING HOURS WITH THE NOCTURNAL LOW
LEVEL JET EXPECTED TO PEAK AROUND 30 MPH WITH SOME SURFACE WIND
GUSTS OF 20 TO 25 MPH POSSIBLE. AS THE DAY PROGRESSES, WINDS WILL
BECOME LESS GUSTY AS THE LOW LEVEL JET SIGNIFICANTLY WEAKENS.
IN THE MID LEVELS OF THE ATMOSPHERE A POTENT SHORTWAVE WILL BE
QUICKLY EXITING NEW ENGLAND WITH SURFACE HIGH PRESSURE FOLLOWING
SUITE. THIS MEANS BY LATE MONDAY, THE SURFACE HIGH WILL ALREADY BE
OFF OF THE COAST OF NORTH CAROLINA WITH A COASTAL TROUGH MOVING
INLAND OVER GEORGIA AND SOUTH CAROLINA. NO PRECIPITATION IS FORECAST
WITH THE COASTAL TROUGH AS AN UPTICK IN DEWPOINTS (AND RELATIVE
HUMIDITY) ARE THE ONLY SENSIBLE WEATHER CHANGES FORECAST. HIGH
CLOUDS WILL BE STREAMING OVERHEAD THROUGH THE DAY, BUT MOSTLY SUNNY
SKIES ARE STILL EXPECTED WITH HIGHS IN THE LOWER 60S. MONDAY NIGHT
EXPECT LOWS IN THE LOWER 40S WITH SOME GUIDANCE HINTING AT THE
POTENTIAL FOR FOG OR STRATUS DEVELOPMENT AS HIGHER DEWPOINTS SURGE
WEST.
TUESDAY THROUGH THURSDAY: ANOTHER MID-LEVEL WAVE WILL DIVE SOUTHEAST
ACROSS ONTARIO AND QUEBEC LATE TUESDAY WHICH WILL SPELL THE END OF
THE SURFACE HIGH PRESSURE AND THE AGEOSTROPHIC CONVERGENCE COMES TO
AN END. EXPECT WARMING TEMPERATURES TUESDAY AS THE AIR MASS QUICKLY
STARTS TO MODIFY. TO PUT IT INTO PERSPECTIVE, 1000/850MB THICKNESSES
MONDAY ARE FORECAST TO BE AROUND 1340M, AND BY TUESDAY AFTERNOON ARE
EXPECTED TO BE 1365 - 1370M. THIS MEANS TEMPERATURES WILL RAPIDLY
RISE INTO THE 50S BY MID TUESDAY MORNING WITH HIGHS AROUND 70
DEGREES FORECAST. TEMPERATURES WILL FURTHER WARM INTO THE LOWER TO
MID 70S FOR WEDNESDAY AND THURSDAY. THE LATEST RUN OF THE NBM SHOWS
A HIGH DEGREE OF CONFIDENCE WITH THESE TEMPERATURES AS THE
INTERQUARTILE RANGE (IQR) FOR HIGHS WEDNESDAY - FRIDAY IS ONLY 2 - 4
DEGREES. NO PRECIPITATION IS FORECAST.
LONG TERM /THURSDAY NIGHT THROUGH SATURDAY/
THE FORECAST FOR FRIDAY REMAINS HIGH CONFIDENCE WITH ABOVE NORMAL
TEMPERATURES CONTINUING. FORECAST CONFIDENCE STARTS TO DECREASE
SATURDAY THANKS TO A POTENT MID-LEVEL LOW JUST EAST OF THE HUDSON
BAY. THIS LOW COULD POTENTIALLY PUSH A STRONG COLD FRONT THROUGH THE
AREA SATURDAY WITH TEMPERATURES RETURNING TO MORE SEASONABLE VALUES.
HOWEVER, MODEL GUIDANCE VARIES WITH THE STRENGTH AND POSITION OF
THIS LOW. SOME ENSEMBLE MEMBERS SHOW A STRONGER MID-LEVEL LOW AND
SLOWER MOVEMENT OF THE WAVE NORTHEAST, WHILE OTHER MEMBERS SHOW A
MUCH WEAKER WAVE AND QUICKER MOVEMENT TO THE NORTHEAST. THE DEEPER
WAVE WOULD FAVOR NEAR NORMAL TO SLIGHTLY BELOW NORMAL TEMPERATURES
SATURDAY INTO SUNDAY, WHILE THE LESS AMPLIFIED WAVE AND FASTER
MOVEMENT WOULD FAVOR SEASONABLE TEMPERATURES AGAIN MODERATING TO
ABOVE NORMAL. TAKING A LOOK AT THE LATEST WPC CLUSTER ANALYSIS
REVEALS AROUND 65% OF MODEL SOLUTIONS FAVORING THE FASTER/ LESS
AMPLIFIED PATTERN WITH 20% SHOWING A HIGHLY AMPLIFIED SOLUTION AND
AROUND 15% ADVERTISING A BLEND BETWEEN THESE SOLUTIONS. EITHER WAY,
NO PRECIPITATION IS FORECAST.
AVIATION /18Z SUNDAY THROUGH FRIDAY/
18Z TAFS - VFR EXPECTED FOR THE REST OF THE DAY, WITH
VARIABLE WINDS AS A FRONT MOVES THROUGH. OVERNIGHT,
NORTH-NORTHEASTERLY WINDS BECOME INCREASINGLY BREEZY AS A COLD
FRONT MOVES IN. ALONG THE FRONT, CAN'T RULE OUT SOME ISOLATED
MVFR CIGS, BUT CLOUD COVERAGE ITSELF IS LOOKING TO BE RATHER MEAGER.
MONDAY AND TUESDAY: MOSTLY VFR CONDITIONS. TWO PERIODS OF MVFR CIGS
OR LOWER ARE POSSIBLE WITH THE FIRST BEING MONDAY MORNING BEHIND THE
COLD FRONT. THE SECOND CHANCE WILL BE TUESDAY MORNING AS MOISTURE
RICH AIR RETURNS TO THE REGION. THESE RESTRICTIONS WILL BE POSSIBLE
DUE TO FOG OR STRATUS DEVELOPMENT.
WEDNESDAY AND THURSDAY: VFR CONDITIONS.
MARINE
THROUGH TONIGHT: TRANQUIL CONDITIONS EXPECTED FOR THE REST OF
THE AFTERNOON HOURS. THIS EVENING INTO THE OVERNIGHT PERIOD,
NORTH- NORTHEASTERLY WINDS STRENGTHEN WITH WAVE HEIGHTS
SIMILARLY BUILDING. CONFIDENCE REMAINS HIGH FOR WIND GUSTS
GREATER THAN 25 KNOTS FOR ALL NEAR AND OFFSHORE WATERS, KEEPING
THE SMALL CRAFT ADVISORY IN GOOD SHAPE. THE EXCEPTION IS FOR THE
CHARLESTON HARBOR WHERE WINDS ARE BORDERLINE BUT CURRENTLY
EXPECTED TO REMAIN BELOW ADVISORY CRITERIA. THIS WILL CONTINUE
TO BE MONITORED, AND UPDATED AS NEEDED. AS FOR WAVE HEIGHTS,
THEY'LL BE BUILDING TOWARDS 5 TO 6 FEET BY DAYBREAK, WITH THE
HIGHEST WAVES REMAINING 10+ NM AWAY FROM THE COAST.
MONDAY AND TUESDAY: BREEZY NORTHEAST WINDS BEHIND A COLD FRONT ARE
EXPECTED MONDAY MORNING WITH GUSTS 25 TO 30 KT. SEAS 4 TO 7 FT. THE
NORTHEAST WINDS WILL THEN START TO RELAX LATE MONDAY MORNING WITH
SEAS SLOWLY STARTING TO COME DOWN MONDAY AFTERNOON. ALL NEARSHORE
WATER SMALL CRAFT ADVISORIES WILL BE DONE BY LATE MONDAY EVENING
WITH THE OFFSHORE GEORGIA WATERS REMAINING THROUGH TUESDAY AFTERNOON
DUE TO THE POTENTIAL FOR 6 FT SEAS.
WEDNESDAY AND THURSDAY: HIGH CONFIDENCE IN NO MARINE HEADLINES. WIND
GUSTS 15 KT OR LESS WITH SEAS 2 TO 3 FT.
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO MIDNIGHT EST
MONDAY NIGHT FOR AMZ350.
SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO MIDNIGHT EST
MONDAY NIGHT FOR AMZ352-354.
SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 6 PM EST
TUESDAY FOR AMZ374.
NEAR TERM...APT
SHORT TERM...HAINES
LONG TERM...HAINES
AVIATION...APT/HAINES
MARINE...APT/HAINES
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