422
FXUS62 KCHS 171121
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
621 AM EST MON NOV 17 2025
SYNOPSIS
AS HIGH PRESSURE BUILDS INTO THE REGION EARLY THIS WEEK, THE
FORECAST IS EXPECTED TO REMAIN RAIN-FREE THROUGHOUT THE WORK
WEEK. A WARM FRONT SHOULD LIFT NORTH OF THE REGION BY
WEDNESDAY, AND ALLOW FOR UNSEASONABLE WARM CONDITIONS TO
PERSIST AFTERWARDS. ANOTHER COLD FRONT COULD PASS THROUGH THE
REGION THIS WEEKEND.
NEAR TERM /THROUGH TONIGHT/
THE MID-LEVELS WILL CONSIST OF WEAK RIDGING BUILDING TOWARDS
OUR AREA. THIS WILL CAUSE WNW FLOW OVERHEAD WITH HEIGHTS
SLIGHTLY RISING. AT THE SURFACE, HIGH PRESSURE WILL BUILD IN
FROM THE NORTHWEST THIS MORNING, PASSING TO OUR NORTH THIS
AFTERNOON AND EVENING, THEN BECOMING LOCATED TO OUR NORTHEAST
TONIGHT. THE HIGH WILL BRING OUR AREA DRY CONDITIONS WITH SOME
PASSING CLOUDS. THERE WILL BE A LARGE RANGE IN HIGH
TEMPERATURES, PEAKING FROM THE MID 60S ACROSS THE CHARLESTON
TRI-COUNTY, TO THE MID 70S NEAR THE ALTAMAHA RIVER AND VICINITY.
MOSTLY CLEAR SKIES AND LIGHT TO CALM WINDS WILL CAUSE PLENTY OF
RADIATIONAL COOLING TONIGHT. THERE WILL ALSO BE A LARGE RANGE
IN LOW TEMPERATURES. THEY SHOULD BOTTOM OUT IN THE UPPER 30S
VERY FAR INLAND, THE 40S ACROSS MOST OF OUR AREA, AND THE LOWER
TO MIDDLE 50S AT/NEAR THE BEACHES.
SHORT TERM /TUESDAY THROUGH THURSDAY/
A SHORTWAVE TROUGH SITUATED OVER THE GREAT PLAINS WILL SLOWLY
WEAKEN AS IT MOVES ACROSS THE APPALACHIAN MTNS., BEFORE RE-
ORGANIZING OFF OF THE MID-ATLANTIC COASTLINE ON WEDNESDAY
AFTERNOON. SIMULTANEOUSLY, AN ASSOCIATED FRONT WILL APPROACH THE
REGION, BUT IT IS EXPECTED TO WEAKEN AND STALL OUT ACROSS THE
MID-ATLANTIC BEFORE WASHING OUT. THERE IS NO PRECIPITATION
EXPECTED WITH THIS SYSTEM AS THE MAJORITY OF FORCING REMAINS TO
THE NORTH OF THE REGION. THIS PATTERN YIELD WEAK RETURN FLOW
ACROSS THE REGION WITH INCREASING LOW- LVL THICKNESSES.
TEMPERATURES WILL PROGRESSIVELY WARM-UP THROUGHOUT THE PERIOD AS
WAA AND MOSTLY SUNNY SKIES PROMOTE UNSEASONABLE WARM
CONDITIONS.
LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/
A STRONG UPPER-LVL RIDGE WITH NEARLY 590 DM WILL BE PRESENT
OVER THE GULF ON THURSDAY NIGHT AND THE MAJORITY OF FRIDAY.
EXPECT TEMPERATURES TO REMAIN GENERALLY 10 TO 12 DEGREES ABOVE
NORMAL WITH A RAIN-FREE FORECAST. HIGH TEMPERATURES THURSDAY AND
FRIDAY WILL REACH NEAR RECORD HIGHS (SEE CLIMATE SECTION), WITH
LOW 80S ACROSS THE SC LOWCOUNTRY TO THE LOW TO MID 80S ACROSS
SE GA. THE NEXT CHANCE FOR PRECIPITATION WILL BE SATURDAY AS A
SURFACE LOW DEVELOPS ACROSS THE CENTRAL CONUS AND THROWS AN
ASSOCIATED COLD FRONT TOWARDS THE REGION. WITH A FAIRLY COMPLEX
SYNOPTIC PATTERN, THERE IS QUITE A BIT UNCERTAINTY AS MODEL
GUIDANCE WIDELY DIFFERS WITH THE TIMING OF THIS FRONT. IT REALLY
DEPENDS ON HOW MUCH OF AN IMPACT THE H5 RIDGE LOCATED ALONG THE
ATLANTIC COAST WILL HAVE ON THE SYSTEM. A STRONGER RIDGE
RESULTS (SEEN IN THE 12Z ECMWF) IN A SLOWER PROGRESSION OF THE
COLD FRONT, WHILE A WEAKER RIDGE (SEEN IN THE 00Z GFS) RESULTS
IN A FASTER MOVING PROGRESSION. IT IS POSSIBLE THE FORECAST MAY
TREND COOLER AND WETTER IF THE 12Z ECMWF GUIDANCE HOLDS TRUE.
AVIATION /12Z MONDAY THROUGH FRIDAY/
12Z TAFS: VFR.
EXTENDED AVIATION OUTLOOK: PREVAILING VFR. IT IS POSSIBLE THAT
PERIODS OF GROUND FOG MAY DEVELOP DURING THE PRE-DAWN HOURS ON
WEDNESDAY.
MARINE
TODAY AND TONIGHT: HIGH PRESSURE WILL BUILD IN FROM THE
NORTHWEST THIS MORNING, PASSING TO OUR NORTH THIS AFTERNOON AND
EVENING, THEN BECOMING LOCATED TO OUR NORTHEAST TONIGHT. THE
HIGH WILL BRING OUR COASTAL WATERS TRANQUIL CONDITIONS.
TUESDAY THROUGH SATURDAY: AS SURFACE HIGH PRESSURE CONTINUES TO
BUILD ACROSS THE LOCAL MARINE ZONES, WEST-SOUTHWESTERLY WINDS
WILL REMAIN LIGHT AND VARIABLE. AHEAD OF THE DEVELOPING SURFACE
LOW ACROSS THE CENTRAL CONUS, WINDS COULD INCREASE TO 10 TO 15
KTS WITH GUSTS UP TO 20 KTS ON FRIDAY NIGHT INTO THE WEEKEND.
SEAS WILL GENERALLY RANGE FROM 1 TO 3 FT.
FIRE WEATHER
HIGH PRESSURE BUILDING IN FROM THE NORTH TODAY WILL BRING DRY
CONDITIONS. RH VALUES ARE EXPECTED TO BE CRITICALLY LOW THIS
AFTERNOON. INLAND RH VALUES SHOULD DROP INTO THE TEENS, WHILE
CLOSER TO THE COAST RH VALUES SHOULD FALL INTO THE 20S. WINDS
SHOULD BE FAIRLY LIGHT TODAY, WHICH SHOULD LIMIT FIRE WEATHER
CONCERNS.
CLIMATE
RECORD HIGH TEMPERATURES:
NOVEMBER 20:
KCHS: 82/1942
KCXM: 78/1900
KSAV: 83/1942
NOVEMBER 21:
KSAV: 82/2011
NOVEMBER 22:
KSAV: 82/1997
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...NONE.
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...
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