353
FXUS62 KGSP 231101
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
701 AM EDT MON MAR 23 2026
WHAT HAS CHANGED
UPDATED FOR 12Z TAF ISSUANCE.
KEY MESSAGES
1. A COLD FRONT WILL ARRIVE THIS MORNING POSSIBLY PRODUCING A FEW
MOUNTAIN SHOWERS. LOW HUMIDITY AND GUSTY WINDS THIS AFTERNOON
WILL INCREASE FIRE DANGER. MUCH COOLER TUESDAY BUT STILL WITH
LOW HUMIDITY, SO FIRE DANGER MAY REMAIN ELEVATED.
2. COLD-AIR DAMMING WILL MAINTAIN BELOW-NORMAL TEMPERATURES AND
POTENTIALLY LIGHT PRECIPITATION FOR SOUTHERN PORTIONS OF THE AREA,
BEFORE TEMPERATURES TREND WARMER AGAIN ON THURSDAY.
3. A BACKDOOR COLD FRONT CROSSES THE AREA ON FRIDAY, POSSIBLY
PRODUCING SOME SHOWERS AND STORMS, AND DEFINITELY USHERING IN A
COOLER AIR MASS FOR NEXT WEEKEND.
DISCUSSION
KEY MESSAGE 1: A COLD FRONT WILL ARRIVE THIS MORNING POSSIBLY
PRODUCING A FEW MOUNTAIN SHOWERS. LOW HUMIDITY AND GUSTY WINDS
THIS AFTERNOON WILL INCREASE FIRE DANGER. MUCH COOLER TUESDAY BUT
STILL WITH LOW HUMIDITY, SO FIRE DANGER MAY REMAIN ELEVATED.
SURFACE COLD FRONT WILL CROSS THE APPALACHIAN SPINE AROUND 12Z
THIS MORNING; CONVECTION IN THE OHIO VALLEY IS EXPECTED TO WANE
NOCTURNALLY BY THAT TIME. A SHALLOW MOIST LAYER SHOULD ACCOMPANY THE
FRONT INTO THE MOUNTAINS, SO SMALL POPS ARE WARRANTED ALONG THE TN
BORDER FOR UPSLOPE SHOWERS BEGINNING AROUND DAYBREAK AND LASTING
THRU MID-MORNING UNTIL THE MOISTURE IS EXHAUSTED. PROFILES DON'T
LOOK TO SATURATE EAST OF THE MOUNTAINS, BUT A FEW SHALLOW CUMULUS
MAY BREAK OUT AT THE TOP OF THE MIXED LAYER. HIGHER ELEVATIONS IN
THE MOUNTAINS SHOULD SEE TEMPS FALL SLOWLY FROM DAYBREAK ONWARD
WITH POST-FRONTAL CAA. DOWNSLOPING WILL OFFSET THE CAA EAST OF THE
MOUNTAINS, BUT THE FOOTHILLS AND FAR NW NC PIEDMONT WILL SEE TEMPS
PEAK AROUND MIDDAY BEFORE FALLING. OTHER PIEDMONT AREAS SHOULD STILL
SEE MAX NEAR THE CLIMATOLOGICAL TIME, WITH TEMPS STILL REACHING THE
MID 70S TO NEAR 80. THINK MIXING MAY PROVE A BIT DEEPER THAN WHAT
MOST MODELS EXPECT SO RAISED GUST POTENTIAL A FEW KT COMPARED TO
THE OPERATIONAL NBM, SO OCCASIONAL GUSTS OF 25-30 KT APPEAR LIKELY
THIS AFTERNOON. THOUGH DEWPOINTS LOOK TO FALL THRU THE AFTERNOON
IN ALL AREAS, THE ONSET OF SUBSTANTIALLY DRIER AIR ALOFT APPEARS TO
COME AFTER PEAK HEATING/MIXING. THUS RH STILL MOST LIKELY WILL FALL
"ONLY" TO THE 25-30% RANGE IN THE NC/SC PIEDMONT, ALTHOUGH RECOVERY
DURING THE EVENING PROBABLY WILL BE SLOWER THAN USUAL. COMBINED
WITH THE WIND, WE WILL RETAIN THE PREVIOUSLY COORDINATED INCREASED
FIRE DANGER STATEMENT; STILL A FEW POINTS OFF RED FLAG CRITERIA.
TEMPS TONIGHT ACTUALLY FALL A FEW DEGREES BELOW NORMAL, WITH A
FREEZE LIKELY IN HIGHER MOUNTAIN ELEVATIONS. SURFACE HIGH WILL
REMAIN CENTERED IN THE UPPER OH VALLEY LATE TONIGHT. WINDS TAPER
OFF SLOWLY THROUGH THE EVENING; NORTHEASTERLY CAA HOWEVER WILL
KEEP BREEZY CONDITIONS ACROSS THE PIEDMONT. TUESDAY, THE HIGH
BUILDS EAST TOWARD THE MID-ATLANTIC COAST IN A CONFIGURATION
THAT EVENTUALLY WILL FOSTER HYBRID CAD, THOUGH WITHOUT PRECIP IT
TECHNICALLY DOESN'T QUALIFY AS CAD DURING THE DAY. WINDS AND
GUSTS TAPER OFF DURING THE AFTERNOON. TEMPS REMAIN A FEW BELOW
NORMAL. EXCEPTIONALLY DRY AIR IS SHOWN ABOVE THE PBL; AGAIN MIXING
WILL BE LIMITED BY SUBSIDENCE BUT ALREADY LOW DEWPOINTS SHOULD
DIP DURING THE AFTERNOON. RH IS EXPECTED TO FALL CLOSER TO 20
PERCENT, BUT WITH LIGHTER WINDS THE OBJECTIVE IFD CRITERIA MAY
NOT BE MET IN NC/SC. FUEL MOISTURES SHOULD TREND LOWER BY THEN,
AND IN SOME SETUPS LIKE THIS LAND MANAGEMENT AGENCIES ASK TO WAIVE
THE CRITERIA. ADDITIONAL COORDINATION MAY BE UNDERTAKEN TODAY.
KEY MESSAGE 2: COLD-AIR DAMMING WILL MAINTAIN BELOW-NORMAL
TEMPERATURES AND POTENTIALLY LIGHT PRECIPITATION FOR SOUTHERN
PORTIONS OF THE AREA, BEFORE TEMPERATURES TREND WARMER AGAIN
ON THURSDAY.
BY EARLY WEDNESDAY MORNING, MODELS DEPICT THE CENTER OF A BROAD
SURFACE HIGH EXTENDING FROM THE CHESAPEAKE BAY INTO THE WESTERN
ATLANTIC AND DRIVING S/SE FLOW ACROSS THE WESTERN CAROLINAS.
WEAK COLD-AIR DAMMING WILL LIKELY ALREADY BE IN PLACE OWING TO
THIS CONFIGURAION...BUT MOSTLY DRY AND SUPPRESSED ON THE EASTERN
PERIPHERY OF A BROAD BLOCKING RIDGE OVER THE WEST-CENTRAL CONUS.
A NUMBER OF MEMBERS OF THE 12Z GEPS MEMBERS AS WELL AS A HANDFUL
OF ENS MEMBERS DEPICT A DECAYING MID-LEVEL VORTICITY MAX DRIFTING
ACROSS THE TENNESSEE VALLEY AND PROMPTING SOME WEAK MOIST UPGLIDE ON
WEDNESDAY AFTERNOON...ENOUGH TO JUSTIFY INTRODUCING A SLIGHT CHANCE
POP BACK INTO THE UPSTATE AND SAVANNAH RIVER VALLEY ON WEDNESDAY
AFTENROON. IT STILL SEEMS MORE LIKELY THAT ANY PRECIPITATION
WILL BE PATCHY AND VERY LIGHT, BUT THERE'S A POTENTIAL SCENARIO
WHERE MORE APPRECIABLE DRIZZLE WILL DEVELOP IF THIS SOLUTION WERE
TO VERIFY. WHATEVER RAINFALL DEVELOPS SHOULD FALL APART THROUGH
LATE EVENING, LEAVING US DRY AGAIN ON WEDNESDAY NIGHT AND THURSDAY.
TEMPERATURES, MEANWHILE, WHICH WITHOUT THE CAD WOULD QUICKLY BE
MODIFYING AT THIS POINT AND TRENDING WARMER, WILL INSTEAD BE HELD IN
CHECK BY WEAK SURFACE CAA AS WELL AS ANY PRECIPITATION THAT OCCURS.
AT LEAST ON WEDNESDAY, THEY'LL LIKELY REMAIN A CATEGORY OR SO BELOW
NORMAL EAST OF THE MOUNTAINS. IF MORE APPRECIABLE RAIN DEVELOPS AS
DESCRIBED ABOVE, TEMPERATURES COULD CONDITIONALLY BE EVEN COOLER
THAN CURRENTLY FORECAST OVER THE UPSTATE. BY THURSDAY, HOWEVER,
AS THE SURFACE HIGH RETREATS INTO THE ATLANTIC, AND SW LOW-LEVEL
FLOW INTENSIFIES AHEAD OF AN APPROACHING BAROCLINIC ZONE, CAD
SHOULD STEADILY ERODE FROM THE BOTTOM UP, ALLOWING TEMPERATURES
TO CLIMB BACK INTO THE 70S - ABOVE NORMAL - FOR THE LOW TERRAIN.
KEY MESSAGE 3: A BACKDOOR COLD FRONT CROSSES THE AREA ON FRIDAY,
POSSIBLY PRODUCING SOME SHOWERS AND STORMS, AND DEFINITELY USHERING
IN A COOLER AIR MASS FOR NEXT WEEKEND.
BY FRIDAY, BROAD, LOW-AMPLITUDE Z500 TROUGHING WILL DRIVE A WELL-
DEFINED COLD FRONT OUT OF THE MID-ATLANTIC AND INTO THE CAROLINAS.
AS DESCRIBED IN PREVIOUS FORECASTS, NAILING DOWN TIMING FOR THIS
FRONTAL PASSAGE REMAINS CHALLENGING...BUT THE LATEST 12Z LREF CYCLE
STRONGLY FAVORS A SLOWER/LATER SOLUTION, ALLOWING AT LEAST A FEW
HUNDRED JOULES OF SBCAPE TO DEVELOP OVER PARTS OF THE FORECAST AREA,
AND SUPPORTING A BAND OF SHOWERS AND EMBEDDED THUNDER CROSSING THE
REGION SOMETIME FRIDAY. THOSE MEMBERS WHICH ARE MORE UNSTABLE ALSO
APPEAR TO FAVOR WEAKER BULK SHEAR, BY VIRTUE OF KEEPING THE UPPER
WAVE FARTHER NORTH DURING PEAK HEATING...SUCH THAT SOME DEGREE OF
ORGANIZATION REMAINS A POSSIBILITY, BUT CONFIDENCE IN ANY SEVERE
RISK REMAINS QUITE LIMITED.
BEHIND THE FRONT, TEMPERATURES WILL PLUMMET AS THE COOLER AIR
MASS SETTLES IN OVER THE WEEKEND. HIGH TEMPERATURES COULD DROP 20
DEGREES OR MORE FROM FRIDAY TO SATURDAY, PUTTING THEM BACK A FEW
DEGREES BELOW NORMAL ON SATURDAY...WHILE LOWS SATURDAY NIGHT SHOULD
FALL AS LOW AS THE MID-30S ACROSS THE PIEDMONT AND UPSTATE...AND
BELOW FREEZING FOR THE NC MOUNTAINS.
AVIATION /12Z MONDAY THROUGH FRIDAY/
AT KCLT AND ELSEWHERE: BREEZY CONDITIONS PERSIST AROUND THE TERMINAL
AREA WITH TEMPERATURES HAVING BEEN ELEVATED OVERNIGHT AND STARTING
OUT ALREADY SOMEWHAT MIXED. COLD FRONT WILL PASS THE TERMINALS THIS
MORNING, BRINGING RAPID ONSET OF GUSTS WITH SFC WARMING; UPSLOPE
MOISTURE ALONG THE APPALACHIANS NEAR THE FRONT WILL MAINTAIN LOW
VFR STRATOCU NEAR KAVL. MIXING SHOULD BRING DOWN NW WINDS AND
INVOKE WIND SHIFT 14-17Z OUTSIDE THE MOUNTAINS. LOW VFR CUMULUS
COULD DEVELOP ALONG THE FRONT BRIEFLY AT THE OTHER SITES, AROUND
MIDDAY, BUT RAPID DRYING POST FROPA SUGGESTS THEY WILL BE SHORT
LIVED. GUST POTENTIAL PEAKS IN MID TO LATE AFTERNOON BY SAME TOKEN,
AT 25-30 KT. GUSTS SLOWLY DIMINISH THRU THE EVENING AS WINDS TURN
NE. TOO DRY FOR FOG TONIGHT.
OUTLOOK: VFR THROUGH TUESDAY. SOME RESTRICTIONS MAY DEVELOP TUE
NIGHT WITH MOIST FRONTAL ZONE FORMING OVER THE AREA. DIURNAL
CONVECTION POSSIBLE LATER IN THE WEEK.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...INCREASED FIRE DANGER FROM 3 PM EDT THIS AFTERNOON THROUGH
THIS EVENING FOR NCZ035>037-056-057-068>072-082-502-504-
506-508-510.
SC...INCREASED FIRE DANGER FROM 3 PM EDT THIS AFTERNOON THROUGH
THIS EVENING FOR SCZ008>014-019-101>109.
JCW/MPR
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page