957
FXUS62 KGSP 260017
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
717 PM EST TUE NOV 25 2025
SYNOPSIS
A COLD FRONT MOVES ACROSS THE AREA TONIGHT AND TO THE CAROLINA
COAST ON WEDNESDAY, PRODUCING WIDESPREAD SHOWERS AND A FEW
THUNDERSTORMS. MUCH COLDER TEMPERATURES ARRIVE BEHIND THE FRONT AND
CONTINUE INTO THE WEEKEND. ANOTHER COLD FRONT ARRIVES SUNDAY AND
SUNDAY NIGHT.
NEAR TERM /THROUGH WEDNESDAY/
AS OF 630 PM EST TUESDAY: A WARM CONVEYOR BELT ASSOCIATED WITH
AN APPROACHING COLD FRONT CAN BE SEEN ON IR AND THE RADAR MOSAIC
ENTERING THE FORECAST AREA THIS EVENING. SO FAR, THE PRECIP HAS
BEEN JUST LIGHT TO MODERATE SHOWERS, WITH DEEPER CONVECTION STILL
WELL SOUTHWEST OF THE AREA OVER EAST-CENTRAL AL. THERE SEEMS TO
BE JUST ENOUGH ISENTROPIC LIFT AND PRECIP TO SUPPORT AN IN-SITU
COLD AIR DAMMING WEDGE NEAR THE BLUE RIDGE, EXTENDING EAST TOWARD
THE I-85 CORRIDOR. THIS WEDGE MAY HOLD ON AND KEEP THE MAJORITY OF
THE CWFA FREE OF SFC-BASED CAPE. HOWEVER, A PLUME OF 200-750 J/KG
OF MUCAPE IS EXPECTED TO CROSS THE AREA AS THE WCB CROSSES THE
AREA THIS EVENING INTO THE OVERNIGHT. THE LATEST CAMS ARE IN GOOD
AGREEMENT ON CONVECTION STAYING DISORGANIZED AND RELATIVELY WEAK
AS IT CROSSES THE AREA. SHEAR WILL SUPPORT SOME ROTATING CELLS,
BUT STORMS WILL LIKELY STAY ELEVATED. THUS, SEVERE THREAT WILL
REMAIN VERY LOW. THE ONE EXCEPTION WOULD BE ALONG THE SOUTHEAST
EDGE OF THE CWFA, WHERE THE WEDGE FRONT MAY LIFT NORTH AND BRING
IN 100-250 J/KG OF SBCAPE AROUND OR JUST AFTER MIDNIGHT. ALONG
THIS BOUNDARY A NON-ZERO WIND AND TORNADO THREAT MAY MATERIALIZE.
OTHERWISE... HEIGHT FALLS WILL ACCOMPANY A NORTHERN STREAM TROUGH
AS IT TAKES ON A NEGATIVE TILT AND SURFACE CYCLOGENESIS WILL
BE UNDERWAY UNDERNEATH THE CORE OF THE TROUGH NEAR THE UPPER
GREAT LAKES THIS EVENING INTO THE OVERNIGHT HOURS. A WARM SECTOR
BECOMES BETTER ESTABLISHED LATER THIS EVENING WITH THE SECOND
ROUND OF CONVECTION. BETTER FORCING FOR ASCENT IS EXPECTED WITH
HEIGHT FALLS AND JET DYNAMICS IN PLACE, WHILE DEEPER MOISTURE
TRANSPORT ALONG AND JUST AHEAD OF THE INCOMING COLD FRONT SETS UP
A FAVORABLE ENVIRONMENT FOR CONVECTIVE DEVELOPMENT. IN THIS CASE,
ROBUST ORGANIZED CONVECTION LATER THIS EVENING THROUGH A GOOD
PORTION OF THE OVERNIGHT AS THE ACTIVITY MOVES IN FROM WEST TO
EAST. ELEVATED INSTABILITY WILL BE PRESENT TO GO ALONG WITH 55-65
KTS OF DEEP LAYER SHEAR. CAN'T RULE OUT A FEW STRONGER STORMS
CAPABLE OF PRODUCING LOCALIZED DAMAGING WIND GUSTS. HOWEVER,
LATEST 12Z CAMS SUGGEST 100-250 J/KG OF SBCAPE WILL BE PRESENT
DESPITE THE NOCTURNAL TIME FRAME. A WARM FRONT WILL BE PRESENT
ACROSS THE PIEDMONT ZONES, SO ANY SURFACE INSTABILITY THAT DEVELOPS
AND INTERACTS WITH THE BOUNDARY COULD FORM AN ISOLATED TORNADO
EVEN THOUGH LOW-LEVEL WIND SHEAR ISN'T THAT IMPRESSIVE (15- 25
KTS). EXPECT THE LINE OF CONVECTION TO MOVE EAST OF THE AREA JUST
BEFORE DAYBREAK WEDNESDAY. OVERNIGHT LOWS WILL RUN 15-20 DEGREES
ABOVE NORMAL THANKS TO THE WARM SECTOR REGIME.
THE COLD FRONT GRADUALLY PUSHES ACROSS THE CWFA DURING THE
DAYTIME PERIOD WEDNESDAY WITH A FULL FROPA EXPECTED JUST
BEFORE SUNSET. STOUT CAA BEHIND THE FRONT WILL BRING IN VERY
GUSTY WINDS ACROSS THE MOUNTAINS, ESPECIALLY AT ELEVATIONS ABOVE
3500' BY WEDNESDAY EVENING. VERY TIGHT PRESSURE GRADIENT (5-8MB)
BECOMES ESTABLISHED AS A RESULT. CONFIDENCE IS FAIRLY HIGH THAT
CRITERIA ADVISORY GUSTS WILL BE MET BY THE VERY END OF THE FORECAST
PERIOD AND INTO THE SHORT TERM. THE ONSET OF CAA WILL BE DELAYED,
ESPECIALLY OUTSIDE OF THE MOUNTAINS WHERE A NORTHWESTERLY DOWNSLOPE
COMPONENT SETTLES IN. WITH DRY CONDITIONS, WEAK DOWNSLOPING, AND
BETTER INSOLATION WITH CLEARING SKIES BEHIND THE FRONT, EXPECT
AFTERNOON HIGHS ON WEDNESDAY TO REMAIN 6-12 DEGREES ABOVE NORMAL.
SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/
AS OF 110 PM EST TUESDAY:
KEY MESSAGE 1: WINDY AND MUCH COLDER CONDITIONS RETURN BEHIND
THE COLD FRONT WEDNESDAY NIGHT
A STRONG COLD FRONT WILL CONTINUE TO PUSH SOUTHEAST ACROSS THE
SOUTHERN PIEDMONT OF NC, THE GA PIEDMONT, AND MUCH OF UPSTATE SC
WEDNESDAY EVENING. RAPID PRESSURE RISES WILL FOLLOW THE FRONT,
WITH SIX HOUR RISES OF 6 TO 7 MB FORECAST ACROSS THE MOUNTAINS
BY 00Z THURSDAY AND 5 TO 6 MB ACROSS THE REMAINDER OF THE AREA
BY 03Z THURSDAY. THIS WILL SUPPORT A BRIEF BUT NOTABLE SURGE OF
POST-FRONTAL WINDS.
NBM ENSEMBLE PROBABILITIES SHOW A HIGH LIKELIHOOD OF IMPACTFUL
WINDS ACROSS THE HIGHER ELEVATIONS WEDNESDAY NIGHT. THE
PROBABILITY OF MAXIMUM GUSTS EXCEEDING 45 MPH APPROACHES NINETY
PERCENT ALONG THE RIDGE TOPS OF THE BLUE RIDGE AND SMOKIES.
COORDINATION WITH SURROUNDING OFFICES SUPPORTS HOLDING OFF ON A
THIRD PERIOD WIND ADVISORY AT THIS TIME, BUT CONFIDENCE IS HIGH
THAT ADVISORY-LEVEL GUSTS WILL ULTIMATELY BE REALIZED.
COLD AIR ADVECTION BEHIND THE FRONT WILL MAINTAIN GUSTY WINDS
THROUGH THE NIGHT AS THE NOCTURNAL BOUNDARY LAYER REMAINS
PARTIALLY MIXED. WINDS WILL GRADUALLY DIMINISH TOWARD DAYBREAK
AS THE LOW LEVEL JET WEAKENS. TEMPERATURES WILL FALL BELOW
FREEZING IN THE HIGHER ELEVATIONS OF THE NC MOUNTAINS, WITH LOWS
MAINLY IN THE MID 30S ELSEWHERE.
KEY MESSAGE 2: COLD AND DRY CONDITIONS FOR THANKSGIVING AND
FRIDAY
WINDS WILL WEAKEN THURSDAY NIGHT INTO FRIDAY AS HIGH PRESSURE
BUILDS OVERHEAD. A MUCH COLDER AIR MASS WILL BE IN PLACE FOR THE
HOLIDAY PERIOD. HIGHS ON THANKSGIVING WILL BE 10 TO 15 DEGREES
BELOW NORMAL IN THE MOUNTAINS AND 5 TO 10 DEGREES BELOW NORMAL
ELSEWHERE. EVEN COLDER CONDITIONS ARRIVE FRIDAY, WITH
TEMPERATURES 15 TO 20 DEGREES BELOW NORMAL IN THE MOUNTAINS AND
10 TO 15 DEGREES BELOW NORMAL ACROSS THE PIEDMONT.
MODEL GUIDANCE SHOWS LIMITED AGREEMENT ON HOW QUICKLY WINDS
DIMINISH ACROSS THE MOUNTAINS. ENSEMBLE SPREAD FOR PEAK WIND
GUSTS REMAINS SIGNIFICANT, RANGING FROM 10 TO 15 MPH BETWEEN THE
25TH AND 75TH PERCENTILES IN THE BROADER MOUNTAIN REGION AND 15
TO 25 MPH AT THE HIGHEST ELEVATIONS. DESPITE THIS SPREAD, DRY
WEATHER IS EXPECTED THROUGH FRIDAY WITH ABUNDANT SUBSIDENCE
UNDER THE HIGH.
LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/
AS OF 115 PM EST TUESDAY:
KEY MESSAGE 1: COLD AND DRY CONDITIONS CONTINUE THROUGH SATURDAY
HIGH PRESSURE WILL REMAIN THE PRIMARY FEATURE FRIDAY NIGHT
INTO SATURDAY, MAINTAINING COLD AND DRY WEATHER ACROSS THE
REGION. ALTHOUGH SOUTHERLY RETURN FLOW BEGINS TO DEVELOP ON SATURDAY
AS THE HIGH SHIFTS TOWARD THE MID ATLANTIC COAST, WARM AIR ADVECTION
DOES NOT ARRIVE IN EARNEST UNTIL AFTER PEAK HEATING. AS A RESULT,
TEMPERATURES ON SATURDAY WILL REMAIN SIMILAR TO FRIDAY, WITH HIGHS
MAINLY IN THE MID TO UPPER 40S DESPITE GRADUAL WARMING ALOFT.
KEY MESSAGE 2: WET WEATHER RETURNS LATE THIS WEEKEND INTO EARLY
NEXT WEEK
A BROAD UPPER TROUGH WILL DEEPEN ACROSS THE NORTH CENTRAL CONUS THIS
WEEKEND WHILE SEVERAL SOUTHERN STREAM DISTURBANCES TRACK EASTWARD
AROUND ITS BASE. THESE WAVES WILL MOVE ACROSS THE SOUTHERN STATES
AND BRING WIDESPREAD PRECIPITATION TO THE CAROLINAS LATE IN THE
WEEKEND AND EARLY NEXT WEEK.
ENSEMBLE GUIDANCE SHOWS CONSIDERABLE SPREAD IN ONSET TIMING. A
FEW FAST MEMBERS BRING PRECIPITATION INTO THE AREA LATE SATURDAY
NIGHT, WHILE MOST EARLY ARRIVING SOLUTIONS FAVOR EARLY TO MID SUNDAY
MORNING. THE MEDIAN AND MEAN CLUSTER MID TO LATE SUNDAY, AND SLOWER
MEMBERS DELAY ONSET UNTIL SUNDAY EVENING. THIS RESULTS IN A ROUGHLY
TWELVE TO EIGHTEEN HOUR WINDOW ACROSS THE FORECAST AREA. CONFIDENCE
IS HIGHEST THAT PRECIPITATION BEGINS AT SOME POINT ON SUNDAY,
BUT EXACT TIMING REMAINS UNCERTAIN, ESPECIALLY ACROSS THE PIEDMONT.
PRECIPITATION WILL FALL MAINLY AS RAIN. IF ONSET OCCURS ON THE
EARLY END OF THE ENSEMBLE ENVELOPE LATE SATURDAY NIGHT, A BRIEF
MIX IS POSSIBLE ACROSS THE HIGHEST ELEVATIONS OF THE NC MOUNTAINS
AND PERHAPS PARTS OF THE NORTHERN FOOTHILLS BEFORE TEMPERATURES
WARM ALOFT EARLY SUNDAY MORNING. ANY WINTRY COMPONENT IS EXPECTED
TO BE BRIEF AND LIMITED TO THE HIGH TERRAIN.
A HYBRID COLD AIR DAMMING PATTERN WILL LIKELY DEVELOP AS THE SURFACE
HIGH SHIFTS OFFSHORE AND INITIAL PRECIPITATION FALLS INTO A DRY
BOUNDARY LAYER. THIS WEDGE WILL BE DIFFICULT TO ERODE WITHOUT A
FULL AIRMASS CHANGE, SO TEMPERATURES WILL LIKELY REMAIN IN THE 40S
AND LOWER 50S FROM SUNDAY THROUGH TUESDAY. NBM ENSEMBLE SPREAD
IS SIZABLE, WITH HIGH TEMPERATURE SPREADS OF 5 TO 10 DEGREES ON
SUNDAY, 8 TO 12 DEGREES ON MONDAY, AND 12 TO 18 DEGREES ON TUESDAY,
REFLECTING CONTINUED GLOBAL MODEL DIFFICULTY RESOLVING THE STRENGTH
OF THE WEDGE.
AVIATION /00Z WEDNESDAY THROUGH SUNDAY/
AT KCLT AND ELSEWHERE: WIDESPREAD SHOWERS AND A FEW EMBEDDED
THUNDERSTORMS WILL MOVE ACROSS THE AREA THIS EVENING INTO THE
EARLY PART OF THE OVERNIGHT, AND WARRANTS PREVAILING SHRA, WITH
TEMPO FOR TSRA. AHEAD OF THE ACTIVITY, LIFR CIGS HAVE FORMED IN
THE FOOTHILLS, INCLUDING KGSP AND KGMU. REDUCED VISIBILITY AND
CIGS ARE POSSIBLE WITH SHOWERS AND STORMS THAT PASS NEAR OR OVER
THE TERMINALS, BUT MAY HELP MIX OUT SOME OF THE LIFR CIGS. THE
SHOWERS AND THUNDERSTORMS SHOULD PUSH OUT OF THE AREA BY DAYBREAK
WEDNESDAY. WINDS ARE MOSTLY VARIABLE AND WILL CONTINUE THIS WAY
THROUGH THE EVENING AND OVERNIGHT, ESPECIALLY WITH SHOWERS AND
STORMS IN THE AREA. BEHIND THE LINE OF SHOWERS AND STORMS OVERNIGHT,
AN LIFR/IFR LOW STRATUS DECK AND MVFR/IFR VSBYS ARE EXPECTED TO
DEVELOP, WHILE WINDS PICK UP OUT OF THE SW, LIMITING DENSE FOG
POTENTIAL. MODEL GUIDANCE SCATTERS OUT CIG/VSBY RESTRICTIONS RATHER
QUICKLY LATER IN THE MORNING WEDNESDAY AS WINDS PICK UP OUT OF THE
SOUTHWEST (KAVL WILL TAKE ON A NORTHWEST COMPONENT). GUSTY WINDS
EXPECTED FROM LATE MORNING THRU THE AFTN ACROSS THE ENTIRE AREA,
TOGGLING TO NW AT KCLT WEDNESDAY EVENING.
OUTLOOK: DRIER AND PREDOMINANTLY VFR CONDITIONS SHOULD LINGER
THROUGH THE END OF THE WEEK.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
SYNOPSIS...DEO
NEAR TERM...ARK/CAC
SHORT TERM...JK
LONG TERM...JK
AVIATION...ARK
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