551
FXUS62 KGSP 251836
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
136 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 TONIGHT/
AS OF 1214 PM EST TUESDAY: LINE OF GUSTY SHOWERS CONTINUES TO MOVE
ACROSS THE CWFA AS THE LINE MOVES INTO THE EASTERN ZONES OVER THE
NEXT FEW HOURS. ALTHOUGH THE ACTUAL GUSTS ARE WEAKENING, THE LINE IS
BEING MAINTAINED BY A 20-30 KT SOUTHERLY LLJ AND MID-LEVEL SUPPORT
FROM THE SOUTHERN STREAM SHORTWAVE MOVING ACROSS THE AREA. A LULL IN
PRECIPITATION OUTSIDE OF A FEW SCATTERED SHOWERS IS EXPECTED THIS
AFTERNOON AS A NORTHERN STREAM TROUGH DIGS INTO THE NORTHERN PLAINS
AND INTO THE MIDWEST BY THIS EVENING, WHILE THE SOUTHERN STREAM
SHORTWAVE PUSHES EAST OF THE REGION. AS A WARM SECTOR REGIME
DEVELOPS INTO THE AREA, EXPECT AFTERNOON HIGHS TO STILL MANAGE TO
REACH 5-10 DEGREES ABOVE NORMAL, BUT WILL VARY AS THE WARM SECTOR
MAY NOT BECOME FULLY ESTABLISHED IN THE NORTHERN PARTS OF THE CWFA,
MAKING FOR A RATHER DIFFICULT FORECAST AS A TIGHT TEMPERATURE
GRADIENT COULD LEAD TO BUST POTENTIAL IN SOME LOCATIONS. HEIGHT
FALLS WILL ACCOMPANY THE AFOREMENTIONED 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 TIMEFRAME. 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 FOR 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 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 /18Z TUESDAY THROUGH SUNDAY/
AT KCLT AND ELSEWHERE: TAF PERIOD REMAINS MESSY AS A STORM SYSTEM
CONTINUES TO MOVE ACROSS THE AREA. CIGS REMAIN VARIABLE AS POCKETS
OF MVFR/IFR LOW STRATUS ROAM UNDERNEATH THE DECK OF STRATOCU THIS
AFTERNOON. SHOWERS CONTINUE TO MOVE ACROSS THE AREA AND PLACED
EITHER A TEMPO OR PROB30 WITH ASSOCIATED RESTRICTIONS THROUGH
THE AFTERNOON. ANOTHER ROUND OF MORE WIDESPREAD SHOWERS AND
THUNDERSTORMS ARE LIKELY LATER THIS EVENING INTO THE OVERNIGHT
PERIOD. REDUCED VISIBILITY AND CIGS ARE POSSIBLE WITH ANY SHOWERS
AND STORMS THAT PASS NEAR OR OVER THE TERMINALS. 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, WHICH IS REFLECTED IN THE 18Z TAF UPDATE. 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) WITH LOW-END GUSTS DEVELOPING BY
THE END OF THE FORECAST PERIOD.
OUTLOOK: DRIER AND PREDOMINANTLY VFR CONDITIONS SHOULD LINGER
THROUGH LATE WEEK.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
SYNOPSIS...DEO
NEAR TERM...CAC
SHORT TERM...JRK
LONG TERM...JRK
AVIATION...CAC
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