354
FXUS62 KGSP 181839
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
139 PM EST THU DEC 18 2025
SYNOPSIS
WIDESPREAD RAIN MOVES EAST OF OUR REGION ON FRIDAY AS A COLD FRONT
TAKES THE RAIN TO THE EAST COAST. GUSTY WIND WILL LINGER OVER THE
AREA UNTIL FRIDAY EVENING. DRY HIGH PRESSURE TRANSITS ACROSS OUR
AREA EARLY IN THE WEEKEND THEN ANOTHER COLD FRONT CROSSES ON SUNDAY.
SMALL CHANCES OF MOUNTAIN PRECIPITATION IN THE MIDDLE OF NEXT WEEK,
OTHERWISE DRY.
NEAR TERM /THROUGH FRIDAY/
AS OF 108 PM THURSDAY:
KEY MESSAGE #1: A COLD FRONT MOVES CROSSES THE AREA OVERNIGHT,
BRINGING MOSTLY RAIN AND A BRIEF BURST OF SNOW FOR ISOLATED
LOCATIONS IN THE MOUNTAINS.
A POTENT SHORTWAVE TROUGH IS CURRENTLY SLIDING ACROSS THE LOWER
MISSISSIPPI VALLEY WITH AN ATTENDANT SURFACE LOW TRANSITING THE
GREAT LAKES. THE TROUGH IS FORECAST TO TAKE ON A NEGATIVE TILT AS IT
SWINGS ACROSS THE APPALACHIANS THIS EVENING AND OVERNIGHT WITH THE
SURFACE LOW GRADUALLY DEEPENING AS WELL. SUBSEQUENT LOW-LEVEL MASS
RESPONSE HAS FOSTERED ROBUST WIND FIELDS WITH A 50KT LOW-LEVEL JET
PROGGED TO TRANSLATE ACROSS THE FORECAST AREA. HEIGHT FALLS
OVERSPREADING THE AREA IN CONCERT WITH WARM ADVECTION AND ISENTROPIC
ASCENT HAS ALLOWED FOR A LARGE AREA OF SCATTERED TO WIDESPREAD
SHOWERS TO SPREAD NORTH ACROSS MUCH OF THE AREA. THIS HAS ALSO
LOCKED IN AN IN-SITU COLD AIR DAMMING WEDGE EXTENDING FROM THE
FOOTHILLS INTO PORTIONS OF THE I-85 CORRIDOR. WITH THE SURFACE HIGH
SHIFTING OFFSHORE THE WEDGE WILL GRADUALLY ERODE THROUGH THE DAY AND
THIS EVENING IN THE FACE OF INCREASING WARM ADVECTION AND MIXING
ALONG THE WEDGE BOUNDARY. THE TRADITIONAL LOCATIONS NESTLED IN THE
IMMEDIATE FOOTHILLS OF MCDOWELL, BURKE AND CALDWELL COUNTIES WILL
LIKELY REMAIN UNDER SOME DEGREE OF CAD THROUGH THE DURATION OF THE
EVENT, HOWEVER.
EVENTUALLY, A STRONGLY FORCED CONVECTIVE LINE ANCHORED JUST AHEAD OF
THE SURFACE COLD FRONT RACING ACROSS TENNESSEE WILL APPROACH THE
MOUNTAINS LATE THIS EVENING. HEAVIER RAINFALL RATES WILL LIKELY
ACCOMPANY THIS ACTIVITY AND A STRAY RUMBLE OF THUNDER CANNOT BE
COMPLETELY RULED OUT. A COUPLE LOCALLY STRONG WIND GUST WITH THE
LINE WILL ALSO BE POSSIBLE ACROSS THE IMMEDIATE TENNESSEE BORDER
BEFORE THE LINE BEGINS TO LOSE STRUCTURE OVER THE MOUNTAINS. AT
LEAST SOME DEGREE OF A BROKEN LINE OF SHOWERS WILL PERSIST EAST OF
THE MOUNTAINS THROUGH THE OVERNIGHT AND ATTENTION WILL HAVE TO BE
CLOSELY PAID AS TO HOW FAR NORTH THE WEDGE BOUNDARY RETREATS AND
WHERE IT RESIDES. 12Z CAMS INDICATE THE POTENTIAL FOR MID TO UPPER
50S DEWPOINTS TO ENCROACH ON THE I-85 CORRIDOR. SHEAR PROFILES ARE
MORE THAN SUPPORTIVE OF ORGANIZED CONVECTION, BUT INSTABILITY WILL
BE HELD IN CHECK OWING TO POOR LAPSE RATES AND NEUTRAL STABILITY.
NONETHELESS, AROUND 100 J/KG OF MLCAPE CANNOT BE COMPLETELY
DISCOUNTED AND STRONGLY FORCED EVENTS CAN OFFSET MARGINAL
THERMODYNAMIC PROFILES VIA INTENSE DYNAMICAL FORCING TO HELP
MAINTAIN CONVECTIVE ELEMENTS IN OTHERWISE POOR ENVIRONMENTS.
CONVECTIVE INTERACTIONS WITH WEDGE BOUNDARIES HAVE ALSO BEEN KNOWN
TO CAUSE MISCHIEF, THUS WHILE THE CHANCES FOR SEVERE WEATHER ARE
VERY LOW, A VERY SMALL BUT NON-ZERO CHANCE FOR A BRIEF DAMAGING WIND
GUST OR ISOLATED TORNADO CANNOT BE DISCOUNTED.
KEY MESSAGE #2: GUSTY WINDS CONTINUE ON FRIDAY, ESPECIALLY AT
HIGHER ELEVATIONS, ALONG WITH A RETURN OF DRY CONDITIONS.
THE SURFACE COLD FRONT WILL RACE ACROSS THE AREA DURING THE
OVERNIGHT HOURS AND SHOULD BE OFF TO OUR EAST BY DAYBREAK. THIS WILL
BRING AN END TO ANY PRECIPITATION OUTSIDE OF A VERY BRIEF WINDOW FOR
A COUPLE ISOLATED SNOW SHOWERS ALONG THE TENNESSEE BORDER OF THE
NORTHERN MOUNTAINS. THE MAIN FOCUS THEN SHIFTS TO STRONG WIND GUSTS
THROUGH MUCH OF THE DAY ON FRIDAY. A TIGHT PRESSURE GRADIENT WILL
SETUP SHOP ACROSS THE MOUNTAINS WITH THE TYPICAL COLD ADVECTION
PORTIONS OF THE BLUE RIDGE ESCARPMENT EXPECTED TO SEE ADVISORY LEVEL
WIND GUSTS. THE WIND ADVISORY REMAINS WELL PLACED AND NO CHANGES
WERE NEEDED. A FEW HIGH ELEVATION LOCATIONS, SUCH AS THE BLACK
MOUNTAINS AND GRANDFATHER MOUNTAIN, WILL LIKELY SEE HIGH WIND
WARNING CRITERIA GUSTS, BUT COVERAGE OF HIGHER GUSTS SHOULD REMAIN
ON ISOLATED PEAKS AND HAVE THUS OPTED TO KEEP THE ADVISORY AND HOLD
OFF ON ANY UPGRADES TO HIGH WIND WARNING AT THIS TIME.
SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/
AS OF 1215 PM THURSDAY...
KEY MESSAGE #1: DRY HIGH PRESSURE AND DIMINISHING WINDS SATURDAY.
ANY LINGERING GUSTY WINDS WILL QUICKLY DIMINISH FRIDAY NIGHT AS THE
CENTER OF SURFACE HIGH PRESSURE SETTLES IN OVER THE AREA AND REMAINS
IN PLACE ON SATURDAY. DRY CONDITIONS EXPECTED WITH LOWS AROUND 5
DEGREES BELOW NORMAL AND HIGHS RANGING FROM NEAR TO 5 DEGREES ABOVE
NORMAL.
KEY MESSAGE #2: A MAINLY DRY COLD FRONT CROSSES THE AREA SUNDAY WITH
GUSTY WINDS.
HIGH PRESSURE SLIDES EAST SATURDAY NIGHT AS A COLD FRONT APPROACHES
FROM THE WEST, THEN CROSSES THE AREA DURING THE DAY SUNDAY. THERE IS
VERY LITTLE MOISTURE OR MOISTURE INFLOW ASSOCIATED WITH THE FRONT.
THERE MAY BE ENOUGH FOR SOME SPRINKLES AS THE FRONT MOVES THROUGH
DURING THE DAY, BUT ANY PRECIP WOULD BE SPOTTY AND VERY LIGHT. WINDS
DO PICK BACK UP AHEAD OF AND BEHIND THE FRONT, WITH WINDY CONDITIONS
ACROSS THE MOUNTAINS AND BREEZY ELSEWHERE, BUT WELL BELOW ADVISORY
LEVEL. LOWS SLIGHTLY ABOVE NORMAL WITH HIGHS NEAR NORMAL FOR THE
MOUNTAINS AND AROUND 5 DEGREES ABOVE NORMAL ELSEWHERE.
LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/
AS OF 1240 PM THURSDAY...
KEY MESSAGE #1: DRY CONDITIONS FOR MOST LOCATIONS, ALTHOUGH SOME
PRECIPITATION MAY RETURN ACROSS THE NORTH CAROLINA MOUNTAINS AT
TIMES.
DRY HIGH PRESSURE BUILDS INTO THE AREA MONDAY THEN WEAKENS AND
SLIDES SOUTH TUESDAY AND WEDNESDAY AS A LOW PRESSURE SYSTEM MOVES BY
TO THE NORTH AND DRAGS A COLD FRONT SOUTH TOWARD THE AREA. THE
GUIDANCE DIFFERS ON THE EXACT LOCATION OF THE FRONT, BUT IT MAY BE
CLOSE ENOUGH FOR SOME LIGHT PRECIP TO DEVELOP ACROSS THE MOUNTAINS
EACH DAY AS MOISTURE MOVES AROUND THE PERIPHERY OF THE SURFACE HIGH.
CONFIDENCE IS LOW ON PRECIP CHANCES, SO THE VERY SMALL COVERAGE AND
POP OF THE NBM IS REASONABLE. TEMPS WOULD BE COLD ENOUGH THAT PRECIP
MOVING INTO THE MOUNTAINS LATE TUE NITE AND EARLY WED COULD INCLUDE
A SPOTTY MIX OF FREEZING RAIN. CONFIDENCE IS LOW ON PRECIP CHANCES
AND TYPES. RIGHT NOW, NO SIGNIFICANT ICE ACCRETION IS EXPECTED.
KEY MESSAGE #2: SEASONAL TEMPS MONDAY THEN A SIGNIFICANT WARM UP
THROUGH CHRISTMAS DAY.
TEMPS ON MONDAY WILL BE AROUND 5 DEGREES BELOW NORMAL, RISING TO
NEAR OR A LITTLE ABOVE NORMAL ON TUESDAY. THE BIGGER WARMING TREND
TAKES PLACE WEDNESDAY INTO CHRISTMAS DAY WITH LOWS AND HIGHS RISING
TO NEARLY 15 DEGREES ABOVE NORMAL.
AVIATION /18Z THURSDAY THROUGH TUESDAY/
AT KCLT AND ELSEWHERE: POOR CONDITIONS WILL CONTINUE THROUGH MUCH OF
THE TAF PERIOD AS A STORM SYSTEM IMPACTS THE REGION. SHOWERS HAVE
SPREAD ACROSS THE AREA THIS AFTERNOON WITH AT LEAST SCATTERED TO
NUMEROUS SHOWERS EXPECTED TO CONTINUE THROUGH THE REMAINDER OF THE
DAY AND INTO THIS EVENING. SOME OF THESE SHOWERS HAVE CONTAINED
MODERATE, TO AT TIMES HEAVY, RAIN RATES WITH RESULTING VISIBILITY
RESTRICTIONS. IN ADDITION, LOW STRATUS HAS DEVELOPED AND WILL KEEP
CEILINGS IFR OR LOWER. OVERNIGHT, A LINE OF SHOWERS ALONG THE
LEADING EDGE OF AN APPROACHING COLD FRONT WILL PUSH ACROSS THE AREA
AND MAY RESULT IN A BRIEF PERIOD OF REDUCED VISIBILITY FROM HEAVY
RAIN. A STRAY LIGHTNING STRIKE CANNOT BE COMPLETELY DISCOUNTED, BUT
CHANCES ARE LOW ENOUGH TO PRECLUDE MENTION OF THUNDER IN THE TAF.
CONDITIONS SHOULD IMPROVE QUICKLY BEHIND THE FRONT TOMORROW MORNING
WITH THE ARRIVAL OF COOLER AND DRIER AIR SCOURING OUT MOISTURE AND
CLOUDS. ALL TERMINALS SHOULD SEE A RETURN TO VFR THROUGH THE MORNING
HOURS. WINDS START OUT OF THE NORTHEAST WITHIN A COLD AIR DAMMING
WEDGE, BUT WILL GRADUALLY TURN TO OUT OF THE SOUTH/SOUTHEAST FROM
SOUTH TO NORTH AS THE COLD AIR DAMMING BOUNDARY SLOWLY RETREATS.
GUSTS WILL ALSO RETURN WITH THE RETURN OF SOUTHERLY WINDS. WINDS
SHIFT AGAIN BEHIND THE FRONT TO OUT OF THE WEST/NORTHWEST WITH
FREQUENT GUSTS AT ALL TERMINALS.
OUTLOOK: VFR CONDITIONS CONTINUE THROUGH THE WEEKEND.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...WIND ADVISORY FROM 7 AM TO 7 PM EST FRIDAY FOR NCZ033-048>053-
058-059-062-063.
SC...NONE.
SYNOPSIS...DEO
NEAR TERM...TW
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...TW
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