005
FXUS62 KGSP 170558
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1258 AM EST WED DEC 17 2025
SYNOPSIS
HIGH PRESSURE KEEPS DRY CONDITIONS OVER THE AREA THROUGH TONIGHT
BEFORE A COLD FRONT BRINGS PRECIPITATION CHANCES BACK THURSDAY INTO
THURSDAY NIGHT. DRIER CONDITIONS RETURN BEHIND THE FRONT FRIDAY INTO
THE WEEKEND AS HIGH PRESSURE BUILDS IN FROM THE NORTHWEST.
NEAR TERM /THROUGH TONIGHT/
AS OF 1230 AM EDT WEDNESDAY:
KEY MESSAGE #1: ANOTHER WARM DAY AHEAD WITH DRY CONDITIONS
PERSISTING.
MILD WEATHER REMAINS IN PLACE THROUGH TONIGHT AHEAD OF A COLD FRONT
INTO THE NEXT PERIOD. SURFACE HIGH PRESSURE SLOWLY STARTS TO MIGRATE
EASTWARD OFF SHORE TONIGHT IN RESPONSE TO AN AREA OF LOW PRESSURE
DEVELOPING ACROSS THE CENTRAL CONUS. NO RAIN IS ANTICIPATED WITH THE
SUBSIDENCE ALOFT THROUGH TONIGHT. WINDS REMAIN LIGHT AND MOSTLY OUT
OF THE SOUTHWEST FOR LOCATIONS EAST OF THE MOUNTAINS, GRADUALLY
INCREASING SURFACE MOISTURE. AHEAD OF THE NEXT COLD FRONT AND PRECIP
CHANCES (NEXT FORECAST PERIOD), CLOUDS ARE EXPECTED TO INCREASE
THROUGHOUT THE DAY. TEMPERATURES TODAY WARM INTO THE UPPER 50S WITH
LOWS TONIGHT STAYING ABOVE FREEZING IN THE MOUNTAINS AND LOWER 40S
IN THE SOUTHERN COUNTIES.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/
AS OF 1230 AM WEDNESDAY...
KEY MESSAGE #1: COLD FRONT BRINGS PRECIPITATION AND GUSTY WINDS
THURSDAY INTO THURSDAY NIGHT.
AN UPPER TROUGH WILL APPROACH OUT OF THE WEST/NORTHWEST THURSDAY
INTO THURSDAY NIGHT WHILE GRADUALLY DEVELOPING A NEGATIVE TILT. AT
THE SFC, A COLD FRONT WILL APPROACH OUT OF THE WEST THROUGH THURSDAY
EVENING BEFORE TRACKING ACROSS THE WESTERN CAROLINAS AND NORTHEAST
GEORGIA THURSDAY NIGHT, BRINGING PRECIPITATION CHANCES AND GUSTY
WINDS.
IN-SITU COLD AIR DAMMING LOOKS TO DEVELOP AS A SURFACE HIGH CENTERED
OFF THE NEW ENGLAND COAST SLOWLY LIFTS NORTHEAST, ALLOWING FOR AN
INFLUX OF MOISTURE (FROM BOTH THE GULF AND ATLANTIC) TO STREAM
ACROSS THE FORECAST AREA AHEAD OF THE COLD FRONT. THIS WILL ALLOW
RAIN CHANCES TO GRADUALLY INCREASE THROUGHOUT THURSDAY. COLD AIR
DAMMING WILL ACT TO LIMIT INSTABILITY WHICH IS GOOD CONSIDERING WE
WILL HAVE 50-60+ KTS OF DEEP LAYER SHEAR AVAILABLE AHEAD OF/ALONG
THE FRONT. SO, DESPITE THE NEGATIVELY TILTED TROUGH, THE SEVERE
THREAT WILL REMAIN LOW, IF ANY. COLD AIR DAMMING WILL ALSO LEAD TO
COOLER TEMPERATURES SO BLENDED IN 20% OF THE NBM 10TH PERCENTILE FOR
HIGHS ON THURSDAY. THIS BLEND LED TO HIGHS ENDING UP ~5 DEGREES
BELOW NORMAL ACROSS THE NORTH CAROLINA FOOTHILLS AND THE NORTHERN
NORTH CAROLINA PIEDMONT (WHERE COLD AIR DAMMING IS WILL BE THE
STRONGEST). ELSEWHERE, HIGHS MAY END UP NEAR NORMAL TO JUST ABOVE
NORMAL. HOWEVER, HIGHS ON THURSDAY MAY END COOLER THAN THIS EAST OF
THE MOUNTAINS (AS WE TYPICALLY SEE IN COLD AIR DAMMING). GUSTY WINDS
WILL DEVELOP AHEAD OF/BEHIND THE FRONT THURSDAY INTO THURSDAY NIGHT.
MOST LOCATIONS WILL GUSTS REMAIN BELOW ADVISORY CRITERIA. HOWEVER,
AVERY COUNTY, ALONG WITH ELEVATIONS ABOVE 3,500 FEET IN MITCHELL,
YANCEY, AND BUNCOMBE COUNTIES, MAY SEE GUSTS HAVE THE BEST CHANCE TO
SEE ADVISORY CRITERIA GUSTS. THUS, A WIND ADVISORY MAY EVENTUALLY BE
NEEDED FOR THESE LOCATIONS.
RAIN ASSOCIATED WITH THE ACTUAL FRONTAL BOUNDARY WILL PUSH ACROSS
THE FORECAST AREA THURSDAY EVENING INTO THURSDAY NIGHT. AS
TEMPERATURES FALL NEAR/BELOW FREEZING ACROSS THE NC/TN BORDER
COUNTIES LATE THURSDAY NIGHT INTO EARLY FRIDAY MORNING, RAIN WILL
BRIEFLY TRANSITION TO SNOW BEFORE PRECIPITATION ENDS AROUND
DAYBREAK. ONLY LIGHT SNOW ACCUMULATION IS EXPECTED, WITH ONLY A
DUSTING TO A FEW TENTHS OF AN INCH EXPECTED. RAINFALL TOTALS WILL
GENERALLY RANGE FROM HALF AND INCH TO AN INCH ACROSS THE FORECAST
AREA, WITH LOCALLY HIGHER AMOUNTS FROM 1.5 TO 2 INCHES POSSIBLE
ACROSS THE SOUTHERN NORTH CAROLINA MOUNTAINS. NO HYDRO CONCERNS WITH
THIS SYSTEM AT THIS TIME. LOW TEMPERATURES THURSDAY NIGHT WILL END
UP ~10-15 DEGREES ABOVE NORMAL THANKS TO CLOUD COVER AND
PRECIPITATION LIMITING RADIATIONAL COOLING.
KEY MESSAGE #2: DRY CONDITIONS RETURN FRIDAY BUT GUSTY WINDS LINGER
THROUGH THE EVENING HOURS BEFORE TAPERING OFF OVERNIGHT.
THE AFOREMENTIONED UPPER TROUGH SWINGS ACROSS THE FORECAST AREA ON
FRIDAY AS DRY HIGH PRESSURE BUILDS IN BEHIND THE DEPARTING COLD
FRONT. GUSTY WINDS LINGER THROUGHOUT THE DAY FRIDAY BEFORE GRADUALLY
TAPERING OFF FRIDAY EVENING INTO FRIDAY NIGHT. HIGHS ON FRIDAY WILL
END UP A FEW DEGREES BELOW NORMAL ACROSS THE MOUNTAINS AND A FEW
DEGREES ABOVE NORMAL ACROSS THE MOUNTAINS. LOWS FRIDAY NIGHT WILL BE
COLDER, RANGING FROM THE MID 20S TO LOWER 30S, THANKS TO MOSTLY
CLEAR SKIES AND LIGHTER WINDS LEADING TO BETTER RADIATIONAL COOLING
CONDITIONS.
LONG TERM /SATURDAY THROUGH TUESDAY/
AS OF 1245 AM WEDNESDAY:
KEY MESSAGE #1: MOSTLY DRY THIS WEEKEND INTO EARLY NEXT WEEK,
ALTHOUGH RAIN CHANCES MAY RETURN ACROSS THE WESTERN HALF OF THE
FORECAST AREA AT TIMES AFTER SATURDAY.
QUASI-ZONAL FLOW DEVELOPS ALOFT SATURDAY INTO SUNDAY BEFORE HEIGHTS
RISE MONDAY INTO TUESDAY IN RESPONSE TO AN UPPER RIDGE BUILDING OVER
THE GULF COAST. AT THE SURFACE, HIGH PRESSURE WILL BE THE DOMINATE
FEATURE OUTSIDE OF A WEAK COLD FRONT TRACKING ACROSS THE AREA ON
SUNDAY. GLOBAL MODEL GUIDANCE SOURCES REMAIN AT ODDS REGARDING THE
EXACT TIMING AND COVERAGE OF RAIN SUNDAY INTO TUESDAY SO CONFIDENCE
ON NBM CHANCE POPS REMAINS LOW. FOR NOW, IT STILL APPEARS THAT THE
WESTERN HALF OF THE FORECAST AREA WILL HAVE THE BEST CHANCE TO SEE
RAIN RETURN. ABOVE NORMAL TEMPERATURES ARE EXPECTED THROUGH THE
PERIOD.
AVIATION /06Z WEDNESDAY THROUGH SUNDAY/
AT KCLT AND ELSEWHERE: VFR CONDITIONS PREVAIL THROUGH THE TAF
PERIOD. HIGH PRESSURE REMAINS IN PLACE. NO VSBY/CIG RESTRICTIONS ARE
ANTICIPATED AT THIS TIME. LIGHT WINDS OUT OF THE SW REMAINS OUTSIDE
THE MOUNTAINS. WINDS GO CALM AT A FEW SITES OVERNIGHT BEFORE PICKING
UP WEDNESDAY MORNING. VRB COMES BACK AFTER SUNSET TONIGHT.
INCREASING CLOUDS AHEAD OF A FRONT THROUGH THE PERIOD, BUT SHOULD
REMAIN CLOSE TO SCT/BKN250.
OUTLOOK: SHOWERS AND ASSOCIATED RESTRICTIONS ARE EXPECTED THURSDAY
INTO FRIDAY, WITH VFR RETURNING BY FRIDAY AFTERNOON AND PERSISTING
THROUGH THE WEEKEND.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
SYNOPSIS...AR
NEAR TERM...CP
SHORT TERM...AR
LONG TERM...AR
AVIATION...CP
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