665
FXUS62 KGSP 250000
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
700 PM EST WED DEC 24 2025
SYNOPSIS
A WARM UPPER RIDGE OVER THE LOWER MISSISSIPPI VALLEY WILL KEEP OUR
REGION WARM AND DRY FOR CHRISTMAS AND THE WEEKEND. THE WARM WEATHER
WILL END DRAMATICALLY EARLY NEXT WEEK AS COLD AIR FROM CANADA DROPS
THE TEMPERATURE ABOUT 30 DEGREES FROM WEEKEND TEMPERATURES.
NEAR TERM /THROUGH THURSDAY/
AS OF 1205 PM EDT WEDNESDAY:
KEY MESSAGE #1: MOSTLY QUIET WITH RECORD WARM TEMPERATURES.
TWAS' THE DAY BEFORE CHRISTMAS AND ALL THROUGH THE HOUSE, THE AC IS
NEEDED BECAUSE WE LIVE IN THE SOUTH. RELATIVELY QUIET WEATHER
CONTINUES AS AN AMPLIFYING RIDGE OVER THE CENTRAL CONUS STARTS TO
MIGRATES EASTWARD, KEEPING HIGH PRESSURE OVER THE AREA. THE RETURN
OF THE HEATMISER KEEPS THE SNOWMISER IN HIDING FOR THE HOLIDAYS AS
HEIGHT RISES TODAY PUSH TEMPERATURES TO RECORD HEAT OUTSIDE THE
MOUNTAINS FOR DECEMBER. EXPECTING TEMPS EAST OF THE MOUNTAINS TO
RISE INTO THE MID 70S AS CONTINUED NW WINDS ALOFT ALLOW FOR
DOWNSLOPING TO HELP FURTHER MIX OUT THE BOUNDARY LAYER AND WARM
SURFACE TEMPS. THOUGH DOWNSLOPING WEAKENS THROUGHOUT THE DAY, THE
INCREASED HEIGHTS KEEP THE CONFIDENCE UP AT A TIE OR BREAKING THE
DAILY HIGH RECORD FOR AT KGSP AND KCLT (71 AND 73, RESPECTIVELY).
TONIGHT, TEMPS REMAIN WARM AND SOMEWHAT HUMID AS MOISTURE STAYS PUT.
EXPECT NEARLY THE SAME DISMALLY WARM TEMPERATURES FOR THURSDAY.
KEY MESSAGE #2: ISOLATED LIGHT RAIN SHOWERS MAINLY IN THE MOUNTAINS
NEAR THE TN BORDER ON THURSDAY.
BESIDES THE HEAT, AN EXTREMELY WEAK FRONTAL BOUNDARY SEESAWS ACROSS
THE NORTHERN PORTION OF THE CWA TONIGHT BEFORE EXITING AS A WARM
FRONT TOMORROW. THIS INCREASES POPS (30-50%) TONIGHT AND TOMORROW
MORNING ACROSS THE NORTHERN MOUNTAINS, BUT WITH MINIMAL QPF
RESPONSE. SO WHILE THIS IS A QUICK SHOT OF A BRIEF SHOWER, DON'T
EXPECT MUCH. THERE COULD ALSO BE A SPOTTY LIGHT SHOWER OR TWO OVER
THE NC PIEDMONT TONIGHT, BUT EVEN THE CAMS ARE NOT IMPRESSED. WILL
KEEP POPS UNMENTIONABLE AS THE CONFIDENCE IS JUST TOO LOW. AS THE
INCONSEQUENTIAL FRONT PASSES BY TO THE NORTH, WIND GUSTS ELEVATE A
BIT ACROSS THE HIGHER ELEVATIONS. NOTHING TOO IMPRESSIVE WITH 15-25
MPH GUSTS POSSIBLE OVERNIGHT AND INTO THURSDAY.
SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/
AS OF 1145 AM EST WEDNESDAY:
AS WE MOVE INTO THE SHORT-TERM CHRISTMAS NIGHT, THE PLAINS RIDGE
WILL BEGIN TO BREAK DOWN SLIGHTLY AND SLIDE EAST IN THE WAVETRAIN.
MORE IMPORTANTLY, A STRONG UPPER TROUGH WILL SLIDE ACROSS EASTERN
CANADA, WITH THE CONFLUENT FLOW BETWEEN THE TWO ALLOWING A STRONG
AND COOL HIGH PRESSURE TO TRANSIT ACROSS ONTARIO AND TOWARDS QUEBEC.
THIS WILL PUSH A FRONT DOWN THE EASTERN SEABOARD AHEAD OF THE
SURFACE HIGH RIDGING DOWN THE EASTERN SLOPES OF THE APPALACHIANS,
AND THE FRONT IS PROGGED TO DROP SOMEWHERE ACROSS OUR FORECAST AREA
DURING THE DAY FRIDAY. BETWEEN THE MOIST FLOW AROUND THE SURFACE
HIGH AND ATTENDANT MOISTURE ALOFT ASSOCIATED WITH A VORTMAX COMING
DOWN THE NW FLOW, THIS WILL BE ENOUGH FOR SLIGHT CHANCES OF RAIN
ESPECIALLY ACROSS NC ZONES EARLY FRIDAY. THE QUESTION THEN BECOMES
HOW STRONG THE DAMMING WILL BE UNDERNEATH THE ISENTROPIC UPGLIDE AND
HOW FAR SOUTH THE DRIER DEWPOINTS WILL ADVECT INTO THE AREA, LEADING
TO EVAPORATIONAL COOLING. TEMPERATURES HAVE VERY HIGH BUST POTENTIAL
ON BOTH THE WARM AND COOL SIDE, WITH NBM ENSEMBLES SHOWING A SPREAD
ACROSS THE UPSTATE FROM THE 50S TO THE 70S FOR HIGHS. HAVE KEPT THE
FORECAST WITH THE NBM MEAN BUT THIS WILL BE HIGHLY DEPENDENT ON THE
STRENGTH OF THE TRANSIENT DAMMING AND WHERE THE FRONT LINES UP.
POPS WILL INCREASE AGAIN FRIDAY NIGHT ESPECIALLY IN THE MOUNTAINS AS
ANOTHER SHORTWAVE EMBEDDED IN THE FLOW PASSES TO THE NORTH AND A
SURFACE LOW APPROACHES FROM THE OH VALLEY TO SCOUR OUT THE DAMMING.
THE UPPER RIDGE WILL AMPLIFY SOMEWHAT AGAIN ON SATURDAY IN RESPONSE
TO A DIGGING TROUGH OUT WEST. THE RIDGE AXIS WILL SHIFT EAST AND
OVER OUR AREA, AND BETWEEN DOWNSLOPING IN THE NW FLOW ALOFT AS WELL
AS INCREASING THICKNESSES, HIGHS ON SATURDAY WILL ONCE AGAIN
APPROACH IF NOT EXCEED RECORDS.
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/
AS OF 1215 PM EST WEDNESDAY:
A MAJOR PATTERN CHANGE IS IN STORE FOR THE EXTENDED PERIOD, SO FOR
THOSE READERS WHO LIKE IT TO BE COLD AROUND NEW YEARS, THIS IS FOR
YOU. THE UPPER RIDGE WILL BEGIN TO BREAK DOWN AND DEAMPLIFY AS A
STRONG UPPER LOW DIGS INTO THE NORTHERN PLAINS (A CUTOFF LOW WILL
REMAIN OVER THE DESERT SW AND BAJA AREA). AN ARCTIC FRONT WILL SWEEP
ACROSS THE PLAINS AND TOWARD THE SOUTHERN APPALACHIANS BY SUNDAY
NIGHT. INCREASED MOISTURE AHEAD OF THE FRONT WILL LIMIT INSOLATION
ON SUNDAY, BRINGING HIGH TEMPERATURES DOWN SEVERAL DEGREES FROM
SATURDAY BUT STILL WELL ABOVE-NORMAL. HIGHS ON MONDAY WILL DEPEND ON
HOW QUICKLY THE (VERY STRONG) CAA SETS UP, AND FOR THE PAST FEW RUNS
THE FRONT HAS BEEN SLOWING DOWN, RESULTING IN SLIGHT INCREASES FOR
HIGHS ON MONDAY ACROSS THE PIEDMONT WITH EACH RUN. MUCH LIKE WITH
THE UPSTATE AREAS ON FRIDAY IN THE PROXIMITY OF THE WEDGE FRONT,
SPREAD FOR MONDAY IS QUITE HIGH AND WILL CONTINUE TO BE REFINED OVER
THE NEXT FEW DAYS. MEANWHILE, ENOUGH MOISTURE SHOULD LINGER IN THE
MOUNTAINS BEHIND THE FRONT MONDAY MORNING FOR A CHANGEOVER FROM
LIGHT RAIN TO LIGHT SNOW, THOUGH ACCUMULATIONS IF ANY WOULD BE LIGHT
WITH THE EXITING MOISTURE.
BY TUESDAY, SOME AREAS IN THE MOUNTAINS WILL STRUGGLE TO GET ABOVE
FREEZING AS THE UPPER TROUGH DOMINATES THE EASTERN HALF TO 2/3 OF
THE COUNTRY, WITH OVERALL HIGHS ACROSS THE AREA COLDER THAN LOWS
THROUGH THE THE SHORT-TERM. ANOTHER SERIES OF REINFORCING SHORTWAVE
ARE PROGGED TO ROTATE AROUND THE UPPER LOW BEYOND THE END OF THE
PERIOD, WITH TEMPERATURES REMAINING BELOW NORMAL.
AVIATION /00Z THURSDAY THROUGH MONDAY/
AT KCLT AND ELSEWHERE: PREVAILING VFR AT ALL TERMINALS THROUGH THE
PERIOD, WITH A CAVEAT. HIGH CLOUDS WILL STREAM OVERHEAD THROUGH THE
NIGHT, ALONG WITH A HIGH-BASED STRATOCU DECK THAT WILL MOVE IN LATE
THIS EVENING. THE INCREASED CLOUD COVER WILL MOST LIKELY KEEP THE
VALLEY FOG AT BAY, SO THE FOG RESTRICTION WITH AN MVFR VISIBILITY
THAT WAS AT KAVL IN THE PREVIOUS FCST WAS REMOVED. WIND SHOULD BE
LIGHT/VARIABLE OVERNIGHT, THEN LIGHT SE TO S WHEN IT RETURNS IN
THE MORNING. BY AFTERNOON, THE LOW CLOUDS SHOULD BE GONE AND THERE
COULD BE A FEW LOW-END WIND GUSTS AT ANY OF THE TERMINALS. NOW FOR
THE CAVEAT...AT KCLT A RETURN OF LOW LEVEL MOISTURE IS EXPECTED
AFTER SUNSET AND SOME OF THE GUIDANCE SHOWS THE DEVELOPMENT OF AN
MVFR CLOUD DECK AFTER 00Z FRIDAY. FOR THE TIME BEING, CONFIDENCE
IS NOT HIGH ENOUGH TO INCLUDE THIS RESTRICTION.
OUTLOOK: POSSIBLE MVFR OR LOWER CIGS DEVELOP THROUGH FRIDAY NIGHT
ACROSS MOST OF THE AREA. VFR RETURNS FOR THE WEEKEND.
CLIMATE
RECORDS FOR 12-24
MAX TEMPERATURE MIN TEMPERATURE
STATION HIGH LOW HIGH LOW
------- ---------- ---------- ---------- ----------
KAVL 72 1955 17 1906 59 2015 -5 1983
KCLT 73 2015 29 2022 63 2015 6 1983
1906
KGSP 71 1964 28 2022 61 2015 7 2022
RECORDS FOR 12-25
MAX TEMPERATURE MIN TEMPERATURE
STATION HIGH LOW HIGH LOW
------- ---------- ---------- ---------- ----------
KAVL 71 2021 14 1983 59 2015 -7 1983
KCLT 77 1955 22 1983 63 2015 4 1983
KGSP 78 1955 22 1983 61 2015 6 1983
RECORDS FOR 12-26
MAX TEMPERATURE MIN TEMPERATURE
STATION HIGH LOW HIGH LOW
------- ---------- ---------- ---------- ----------
KAVL 78 1971 17 1902 55 2015 0 1983
KCLT 77 2021 27 1983 58 2015 6 1983
1964
KGSP 76 2021 28 1983 62 1987 5 1985
2015 1980
RECORDS FOR 12-27
MAX TEMPERATURE MIN TEMPERATURE
STATION HIGH LOW HIGH LOW
------- ---------- ---------- ---------- ----------
KAVL 72 1971 19 1902 59 2015 3 1925
KCLT 72 2021 22 1892 65 2015 15 1970
2015 1948
1971 1925
KGSP 75 1971 29 1925 64 2015 12 1925
RECORDS FOR 12-28
MAX TEMPERATURE MIN TEMPERATURE
STATION HIGH LOW HIGH LOW
------- ---------- ---------- ---------- ----------
KAVL 73 1889 19 1894 56 2015 0 1925
KCLT 77 1971 30 1950 58 2015 10 1925
1935
1925
KGSP 75 1971 31 1950 64 2015 9 1925
1925
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
SYNOPSIS...DEO
NEAR TERM...CP
SHORT TERM...TDP
LONG TERM...TDP
AVIATION...PM
CLIMATE...
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