218
FXUS62 KGSP 122337
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
637 PM EST FRI DEC 12 2025
SYNOPSIS
COOL HIGH PRESSURE LINGERS OVER THE AREA THROUGH SATURDAY.
THEN AN ARCTIC COLD FRONT WILL CROSS THE REGION EARLY SUNDAY,
USHERING IN VERY COLD TEMPERATURES TO START THE WEEK. TEMPERATURES
QUICKLY REBOUND BY THE MIDDLE OF NEXT WEEK.
NEAR TERM /THROUGH SATURDAY/
AS OF 633 PM EST FRIDAY:
KEY MESSAGE #1: CLEARING SKIES THIS EVENING WITH DRY CONDITIONS
THROUGH TONIGHT.
A SUBTLE SHORTWAVE EMBEDDED IN MUCH BROADER CYCLONIC FLOW ALOFT
IS NOW ANALYZED WELL EAST OF THE AREA AS WE HEAD INTO TONIGHT.
CLOUDS ARE CLEARING QUICKLY BEHIND THE SHORTWAVE AND SHOULD REMAIN
THAT WAY THROUGH THE REST OF THE NIGHT OUTSIDE OF THE IMMEDIATE
TENNESSEE BORDER IN THE NORTHERN MOUNTAINS. GOOD RADIATIONAL
COOLING CONDITIONS WILL LEAD TO OVERNIGHT LOWS DROPPING
APPROXIMATELY A CATEGORY BELOW NORMAL.
KEY MESSAGE #2: WARMEST DAY SO FAR IN DECEMBER EXPECTED SATURDAY,
AHEAD OF AN ARCTIC COLD FRONT.
THE FLOW ALOFT WILL FLATTEN SATURDAY WHILE BACKING FROM A
WEST-NORTHWESTERLY COMPONENT TO WEST-SOUTHWESTERLY IN RESPONSE
TO A DIGGING CLOSED UPPER LOW OVER THE NORTHERN GREAT LAKES
REGION. THIS SHIFT WILL ALLOW FOR SUBTLE HEIGHT RISES AS A WEAK
DOWNSLOPE COMPONENT DEVELOPS WITH SOME COMPRESSIONAL WARMING AS WELL
AHEAD OF THE ARCTIC FRONT IN THE SHORT-TERM PERIOD. AS A RESULT,
AFTERNOON HIGHS ARE FORECAST TO RUN UP TO 5 DEGREES ABOVE NORMAL,
WITH LOCATIONS ACROSS THE UPPER SAVANNAH RIVER VALLEY AND LAKELANDS
LIKELY EXCEEDING THE 60 DEGREE MARK.
SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/
AS OF 1235 PM EST FRIDAY:
KEY MESSAGE 1: LIGHT PRECIPITATION POSSIBLE SATURDAY NIGHT AHEAD
OF AN ARCTIC FRONT.
AN UPPER-LEVEL POLAR VORTEX WILL SLING A STRONG VORT MAX THRU THE
OHIO VALLEY TO THE CAROLINAS SATURDAY NIGHT THRU SUNDAY. THIS
WILL BRING AN ARCTIC COLD FRONT THRU THE SOUTHERN APPALACHIANS
SATURDAY NIGHT AND THE REST OF THE CWFA SUNDAY MORNING. SHALLOW
MOISTURE ALONG/AHEAD OF THE FRONT MAY PRODUCE A FEW RAIN SHOWERS
OVERNIGHT SATURDAY NIGHT, WITH SOME LINGERING UPSLOPE SHOWERS
NEAR THE TN BORDER THRU LATE SUNDAY MORNING. A DUSTING TO UP TO
AN 1 INCH OF SNOW WILL BE POSSIBLE IN THE HIGH ELEVATIONS OF THE
TN BORDER COUNTIES, BUT OTHERWISE, WITH GENERALLY A TRACE OF RAIN
ELSEWHERE. LITTLE TO NO IMPACTS EXPECTED, BUT IF ROADS MANAGE TO
GET WET ANYWHERE IN THE MOUNTAINS, TEMPS WILL BEGIN TO PLUMMET BY
DAYBREAK SUNDAY AND COULD FLASH-FREEZE INTO SOME BLACK ICE. MOUNTAIN
TEMPS ARE NOT EXPECTED TO WARM ABOVE FREEZING THE REST OF THE DAY.
KEY MESSAGE 2: ARCTIC FRONT BRINGS GUSTY WINDS WITH BITTERLY COLD
TEMPERATURES SUNDAY THROUGH MONDAY.
AN ARCTIC AIR MASS SPILLS INTO THE AREA DURING THE DAY SUNDAY AND
CONTINUES THRU SUNDAY NIGHT. STRONG LOW-LEVEL CAA WILL HELP MIX
DOWN GUSTY WINDS, WITH HIGH ELEVATIONS LIKELY TO SEE GUSTS OVER 40
MPH FROM BEFORE DAYBREAK SUNDAY THRU EARLY SUNDAY EVENING. GUSTS
EAST OF THE MOUNTAINS OF 25-35 MPH WILL BE POSSIBLE SUNDAY AFTN
THRU EARLY SUNDAY EVENING. WINDS WILL BEGIN TO WEAKEN SUNDAY
NIGHT, BUT REMAIN BREEZY AND COMBINE WITH BITTERLY COLD TEMPS TO
PRODUCE WIND CHILLS IN THE +5 TO -15 DEGREES F RANGE ACROSS THE
MOUNTAINS (AND EVEN COLDER ON THE HIGHEST RIDGETOPS). CONFIDENCE
CONTINUES TO INCREASE THAT A COLD WEATHER ADVISORY WILL BE NEEDED
FOR PORTIONS OF THE MOUNTAINS. EAST OF THE MOUNTAINS, TEMPS WILL
FALL INTO THE TEENS TO LOWER 20S WITH WIND CHILLS IN THE LOWER TO
MID TEENS. WHILE THESE ARE CERTAINLY THE COLDEST TEMPS AND WIND
CHILLS OF THE SEASON SO FAR, THEY DO FALL A FEW DEGREES SHORT OF
RECORDS OR COLD ADVISORY CRITERIA (OUTSIDE THE MOUNTAINS).
WINDS WILL CONTINUE TO SUBSIDE MONDAY, BUT TEMPS WILL STRUGGLE
TO GET INTO THE UPPER 30S TO LOWER 40S DESPITE SUNNY SKIES. HIGHS
SHOULD GET ABOVE FREEZING EVERYWHERE, EXCEPT PERHAPS THE HIGHEST
PEAKS.
LONG TERM /MONDAY NIGHT THROUGH FRIDAY/
AS OF 1245 PM EST FRIDAY:
1) COLD AIR QUICKLY EXITS THE AREA WITH TEMPERATURES REBOUNDING
BY THE MIDDLE OF THE WEEK.
THE CENTER OF ARCTIC HIGH PRESSURE WILL CROSS THE CENTRAL
APPALACHIANS TO THE CAROLINA COAST BY MONDAY EVENING UNDER
FLATTENING FLOW ALOFT. THIS SHOULD RESULT IN CLEAR SKIES AND
LIGHT WIND ACROSS THE REGION, ALLOWING FOR GOOD RADIATIONAL
COOLING. UNDERCUT THE NBM MIN TEMPS WITH MOS AND THE NBM 25TH
PERCENTILE FOR LOWS MONDAY NIGHT. THIS RESULTS IN ANOTHER CHILLY
NIGHT, BUT NOT AS COLD AS SUNDAY NIGHT. TEMPS REBOUND NICELY
TUESDAY, AS RETURN FLOW PICKS UP BEHIND THE DEPARTING HIGH
PRESSURE. HIGHS BACK TO LOWER TO MID 50S IN THE MOUNTAIN VALLEYS
AND PIEDMONT (40S IN THE HIGH ELEVATIONS). DRY WEATHER CONTINUES
WEDNESDAY WITH ZONAL FLOW ALOFT. TEMPS CONTINUE TO MODERATE BACK
TO NEAR OR EVEN SLIGHTLY ABOVE NORMAL.
2) PRECIP CHANCES MAY RETURN BY THE END OF THE WEEK.
MODELS DIVERGE ON DEPICTION OF AN UPPER TROUGH DIGGING ACROSS
THE CENTRAL CONUS LATE WEDNESDAY INTO THURSDAY. THE 12Z GFS
SHOWING A VERY FLAT AND FAST-MOVING TROUGH SEEMS TO BE MORE OF AN
OUTLIER SOLUTION, WITH THE ECMWF AND CANADIAN SHOWING A DEEPER AND
SLOWER TROUGH. THEIR SOLUTIONS BRINGS A COLD FRONT THRU THE AREA
THURSDAY INTO THURSDAY NIGHT. THE FRONT WOULD LIKELY BE TOO WARM
FOR ANYTHING BUT RAIN, EXCEPT PERHAPS SOME WINTRY P-TYPES IN THE
HIGHEST ELEVATIONS. THE NBM POPS RAMPING UP INTO THE CHANCE RANGE
THU-THU NIGHT LOOKS GOOD. TEMPS WILL REMAIN NEAR TO SLIGHTLY ABOVE
NORMAL THURSDAY, THEN LIKELY COOL TO SLIGHTLY BELOW NORMAL FRIDAY
(THE LATEST NBM TEMPS LOOK A LITTLE TOO WARM).
AVIATION /00Z SATURDAY THROUGH WEDNESDAY/
AT KCLT AND ELSEWHERE: VFR ON TAP FOR THE 00Z TAF PERIOD. A BANK
OF MID-LEVEL ALTOCU IS VISIBLE SATELLITE IMAGERY ALONG AND NORTH
OF I-40, BUT GUIDANCE GENERALLY SUGGESTS IT'LL RETREAT NORTHWARD
OVERNIGHT, GIVING WAY TO SKC/FEW CIRRUS FOR THE REMAINDER OF THE
TAF PERIOD. LIGHT AND VARIABLE WINDS OVERNIGHT WILL GIVE WAY TO
A STEADY 5-7KT SW BREEZE DURING THE DAYLIGHT HOURS SATURDAY.
OUTLOOK: A STRONG COLD FRONT WILL BRING SOME CLOUD COVER SATURDAY
NIGHT INTO SUNDAY, BUT MOST TERMINALS SHOULD REMAIN DRY WITH NO
REAL INDICATIONS OF ASSOCIATED VSBY/CIG RESTRICTIONS. VERY GUSTY
WINDS ARE EXPECTED LATE SATURDAY NIGHT THROUGH THE DAYTIME PERIOD
SUNDAY. DRY HIGH PRESSURE WILL KEEP VFR CONDITIONS IN PLACE THROUGH
THE EARLY PART OF NEXT WEEK.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
SYNOPSIS...ARK
NEAR TERM...CAC/MPR
SHORT TERM...ARK
LONG TERM...ARK
AVIATION...MPR
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