605
FXUS62 KGSP 170610
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
110 AM EST TUE DEC 17 2024
SYNOPSIS
CLOUD COVER WILL PERSIST TODAY AS A FRONT STALLS IN THE AREA, ALONG
WITH SCATTERED SHOWERS OVER THE MOUNTAINS. TEMPS WILL BE ABOVE
NORMAL TODAY AND WEDNESDAY, WITH A STRONGER FRONT APPROACHING
FROM THE WEST AND INCREASING RAIN CHANCES AREA-WIDE WEDNESDAY
AFTERNOON AND EVENING. COOLER CONDITIONS ARE EXPECTED BEHIND THE
FRONT THROUGH THE WEEKEND.
NEAR TERM /THROUGH TODAY/
AS OF 1255 AM TUE: WEAKENING COLD FRONT HAS PROGRESSED ABOUT A THIRD
OF THE WAY ACROSS KY/TN, AND EMBEDDED WITHIN BROAD CYCLONIC FLOW
AROUND THE PARENT SYSTEM, NOW NORTH OF THE GREAT LAKES. WINDS HAVE
BEGUN TO TURN WESTERLY INTO THE SOUTHERN APPALACHIANS, AND WITH THAT
AND A WEAK RIPPLE OF VORT, A NARROW AND DECAYING BAND OF SHOWERS HAS
REACHED OUR NC MOUNTAIN ZONES. SOME MORE PRECIP ACTIVITY MAY ENTER
SW NC OR NE GA LATER THIS MORNING AHEAD OF THE FRONT BUT POPS REMAIN
CHANCY AND THERE STILL APPEARS LITTLE REASON TO BELIEVE ANY PRECIP
WILL MAKE IT FARTHER EAST INTO THE AREA THIS MORNING. FOG/STRATUS
DECK BLANKETS MOST OF THE CWA EAST OF THE MOUNTAINS, BASICALLY
AT THE SAME EXTENT IT WAS WHEN DENSE FOG ADVISORY WAS ISSUED
IN THE EVENING; LIGHT WINDS ARE ACTUALLY BLOWING AT SOME SITES
AND THIS HAS ALLOWED SOME PERIODS OF IMPROVEMENT AT TIMES, BUT
ONLY BRIEFLY. DON'T THINK THE RAIN WILL BE ENOUGH TO IMPACT THE
FOG. IT STILL LOOKS MOST LIKELY THE FOG WILL PERSIST THROUGH THE
MORNING COMMUTE. ACTUALLY WON'T RULE OUT AN EXTENSION BY AN HR OR
TWO WITH THE 330 AM PACKAGE, PER LATEST GUIDANCE. MAIN CHANGES AT
THIS UPDATE WERE TO WIND/SKY TRENDS FOR THE AVIATION PACKAGE.
THE FRONT, AS IT WERE, SHOULD LAY OUT ACROSS THE FCST AREA TODAY
WITH THE UPPER FLOW BECOMING MORE WSW, BUT WHAT MEAGER FORCING
THERE IS SHOULD MOVE OUT TO THE EAST BY THE MIDDLE PART OF THE
DAY. NOT A LOT OF POTENTIAL FOR ANYTHING MORE THAN PASSING VERY
LIGHT RAIN. THE POSITION OF THE FRONT AND TRACK OF THE VORT SUGGESTS
THE AREA S/E OF I-85 WILL STAY DRY. THE TREND HAS BEEN FOR LESS
COVERAGE AND AN EARLIER DEPARTURE AS WELL, SO PRECIP PROBS ARE
CURTAILED TO THE FAR WESTERN PART BY THE END OF THE DAY. TEMPS WILL
ONCE AGAIN BE TRICKY BECAUSE OF THE TRAPPED REMNANT COOL POOL. LOW
CLOUDS AND FOG SHOULD DELAY THE WARMUP THROUGH THE LATE MORNING,
BUT IT APPEARS THAT WITH THE FRONT LAYING OUT WE WILL SEE ENOUGH
SFC WARM ADVECTION AND MIXING TO EVENTUALLY ELIMINATE THE COLD POOL
IN THE AFTERNOON, SO A NICE REBOUND ABOVE NORMAL IS STILL EXPECTED.
SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/
AS OF 130 PM EST MONDAY...
KEY MESSAGES:
1) TRENDING DRIER TUESDAY EVENING INTO WEDNESDAY MORNING WITH RAIN
HOLDING OFF UNTIL LATE WEDNESDAY AFTERNOON/EVENING
2) WELL ABOVE NORMAL TEMPERATURES LINGER THROUGH WEDNESDAY NIGHT
3) DRIER AND COOLER ON THURSDAY WITH THE SUNSHINE RETURNING
A COLD FRONT WILL APPROACH OUT OF THE WEST TUESDAY EVENING INTO
WEDNESDAY AFTERNOON BEFORE TRACKING ACROSS THE FORECAST AREA
WEDNESDAY EVENING INTO WEDNESDAY NIGHT. THE 12Z CAMS DEPICT MOSTLY
DRY CONDITIONS TUESDAY NIGHT INTO EARLY WEDNESDAY AFTERNOON, SO WENT
WITH LOWER POPS THAN THE PREVIOUS FORECAST HAD. CAMS SHOW THE BEST
TIMING FOR WILL BE LATE WEDNESDAY AFTERNOON INTO WEDNESDAY NIGHT
AHEAD OF AND ALONG THE FRONTAL BOUNDARY. HAVE THE HIGHEST POPS
CONFINED TO THE WESTERN NORTH CAROLINA MOUNTAINS WITH LOWER POPS
ELSEWHERE FOR NOW BASED ON THE LATEST CAM AND GLOBAL MODEL GUIDANCE
TRENDS. ALL LIQUID PRECIP IS EXPECTED WITH TEMPS TRENDING WELL ABOVE
NORMAL THROUGH WEDNESDAY NIGHT. LOWS TUESDAY NIGHT WILL END UP ~20
DEGREES ABOVE NORMAL THANKS TO INCREASING CLOUD COVER. HIGHS ON
WEDNESDAY WILL REMAIN WELL ABOVE NORMAL (~15 DEGREES) THANKS TO
STRONG SW'LY FLOW AHEAD OF THE FRONT. BREEZY SW WINDS CAN BE
EXPECTED AHEAD OF THE FRONT AREA-WIDE ON WEDNESDAY. WINDS WILL
GRADUALLY TURN NW BEHIND THE FRONT, WITH GUSTS LINGERING ACROSS THE
MOUNTAINS THROUGH WEDNESDAY NIGHT BEFORE TAPERING OFF AROUND
DAYBREAK THURSDAY. LOWS WEDNESDAY NIGHT WILL BE COOLER, BUT STILL
~10-12 DEGREES ABOVE NORMAL.
DRIER CONDITIONS ARE EXPECTED BEHIND THE FRONT BY EARLY THURSDAY
MORNING THANKS TO SFC HIGH PRESSURE BUILDING IN FROM THE WEST. HIGHS
ON THURSDAY WILL BE NOTICEABLY COOLER BEHIND THE FRONT, DESPITE THE
RETURN OF SUNSHINE, BUT WILL STILL END UP ~3-6 DEGREES ABOVE NORMAL.
LOWS THURSDAY NIGHT WILL DROP INTO THE 30S IN MOST AREAS BUT TEMPS
WILL STILL END UP ~5-8 DEGREES ABOVE NORMAL THANKS TO PARTLY CLOUDY
SKIES.
LONG TERM /FRIDAY THROUGH MONDAY/
AS OF 200 PM EST MONDAY...
KEY MESSAGES:
1) COOLING TREND CONTINUES INTO THE WEEKEND, WITH WELL BELOW NORMAL
TEMPERATURES RETURNING ON SATURDAY
2) DRY THROUGH THE LONG TERM OUTSIDE OF NW FLOW SNOW SHOWERS IN THE
WESTERN NC MOUNTAINS FRIDAY INTO EARLY SATURDAY
2 GUSTY WINDS MAY DEVELOP FRIDAY INTO SATURDAY, ESPECIALLY ACROSS
THE MOUNTAINS
A MOSTLY DRY COLD FRONT WILL TRACK ACROSS THE WESTERN CAROLINAS AND
NORTHEAST GEORGIA ON FRIDAY, ALLOWING GUSTY NW WINDS TO DEVELOP
ACROSS THE MOUNTAINS. GUSTY WINDS WILL LINGER THROUGH FRIDAY NIGHT
BEFORE GRADUALLY TAPERING OFF SATURDAY. THE LATEST GLOBAL MODEL
GUIDANCE AGREE THAT THERE WILL BE ENOUGH MOISTURE BEHIND THE FRONT
FOR NW FLOW SNOW SHOWERS TO DEVELOP FRIDAY AFTERNOON INTO EARLY
SATURDAY MORNING ALONG THE NC/TN BORDER. THE NBM DID END UP WITH
SOME VERY LIGHT SNOWFALL ACCUMS (A FEW TENTHS OF AN INCH) THIS
FORECAST CYCLE. THE LREF 90TH PERCENTILE ACCUMULATED SNOWFALL ONLY
SHOWS UP TO AN INCH ALONG THE TN BORDER FRIDAY INTO EARLY SATURDAY
SO NOT ANTICIPATING A MAJOR NW FLOW SNOW EVENT. DRY CONDITIONS ARE
EXPECTED ELSEWHERE THANKS TO SFC HIGH PRESSURE BUILDING INTO THE
REGION BEHIND THE FRONT AND LINGERING THROUGH THE REST OF THE
FORECAST PERIOD. WE WILL HAVE ONE MORE DAY OF ABOVE NORMAL TEMPS ON
FRIDAY AHEAD OF THE FRONT BEFORE WELL BELOW NORMAL TEMPS RETURN
BEHIND THE FRONT THIS WEEKEND INTO EARLY NEXT WEEK.
AVIATION /06Z TUESDAY THROUGH SATURDAY/
AT KCLT AND ELSEWHERE: NO APPRECIABLE CHANGE IN FLIGHT CATEGORY
AT THE SC SITES OR KHKY UNTIL FOG LAYER BEGINS TO MIX OUT, WHICH
STILL LOOKS TO OCCUR 14-15Z. CONDITIONS THERE ARE LIKELY TO REMAIN
BELOW MINIMA, EVEN WITH A LIGHT WIND AT KGSP/KGMU. KCLT SHOULD
REMAIN BELOW MINIMA ALTHOUGH IT IS CLOSER TO THE EDGE OF THE DECK,
AND WIND HAS BEEN ASSOCIATED WITH SOME BRIEF IMPROVEMENT THERE,
HENCE TEMPO. AT KAVL, STARTING OFF VFR, BUT A BAND OF LIGHT PRECIP
AHEAD OF A STALLING FRONT MAY BRING A PERIOD OF MVFR WHICH PROBABLY
THEN WILL LINGER THRU DAYBREAK.
SFC WINDS WILL BE PREDOMINANTLY SW WHEN BLOWING AT ALL SITES EXCEPT
KAVL. AS WINDS TURN MORE WESTERLY ALOFT, KAVL PROBABLY WILL TURN
TO NW, AND UPSLOPE GENERATED CLOUDS ARE LIKELY TO BE SEEN THERE
MUCH OF THE REMAINDER OF THE MORNING. ELSEWHERE, ONCE FOG LAYER
DISSIPATES TODAY, CLOUDS ARE EXPECTED TO REMAIN AT MVFR FOR MOST
OF THE DAY, TRAPPED UNDER INVERSION, ALTHOUGH THEY PROBABLY WILL
SCATTER TO VFR LATE. THE FRONT STALLS AND REACTIVATES OVER NORTHERN
NC TONIGHT, WITH ANOTHER LIFR DECK AND AREAS OF IFR TO LIFR FOG
LIKELY TO DEVELOP AFTER MIDNIGHT.
OUTLOOK: AN UNSETTLED PATTERN CONTINUES THROUGH EARLY THURSDAY,
WHEN A COLD FRONT FINALLY INDUCES A CHANGE TO A DRIER CONTINENTAL
AIRMASS. PERIODIC RESTRICTIONS ARE LIKELY THROUGH THEN. GENERALLY
DRY AND VFR TO END THE WEEK.
GSP WATCHES/WARNINGS/ADVISORIES
GA...DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR GAZ017-018-
026-028-029.
NC...DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR NCZ035>037-
056-057-068>072-502-504-506-508-510.
SC...DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR SCZ008>014-
019-104>109.
SYNOPSIS...WIMBERLEY
NEAR TERM...MPR/PM/WIMBERLEY
SHORT TERM...AR
LONG TERM...AR
AVIATION...WIMBERLEY
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