129
FXUS62 KGSP 091151
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
651 AM EST SAT NOV 9 2024
SYNOPSIS
DRY HIGH PRESSURE BUILDS IN FROM THE NORTH TODAY BEFORE A STRONG
COLD FRONT BRINGS RAIN CHANCES BACK TO THE AREA SUNDAY INTO MONDAY.
HIGH TEMPERATURES WILL BE MUCH COOLER THIS THE WEEKEND, WITH
AFTERNOON TEMPERATURES ON SUNDAY EXPECTED TO FALL BELOW NORMAL,
BEFORE HIGHS TREND BACK TO ABOVE NORMAL VALUES EARLY NEXT WEEK. DRY
HIGH PRESSURE RETURNS TUESDAY INTO WEDNESDAY BEFORE ANOTHER COLD
FRONT INCREASES RAIN CHANCES AGAIN ON THURSDAY.
NEAR TERM /THROUGH TONIGHT/
AS OF 630 AM: NE FLOW OBSERVED OVER MOST OF THE CWA AS HIGH PRESSURE
BUILDS IN FROM THE GREAT LAKES BEHIND A BACKDOOR COLD FRONT WHICH
PASSED OVERNIGHT. THE SFC HIGH WILL BUILD SOUTH AND EAST TOWARD
THE MID-ATLANTIC COAST BY THE END OF THE DAY TODAY, SUPPORTED BY
A MODERATELY STRONG UPPER RIDGE. CONVERGENCE WITHIN EASTERLY FLOW
ABOVE THE PBL, AND BELOW SUBSIDENCE INVERSION, HAS RESULTED IN
AREAS OF STRATOCU OVER MUCH OF THE CWA. THIS IS LIKELY TO PERSIST
IN SOME FASHION THRU THE DAY, WITH WARM UPGLIDE DEVELOPING AS
WINDS TURN MORE SOUTH, BUT WITH MOISTURE PERHAPS DIMINISHING AND
ALLOWING SOME SCATTERING FOR THE AFTERNOON. HIGHER CLOUDS WILL
ALSO FILTER IN, EMANATING FROM THE MIDLATITUDE CYCLONE ON THE OTHER
SIDE OF THE RIDGE AXIS. NOT SEEING ENOUGH MOISTURE DURING THE DAY
TO SUPPORT MENTIONABLE POPS; ACCORDINGLY WE DO NOT EXPECT CAD TO
AFFECT HIGH TEMPERATURE POTENTIAL. TEMPS WILL BE COOLER DUE TO A
COMBO OF CLOUD COVER AND A FRESHLY ARRIVED CONTINENTAL AIRMASS;
THE PIEDMONT AND LOWER ELEVATIONS WILL SEE HIGHS IN THE UPPER 60S
TO NEAR 70, STILL A FEW DEGREES ABOVE NORMAL.
THE WARM UPGLIDE WILL MOISTEN TONIGHT AND STRATUS OR STRATOCU
WILL THICKEN OVER THE WESTERN PART OF THE AREA, BUT CHANCE OF POP
STILL WILL BE CONFINED TO THE MOUNTAINS, GIVEN PROXIMITY TO FRONT
AND WHERE MOISTURE WILL BE BEST ALOFT; EVEN THEN CHANCE IS BELOW
30%. MINS WILL BE NOTABLY COOLER AS WELL, BUT STILL A FEW DEGREES
ABOVE NORMAL WITH CLOUD COVER, AND WITH HYBRID CAD STILL NOT
LOOKING PARTICULARLY LIKELY TO DEVELOP GIVEN LOW CHANCE OF PRECIP.
SHORT TERM /SUNDAY THROUGH MONDAY/
AS OF 130 AM EST SATURDAY...
KEY MESSAGES:
1) COLD AIR DAMMING WILL ALLOW FOR BELOW NORMAL HIGHS ON SUNDAY
2) A COLD FRONT BRINGS RAIN SUNDAY INTO MONDAY
3) ABOVE NORMAL HIGHS RETURN MONDAY AS COLD AIR DAMMING ERODES
COLD AIR DAMMING WILL BE IN PLACE SUNDAY AHEAD OF AN ADVANCING COLD
FRONT LEADING TO MOSTLY CLOUDY SKIES AND INCREASING RAIN CHANCES
THROUGH THE DAY. AS A RESULT, HIGHS ON SUNDAY WILL END UP A FEW
DEGREES BELOW NORMAL. LOWS SUNDAY NIGHT WILL END UP ~15 DEGREES
ABOVE CLIMO THANKS TO CLOUD COVER AND RAIN LIMITING RADIATIONAL
COOLING. THE FRONT WILL SWEEP ACROSS THE FORECAST AREA ON MONDAY,
KEEPING RAIN CHANCES AROUND AND GRADUALLY SCOURING OUT COLD AIR
DAMMING. HOW QUICKLY THE COLD AIR DAMMING ERODES ON MONDAY WILL BE
THE MAIN QUESTION. IF IT ERODES PRIOR TO PEAK HEATING A RUMBLE OF
THUNDER CANNOT BE ENTIRELY RULED OUT. HOWEVER, REMOVED THUNDER
CHANCES FOR NOW AS COLD AIR DAMMING USUALLY ERODES SLOWER THAN WHAT
THE GLOBAL MODEL GUIDANCE SHOWS. HIGHS ON MONDAY SHOULD REBOUND TO
~10 DEGREES ABOVE NORMAL BUT COULD BE LIMITED SOMEWHAT IF THE WEDGE
LINGERS THROUGH PEAK HEATING. RAIN CHANCES WILL GRADUALLY TAPER OFF
OVERNIGHT MONDAY AS THE FRONT PUSHES EAST. LOWS WILL REMAIN ~15
DEGREES ABOVE NORMAL MONDAY NIGHT DESPITE GRADUALLY DECREASING CLOUD
COVER.
LONG TERM /MONDAY NIGHT THROUGH FRIDAY/
AS OF 200 AM EST SATURDAY...
KEY MESSAGES:
1) DRIER CONDITIONS RETURN TUESDAY INTO WEDNESDAY
2) ABOVE NORMAL TEMPERATURES LINGER THROUGH MUCH OF THE WORKWEEK
3) A COLD FRONT INCREASES RAIN CHANCES ON THURSDAY WITH DRIER
CONDITIONS EXPECTED ON FRIDAY BEHIND THE FRONT
HIGH PRESSURE BUILDS IN FROM THE NORTH ON TUESDAY, LINGERING THROUGH
WEDNESDAY. THIS WILL ALLOW DRY CONDITIONS AND MOSTLY SUNNY SKIES TO
RETURN TO THE FORECAST AREA. HIGHS WILL REMAIN WELL ABOVE NORMAL ON
TUESDAY, DROPPING TO NEAR NORMAL ON WEDNESDAY. LOWS TUESDAY NIGHT
WILL END UP SEVERAL DEGREES ABOVE CLIMO DESPITE GOOD RADIATIONAL
COOLING CONDITIONS. CLOUD COVER WILL GRADUALLY INCREASE WEDNESDAY
NIGHT AHEAD OF THE NEXT COLD FONT, KEEPING LOWS SEVERAL DEGREES
ABOVE NORMAL. THE COLD FRONT WILL PUSH ACROSS THE FORECAST AREA
OVERNIGHT WEDNESDAY INTO EARLY THURSDAY MORNING, POTENTIALLY
BRINGING RAIN CHANCES BACK INTO THE FORECAST. HOWEVER, THE LATEST
GLOBAL MODEL GUIDANCE IS TRENDING DRIER SO CAPPED POPS TO CHANCE
WEDNESDAY NIGHT INTO THURSDAY. SFC HIGH PRESSURE BUILDS IN FROM THE
WEST BEHIND THE DEPARTING FRONT ON FRIDAY LEADING TO DRIER WEATHER.
HIGHS WILL REBOUND TO ABOVE NORMAL VALUES THURSDAY INTO FRIDAY, WITH
LOWS REMAINING SEVERAL DEGREES ABOVE NORMAL THROUGH THE REST OF THE
LONG TERM.
AVIATION /12Z SATURDAY THROUGH WEDNESDAY/
AT KCLT AND ELSEWHERE: A CAD-LIKE WEDGE REGIME IS IN PLACE, WITH
WINDS PICKING UP FROM THE NE AT ALL SITES EXCEPT KAVL, WHICH INSTEAD
WILL SEE SE WINDS. STRATOCU MAINLY AT LOW VFR LEVEL WILL PRODUCE
CIGS THIS MORNING, WITH AN MVFR CIG AT TIMES NEAR KAND. THESE
CLOUDS ARE EXPECTED TO PARTLY SCATTER BY AROUND MIDDAY BUT ARE
UNLIKELY TO COMPLETELY DISAPPEAR. A FEW 15-18 KT GUSTS ARE LIKELY
DURING THE DAY. BY EVENING WARM UPGLIDE OVER SFC HIGH WILL LEAD
TO REDEVELOPMENT OF LOW CLOUD COVER, INITIALLY VFR BUT WITH MVFR
INCREASINGLY POSSIBLE TOWARD DAYBREAK SUNDAY. HOWEVER RESTRICTIONS
ARE MORE LIKELY NOT TO DEVELOP UNTIL AFTER 12Z IN THE WEST; NOT
YET CONFIDENT ENOUGH TO INCLUDE AT KCLT. A CHANCE OF SHRA DEVELOPS
FROM WEST TO EAST LATE TONIGHT AND SUNDAY MORNING, BUT CHANCE TOO
LOW TO MENTION AT ANY SITE BEFORE THE END OF THE PERIOD.
OUTLOOK: WEDGE REGIME WILL PERSIST UNTIL A COLD FRONT PASSES
MONDAY NIGHT OR TUESDAY. PERIODIC RESTRICTIONS AND PRECIP ARE
LIKELY BETWEEN SUNDAY THROUGH MONDAY. DRY AND MOSTLY VFR WEATHER
EXPECTED TUE-WED.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
SYNOPSIS...AR
NEAR TERM...WIMBERLEY
SHORT TERM...AR
LONG TERM...AR
AVIATION...WIMBERLEY
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