316
FXUS62 KGSP 090614
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
114 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 1250 AM SAT: NORTHERLY FLOW OBSERVED OVER MOST OF THE
CWA AS HIGH PRESSURE BUILDS IN FROM THE GREAT LAKES, BEHIND A
BACKDOOR COLD FRONT. DEWPOINTS HAVE FALLEN 10 OR MORE DEGREES
SINCE SUNSET IN SEVERAL SPOTS IN THE NC PIEDMONT (INCLUDING
THE GREATER TRIAD). THIS DRYING TREND WILL CONTINUE TOWARD THE
SW. LOCALLY DENSE FOG HAS FORMED IN PARTS OF THE LAKELANDS, AND
THINKING IS THIS WILL DISSIPATE BEFORE SUNRISE IF EVEN MARGINAL
DRYING IS ABLE TO OCCUR THERE. ALSO, A BAND OF STRATOCU IS ALSO
SEEN CREEPING SOUTH ON SATELLITE WITH THE FRONT; ARRIVAL OF THIS
CLOUD COVER COULD ALSO INHIBIT COOLING ENOUGH TO ALLOW FOG LAYER
TO BREAK UP. WON'T RULE OUT NEED FOR AN SPS TO MENTION THE FOG
THREAT IN THE DAYBREAK TIMEFRAME.
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. THE STRATOCU ARE LIKELY TO PERSIST IN SOME FASHION THRU THE
DAY ACROSS THE SOUTHERN CWA AND NEAR THE ESCARPMENT ALONG/WEST
OF I-26, AS A RESULT OF EITHER CONVERGENCE IN EASTERLY FLOW OR
WARM UPGLIDE. 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 SIMPLY GIVEN THE FRESHLY ARRIVED,
DRY 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
APPEARS SMALL THRU DAYBREAK SUN. MINS WILL BE A FEW DEGREES ABOVE
NORMAL OWING TO EXTENSIVE CLOUD COVER.
SHORT TERM /SUNDAY THROUGH MONDAY/
AS OF 138 PM EDT FRIDAY: WEAK SOUTHEASTERLY ISENTROPIC ASCENT
AND ONSET OF PRECIP WILL REINFORCE A SHALLOW CAD CONFIGURATION
SUNDAY AND SUNDAY NIGHT...KEEPING HIGHS IN THE UPPER 50S FOR
MOST OF THE CWA AND BARELY PERMITTING ANY COOLING SUNDAY NIGHT.
MODEL CONSENSUS DEPICTS SOME WARMING ON MONDAY, WITH HIGHS BACK
IN THE 70S MONDAY AFTERNOON AS HIGH PRESSURE PULLS OFF THE MID-
ATLANTIC COAST AND THE CAD DETERIORATES. ENSEMBLES SUGGEST,
HOWEVER, THAT HIGHS COULD WIND UP AS MUCH AS A CATEGORY COOLER
MONDAY, DEPENDING ON HOW EFFECTIVELY THE CAD BREAKS DOWN AND HOW
LONG CLOUD COVER PERSISTS INTO THE DAY. CERTAINLY, BY LATER IN
THE DAY MONDAY, WE SHOULD BE MORE SOLIDLY LOCKED INTO A
PREFRONTAL TROUGH, AS A COLD FRONT APPROACHES FROM THE NORTHWEST
LATE IN THE DAY. RAIN LOOKS LIKELY WITH THIS, AND EVEN A RUMBLE
OF THUNDER COULD MIX IN...BUT THIS WILL BE HIGHLY DEPENDENT ON
HOW QUICKLY CAD SCATTERS OUT AND THE EXACT CONFIGURATION OF THE
ADVANCING BOUNDARY.
LONG TERM /MONDAY NIGHT THROUGH FRIDAY/
AS OF 155 PM EDT FRIDAY: MULTIPLE LARGE-SCALE FEATURES WILL IMPACT
THE FORECAST AREA DURING THE EXTENDED PERIOD, BUT NEITHER IS
EXPECTED TO CAUSE HAZARDOUS WEATHER. THE FIRST, A COLD FRONT, WILL
LIKELY ARRIVE MONDAY NIGHT. QPF RESPONSE IS VARIABLE AT THIS RANGE,
BUT DOESN'T APPEAR IMPACTFUL. THEN, EXPECT DRYING ON MONDAY AS A
FAST-MOVING HIGH PRESSURE SYSTEM SLIDES ACROSS THE UPPER OHIO VALLEY
AND INTO NEW ENGLAND. BY WEDNESDAY, WE'LL BE BACK IN AN EASTERLY
FLOW REGIME, THOUGH THE PARENT HIGH WILL BE FAR ENOUGH REMOVED FROM
THE CAROLINAS THAT IT SHOULD HAVE A BARELY-NOTICEABLE IMPACT ON
TEMPERATURES...WHICH LOOK TO REMAIN ABOVE NORMAL. THE SECOND ACTIVE
WEATHER FEATURE WILL ARRIVE IN THE FORM OF A SECOND, FAST-MOVING
COLD FRONT EITHER WEDNESDAY NIGHT OR THURSDAY, AND SHOULD BRING
ANOTHER SLUG OF RAINFALL TO THE AREA. MOST OF THE ENSEMBLE GUIDANCE
THEN DEPICTS STOUT HIGH PRESSURE FILTERING IN, AND ALLOWING
TEMPERATURES TO BECOME MORE SEASONABLY COOL TOWARD THE END OF NEXT
WEEK.
AVIATION /06Z SATURDAY THROUGH WEDNESDAY/
AT KCLT AND ELSEWHERE: BACKDOOR COLD FRONT SETTLING THRU THE AREA
WILL INTRODUCE CONSIDERABLY DRIER AIR THIS MORNING AND SET UP A
CAD-LIKE WEDGE REGIME, WITH WINDS PICKING UP FROM THE NE AT ALL
SITES EXCEPT KAVL BY DAYBREAK, WHERE NOT ALREADY. KAVL WILL SEE SE
WINDS DEVELOP AROUND DAYBREAK AND REMAIN SO THRU THE REST OF THE
PERIOD. AHEAD OF THE FRONT, A BAND OF MOSTLY LOW VFR STRATOCU WILL
SHIFT SOUTH, OCCASIONALLY BEING SEEN AT KGSP/KGMU/KAND. SFC DEWPOINT
DEPRESSIONS REMAIN SMALL IN THE SOUTHERN PART OF THE TERMINAL
AREA, SUCH THAT KAND WILL SEE FOG UNTIL SUFFICIENT DRYING OCCURS
10-12Z. A FEW GUSTS ARE LIKELY DURING THE DAY. E'LY FLOW ALOFT WILL
KEEP MAINLY FEW-SCT STRATOCU IN PLACE TODAY BUT SOME VFR CIGS ARE
POSSIBLE THIS MORNING IN THE UPSTATE. ALTO/CIRRUS WILL INCREASE,
AND BY EVENING WARM UPGLIDE OVER SFC HIGH WILL BEGIN TO PRODUCE
CLOUD COVER, WHICH MAY RESULT IN MVFR CIGS IN SOME AREAS BY DAYBREAK
SUNDAY, A MENTION WHICH COULD NEED TO BE MADE IN THE NEXT TAF SET.
OUTLOOK: ADDITIONAL SHOWERS AND ASSOCIATED RESTRICTIONS ARE POSSIBLE
SUNDAY AND INTO EARLY NEXT WEEK AS ANOTHER WEDGE PATTERN DEVELOPS
OVER THE WESTERN CAROLINAS.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
SYNOPSIS...AR
NEAR TERM...WIMBERLEY
SHORT TERM...MPR
LONG TERM...MPR
AVIATION...WIMBERLEY
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