877
FXUS62 KGSP 110615
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
115 AM EST MON NOV 11 2024
SYNOPSIS
A COLD FRONT WILL TRACK ACROSS THE FORECAST AREA TODAY, BRINGING
RAIN CHANCES BACK DURING THE MORNING HOURS. DESPITE THE FRONT, HIGHS
WILL REBOUND TO WELL ABOVE NORMAL THIS AFTERNOON AS COLD AIR DAMMING
ERODES. DRY HIGH PRESSURE RETURNS TUESDAY INTO WEDNESDAY BEFORE
ANOTHER COLD FRONT INCREASES RAIN CHANCES WEDNESDAY NIGHT INTO
THURSDAY. BELOW NORMAL HIGHS RETURN ON WEDNESDAY AND THURSDAY,
BEFORE ABOVE NORMAL HIGHS ARRIVE AGAIN FRIDAY INTO THE WEEKEND AS
DRY HIGH PRESSURE BUILDS INTO THE REGION.
NEAR TERM /THROUGH TODAY/
AS OF 100 AM: CAD APPEARS TO BE HANGING ON BY A THREAD ACROSS THE
CWA, BUT WILL REMAIN IN PLACE UNTIL LATE MORNING. SFC COLD FRONT IS
JUST BEGINNING TO PUSH INTO WESTERN KY/TN, MOVING SLOWLY SE THRU
THE DAY. IT IS PROGGED TO ACTUALLY CROSS THE MOUNTAINS AFTER 00Z
TONIGHT. SOME ELEVATED INSTABILITY HAS DEVELOPED AS EXPECTED AHEAD
OF THE FRONT, BENEATH UPPER TROUGH. SHOWERS HAVE EXPANDED OVER EAST
TN SINCE LATE EVENING. MOST OF THIS INSTABILITY WILL REMAIN ON THE
WEST SIDE OF THE APPALACHIANS, ALTHOUGH THE SHOWERS WILL BE ABLE TO
ADVECT TO OUR TN BORDER COUNTIES BEFORE DAWN. A FEW LIGHT RETURNS
ARE SEEN WITHIN THE CWA WHERE WEAK UPGLIDE CONTINUES AND WHERE MORE
MARGINAL MUCAPE EXISTS. SHORT-TERM PROGS STILL SHOW INSTABILITY
INCREASING WITHIN PLUME OF WAA ON OUR EASTERN PERIPHERY BY DAYBREAK
AND LINGERING THROUGH MID-MORNING. AS A RESULT OF THESE FINDINGS,
KEPT POPS GENERALLY SIMILAR TO WHAT WAS PUT IN AT THE LATE EVENING
UPDATE. STILL THINK THE LOW STRATUS OVER MOST OF THE AREA WILL FILL
IN AND GENERALLY LOWER TOWARD DAWN; LOCALLY DENSE FOG IS POSSIBLE
ALTHOUGH PRESENTLY NOT LIKELY ENOUGH TO WARRANT A HEADLINE.
FLOW OVER THE WEDGE WILL GRADUALLY TURN MORE WESTERLY THRU THE
EARLY MORNING AND THEN SLIGHTLY NW AFTER DAWN, BUT RELATIVELY
WEAK WIND SPEEDS IMPLY DOWNSLOPE WON'T BE ALL THAT EFFECTIVE IN
SCOURING OUT THE WEDGE. INSOLATION ONTO THE STRATUS DECK MAY BE
LIMITED BY CLOUD DEBRIS ASSOCIATED WITH THE ELEVATED CONVECTION,
SO CLOUDS ARE EXPECTED TO BE SLOW TO DISSIPATE. AN PARTLY TO MOSTLY
SUNNY AFTERNOON IS EXPECTED, AND MAX TEMPS ARE STILL EXPECTED TO
REBOUND INTO THE 70S IN MOST LOWER ELEVATIONS.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/
AS OF 100 AM EST MONDAY...
KEY MESSAGES:
1) DRY HIGH PRESSURE BUILDS IN FROM THE NORTH TUESDAY INTO WEDNESDAY
LEADING TO MOSTLY SUNNY/CLEAR SKIES
2) HIGHS REMAIN ABOVE NORMAL TUESDAY, DROPPING BELOW NORMAL WEDNESDAY
3) CLOUD COVER AND RAIN CHANCES INCREASE WEDNESDAY EVENING INTO
WEDNESDAY NIGHT AHEAD OF A COLD FRONT
DRY SFC HIGH PRESSURE WILL BUILD INTO THE EASTERN CONUS ON TUESDAY,
WITH THE SOUTHERN PERIPHERY OVER THE SOUTHEAST. THIS WILL LEAD TO
MOSTLY SUNNY SKIES AND SLIGHTLY COOLER, BUT STILL ABOVE NORMAL HIGHS
(~4-8 DEGREES) ON TUESDAY. THE CENTER OF THE SFC HIGH WILL LIFT
NORTHEAST TUESDAY NIGHT INTO WEDNESDAY, ENDING UP CENTERED OVER
EASTERN CANADA. WITH CAA FILTERING INTO THE REGION AS THE HIGH LIFTS
NE, LOWS TUESDAY NIGHT WILL DIP INTO THE LOW TO MID 30S ACROSS THE
MOUNTAINS AND THE MID 30S TO MID 40S EAST OF THE MOUNTAINS. HOWEVER,
LOWS SHOULD STILL END UP NEAR NORMAL TO A FEW DEGREES ABOVE NORMAL.
COLD AIR DAMMING WILL DEVELOP ON WEDNESDAY THANKS TO NE'LY SFC
WINDS, WHICH WILL ALLOW HIGHS TO DROP ~3-6 DEGREES BELOW NORMAL FOR
MOST LOCATIONS. CLOUD COVER AND RAIN CHANCES WILL BOTH GRADUALLY
INCREASE WEDNESDAY EVENING INTO WEDNESDAY NIGHT AHEAD OF THE NEXT
COLD FRONT. HAVE THE HIGHEST POPS ACROSS THE MOUNTAIN ZONES WITH
LOWER POPS EAST OF THE MOUNTAINS WEDNESDAY NIGHT AS GLOBAL MODEL
GUIDANCE ARE IN AGREEMENT THAT THE MOUNTAINS WILL HAVE THE BEST
CHANCE FOR RAIN. LOWS WEDNESDAY NIGHT WILL BE A FEW DEGREES WARMER
COMPARED TO TUESDAY NIGHT, AND ~3-5 DEGREES ABOVE CLIMO THANKS TO
BOTH CLOUD COVER AND RAIN.
LONG TERM /THURSDAY THROUGH SUNDAY/
AS OF 1253 PM EDT SUNDAY: THURSDAY REMAINS MURKIER. THE ADVANCE OF
A PREFRONTAL TROUGH CONTINUES TO BE DEPICTED BY OPERATIONAL MODELS,
WHICH IN THEORY SHOULD HELP SCATTER OUT THE RESIDUAL WEDGE FROM THE
BOTTOM UP. BUT, MODELS ARE NOTORIOUSLY OVERAGGRESSIVE IN SCATTERING
OUT WEDGES. EITHER WAY, THE ARRIVAL OF THE FRONT THURSDAY EVENING
SHOULD SCOUR OUT THE WEDGE...GIVING US ANOTHER SLUG OF CAA LASTING
THROUGH EARLY FRIDAY AS HIGH PRESSURE BUILDS IN FROM THE NORTHWEST.
MODEL SOLUTIONS BEGIN TO DIVERGE WILDLY PAST THIS POINT. THERE'S A
ROUGH CONSENSUS THAT HIGH PRESSURE WILL PERSIST THROUGH FRIDAY AND
THE FIRST HALF OF SATURDAY, WHILE A HIGHLY-AMPLIFIED TROUGH DEVELOPS
OVER THE FOUR CORNERS REGION AND CENTRAL GREAT PLAINS. SOME
GUIDANCE MAINTAINS HIGH PRESSURE RIGHT UP THROUGH SUNDAY, BUT MORE
PROGRESSIVE SOLUTIONS TAKE THE TROUGH INTO THE OHIO VALLEY BY
SUNDAY, WHICH RESULTS IN A RETURN OF MOISTURE TO THE AREA THROUGH
THE END OF THE WEEKEND. SO, CONFIDENCE REMAINS LOW ON THE EVOLUTION
OF THINGS PAST FRIDAY OR SO.
AVIATION /06Z MONDAY THROUGH FRIDAY/
AT KCLT AND ELSEWHERE: TRICKY TAFS THROUGH ABOUT MIDDAY, AS COLD
AIR DAMMING WEDGE BEGINS TO BREAK DOWN. CIGS ARE ALREADY MOSTLY
LIFR, BUT SOME BREAKS TO MVFR ARE POSSIBLE AT LEAST BRIEFLY, WHERE
LIGHT SHRA DEVELOP BETWEEN NOW AND DAWN. EXCEPTING THAT POSSIBILITY,
CIGS SHOULD TREND LOWER IN THAT TIMEFRAME. WINDS MOSTLY WILL FAVOR
SW BUT WILL EXHIBIT VARIABILITY EARLY ON. COLD FRONT WILL PASS
THE AREA FROM NW TO SE TODAY; HIGHER CLOUD DECKS ALONG/AHEAD OF
IT WOULD APPEAR TO SHELTER THE STRATUS LAYER, BUT AS THOSE ADVECT
OUT AND AS WINDS VEER TO DOWNSLOPE OVER THE WEDGE, THE RESTRICTIVE
CIGS SHOULD SCATTER OUT. FEW-SCT CLOUDS AT IFR TO LOW MVFR LEVEL
MAY LINGER INTO AFTERNOON IN SOME PIEDMONT LOCATIONS. WINDS WILL
PICK UP AND SHIFT TO NW AT KAVL BY MIDDAY, AND TO WNW AT THE OTHER
SITES BY AROUND SUNSET. NO RESTRICTIONS ANTICIPATED TONIGHT ALTHOUGH
FEW-SCT CLOUDS BELOW 030 MAY BE SEEN AT KAVL DUE TO UPSLOPE.
OUTLOOK: DRY AND MOSTLY VFR WEATHER EXPECTED TUE-WED. A COLD FRONT
WILL BRING A CHANCE OF RAIN AND RESTRICTIONS THURSDAY, FOLLOWED
BY DRYING FRIDAY.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
SYNOPSIS...AR
NEAR TERM...WIMBERLEY
SHORT TERM...AR
LONG TERM...MPR
AVIATION...WIMBERLEY
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