284
FXUS62 KGSP 032156
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
556 PM EDT SUN AUG 3 2025
SYNOPSIS
COLD AIR DAMMING SETUP WILL KEEP TEMPERATURES WELL BELOW NORMAL
THROUGH THE FIRST COUPLE OF DAYS INTO THE NEW WORKWEEK. A GRADUAL
WARMING TREND IS EXPECTED BY THE MIDDLE PART OF THE WEEK INTO THE
WEEKEND. SHOWER AND THUNDERSTORM CHANCES STICK AROUND EACH DAY
THROUGHOUT THE WEEK.
NEAR TERM /THROUGH MONDAY/
AS OF 545 PM EDT SUNDAY: SFC HIGH PRESSURE WILL REMAIN
NOSED SWWD INTO THE CWFA THROUGH MONDAY IN CAD OR CAD-LIKE
ORIENTATION. SHORTWAVE AXIS IS EVIDENT FROM WATER VAPOR IMAGERY
OVER EASTERN KY/TN AND SEEMS TO BE THE DRIVER FOR BROAD AREA OF
PRECIP MOVING ATOP THE SFC WEDGE. POPS GENERALLY SHOULD DIMINISH
IN THE PIEDMONT OF GA/SC AND THEN NC AS THE SHORTWAVE PROGRESSES
AND THE PRECIP EXITS. HOWEVER, EASTERLY FLOW IN THE SFC TO 925MB
LAYER WILL DRIVE PERSISTENT PRECIP DEVELOPMENT FOR A FEW MORE HOURS,
ALTHOUGH DRY ADVECTION AT THAT LEVEL SHOULD ALLOW THAT TO DECREASE
OVERNIGHT. 925-850MB MOISTURE PLUME WILL PERSIST OVER THE SW HALF
OF THE CWA TONIGHT INTO MONDAY, AROUND THE PERIPHERY OF THE DAMMING
HIHG AND INTO THE NEXT SHORTWAVE NOW IN THE MIDWEST. CONSIDERABLE
CLOUDINESS WILL LINGER REGIONWIDE THROUGH TONIGHT, BUT PARTICULARLY
IN THE SW AREAS WHERE LIGHT SHOWER CHANCES CONTINUE AND THEN
INCREASE INTO MORNING. WITH THE SWWD PUSH OF LOWER SFC DWPTS TODAY,
ESPECIALLY IN THE NC PIEDMONT, MINIMUM TEMPERATURES MONDAY MORNING
ARE EXPECTED TO BE WELL INTO THE LOWER 60S, ALTHOUGH SVRL LOCALES
ARE NOT TOO FAR AWAY FROM THOSE VALUES ATTM.
THE SENSIBLE WX ON MONDAY MAY WIND UP BEING NOT TOO TERRIBLY
DIFFERENT THAN TODAY FEATURING A SW TO NE GRADIENT WITH RESPECT
TO THE STRENGTH OF THE UPGLIDE FLOW FORCING SHOWER ACTIVITY.
SHOWERS SHOULD AGAIN BECOME NUMEROUS IN THE ESCARPMENT AND SW
CWFA WHILE THE NC PIEDMONT REMAINS JUST WITH A TOKEN PROBABILITY.
CONVERSELY, WITH THE POTENTIAL FOR MORE INSOLATION, LOWER 80S ARE
IN THE FORECAST FOR THE I-77 CORRIDOR WHILE THE UPPER SAVANNAH
VALLEY MAY FALL SHORT OF 75 FOR MAXIMUM TEMPERATURES.
SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/
AS OF 120 PM EDT SUNDAY: AN UPPER TROUGH WILL SHIFT OVER THE MS
VALLEY, WHILE SHARPENING WITHOUT MUCH MOVEMENT AND PULLING IN
BETTER MOISTURE ACROSS THE CWA MONDAY NIGHT INTO TUESDAY. THIS
IS THANKS TO A DEEPENING UPPER ANTICYCLONE OVER THE SOUTHWESTERN
CONUS AND ANOTHER OVER WESTERN ATLANTIC. AT THE SURFACE, AN
IN-SITU CAD WILL PERSIST AS A WEAK SURFACE HIGH CONTINUES TO
NOSE IN FROM THE NORTHEAST, ONLY TO BE REINFORCED MONDAY NIGHT
INTO TUESDAY AS A SECOND CANADIAN HIGH SHIFTS OVER ATLANTIC
CANADA AND NEW ENGLAND. THE SREF CONTINUES TO SUPPORT A LI INDEX
BETWEEN 4-6, INDICATING SUPPORT FOR HIGHER STATIC STABILITY TO
HELP KEEP PERSISTENT CAD-LIKE CONDITIONS WITH A STEADY NORTHEASTERLY
COMPONENT AT THE SURFACE. THE AFOREMENTIONED UPPER TROUGH, HOWEVER,
WILL START TO BREAKDOWN IN BETWEEN THE TWO ANTICYCLONES BY THE
LATTER HALF OF THE PERIOD, WHILE DEEP LAYER WAA WITH SOUTHEAST
TO SOUTHWESTERLY FLOW FILTERS IN ATOP THE SURFACE LAYER. THIS MAY
HELP TO KEEP THE CAD DOME INTACT THROUGH WEDNESDAY, WHILE BETTER
MOISTURE TRANSPORT AND UPGLIDE HELP TO INCREASE POPS THROUGHOUT
THE FORECAST PERIOD. THE GFS REMAINS A DRY OUTLIER WITH KEEPING
MOST OF THE QPF RESPONSE CLOSER TO THE WEDGE BOUNDARY SOUTH AND
WEST OF THE CWA, WHILE THE REST OF THE DETERMINISTIC GUIDANCE
PRODUCES GOOD QPF RESPONSE ACROSS THE AREA MONDAY NIGHT THROUGH
WEDNESDAY. CURRENT PROFILES INDICATE BETTER MIXING IN THE
LOW-LEVELS WITH INVERTED-V PROFILES AND A LI INDEX CLOSER TO 0
AND BELOW (-1 TO -3) BY WEDNESDAY, WHICH SUGGEST THAT THE CAD
EROSION PROCESS SHOULD BEGIN BY THE END OF THE WORKWEEK NEAR THE
START OF THE EXTENDED PERIOD. TEMPERATURES WILL CERTAINLY CONTINUE
THE CAD TREND WITH OVERNIGHT LOWS MONDAY AND TUESDAY REMAINING A
CATEGORY OR SO BELOW NORMAL, WHILE AFTERNOON HIGHS ON TUESDAY AND
WEDNESDAY GRADUALLY REBOUND COMPARED TO THE NEAR-TERM, LIKELY DUE
TO SOME SCATTERING CLOUDS AS STRONG AUGUST SOLAR HEATING REACHES
THE SURFACE AT TIMES. AFTERNOON HIGHS REMAIN 8-12 DEGREES BELOW
NORMAL TUESDAY AND 5-10 ON WEDNESDAY.
LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/
AS OF 200 PM EDT SUNDAY: THE FLOW ALOFT AND AT THE SURFACE BEGINS TO
MAKE SUBTLE CHANGE BY THE END OF THE WORKWEEK AS A STALLED FRONTAL
BOUNDARY REMAINS DRAPED SOUTH OF THE CWA AND THE SURFACE HIGH
SLOWLY SLIDES OVER THE NORTHERN ATLANTIC. A COASTAL LOW FEATURE
IS EVIDENT IN MOST OF THE LATEST GUIDANCE BY THURSDAY AND LIFTS
NORTH GOING INTO THE WEEKEND. THIS WOULD ESSENTIALLY ERODE ANY CAD
THAT'S LEFT LINGERING, BUT OVERALL CONFIDENCE REMAINS LOW ON HOW
THE SYNOPTIC PATTERN FULLY EVOLVES DURING THE FORECAST PERIOD. A
PERSISTENT COLD POOL LIKELY REMAINS INTACT, WHILE TRUE CAD ERODES
THANKS TO STRONG AUGUST SOLAR HEATING AND LI VALUES LOWERING,
INDUCING MUCH LOWER STATIC STABILITY. SURFACE DIVERGENCE WILL
SUPPORT CAD EROSION AS WELL IF THE COASTAL LOW GETS GOING AND
LIFTS NORTH OVER THE MID-ATLANTIC COAST AS IS DEPICTED IN SOME
DETERMINISTIC RUNS. THE FLOW ALOFT WILL BE FAIRLY SATURATED AS
CONTINUED SOUTHERLY FLOW FILTERS IN, WHILE DRY NORTHEASTERLY
FLOW ADVECTS IN THE SURFACE LAYER. TEMPERATURES GRADUALLY WARM
THROUGH THE PERIOD, BUT REMAIN SLIGHTLY BELOW NORMAL AS A RESIDUAL
COLD POOL TRIES TO HOLD ON WITH PERSISTENT NORTHEASTERLY FLOW AT
THE SURFACE TO GO ALONG WITH ELEVATED POPS. SOUNDINGS DO SUPPORT
BETTER INSOLATION AND BOUNDARY LAYER MIXING BY THURSDAY THROUGH THE
WEEKEND, WHICH LIKELY IS CONTRIBUTING TO THE WARMING TREND AS WELL.
AVIATION /22Z SUNDAY THROUGH FRIDAY/
AT KCLT...OUTSIDE OF THE SMALL POSSIBILITY OF A PASSING SHOWER THIS
AFTERNOON IT LOOKS LIKE KCLT WILL BE JUST FAR ENOUGH REMOVED FROM
THE MOIST LIFT TO KEEP CIGS VFR. WINDS WILL REMAIN NE AROUND 10 KTS
WITHIN DAMMING HIGH PRESSURE. QUIET WX AND VFR CONDITIONS ARE
SLATED TO CONTINUE INTO TONIGHT AND MONDAY MORNING WITH THE PROGGED
DRYING WITHIN THE 85-70H LAYER. ELSEWHERE ACRS THE FA, FLIGHT
CONDITIONS REMAIN AND/OR BECOME MORE UNSETTLED ALTHOUGH NOT TERRIBLY
IMPACTFUL AS WE WILL DEAL WITH A MIX OF VFR/MVFR CIGS INTO TONIGHT
ALONG WITH THE ONGOING LIGHT SHOWER CHANCES LINGERING THROUGH MONDAY.
OUTLOOK: RELATIVELY COOL AND DAMP CONDITIONS WILL LINGER INTO
MONDAY, WITH BETTER CHANCES FOR SHOWERS. ALTHOUGH TEMPERATURES ONLY
GRADUALLY WARM BACK UP OVER THE REMAINDER OF THE WEEK, PRECIPITATION
CHANCES TREND TOWARD A MORE TYPICAL SUMMERTIME REGIME WITH CHANCES
MAINLY IN THE AFTERNOONS AND EARLY EVENINGS BY MIDWEEK. PERIODIC
RESTRICTIONS REMAIN POSSIBLE.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
SYNOPSIS...CAC
NEAR TERM...CSH/WIMBERLEY
SHORT TERM...CAC
LONG TERM...CAC
AVIATION...CSH
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