289
FXUS62 KGSP 031036
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
636 AM EDT SUN AUG 3 2025
SYNOPSIS
COLD AIR DAMMING KEEPS SHOWER AND THUNDERSTORM CHANCES AS WELL AS
BELOW NORMAL HIGH TEMPERATURES AROUND THE REST OF THIS WEEKEND AND
INTO MUCH OF NEXT WEEK. DESPITE BELOW NORMAL HIGH TEMPERATURES, A
GRADUAL WARMING TREND CAN BE EXPECTED THROUGH NEXT WEEKEND.
NEAR TERM /THROUGH TONIGHT/
AS OF 630 AM EDT SUNDAY: SUMMER COLD AIR DAMMING REGIME CONTINUES
ACROSS THE FORECAST AREA THIS MORNING. WITH THE PARENT HIGH LOCATED
RELATIVELY FAR TO THE SOUTH ACROSS THE NORTHERN MID-ATLANTIC,
RELATIVELY DEEP NE FLOW CONTINUES TO PUSH DRIER AIR INTO THE
FORECAST AREA, LIFTING THE CLOUD LAYERS AND GENERALLY BRINGING AN
END TO -DZ AND SHOWERS. MEANWHILE, SCATTERED SHOWERS CONTINUE ALONG
AN ARC FROM THE LAKELANDS, TO THE SOUTHERN BLUE RIDGE ESCARPMENT
AND THROUGH THE NC FOOTHILLS WITHIN DEEPER MOISTURE PLUME THAT
IS ALIGNED WITH UPSLOPE FLOW AND WEAK ISENTROPIC LIFT. SOME OF
THIS ACTIVITY MAY SLOWLY BECOME MORE SHUNTED TO THE SW AS DRIER
AIR CONTINUES TO GRADUALLY FILTER THROUGH THE CWA. NEVERTHELESS,
INSTABILITY AND MOISTURE WEST OF THE CWA INTERACTING WITH THERMAL
MOISTURE BOUNDARY DELINEATING THE LEADING EDGE OF THE CAD HAS
RESULTED IN AN AREA OF SHOWERS ACROSS CENTRAL GEORGIA THAT WILL
CONTINUE TO MOVE STEADILY NORTHEAST TOWARD OUR WESTERN ZONES THROUGH
THE MORNING. UPSLOPE FLOW WILL ALSO CONTINUE TO SOME DEGREE, SO
50-67 POPS ARE WARRANTED ACROSS ROUGHLY THE WESTERN 1/3 OF THE CWA
FROM LATE MORNING THROUGH THE AFTERNOON. PRECIP CHANCES TAPER DOWN
TO LESS THAN 20% IN THE DRIER AIR EAST OF I-77. INSTABILITY IN OUR
FORECAST AREA IS EXPECTED TO BE LIMITED TO THE SMOKIES AND VICINITY,
AND A THUNDER MENTION IS THEREFORE CONFINED TO THAT AREA. TEMPS
WILL BE WARMER THAN YESTERDAY, ESPECIALLY ACROSS THE NC PIEDMONT,
WHERE LOWER 80S EXPECTED WITH AT LEAST SOME PEAKS OF SUN LIKELY
THIS AFTERNOON. STILL...MAXES WILL BE AROUND 10 DEGREES BELOW NORMAL
GIVE OR TAKE. THE UNSEASONABLY COOL CONDITIONS CONTINUE INTO TONIGHT
WITH SHOWERS CONTINUING, ALBEIT BECOMING MORE SPOTTY IN COVERAGE.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/
AS OF 100 AM EDT SUNDAY...
KEY MESSAGES:
1) COLD AIR DAMMING REMAINS IN PLACE
2) WELL BELOW NORMAL HIGH TEMPERATURES CONTINUE
3) SHOWER AND THUNDERSTORM CHANCES RAMP UP THROUGH THE PERIOD
COLD AIR DAMMING REMAINS IN PLACE EARLY NEXT WEEK THANKS TO THE
SOUTHERN PERIPHERY OF A SFC HIGH NOSING DOWN INTO THE SOUTHERN
APPALACHIANS. DESPITE THE NBM TRENDING SLIGHTLY WARMER REGARDING
AFTERNOON TEMPS FOR SOME LOCATIONS DURING THE SHORT TERM, HIGHS EACH
AFTERNOON WILL STILL END UP AROUND 5-10 DEGREES BELOW NORMAL. LOWS
EACH NIGHT WILL END UP A FEW DEGREES BELOW NORMAL TO NEAR NORMAL.
MOSTLY CLOUDY SKIES WILL CONTINUE, ALTHOUGH SOME SUNSHINE MAY PEAK
THROUGH ACROSS MAINLY THE NC FOOTHILLS AND PIEDMONT MONDAY MORNING
INTO MONDAY AFTERNOON BEFORE CLOUD COVER INCREASES AGAIN ACROSS
THESE ZONES BY MONDAY EVENING.
THE 00Z HRRR AND NAMNEST, AS WELL AS MOST OF THE GLOBAL GUIDANCE
SOURCES, SHOW RAIN CHANCES STEADILY INCREASING FROM SW TO NE
THROUGHOUT THE DAY MONDAY. HOWEVER, NBM POPS ON MONDAY APPEAR TO BE
MORE IN LINE WITH THE GFS WHICH CONTINUES TO BE THE DRIEST OF THE
GUIDANCE SOURCES. THE NBM ONLY HAS CHANCE POPS ACROSS MUCH OF THE
FORECAST AREA AND THIS COULD BE TOO LOW PER THE HIGH-RES GUIDANCE AS
WELL AS THE ECMWF, NAM, AND CANADIAN. THUS, CONFIDENCE ON MONDAY'S
POPS ON REMAINS LOW. OUTSIDE OF THE MOSTLY DRY GFS, GUIDANCE
GENERALLY AGREES THAT COVERAGE OF RAIN WILL CONTINUE INCREASING
MONDAY EVENING INTO TUESDAY NIGHT. THE NBM POP TREND DOES REFLECT
THIS TREND SO CONFIDENCE ON POPS THE REMAINDER OF THE SHORT TERM IS
HIGHER. MAJORITY OF MODEL GUIDANCE, WITH THE EXCEPTION OF THE NAM,
HAS VERY LITTLE IN THE WAY OF SBCAPE AND EVEN MUCAPE EARLY NEXT
WEEK. HOWEVER, THE NAM IS SHOWING SBCAPE AND MUCAPE VALUES FROM
~1,000-1,500 J/KG ACROSS THE FAR SE FRINGE OF THE CWA TUESDAY
AFTERNOON AND EVENING. THUS, A FEW THUNDERSTORMS LOOK PLAUSIBLE,
ESPECIALLY DURING PEAK HEATING ON TUESDAY. HOWEVER, CONFIDENCE IS
LOW WITH ONLY THE NAM DEPICTING DESTABILIZATION. PWATS WILL STEADILY
INCREASE FROM SOUTH TO NORTH THROUGHOUT THE SHORT TERM SO LOCALIZED
HYDRO CONCERNS MAY RETURN, ESPECIALLY ON TUESDAY.
LONG TERM /WEDNESDAY THROUGH SATURDAY/
AS OF 100 AM EDT SUNDAY...
KEY MESSAGES:
1) COLD AIR DAMMING MAY LINGER THROUGH ENTIRE PERIOD
2) GRADUAL WARMING TREND IS EXPECTED BUT HIGHS REMAIN BELOW NORMAL
3) SHOWER AND THUNDERSTORM CHANCES MAY STICK AROUND
WITH THE SOUTHWESTERN PERIPHERY OF THE SFC HIGH EXTENDING DOWN INTO
THE SOUTHERN APPALACHIANS THROUGHOUT THE LONG TERM, AND WITH NO REAL
MECHANISM TO ERODE THE WEDGE (AT LEAST PER THE NBM AND ECMWF),
PERSISTENT NE SFC WINDS MAY HELP KEEP COLD AIR DAMMING LOCKED INTO
PLACE, ALBEIT WEAKER AS TIME GOES ON. HOWEVER, BOTH THE GFS AND
CANADIAN DEPICT A COASTAL LOW DEVELOPING, WHICH COULD HELP ERODE THE
CAD LAYER EITHER PARTIALLY OR COMPLETELY. CONFIDENCE ON CAD EROSION
IS VERY LOW WITH THE GFS SHOWING AN IMPRESSIVELY STRONG COASTAL LOW
DEVELOPING THE SECOND HALF OF THE PERIOD WHILE THE CANADIAN DEVELOPS
A MUCH WEAKER COASTAL LOW. THE ECMWF DOES NOT EVEN HAVE A COASTAL
LOW DEVELOPING...WHICH IS MORE IN LINE WITH THE NBM IN KEEPING THE
CAD LAYER AROUND. THE GFS REMAINS THE OUTLIER WITH MOSTLY DRY
CONDITIONS WHILE THE CANADIAN AND ECMWF DEPICT WETTER CONDITIONS
THROUGH MUCH OF NEXT WEEK ACROSS THE WESTERN CAROLINAS AND NORTHEAST
GEORGIA. ALL THIS TO SAY, CONFIDENCE ON THE SENSIBLE WEATHER WILL BE
VERY LOW DURING THE SECOND HALF OF THE FORECAST PERIOD DUE TO THE
INCONSISTENCY FROM THE GLOBAL MODELS REGARDING THE OVERALL WEATHER
PATTERN. PWATS MAY REMAIN ELEVATED, ESPECIALLY IF THE WETTER MODEL
SOLUTIONS PAN OUT, SO LOCALIZED HYDRO CONCERNS COULD LINGER THROUGH
THE LONG TERM. ALTHOUGH TEMPS WILL BE ON A GRADUAL WARMING TREND,
HIGHS APPEAR TO REMAIN A FEW TO SEVERAL DEGREES BELOW NORMAL EACH
DAY, WITH LOWS EACH NIGHT ROUGHLY AROUND NORMAL (PER THE NBM).
HOWEVER, IF THE WEDGE ERODES THE SECOND HALF OF THE PERIOD, TEMPS
COULD END UP MUCH WARMER (AGAIN CONFIDENCE IS LOW). PER THE NBM,
MOSTLY CLOUDY SKIES LINGER THROUGH THURSDAY EVENING, POSSIBLY
BREAKING UP A BIT OVERNIGHT THURSDAY INTO FRIDAY MORNING BEFORE
INCREASING AGAIN FRIDAY AFTERNOON AND EVENING. THE SAME PATTERN
REGRADING CLOUD COVER REPEATS ITSELF OVERNIGHT FRIDAY INTO SATURDAY.
AVIATION /12Z SUNDAY THROUGH THURSDAY/
AT KCLT AND ELSEWHERE: NE SURFACE WINDS OF 5-10 KTS CONTINUE ACROSS
THE TERMINAL FORECAST AREA THIS MORNING. THE NE WINDS ARE PUSHING
DRIER NEAR-SURFACE AIR INTO THE AREA, AND THIS WILL RESULT IN VFR
CONDITIONS AT KCLT AND KHKY THROUGH THE PERIOD. MEANWHILE,
CONDITIONS HAVE IMPROVED TO MVFR AT ALL BUT A FEW OF THE OTHER
TERMINALS. BRIEF PERIODS OF IFR REMAIN POSSIBLE AT THESE FEW HOLDOUT
SITES UNTIL LATE MORNING, BUT OTHERWISE IMPROVEMENT TO VFR IS
EXPECTED AT ALL SITES EXCEPT KAND AND PERHAPS KAVL BY NOON, WITH ALL
SITES LIKELY SEEING VFR BY MID-AFTERNOON. MEANWHILE, SHOWERS AND
AREAS OF -DZ HAVE GENERALLY RETREATED TO THE MOUNTAINS, WITH PERIODS
OF PRECIP AND MVFR VISBY REMAINING POSSIBLE AT KAVL UNTIL LATE
MORNING. SHOWER CHANCES ARE EXPECTED TO INCREASE FROM THE SOUTHWEST
LATE THIS MORNING INTO THE AFTERNOON, AS AN AREA OF SHOWERS
CURRENTLY OVER CENTRAL GA MOVES STEADILY NE. FOR THE TIME BEING,
TEMPOS FOR -SHRA W/ MVFR VISBY ARE LIMITED TO KAND FROM 15-18Z, WITH
PROB30S FOR THE SAME AT KGSP/KGMU/KAVL DURING THE AFTERNOON. WINDS
WILL REMAIN NE AT 5-10 KTS THROUGH THE PERIOD...EXCEPT FOR LIGHT NE
WINDS TONIGHT.
OUTLOOK: RELATIVELY COOL AND DAMP CONDITIONS ARE EXPECTED 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...AR
NEAR TERM...JDL
SHORT TERM...AR
LONG TERM...AR
AVIATION...JDL
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