891
FXUS62 KGSP 301744
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
144 PM EDT SAT AUG 30 2025
SYNOPSIS
COOLING HIGH PRESSURE REMAINS ACROSS THE AREA INTO EARLY NEXT WEEK.
A FEW SHOWERS AND THUNDERSTORMS ARE POSSIBLE EACH DAY ACROSS THE
MOUNTAINS. TEMPERATURES REMAIN BELOW SEASONAL NORMALS THROUGH THE
WEEK.
NEAR TERM /THROUGH SUNDAY/
AS OF 130 PM EDT SATURDAY: SCATTERED CONGESTUS HAS DEVELOPED ALONG
THE RIDGE TOPS OF THE SOUTHERN APPALACHIANS THIS AFTERNOON WITHIN
A WEAKLY UNSTABLE AIR MASS. A FEW OF THESE ARE LIKELY TO EVOLVE
INTO SHOWERS, BUT INITIALIZED SOUNDINGS FROM THE HRRR/RAP INDICATE
POSITIVE BUOYANCY IS IN A QUITE SHALLOW LAYER...SO ANY SHOWERS THAT
DEVELOP ARE LIKELY TO BE QUITE WEAK...AND THUNDERSTORM POTENTIAL
IS VIRTUALLY NON-EXISTENT.
OTHERWISE, UPPER TROUGH AXIS WILL REMAIN CENTERED OVER THE EAST
THROUGH THE PERIOD...REINFORCED YET AGAIN BY ANOTHER SPEED MAX
DIGGING SSE FROM THE GREAT LAKES. THIS IS FORECAST TO CARVE OUT
A WEAK UPPER LOW OVER THE CENTRAL APPALACHIANS AND MID-ATLANTIC
BY TOMORROW, ALLOWING FOR AN OVERALL SYNOPTIC PATTERN CONDUCIVE TO
UPWARD VERTICAL MOTION OVER THE REGION. THIS ALONG WITH MORE OF AN
EASTERLY LOW LEVEL FLOW AND A SLIGHTLY MORE UNSTABLE AIR MASS IS
EXPECTED TO RESULT IN AN UPTICK IN THE DIURNAL CONVECTIVE POTENTIAL
SUNDAY AFTERNOON, MAINLY OVER THE MOUNTAINS AND FOOTHILLS, WHERE
POPS IN THE 20-40% RANGE WILL BE ADVERTISED. FORECAST PROFILES ARE
SLIGHTLY MORE CONDUCIVE TO THUNDER POTENTIAL, BUT DEEP CONVECTION
SHOULD AGAIN BE PRIMARILY SHOWERY IN NATURE. TEMPS ARE FORECAST TO
BE A FEW DEGREES BELOW CLIMO THROUGH THE PERIOD (WITH MAXES A
CATEGORY OR TWO COOLER THAN TODAY).
SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/
AS OF 125 PM EDT SATURDAY: BY SUNDAY NIGHT, A PERSISTENT RIDGE OUT
WEST CONTINUES TO INFLUENCE THE DOWNSTREAM PATTERN IN THE EASTERN
CONUS. A WEAK CUTOFF LOW PUSHES EAST AS YET ANOTHER EVEN STRONG
UPPER LOW STARTS TO DIVE SOUTHWARD FROM CANADA, STRENGTHENING THE
TROUGH OVER THE EASTERN PORTION OF THE COUNTRY. MEANWHILE, SURFACE
HIGH PRESSURE OFF TO THE NE SLOWLY MOVES EASTWARD AND GUIDANCE
BRINGS IN AN IN-SITU WEDGE FEATURE, WHICH BRINGS IN ANOTHER BURST OF
DRIER AIR FOR MONDAY AND INTO MONDAY NIGHT. BY TUESDAY, A SMALL
SWATH OF DPVA CROSSES THE NORTHERN PORTION OF THE CWA. GIVEN THE
DRIER AIR IN PLACE, NOT ANTICIPATING MUCH IN TERMS OF SHOWER OR
THUNDERSTORM ACTIVITY. HOWEVER, CANNOT RULE OUT A FEW STRAY SHOWERS
OR RUMBLES OF THUNDER OVER THE MOUNTAINS, ESPECIALLY GIVEN THE WEAK
RETURN OF E/SE FLOW AND MOISTURE RETURNS TRY TO CREEP BACK IN. FOR
THIS LOW CONFIDENCE IN PRECIP CHANCES, WILL KEEP A SLIGHT CHANCE (15-
35%) FOR THE MORE WESTERN NC MOUNTAINS THROUGH THE SHORT TERM
PERIOD. QPF RESPONSE IS VERY LOW WITH A <10% CHANCE FOR RAIN AMOUNTS
GREATER THAN 0.25". TEMPERATURES DIP INTO THE UPPER 70S MONDAY AND
TUESDAY, MAINLY DUE TO THE NE SURFACE FLOW. OVERALL, THIS IS A LOT
OF WAYS TO SAY THAT THE WEATHER IS QUIET, ALMOST NO RAIN IS EXPECTED
AND ENJOY THE COOLER TEMPS.
LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/
AS OF 130 PM EDT SATURDAY: THE PATTERN REMAINS RELATIVELY THE SAME
AS THE SHORT TERM, QUIET-ISH. BY TUESDAY NIGHT, THE UPPER LOW OVER
CANADA DECIDES TO MAKE A RUN FOR THE US AND PLUNGES ITSELF INTO THE
MIDWEST AND GREAT LAKES REGION. IN RESPONSE, THE RIDGE OUT WEST
AMPLIFIES AND THE PERSISTENT TROUGH ACROSS THE EASTERN CONUS
CONTINUES. AHEAD OF THE LOW DROPPING DOWN, GUIDANCE SHOVES A FEW
EMBEDDED SHORTWAVES ACROSS THE CWA, INCREASING RAIN CHANCES OVER AT
LEAST THE MOUNTAINS ON WEDNESDAY. FOR NOW, KEEPING THE HIGHER POPS
IN THE MOUNTAINS NEAR SLIGHT CHANCE/CHANCE (20-50%), WITH THURSDAY
BEING THE GREATER CHANCES. BUT IT WILL CHANGE AS THIS TROUGH DIGS
FURTHER SOUTH OR STAYS A LITTLE MORE CENTERED TO THE NORTH. A
WEAKENING FRONTAL BOUNDARY APPROACHES THE AREA TOWARD THE END OF THE
WORK WEEK, MAINTAINING THE COOLER TEMPS AND DRIER AIR. IF THIS COMES
TO PASS, THE DRIER AIR COULD SHUNT MOST PRECIP CHANCES INTO NEXT
WEEKEND, BUT THINGS WILL CHANGE THIS FAR OUT. GIVEN THE TIGHT
PRESSURE GRADIENT, WINDS ARE EXPECTED TO PICK UP WEDNESDAY THROUGH
AT LEAST FRIDAY, BUT REMAIN WELL BELOW ANY CONCERNS. PAST THE DAY 7
THRESHOLD, LONG RANGE GUIDANCE DOES WANT TO LIFT THE TROUGH AND
RETURN THE AREA INTO MORE BROAD FLOW. SINCE THIS IS PAST THE
FORECAST RANGE, THINGS WILL DEFINITELY CHANGE. OH, AND TEMPERATURES
REMAIN JUST BELOW NORMAL THROUGH THE END OF THE PERIOD.
AVIATION /18Z SATURDAY THROUGH THURSDAY/
AT KCLT AND ELSEWHERE: VFR CONDITIONS ARE FORECAST TO CONTINUE AT
MOST TAF SITES THROUGH THIS FORECAST PERIOD. THE ONLY EXCEPTION
IS AT KAVL, WHERE CHANCES FOR RESTRICTIONS IN LOW STRATUS
AND/OR FOG WILL INCREASE LATE TONIGHT AND EARLY SUNDAY. HAVING
SAID THAT, RESTRICTIONS ARE FAR FROM A SLAM DUNK AT KAVL, BUT
THERE IS ENOUGH OF A SIGNAL IN GUIDANCE AND OBSERVATIONAL DATA
TO FORECAST MVFR VISBY THERE FROM 09-13Z. OTHERWISE, CUMULUS IS
BUILDING UP ALONG THE RIDGE TOPS THIS AFTERNOON...AND A FEW OF
THESE ARE EXPECTED TO DEVELOP INTO SHOWERS. CAN'T RULE OUT ONE
OF THESE DRIFTING TOWARD KAVL, BUT THE PROBABILITY IS 20% AT
MOST...AND THEREFORE NOT WORTHY OF A TAF MENTION.
WITH EASTERLY FLOW EXPECTED TO DEVELOP ABOVE THE SURFACE TONIGHT
INTO EARLY SUNDAY, THERE IS SOME POSSIBILITY OF LOW CLOUDS MAKING
A RUN FOR KCLT AND KHKY. CONFIDENCE IN A CIG IS LOW AT THIS
JUNCTURE, BUT FEW CLOUDS AT THE MVFR/IFR LEVEL APPEARS PRUDENT AT
BOTH SITES. CHANCES FOR DIURNAL SHOWERS AND EVEN A TS OR TWO WILL
INCREASE SUNDAY AFTERNOON (MAINLY ACROSS THE MOUNTAINS), BUT THE
BEST CHANCES FOR CONVECTION ARE EXPECTED BEYOND THIS FORECAST
PERIOD. WINDS WILL GENERALLY FAVOR NE AT 5-10 KTS THROUGH THE
PERIOD...WITH PERHAPS A BRIEF EXCURSION TO LIGHT ESE THIS AFTERNOON.
OUTLOOK: SCATTERED AFTERNOON/EVENING CONVECTION RETURNS EARLY
NEXT WEEK, MAINLY ACROSS THE MOUNTAINS, AND PERSISTS THROUGH
MIDWEEK. VALLEY FOG AND/OR LOW STRATUS WILL ALSO BE POSSIBLE EACH
NIGHT AND EARLY MORNING, ESPECIALLY ACROSS MOUNTAIN LOCATIONS.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
SYNOPSIS...CP
NEAR TERM...JDL
SHORT TERM...CP
LONG TERM...CP
AVIATION...JDL
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