935
FXUS62 KGSP 291036
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
636 AM EDT FRI AUG 29 2025
SYNOPSIS
HIGH PRESSURE REMAINS IN CONTROL TODAY, THEN A WEAK COLD FRONT
CROSSES THE AREA SATURDAY AND BECOMES STATIONARY TO THE SOUTH
OF OUR REGION INTO EARLY NEXT WEEK. ISOLATED TO SCATTERED MAINLY
AFTERNOON AND EARLY EVENING MOUNTAIN SHOWERS AND STORMS EXPECTED
EACH DAY ACROSS THE REGION. TEMPERATURES REMAIN JUST BELOW SEASONAL
NORMALS THROUGH THE WEEK.
NEAR TERM /THROUGH TONIGHT/
AS OF 130 AM FRIDAY: DEEP UPPER TROUGH IN PLACE DOWN THE EAST COAST
WILL BEGIN TO LIFT TODAY, THOUGH BROAD TROUGHINESS WILL REMAIN AS
SHORTWAVES ROUND THE BASE THROUGH THE PERIOD. W TO NW FLOW ALOFT
WILL BRING A BIT OF A DOWNSLOPE COMPONENT TODAY, ALLOWING
TEMPERATURES TO CLIMB SOMEWHAT ESPECIALLY WITH SURFACE HIGH PRESSURE
CENTERED OVER THE GREAT LAKES AND RIDGING TOWARD THE SOUTHERN
APPALACHIANS. ALL IN ALL, A GENERALLY PLEASANT DAY IN STORE FOR THE
LAST FRIDAY IN AUGUST, SLIGHTLY WARMER THAN THE PAST COUPLE OF DAYS
BUT TEMPERATURES STILL A COUPLE OF DEGREES BELOW SEASONAL NORMALS.
MEANWHILE TONIGHT, AS ANOTHER SHORTWAVE ROUNDS THE BASE OF THE UPPER
TROUGH, DPVA WILL INCREASE AS MOISTURE IS PULLED NORTH FROM THE
GULF. OPERATIONAL GUIDANCE DIFFERS ON HOW MUCH MOISTURE WITH THE
ECMWF REMAINING ON THE WET SIDE, AND ENOUGH THAT IT WANTS TO DEVELOP
A LITTLE INSITU DAMMING ON THE LEE SLOPES AS THE SURFACE HIGH RIDGES
DOWN. IT SEEMS TO BE A BIT OF A WET OUTLIER AS MOST ENSEMBLES POINT
TO A SLIGHTLY DRIER SOLUTION AT LEAST IN OUR AREA, KEEPING MOST OF
THE MOISTURE A LITTLE FURTHER SOUTH. HOWEVER, WITH SOME UPSLOPE
AROUND THE BASE OF THE SURFACE HIGH, SHOULD SEE INCREASING
CLOUDINESS OVERNIGHT AND CANNOT RULE OUT SOME SPRINKLES. FOR NOW
THOUGH, POPS ARE LIMITED TO THE EXTREME SOUTHERN TIER OVERNIGHT.
OVERNIGHT LOWS TONIGHT WILL BE A FEW DEGREES WARMER THAN WHAT WE'LL
SEE THIS MORNING GIVEN THE INCREASED MOISTURE/CLOUDINESS, BUT STILL
A HANDFUL OF DEGREES BELOW NORMAL.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/
AS OF 130 AM FRIDAY...A DEEP, PERSISTENT UPPER TROUGH WILL BE
REINFORCED BY MORE SHORTWAVE ENERGY DIVING THRU THE WESTERN GREAT
LAKES TO THE MID-ATLANTIC OVER THE WEEKEND. THE 00Z GUIDANCE IS
IN DECENT AGREEMENT THAT THE TROUGH WILL CLOSE OFF INTO AN UPPER
LOW INVOF THE NORTHERN MID-ATLANTIC BY 12Z MONDAY. AT THE SFC, A
1024 MB HIGH WILL PERSIST ACROSS THE GREAT LAKES TO THE NORTHEAST,
KEEPING AN INVERTED RIDGE/WEDGE-LIKE PATTERN ACROSS THE CAROLINAS. A
SERIES OF WEAK LOW PRESSURE WAVES ARE EXPECTED TO FORM ALONG A
STALLED FRONT ALONG THE GULF COAST AND TRACK EAST, WHICH MAY BRING
A COUPLE OF ROUNDS OF ELY/SELY LOW-LEVEL UPGLIDE FLOW ATOP THE
FORECAST AREA SATURDAY AND SUNDAY. THERE WILL BE A FAIRLY TIGHT
GRADIENT OF PWATS FROM NORTH TO SOUTH ACROSS THE REGION, WITH THE
DEEPER MOISTURE REMAINING TO OUR SOUTH. FORECAST SOUNDINGS SHOW
SOME ELEVATED INSTABILITY SATURDAY, ENOUGH TO WARRANT A THUNDER
MENTION. BUT OVERALL, SEVERE WEATHER THREAT SHOULD BE LOW. WITH
PLENTY OF CLOUD COVER AND SPOTTY SHOWERS, ALONG WITH THE WEDGE-LIKE
PATTERN, HIGHS WILL CONTINUE TO BE BELOW NORMAL, COOLEST SOUTH. ON
SUNDAY, PWATS SPREAD IN A LITTLE MORE FROM THE SOUTH, GENERALLY
1.0-1.5". GUIDANCE SHOWS A LITTLE BETTER INSTABILITY IN THE AFTN,
WITH MUCAPE IN THE 1000-1500 J/KG RANGE. THIS ENVIRONMENT COMBINED
WITH HEIGHT FALLS ALOFT MAY SUPPORT A NON-ZERO HEAVY RAIN/FLASH
FLOOD THREAT AND SEVERE TSTM THREAT. TEMPS WILL CONTINUE TO BE
BELOW NORMAL SUNDAY, WITH PERHAPS MORE CLOUD COVER THAN SATURDAY.
LONG TERM /MONDAY THROUGH THURSDAY/
AS OF 140 AM FRIDAY...BELOW-NORMAL TEMPS WILL BE THE STORY FOR
THE MEDIUM RANGE, AS AN EASTERN CONUS TROUGH PERSISTS THRU THE
PERIOD. MONDAY STARTS OUT WITH A CLOSED LOW THAT WOBBLES NORTH,
WHILE ANOTHER SHORTWAVE TROUGH ENTERS THE MEAN LONGWAVE TROUGH OVER
THE MID-MS VALLEY TO THE SOUTHEAST. A DEEP, VIGOROUS SHORTWAVE
DIVES INTO THE UPPER MIDWEST AND DEEPENS THE OVERALL MEAN TROUGH
TUESDAY THRU THURSDAY. SCATTERED SHOWERS AND A FEW TSTMS WILL BE
POSSIBLE ON LABOR DAY ACROSS MAINLY THE MOUNTAINS, WHILE TUESDAY
LOOKS MOSTLY DRY, AS SFC HIGH PRESSURE HOLDS ON ALONG THE EAST
COAST. AS THE AFOREMENTIONED TROUGH DEEPENS, IT TAPS INTO A LITTLE
GULF MOISTURE, BUT THE LATEST DETERMINISTIC GUIDANCE ISN'T TOO
EXCITED ABOUT PRECIP CHANCES WEDNESDAY. FOR NOW, MAINLY CHC POPS
FOR WED AND THU, FAVORING THE MOUNTAINS.
AVIATION /12Z FRIDAY THROUGH TUESDAY/
AT KCLT AND ELSEWHERE: VFR THROUGH THE PERIOD FOR ALL BUT KAVL.
CONFIDENCE IS MUCH LOWER ON MOUNTAIN VALLEY FOG FORMING THIS MORNING
SO HAVE REMOVED THE TEMPO FOR THE 12Z FORECAST, BUT INCREASING
MOISTURE LATE IN THE PERIOD MAY LEAD TO RESTRICTIONS FOR SATURDAY
MORNING, AND HAVE INTRODUCED MVFR CONDITIONS (THOUGH IF IT OCCURS IT
WOULD LIKELY BE LOWER). LGT/VRB WINDS THIS MORNING WILL INCREASE OUT
OF THE SW THIS AFTERNOON FOR MOST SITES. KAVL SHOULD REMAIN NW AND
KCLT IS STARTING OF VERY LIGHT NW AND SHOULD REMAIN BUT SPEEDS
INCREASE SOMEWHAT THROUGH THE DAY. WINDS DIMINISH BACK TO LGT/VRB
AGAIN THIS EVENING. AT THE END OF THE PERIOD FOR KCLT, EXPECT WINDS
TO TREND MORE TOWARD ESE. INCREASING MID-LEVEL CLOUDINESS EXPECTED
THIS EVENING INTO THE OVERNIGHT PERIOD.
OUTLOOK: SHOWERS AND THUNDERSTORMS MAY RETURN FOR THE WEEKEND INTO
TUESDAY. FOG AND/OR LOW STRATUS MAY DEVELOP EACH NIGHT, MAINLY IN
THE MOUNTAIN VALLEYS.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
SYNOPSIS...ARK
NEAR TERM...TDP
SHORT TERM...ARK
LONG TERM...ARK
AVIATION...TDP
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