305
FXUS62 KGSP 121021
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
621 AM EDT FRI SEP 12 2025
SYNOPSIS
DRY HIGH PRESSURE WILL PERSIST OVER THE REGION THROUGH THE WEEKEND.
A DEVELOPING COASTAL LOW PRESSURE SYSTEM MAY BRING RAIN INTO THE
AREA BY THE MIDDLE OF NEXT WEEK.
NEAR TERM /THROUGH TONIGHT/
AS OF 620 AM EDT FRIDAY...
KEY MESSAGES:
1) MOSTLY SUNNY, DRY, AND WARM AGAIN TODAY
2) MOUNTAIN VALLEY FOG AND LOW STRATUS POSSIBLE EACH MORNING
SEEING PATCHY TO LOCALLY DENSE (AT TIMES) FOG AS WELL AS LOW STRATUS
ACROSS THE MOUNTAIN VALLEYS THIS MORNING. FOG AND STRATUS WILL LIFT
AN HOUR OR TWO AFTER SUNRISE AS MIXING DEVELOPS. OTHERWISE, UPPER
TROUGHING REMAINS OVERHEAD WHILE THE SOUTHERN PERIPHERY OF A SFC
RIDGE EXTENDS ACROSS THE SOUTHEAST THROUGH THE PERIOD. THIS KEEPS
MOSTLY DRY CONDITIONS AROUND AND ALLOWS NE'LY FLOW TO CONTINUE EAST
OF THE MOUNTAINS. HIGHS THIS AFTERNOON WILL BE SIMILAR YESTERDAY'S
THANKS TO MOSTLY SUNNY SKIES. AFTERNOON TEMPS EAST OF THE MOUNTAINS
WILL CLIMB BACK INTO THE LOW TO MID 80S, WITH THE UPPER 70S TO LOWER
80S ACROSS THE MOUNTAIN VALLEYS. HIGHER ELEVATIONS WILL SEE COOLER
AFTERNOON TEMPS, RANGING FROM THE UPPER 60S TO UPPER 70S. MOUNTAIN
VALLEY FOG AND LOW STRATUS SHOULD DEVELOP AGAIN OVERNIGHT INTO
DAYBREAK SATURDAY. PATCHY FOG COULD ALSO DEVELOP ACROSS THE NORTHERN
NC FOOTHILLS OVERNIGHT BUT CONFIDENCE IS LOW. LOWS TONIGHT WILL END
UP NEAR NORMAL TO JUST BELOW NORMAL.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/
AS OF 130 AM EDT FRIDAY: AN UPPER TROUGH AXIS REMAINS CENTERED ALONG
THE EASTERN COASTLINE THROUGH THE PERIOD. AN UPPER RIDGE REMAINS
OVER THE MS VALLEY BUT THE NORTHERN PORTION BEGINS TIPPING OVER THE
GREAT LAKES BY THE END OF THE PERIOD. THIS KEEPS A NORTHERLY FLOW
OVER OUR AREA. AT THE SURFACE, HIGH PRESSURE REMAINS CENTERED OVER
OR NEAR THE AREA KEEPING DRY CONDITIONS IN PLACE. HIGHS NEAR NORMAL
SATURDAY RISE A FEW DEGREES ABOVE NORMAL ON SUNDAY. LOWS AROUND 5
DEGREES BELOW NORMAL SATURDAY NIGHT RISE A FEW DEGREES SUNDAY NIGHT.
LONG TERM /MONDAY THROUGH THURSDAY/
AS OF 150 AM EDT FRIDAY: THE GFS IS ALONE IN THE DETERMINISTIC
MODELS IN KEEPING A DRY FORECAST ACROSS OUR AREA OVER THE MEDIUM
RANGE. IT DOES DEVELOP AN UPPER LOW AND ASSOCIATED SURFACE LOW BUT
KEEPS THEM WELL OFF THE ATLANTIC COAST WITH DRY HIGH PRESSURE OVER
OUR AREA. THE CANADIAN AND ECMWF DEVELOP THE UPPER AND SURFACE LOWS
OFF THE SC COAST ON MONDAY AND MOVE THEM WEST INTO THE CAROLINAS
DEVELOPING AN EASTERLY FLOW BRINGING MOISTURE AND PRECIP INTO THE
AREA BY TUESDAY, KEEPING IT IN PLACE ON WEDNESDAY, BEFORE MOVING
THEM NORTHEASTWARD ON THURSDAY WITH PRECIP TAPERING OFF. THE GFS AND
CANADIAN ENSEMBLE MEANS SHOW PRECIP DEVELOPING AS WELL. THE GUIDANCE
BLEND HAS SLIGHT CHANCE POP ACROSS THE AREA DURING THIS TIME PERIOD,
AND THAT SEEMS REASONABLE FOR NOW GIVEN THE MODEL TRENDS. HIGHS NOW
START OUT NEAR NORMAL ON MONDAY DROPPING TO AS MUCH AS 5 DEGREES
ABOVE NORMAL THROUGH THE REST OF THE PERIOD. LOWS REMAIN NEARLY
STEADY AROUND NORMAL.
AVIATION /12Z FRIDAY THROUGH TUESDAY/
AT KCLT AND ELSEWHERE: VFR AND DRY THROUGH THE 12Z TAF PERIOD
OUTSIDE OF MOUNTAIN VALLEY FOG AND LOW STRATUS EACH MORNING. FOG
AND/OR LOW STRATUS COULD STILL MAKE IT TO KAVL THIS MORNING BUT
CONFIDENCE IS LOW SINCE ONLY THIN STRATUS AND PATCHY MVFR FOG
DEVELOPED BRIEFLY. SOME VFR CU MAY DEVELOP DURING THE AFTERNOON AND
EARLY EVENING HOURS. WINDS WILL BE MAINLY N/NE EAST OF THE MOUNTAINS
THROUGH THE 12Z TAF PERIOD. WINDS AT KAVL SHOULD REMAIN CALM THROUGH
DAYBREAK BEFORE GRADUALLY TURNING SE THROUGHOUT THE MORNING HOURS.
WINDS AT KAVL WILL GO LIGHT AND VRB TO CALM AGAIN THIS EVENING INTO
TONIGHT, WITH ANOTHER ROUND OF MOUNTAIN VALLEY FOG AND LOW STRATUS
POSSIBLE AT THE TERMINAL. MVFR FOG MAY DEVELOP AT KHKY OVERNIGHT
INTO DAYBREAK SATURDAY BUT CONFIDENCE IS LOW AS GUIDANCE IS NOT IN
AGREEMENT ON THIS POTENTIAL.
OUTLOOK: DRY AND MOSTLY VFR THROUGH EARLY NEXT WEEK, OUTSIDE OF THE
POTENTIAL FOR MOUNTAIN VALLEY FOG AND/OR LOW STRATUS EACH MORNING.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
SYNOPSIS...RWH
NEAR TERM...AR
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...AR
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