554
FXUS62 KGSP 051006
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
606 AM EDT SUN OCT 5 2025
SYNOPSIS
HIGH PRESSURE REMAINS IN CONTROL OVER THE NEXT FEW DAYS WITH NEAR-
NORMAL TEMPERATURES. CONTINUED WARMING IS EXPECTED TUESDAY AND
WEDNESDAY, AHEAD OF A COLD FRONT. INCREASING CLOUDS AND BETTER
RAIN CHANCES WILL BE IN STORE FOR WEDNESDAY IN ASSOCIATION WITH
THE COLD FRONT. COOLER TEMPERATURES EXPECTED BEHIND THE FRONT FOR
THE LATTER HALF OF THE WEEK.
NEAR TERM /THROUGH TONIGHT/
AS OF 600 AM EDT SUNDAY...
KEY MESSAGES:
1) MORNING MOUNTAIN VALLEY FOG/LOW STRATUS POSSIBLE
2) ABOVE NORMAL TEMPERATURES EXPECTED
3) RAIN CHANCES RETURN ALONG AND WEST OF I-26 THIS AFTERNOON
BROKEN TO OVERCAST CLOUD COVER REMAINS IN PLACE THIS MORNING WITH
SOME STRATOCU RIDING UNDERNEATH THE CIRRUS SHIELD. THIS CLOUD COVER
HAS MOSTLY KEPT FOG AND LOW STRATUS AT BAY, WITH THE EXCEPTION OF
BRIEF FOG AND LOW STRATUS THAT DEVELOPED AT KHKY AND ACROSS A
PORTION OF THE LITTLE TN VALLEY OVERNIGHT. STILL CANNOT ENTIRELY
RULE OUT ADDITIONAL FOG/LOW STRATUS DEVELOPMENT THROUGH DAYBREAK
WHERE ANY BREAKS IN THE CLOUDS OCCUR, MAINLY IN THE MOUNTAIN VALLEYS
AND AT KHKY. OTHERWISE, MORNING TEMPS ARE MOSTLY RANGING FROM THE
LOWER TO UPPER 50S ACROSS WESTERN NC AND THE UPPER 50S TO MID 60S
ACROSS NE GA AND THE SC UPSTATE.
UPPER ANTICYCLONE WILL REMAIN CENTERED OVER EASTERN NC/VA THROUGH
THE PERIOD BUT WILL GRADUALLY WEAKEN STARTING TONIGHT AS AN UPPER
TROUGH NUDGES EASTWARD TOWARDS THE GREAT PLAINS. AT THE SFC, HIGH
PRESSURE CENTERED OVER THE WESTERN ATLANTIC WILL SLOWLY DRIFT EAST
AS A COLD FRONT TRACKS ACROSS THE CENTRAL UNITED STATES. THIS WILL
ALLOW LOW-LEVEL FLOW TO TURN E'LY (EAST OF THE MOUNTAINS) AND SE'LY
(ACROSS THE MOUNTAINS) THROUGHOUT THE MORNING AND EARLY AFTERNOON
HOURS, LEADING TO AN INFLUX OF MOISTURE FROM THE ATLANTIC. THIS WILL
HELP KEEP CLOUD COVER AROUND THROUGH THE PERIOD, AS WELL AS BRING
RAIN CHANCES BACK TO THE FORECAST AREA THIS AFTERNOON, MAINLY ALONG
AND WEST OF I-26. THE WESTERN SC UPSTATE AND NE GA APPEAR TO HAVE
THE BEST CHANCE TO SEE ISOLATED TO SCATTERED SHOWERS DEVELOP WITH
THE HIGHEST POPS (25% TO 30%) IN PLACE ACROSS THESE ZONES. 06Z CAMS
ARE STILL NOT IN THE GREATEST AGREEMENT REGARDING COVERAGE, BUT THEY
DO GENERALLY AGREE THAT THE HIGHEST RAIN CHANCES WILL REMAIN SOUTH
AND WEST OF THE GSP CWA. WITH LIMITED INSTABILITY AVAILABLE DURING
PEAK HEATING, THUNDER IS NOT EXPECTED TO ACCOMPANY THESE SHOWERS.
HIGHS THIS AFTERNOON WILL BE SIMILAR TO YESTERDAY, ENDING UP A FEW
DEGREES ABOVE NORMAL. LOWS MONDAY MORNING WILL END UP ~8-12 DEGREES
ABOVE NORMAL THANKS TO LINGERING CLOUD COVER. MOUNTAIN VALLEY
FOG/LOW STRATUS MAY DEVELOP OVERNIGHT INTO DAYBREAK MONDAY BUT
LINGERING CLOUD COVER MAY LIMIT THIS POTENTIAL.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/
AS OF 119 AM EDT SUNDAY: UPPER RIDGE AXIS AND AREA OF HIGH PRESSURE
RIDING UNDERNEATH WILL BE IN THE MIDST OF DRIFTING OFFSHORE THE
EASTERN SEABOARD BY THE START OF THE NEW WORKWEEK. IN THIS SETUP,
BETTER LOW-LEVEL EAST-SOUTHEASTERLY WAA FILTERS IN, WHILE HELPING
TO DETERIORATE ANY LINGERING WEDGE AS THE SYNOPTIC SUPPORT DIMINISHES
WITH THE RETREATING HIGH, AND STRONGER BOUNDARY LAYER MIXING LEADING
TO SCATTERING OF LOW-LEVEL CLOUDS. DEEP FRONTAL ZONE STRETCHED FROM
THE CENTRAL GULF COAST, THROUGH THE FLORIDA PENINSULA, AND OVER
THE BAHAMAS GRADUALLY LIFTS NORTH AND WILL PRODUCE GOOD CONVECTION
ALONG THE GULF COAST, WHICH WILL LIMIT BETTER MOISTURE TRANSPORT
THIS FAR NORTH. HOWEVER, MOIST UPGLIDE COULD INDUCE SOME SHOWER
COVERAGE OVER THE SOUTHWESTERN ZONES MONDAY INTO MONDAY NIGHT,
BUT COVERAGE IS SPARSE BASED ON MODEL GUIDANCE, WITH CONFIDENCE
BEING TOO LOW FOR A MENTIONABLE POP AT THIS TIME. SUBTLE HEIGHT
FALLS ON TUESDAY IN RESPONSE TO A LONGWAVE UPPER TROUGH THAT WILL BE
SITUATED FROM THE HUDSON BAY THROUGH THE GREAT LAKES REGION AND INTO
THE OH VALLEY. THE ASSOCIATED COLD FRONT WILL ENCROACH THE CWFA AS
A RESULT, BUT REMAIN NORTHWEST THROUGH TUESDAY NIGHT. SOME OF THE
MODEL GUIDANCE HAVE PRODUCED BETTER QPF RESPONSE BY TUESDAY NIGHT
NEAR THE NC/TN BORDER, BUT THE BRUNT OF THE PRECIP WILL REMAIN IN
THE BEGINNING PORTIONS OF THE EXTENDED PERIOD.
TEMPERATURES ON MONDAY WILL BE AT OR SLIGHTLY ABOVE NORMAL AS
LOW-LEVEL WAA FILTERS IN, BUT BETTER CLOUD COVER MAY HINDER
THE FULL POTENTIAL OF AFTERNOON HIGHS CLIMBING HIGHER DESPITE
ANOMALOUSLY HIGH THICKNESSES. BETTER INSOLATION AND COMPRESSIONAL
WARMING ON TUESDAY WILL HELP AFTERNOON HIGHS RISE A CATEGORY OR
SO ABOVE NORMAL AS A RESULT. OVERNIGHT LOWS FOR MONDAY AND TUESDAY
NIGHT WILL BE 5-10 DEGREES ABOVE NORMAL THANKS TO THE ONGOING WAA,
LEADING TO ELEVATED DEWPOINTS.
LONG TERM /WEDNESDAY THROUGH SATURDAY/
AS OF 139 AM EDT SUNDAY: THE AFOREMENTIONED COLD FRONT WILL BEGIN
ITS TRACK ACROSS THE CWFA ON WEDNESDAY. AHEAD OF THE FRONT, GOOD
COMPRESSIONAL HEATING WILL LEAD TO AFTERNOON HIGHS REMAINING A
CATEGORY OR SO ABOVE NORMAL. BETTER FORCING AND DEEP LAYER SHEAR
STILL REMAINS NORTH OF THE AREA, BUT ENOUGH SHEAR AND SOME FORM OF
INSTABILITY MAY GET SOME LOOSELY ORGANIZED CONVECTION GOING, BUT NOT
EXPECTING A REAL SEVERE THREAT AT THIS TIME. MODEL GUIDANCE STILL
SUGGEST A FULL FROPA OCCURRING DURING THE FIRST HALF OF THURSDAY
AS A STOUT CONTINENTAL HIGH (~1030+MB) DRIFTS ACROSS THE GREAT
LAKES REGION WEDNESDAY NIGHT INTO THURSDAY AND SETTING UP SHOP
OVER NEW ENGLAND BY THURSDAY NIGHT. LOW-LEVEL CAA SHOULD FILTER IN
BEHIND THE FRONT AND KEEP THE CWFA ON THE COOLER SIDE STARTING ON
THURSDAY, WITH A WEDGE-LIKE CONFIGURATION TRYING TO NOSE INTO THE
REGION. HOWEVER, LATEST TRENDS QUICKLY SHIFTS THE SURFACE HIGH AS
AN ANTICYCLONE DEEPENS OVER THE SOUTHERN PLAINS AND HELPS TO CARVE
A TROUGH OVER THE SOUTHEASTERN CONUS BY UPCOMING WEEKEND. MOST OF
THE GUIDANCE DOESN'T HAVE MUCH FANFARE WITH THE TROUGH, BUT LOWER
THICKNESSES SHOULD HELP TEMPERATURES REMAIN IN CHECK. TEMPERATURES
ARE FORECAST TO DROP 5-10 DEGREES BELOW NORMAL THURSDAY BEHIND THE
FRONT, WITH ONLY A GRADUAL REBOUND THROUGH THE END OF THE FORECAST
PERIOD WITH SLIGHTLY BETTER AIRMASS MODIFICATION.
AVIATION /12Z SUNDAY THROUGH THURSDAY/
AT KCLT AND ELSEWHERE: COVERAGE OF STRATOCU AND CIRRUS WILL BE
SCT TO BKN THROUGH THE 12Z TAF PERIOD BUT CIGS WILL REMAIN VFR
OUTSIDE OF THE POTENTIAL FOR MORNING MOUNTAIN VALLEY FOG/LOW
STRATUS. SO FAR THIS MORNING, CLOUD COVER HAS LIMITED FOG AND
LOW STRATUS FORMATION. HOWEVER, ANY BREAKS IN CLOUD COVER MAY
ALLOW RESTRICTIONS TO DEVELOP, MAINLY AT KAVL AND KHKY, THROUGH
DAYBREAK (KHKY ALREADY SAW THIS HAPPEN OVERNIGHT BEFORE CLOUD
COVER INCREASED). OTHERWISE, WINDS EAST OF THE MOUNTAINS WILL
REMAIN N/NE THROUGH MID-MORNING BEFORE TOGGLING MORE ENE/E BY
LATE THIS MORNING OR EARLY THIS AFTERNOON. WINDS AT KAVL WILL
REMAIN CALM TO LIGHT AND VRB THROUGH DAYBREAK, PICKING UP OUT OF
THE SE SHORTLY AFTER DAYBREAK. WIND SPEEDS TODAY WILL BE A BIT
STRONGER COMPARED TO YESTERDAY, RANGING FROM 5-10 KTS. COULD NOT
ENTIRELY RULE OUT SOME LOW-END WIND GUSTS, MAINLY AT KAND AND
KGMU, BUT CONFIDENCE IS LOW. KAND ALSO HAS THE BEST CHANCE TO
SEE SHRA THIS AFTERNOON SO MAINTAINED THE PROB30 AT THE TERMINAL
FROM 17Z-22Z. HOWEVER, CONFIDENCE ON SHRA OCCURRING DIRECTLY
OVER THE TERMINAL REMAINS LOW. MOUNTAIN VALLEY FOG/STRATUS MAY
DEVELOP OVERNIGHT INTO DAYBREAK MONDAY WITH CLOUD COVER EXPECTED
TO SCATTER OUT A BIT, BUT CONFIDENCE WILL ONCE AGAIN BE LOW.
OUTLOOK: OTHER THAN THE CONTINUED LIKELIHOOD OF EARLY MORNING
MOUNTAIN VALLEY FOG/LOW STRATUS, GENERALLY VFR CONDITIONS ARE
EXPECTED THROUGH AT LEAST EARLY NEXT WEEK. CHANCES FOR SHOWERS AND
POSSIBLY RESTRICTIONS INCREASE TOWARD MID-WEEK AHEAD OF AN
APPROACHING COLD FRONT.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
SYNOPSIS...CAC
NEAR TERM...AR
SHORT TERM...CAC
LONG TERM...CAC
AVIATION...AR
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