357
FXUS62 KGSP 041000
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
600 AM EDT SAT OCT 4 2025
SYNOPSIS
HIGH PRESSURE REMAINS IN CONTROL THROUGH THE WEEKEND WITH NEAR-
NORMAL TEMPERATURES. CONTINUED WARMING IS EXPECTED EARLY NEXT WEEK,
AHEAD OF A COLD FRONT. A FEW SHOWERS CAN'T BE RULED OUT MONDAY AND
TUESDAY, BUT THE BETTER RAIN CHANCES ARE EXPECTED WEDNESDAY WHEN THE
COLD FRONT ARRIVES. EXPECT COOLER TEMPERATURES BEHIND THE FRONT FOR
THE LATTER HALF OF NEXT WEEK.
NEAR TERM /THROUGH TONIGHT/
AS OF 600 AM EDT SATURDAY...
KEY MESSAGES:
1) MOUNTAIN VALLEY FOG AND LOW STRATUS LINGER THROUGH DAYBREAK
2) WARMER TODAY WITH HIGHS ENDING UP A FEW DEGREES ABOVE NORMAL
3) DRY CONDITIONS CONTINUE AS CIRRUS STREAM OVERHEAD
4) MOUNTAIN VALLEY FOG/LOW STRATUS POSSIBLE AGAIN SUNDAY MORNING
DESPITE SCATTERED TO BROKEN CIRRUS STREAMING OVER THE FORECAST AREA
THIS MORNING, PATCHY TO LOCALLY DENSE MOUNTAIN VALLEY FOG AND LOW
STRATUS DEVELOPED OVERNIGHT. PATCHY TO LOCALLY DENSE (AT TIMES) FOG
AND LOW STRATUS ALSO DEVELOPED AT KHKY AND KMRN OVERNIGHT. FOG AND
LOW STRATUS WILL LIFT SHORTLY AFTER SUNRISE AS DAYTIME MIXING GETS
UNDERWAY. TEMPS THIS MORNING ARE RANGING MOSTLY FROM THE MID 40S TO
MID 50S.
OTHERWISE, UPPER RIDGING REMAINS OVER THE EASTERN UNITED STATES
THROUGH THE NEAR TERM WHILE THE CENTER OF SFC HIGH PRESSURE OVER THE
MID-ATLANTIC NUDGES EASTWARD INTO THE WESTERN ATLANTIC BY MID-
MORNING. THE SW PERIPHERY OF THE HIGH WILL REMAIN OVER THE SOUTHEAST
THROUGH THE PERIOD KEEPING DRY CONDITIONS AROUND. IT WILL BE A FEW
DEGREES WARMER TODAY, MAINLY EAST OF THE MOUNTAINS, WITH HIGHS
EXPECTED TO END UP ~1-3 DEGREES ABOVE NORMAL. AFTERNOON TEMPS EAST
OF THE MOUNTAINS WILL REACH INTO THE MID TO UPPER 70S. WIND SPEEDS
WILL BE LIGHTER TODAY WITH NO GUSTS EXPECTED. BROKEN TO SCATTERED
CIRRUS WILL CONTINUE STREAMING OVERHEAD THROUGH THE NEAR TERM. WITH
THICKER CIRRUS DEVELOPING TONIGHT INTO DAYBREAK SUNDAY, LOWS WILL BE
SEVERAL DEGREES WARMER COMPARED TO THIS MORNING, ENDING UP ~5-10
DEGREES ABOVE NORMAL. DESPITE THICKER CLOUD COVER, MOUNTAIN VALLEY
FOG/STRATUS MAY RETURN OVERNIGHT INTO DAYBREAK SUNDAY.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/
AS OF 1249 AM EDT SATURDAY: WEAK, DRY HYBRID CAD REMAINS IN PLACE
FOR SUNDAY INTO SUNDAY NIGHT AS A SURFACE HIGH STRAGGLES NEAR THE
MID-ATLANTIC COAST BEFORE GENTLY DRIFTING OFFSHORE AND WILL DRIVE
CONTINUED NORTHEASTERLY WINDS AT THE SURFACE, WHILE UPPER RIDGING
HOVERS OVER THE EASTERN SEABOARD. MODEL GUIDANCE PUSH THE SURFACE
HIGH AND UPPER RIDGE FURTHER OFFSHORE THROUGH THE PERIOD IN RESPONSE
TO AN INCOMING UPPER TROUGH AND ASSOCIATED COLD FRONT MOVING IN FROM
THE NORTHWEST THAT WILL IMPACT THE AREA IN THE EXTENDED. LINGERING
CAD, TURNED IN-SITU MAY CONTINUE INTO MONDAY BEFORE DEEPER BOUNDARY
LAYER MIXING HELPS TO SLOWLY ERODE WHATEVER WEDGE IS LEFT,
ESPECIALLY BY PEAK HEATING. LATEST MODEL TRENDS SUPPORT DRIER
SENSIBLE WEATHER CONDITIONS FOR MONDAY INTO MONDAY NIGHT. A
BAROCLINIC ZONE STRETCHED FROM THE CENTRAL GULF COAST, OVER THE
FLORIDA PENINSULA, AND INTO THE BAHAMAS WILL SLOWLY LIFT NORTH IN
RESPONSE TO THE DEPARTING LOW-LEVEL ANTICYCLONE SUNDAY INTO MONDAY.
IN TURN, EXPECT LOW-LEVEL WINDS ABOVE THE SURFACE TO VEER MORE
EASTERLY TO SOUTHEASTERLY BY THE BEGINNING PORTIONS OF THE FORECAST
PERIOD, WHILE SURFACE WINDS RESPOND IN THIS WAY BY THE DAYTIME
PERIOD MONDAY. MOIST UPGLIDE ALONG THE WEDGE BOUNDARY COULD HELP TO
SPARK A FEW LIGHT SHOWERS, MAINLY AFTER SUNSET SUNDAY, BUT
CONVECTION ALONG THE GULF COAST IS SHOWN KEEPING THE BETTER MOISTURE
FROM TRANSPORTING THIS FAR NORTH. AS A RESULT, MENTIONABLE POPS HAVE
MOSTLY BEEN TAKEN OUT OF THE SHORT TERM, BUT STILL THINK THAT THE
UPPER SAVANNAH RIVER VALLEY, SOUTHEAST FACING SLOPES ALONG THE BLUE
RIDGE ESCARPMENT, AND BALSAMS COULD PICK UP A COUPLE OF SHOWERS
BETWEEN SUNDAY NIGHT, MONDAY, AND MONDAY NIGHT. OTHERWISE, MOSTLY
DRY FORECAST IS IN STORE FOR A GOOD PORTION OF THE CWFA WITH ONLY
DECENT CLOUD COVER TO SHOW FOR. AFTERNOON HIGHS FOR SUNDAY AND
MONDAY WILL BE NEAR-NORMAL FOR THIS TIME OF THE YEAR, WITH MONDAY
POTENTIALLY RISING A DEGREE OR TWO, DEPENDING ON HOW MUCH OF THE
CLOUD COVER CAN MIX OUT BY THE AFTERNOON. OVERNIGHT LOWS BOTH SUNDAY
AND MONDAY NIGHTS ARE EXPECTED TO RUN 4-8 DEGREES ABOVE NORMAL
THANKS TO INCREASED CLOUD COVER AND ELEVATED DEWPOINTS.
LONG TERM /TUESDAY THROUGH FRIDAY/
AS OF 127 AM EDT SATURDAY: LONGWAVE UPPER TROUGH WILL STRETCH FROM
THE HUDSON BAY INTO THE NORTHERN GREAT PLAINS AND UPPER GREAT
LAKES REGION ON TUESDAY. AN ASSOCIATED COLD FRONT WILL BEGIN TO
MOVE TOWARDS THE REGION IN RESPONSE AS THE TROUGH SLIDES OVER
THE NORTHEASTERN CONUS AND ATLANTIC CANADA BY WEDNESDAY. SLIGHTLY
BETTER MOISTURE ADVECTION AND COMPRESSIONAL WARMING IS EXPECTED BY
WEDNESDAY, AHEAD OF THE FRONT. MODEL GUIDANCE STILL VARY AS FAR AS
QPF RESPONSE ON WEDNESDAY AS THE FRONT KNOCKS ON THE DOOR OF THE
NC/TN BORDER. BETTER DEEP LAYER SHEAR AND FORCING STILL RESIDES
NORTH OF THE AREA, SO THE SEVERE THREAT REMAINS RATHER LOW AT THIS
TIME, BUT IF THE FRONT SLIDES INTO THE AREA DURING PEAK HEATING
WEDNESDAY, SOME LOOSELY ORGANIZED CONVECTION MAY GET GOING. THE
LATEST TRENDS IN THE MODEL GUIDANCE HAVE COME TO A BETTER CONSENSUS
OF A FULL FROPA OCCURRING ACROSS THE CWFA BY LATER WEDNESDAY INTO
THURSDAY MORNING AS A STOUT CONTINENTAL HIGH (~1030MB) DRIFTS
ACROSS THE GREAT LAKES REGION WEDNESDAY NIGHT INTO THURSDAY BEFORE
SETTING UP SHOP OVER NEW ENGLAND BY THURSDAY NIGHT. LOW-LEVEL CAA
IS EXPECTED AS A RESULT, WITH A WEDGE-LIKE CONFIGURATION SETTING
UP. THE AFOREMENTIONED COLD FRONT SEEMS TO STRUGGLE PUSHING MUCH
FURTHER SOUTH ONCE IT REACHES THE GULF COAST. IF A WEDGE BOUNDARY
DEVELOPS IN LIEU OF THE QUASI-STATIONARY FRONT OVER THE GULF, EXPECT
SOME ISENTROPIC FEEDBACK BY THE VERY END OF THE FORECAST PERIOD.
TEMPERATURES ARE EXPECTED TO RISE A CATEGORY OR SO ABOVE NORMAL
TUESDAY, ESPECIALLY WEDNESDAY WITH GOOD COMPRESSIONAL HEATING
AHEAD OF THE COLD FRONT. TEMPERATURES ARE FORECAST TO DROP 5-10
DEGREES BELOW NORMAL BY THURSDAY BEHIND THE FRONT THANKS TO THE
INFLUENCE FROM THE CONTINENTAL HIGH AND CAA, WITH ONLY A SLIGHT
REBOUND IN TEMPERATURES BY FRIDAY AND SATURDAY WITH BETTER AIRMASS
MODIFICATION.
AVIATION /12Z SATURDAY THROUGH WEDNESDAY/
AT KCLT AND ELSEWHERE: VFR AND DRY THROUGH THE 12Z TAF PERIOD
OUTSIDE OF MOUNTAIN VALLEY FOG AND LOW STRATUS THIS MORNING AND
AGAIN OVERNIGHT INTO DAYBREAK SUNDAY. CIGS AND VSBYS AT KAVL ARE
RANGING FROM VLIFR TO LIFR THIS MORNING DESPITE CIRRUS
STREAMING OVERHEAD. THUS, MAINTAINED THE TEMPO FOR RESTRICTIONS
THROUGH DAYBREAK. KHKY HAS ALSO SEEN VLIFR TO IFR VSBYS AND
VLIFR CIGS DEVELOP THIS MORNING SO ADDED A TEMPO TO ACCOUNT FOR
RESTRICTIONS THROUGH DAYBREAK. FOG AND LOW STRATUS WILL LIFT AN
HOUR OR TWO AFTER SUNRISE. OTHERWISE, WINDS WILL REMAIN CALM TO
LIGHT AND VRB AT KAVL THROUGH DAYBREAK, PICKING UP OUT OF THE SE
BY LATE THIS MORNING OR EARLY THIS AFTERNOON. WINDS AT KAVL
WILL GO CALM TO LIGHT AND VRB AGAIN THIS EVENING INTO TONIGHT.
WINDS WILL REMAIN NE EAST OF THE MOUNTAINS THROUGH THE PERIOD.
WIND SPEEDS WILL GENERALLY RANGE FROM 4-9 KTS TODAY WITH NO
GUSTS EXPECTED. SCT TO BKN CIRRUS WILL CONTINUE STREAMING
OVERHEAD THROUGH THIS EVENING, WITH BKN CIRRUS EXPECTED
OVERNIGHT INTO DAYBREAK SUNDAY. THICKER COVERAGE OF CIRRUS MAY
ACT TO LIMIT THE MOUNTAIN VALLEY FOG/LOW STRATUS DEVELOPMENT
SOMEWHAT OVERNIGHT INTO DAYBREAK SUNDAY.
OUTLOOK: DRY HIGH PRESSURE AND VFR CONDITIONS EXPECTED ACROSS THE
TERMINALS THROUGH THE REST OF THE WEEKEND, OUTSIDE OF MOUNTAIN
VALLEY FOG/LOW STRATUS EACH MORNING. RAIN CHANCES, AND POSSIBLY
RESTRICTIONS, MAY RETURN EARLY NEXT WEEK.
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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