733
FXUS62 KGSP 101944
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
344 PM EDT SAT OCT 10 2026
WHAT HAS CHANGED
NO CHANGES TO FLOOD OR WIND HEADLINES AS OF THIS ISSUANCE, BUT
WIND HEADLINES MAY BE REVISITED THIS EVENING.
PRECIP AMOUNTS HAVE INCREASED SLIGHTLY ALONG THE SOUTHEAST-FACING
BLUE RIDGE ESCARPMENT.
KEY MESSAGES
1. ISAIAS WILL MOVE NORTH INTO THE LOWER OHIO VALLEY
TONIGHT. PERIODS OF RAINFALL WILL CONTINUE ACROSS THE WESTERN
CAROLINAS AND NORTHEAST GEORGIA THROUGH TONIGHT, AND WILL BE
HEAVY AT TIMES. FLASH FLOODING IS POSSIBLE AND A FEW RIVERS ALSO
ARE LIKELY TO REACH FLOOD STAGE. LANDSLIDES REMAIN POSSIBLE OVER
EASTERN PARTS OF THE MOUNTAINS. STRONG WIND GUSTS REMAIN POSSIBLE
THIS EVENING MAINLY IN HIGH ELEVATIONS. ISOLATED SEVERE STORMS
ALSO MAY DEVELOP ALONG AND SOUTH/EAST OF I-85 THROUGH TONIGHT. THE
RISKS SHOULD DIMINISH BY SUNDAY MORNING.
2. GUSTY NORTHWEST WINDS MAY DEVELOP ACROSS THE HIGHER ELEVATIONS
SUNDAY NIGHT THROUGH MONDAY AS A DRIER AIRMASS BUILDS BACK INTO
THE REGION. AFTER THAT, DRY WEATHER WITH A WARMING TREND INTO
THE MIDDLE OF NEXT WEEK.
DISCUSSION
KEY MESSAGE 1: ISAIAS WILL MOVE NORTH INTO THE LOWER OHIO VALLEY
TONIGHT. PERIODS OF RAINFALL WILL CONTINUE ACROSS THE WESTERN
CAROLINAS AND NORTHEAST GEORGIA THROUGH TONIGHT, AND WILL BE
HEAVY AT TIMES. FLASH FLOODING IS POSSIBLE AND A FEW RIVERS ALSO
ARE LIKELY TO REACH FLOOD STAGE. LANDSLIDES REMAIN POSSIBLE OVER
EASTERN PARTS OF THE MOUNTAINS. STRONG WIND GUSTS REMAIN POSSIBLE
THIS EVENING MAINLY IN HIGH ELEVATIONS. ISOLATED SEVERE STORMS
ALSO MAY DEVELOP ALONG AND SOUTH/EAST OF I-85 THROUGH TONIGHT. THE
RISKS SHOULD DIMINISH BY SUNDAY MORNING.
POST-TROPICAL CYCLONE ISAIAS IS NOW CENTERED OVER ALABAMA AS OF 3
PM SAT AND WILL TRACK NORTHWARD INTO THE LOWER OHIO VALLEY TONIGHT,
WEST OF THE APPALACHIANS, BEFORE BEGINNING TO TURN NORTHEAST AS IT
INTERACTS WITH THE WESTERLIES. COLD-AIR DAMMING REMAINS LOCKED IN
EAST OF THE APPALACHIANS. RAINFALL HAS REMAINED SHOWERY OVER THE
WEDGE, WITH THE DRY SLOT AROUND ISAIAS HAVING TAKEN A BIT LONGER TO
SHIFT OVER THE CWA THAN ONCE EXPECTED, DESPITE THE LLJ SEEMINGLY
HAVING WEAKENED AND/OR SHIFTING FURTHER NORTH. RAINFALL RATES SO
FAR TODAY HAVE GENERALLY NOT BEEN MORE THAN AN INCH IN 3 HOURS,
BUT GIVEN THE DURATION, SOME AREAS ALONG THE SOUTHEAST-FACING BLUE
RIDGE ESCARPMENT HAVE ALREADY SEEN TOTALS AROUND 3 INCHES. CREEKS
AND STREAMS ARE ALREADY RESPONDING, AND AS SIMILAR RATES LOOK TO
CONTINUE FOR A WHILE LONGER, THOSE RESPONSES SHOULD CONTINUE AND
EVENTUALLY A FEW MAINSTEM RIVERS ARE EXPECTED TO REACH FLOOD STAGE,
ESPECIALLY THE FRENCH BROAD AND PIGEON. CAN'T RULE OUT FLOODING ON
THE CATAWBA/BROAD EITHER, AS THOSE DRAIN THE EAST-FACING ESCARPMENT.
THERE REMAINS POTENTIAL FOR CONVECTIVE BANDS OF HEAVIER PRECIP
TO DEVELOP AND POSE A FLASH FLOOD RISK WHERE THE RAIN WILL HAVE
SATURATED THE SOIL. SOME CLEARING HAS OCCURRED TO OUR SW IN GEORGIA
ALONG THE PERIPHERY OF THE WEDGE, WHICH HAS LED TO SOME BANDS OF
CONVECTION STARTING TO TAKE SHAPE. THESE INITIALLY WILL BE LIMITED
IN THEIR NORTHWARD MOTION AS THEY RIDE OVER THE WEDGE AND LIKELY
WEAKEN WITH DIMINISHING INSTABILITY. HOWEVER, OVER THE COURSE OF THE
EVENING, 925MB WINDS OVER THE WEDGE STILL SHOULD VEER AHEAD OF THE
EFFECTIVE COLD FRONT WRAPPING AROUND ISAIAS ON ITS SOUTH FLANK. CAMS
CONTINUE TO SHOW BANDS OF MAINLY ELEVATED CONVECTION OVER THE WEDGE,
FORMING VIA THE ENHANCED UPGLIDE. SUCH CONVECTION STILL APPEARS
CAPABLE OF 1-2" ACCUM IN AS LITTLE AS AN HOUR WHICH COULD POSE A
RISK OF FLASH FLOODING WHERE SOILS HAVE BECOME SATURATED, AND COULD
PUSH ACCUMS OVER THE THRESHOLD OF 5"/24HR, WHICH IS ASSOCIATED
WITH AN INCREASED RISK OF LANDSLIDES. SEE OUR PUBLIC INFORMATION
STATEMENT ISSUED FRIDAY EVENING FOR PREPAREDNESS INFORMATION ON
LANDSLIDES. INCREASED CONFIDENCE IN THE POSSIBILITY OF SHORT-TERM
HEAVY RAIN TONIGHT HAS PUSHED STORM TOTAL QPF A BIT HIGHER IN THE
CENTRAL CWA, PARTICULARLY IN THE EAST-FACING ESCARPMENT AREAS. FLASH
FLOOD WATCH IS UNCHANGED WITH TOTALS HAVING REMAINED SIMILAR IF
NOT COME DOWN SLIGHTLY IN SOME AREAS OUTSIDE THE WATCH.
THE ONSET OF THE STRONG SOUTHERLY NEAR-SFC FLOW SHOULD BEGIN TO
ERODE THE WEDGE AFTER SUNSET; SFC TEMPS MAY WARM SLIGHTLY IN OUR SW
AREAS AS THAT OCCURS, AND AS THE AFOREMENTIONED COLD FRONT SHIFTS
EASTWARD THROUGH THE CWA OVERNIGHT. 0-1KM SHEAR MAY EXCEED 30 KT
AND 0-3KM HELICITY ABOVE 200 M2/S2, SO ANY MEAGER SFC-BASED CAPE
THAT IS ABLE TO DEVELOP STILL COULD RESULT IN A RISK OF DAMAGING
WINDS AND BRIEF AND SHORT-TRACK TORNADOES. OVER THE NIGHT THE
RETREAT OF THE WEDGE BOUNDARY MAY CONTINUE UP TO AROUND THE I-85
CORRIDOR AND SO THOSE AREAS ARE IN THE SPC DAY 1 MARGINAL RISK
AREA. PER HREF/REFS TIMING A LINE OF CONVECTION MAY NOT CLEAR THE
EASTERN CWA UNTIL 12-15Z SUNDAY, WHICH IS REFLECTED IN OUR EASTERN
PIEDMONT BEING INCLUDED ON THE DAY 2.
THE GRADIENT WIND RISK ASSOCIATED WITH ISAIAS GENERALLY LOOKS TO
HAVE PEAKED OVER THE SW NC MOUNTAINS, NE GA, AND UPSTATE, WITH
THE LLJ NOW HAVING FOCUSED FARTHER NORTH ON THE FORWARD FLANK
OF THE STORM; GUSTS AT MOST OBS SITES ARE NOW BELOW 30 MPH. THERE
REMAINS THE POSSIBILITY OF BETTER MIXING IN THOSE AREAS AS THE WEDGE
BECOMES MORE SHALLOW LATER THIS EVENING AND PENDING COORDINATION
WITH NEIGHBORING OFFICES WE LIKELY WILL BE ABLE TO LET THE WIND
ADVISORY AND HIGH-ELEVATION WARNING GO DURING THE EVENING. NOT
AS CONFIDENT THAT THE NORTHERN MOUNTAINS AND EASTERN ESCARPMENT
AREAS CAN BE LET GO JUST YET.
EXPECT GRADUALLY LIFTING CLOUDS FROM WEST TO EAST FROM LATE SUNDAY
MORNING ONWARD, THOUGH WITH MOISTURE WRAPPING AROUND THE SYSTEM
SOME CLOUD COVER IS LIKELY TO BE SEEN MOST OF THE DAY. TEMPS SHOULD
RETURN BACK TO NEAR NORMAL FOR AFTERNOON MAXES.
KEY MESSAGE 2: GUSTY NORTHWEST WINDS MAY DEVELOP ACROSS THE HIGHER
ELEVATIONS SUNDAY NIGHT THROUGH MONDAY AS A DRIER AIRMASS BUILDS
BACK INTO THE REGION. AFTER THAT, DRY WEATHER WITH A WARMING TREND
INTO THE MIDDLE OF NEXT WEEK.
LIGHT RAINFALL MAY CONTINUE INTO SUNDAY NIGHT OR EARLY MONDAY ALONG
THE TN BORDER AND WIND GUSTS OF 25-35 MPH MAY REDEVELOP ACROSS THE
MOUNTAINS, GRADUALLY TAPERING OFF MONDAY. OTHERWISE THE RIDGE WILL
MAINTAIN DRY WEATHER FOR MOST OF THE WORK WEEK, WITH LIGHT WINDS
AND TEMPS TRENDING WELL ABOVE NORMAL TUE-THU. A COLD FRONT LATE
IN THE WEEK SHOULD BRING TEMPERATURES BACK NEAR OR BELOW NORMAL.
AVIATION /19Z SATURDAY THROUGH THURSDAY/
AT KCLT AND ELSEWHERE: SHRA MAY COME AND GO WITH CEILINGS GRADUALLY
FALLING TO IFR THIS AFTERNOON WHERE NOT ALREADY. OCCASIONAL VSBY
DROPS TO 1 TO 2 SM DUE TO HEAVIER SHRA. GENERALLY HANDLED THIS
WITH TEMPOS. GUSTS ASSOCIATED WITH THE FLOW AROUND ISAIAS HAVE
LIKELY PEAKED FOR THE EVENT, BUT GUSTS OF 20+ KT STILL POSSIBLE
THROUGH EARLY EVENING. SHRA SHOULD BECOME SPOTTIER DURING THE
EVENING BUT THE LOSS OF DOWNWARD MOTION SHOULD ALLOW CIGS TO SINK
EVEN LOWER AFTER SUNSET. HOWEVER, AS ISAIAS MOVES NORTHWEST OF THE
TERMINAL AREA, CONDITIONS BECOME FAVORABLE FOR ISOLATED +SHRA IF
NOT TSRA TO DEVELOP FROM WEST TO EAST, LATE THIS AFTERNOON THROUGH
TONIGHT. CHANCE OF TSRA APPEARS NO BETTER THAN PROB30, AND THOUGH
THE CHANCES MAY LAST LONGER THAN 6 HR, TRIED TO LIMIT DURATION AS
MUCH AS WAS FEASIBLE. TSRA ARE LIKELY TO CAUSE IFR VSBY AND PERHAPS
LOCALLY ENHANCED GUSTS BACK TO 25+ KT. TSRA CHANCES DROP OFF AND
LOW CIGS SHOULD SLOWLY IMPROVE DURING SUNDAY MORNING, FIRST IN
THE LEE OF THE MOUNTAINS AND WORKING EAST FROM THERE. WINDS TURN
SW FOR SUNDAY AND SUBSEQUENTLY NW SUNDAY NIGHT OR EARLY MONDAY.
OUTLOOK: VFR WITH GUSTY NW WIND ON MONDAY. VFR OUTSIDE OF MOUNTAIN
VALLEY FOG TUESDAY AND WEDNESDAY, WITH LIGHT WINDS.
GSP WATCHES/WARNINGS/ADVISORIES
GA...WIND ADVISORY UNTIL 8 AM EDT SUNDAY FOR GAZ010-017-018-026-028-
029.
FLOOD WATCH THROUGH SUNDAY AFTERNOON FOR GAZ010-017-018-026-
028-029.
NC...WIND ADVISORY UNTIL 8 AM EDT SUNDAY FOR NCZ033-048>053-058-059-
062>065-501-503-505-507-509.
FLOOD WATCH THROUGH SUNDAY AFTERNOON FOR NCZ033-049-050-052-
053-059-062>065-501>510.
HIGH WIND WARNING UNTIL 8 AM EDT SUNDAY FOR NCZ048>053-058-059-
062>064.
SC...WIND ADVISORY UNTIL 8 AM EDT SUNDAY FOR SCZ010-011-019-101>107.
FLOOD WATCH THROUGH SUNDAY AFTERNOON FOR SCZ010>012-019-
101>109.
JCW
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