861
FXUS61 KRNK 091803
AFDRNK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
203 PM EDT FRI OCT 9 2026
WHAT HAS CHANGED
RAINFALL AND GUSTY WINDS STILL EXPECTED TO BE THE MAIN IMPACTS
SATURDAY AFTERNOON THROUGH SUNDAY.
KEY MESSAGES
1) RAIN ASSOCIATED WITH THE REMNANTS OF HURRICANE ISAIAS
ARRIVES LATE SATURDAY MORNING AND WITH WIDESPREAD RAINFALL
EXPECTED BY SATURDAY EVENING.
DISCUSSION
KEY MESSAGE 1...RAIN ASSOCIATED WITH THE REMNANTS OF HURRICANE ISAIAS
ARRIVES LATE SATURDAY MORNING AND WITH WIDESPREAD RAINFALL
EXPECTED BY SATURDAY EVENING.
SURFACE HIGH PRESSURE WILL CONTINUE TO RETREAT TO THE NORTHEAST
OVER NEW ENGLAND THROUGH SATURDAY, WHICH WILL CREATE A ROBUST
WEDGING SETUP ACROSS THE REGION. THIS WILL LEAD TO MUCH OF THE
PIEDMONT UNDER MUCH COOLER TEMPERATURES, WITH RAINY CONDITIONS
STARTING SATURDAY AFTERNOON AND CONTINUING THROUGH SUNDAY
AFTERNOON FOR MUCH OF THE AREA. RAINFALL SHOULD START ACROSS
PORTIONS OF NW NORTH CAROLINA BY THE MID MORNING HOURS SATURDAY,
AND CONTINUE TO SPREAD NORTH AND EASTWARD TO ENCOMPASS THE
REMAINDER OF THE AREA BY THE AFTERNOON AND EARLY EVENING HOURS
ON SATURDAY. IN GENERAL, MUCH OF THE FORECAST AREA IS LIKELY TO
SEE 1-2 INCHES OF RAINFALL, WITH HIGHER TOTALS EXPECTED ALONG
AND EAST OF THE BLUE RIDGE DUE TO UPSLOPE FLOW, AND LOWER TOTALS
WEST OF THE BLUE RIDGE GIVEN A RAIN SHADOW EFFECT.
FAVORED REGIONS FOR HIGHER TOTALS LOOK TO BE ALONG PORTIONS OF
THE BLUE RIDGE AS A 50-60KT SOUTHEASTERLY 850MB LLJ PUSHES INTO
THE AREA AS THE REMNANTS OF ISAIAS MOVE INTO THE TENNESSEE
VALLEY. UPSLOPE FLOW FROM THIS LLJ WILL LIKELY LEAD TO INCREASED
RAINFALL TOTALS INTO THE 2 TO 4 INCHES RANGE, WITH PERHAPS SOME
LOCALIZED HIGHER AMOUNTS IN THE 5 TO 6 INCH RANGE PARTICULARLY
IN NORTHWEST NORTH CAROLINA. THIS GENERAL AREA HAS THE GREATEST
CONCERN FOR FLOODING GIVEN THE UPSLOPE ENHANCEMENT, ALONG WITH
INCREASING DEEP TROPICAL MOISTURE (PWAT VALUES NEARING 2"),
WHICH COULD RESULT IN PERIODS OF HIGHER INTENSITY RAIN RATES.
TIMEFRAME FOR THE HIGHEST RAINFALL RATES BASED ON REFS GUIDANCE
WILL BE LATE SATURDAY NIGHT INTO EARLY SUNDAY MORNING. A FLOOD
WATCH HAS NOW BEEN ISSUED FOR THIS REGION EXTENDING FROM FLOYD
AND PATRICK COUNTY IN SW VIRGINIA TOWARDS WILKES AND WATAUGA
COUNTY IN NW NORTH CAROLINA.
THE AFOREMENTIONED 850MB LLJ IS EXPECTED TO LEAD TO A DOWNSLOPE
WIND EVENT FOR AREAS IN SE WEST VIRGINIA AND SW VIRGINIA. HI-RES
CAM GUIDANCE FROM THE RRFS HAVE PROBABILITIES OF 50%-80% FOR
WINDS GUSTING TO GREATER THAN 50 MPH ACROSS THIS WESTERN
CORRIDOR OF THE CWA. THIS HAS PROMPTED THE ISSUANCE OF A WIND
ADVISORY FOR THESE AREAS, WITH THE POSSIBILITY OF SEEING
ISOLATED GUSTS TO NEAR 60 MPH ALONG RIDGE LINES ABOVE 3500 FT
SATURDAY NIGHT INTO SUNDAY MORNING. WIND GUSTS SHOULD DIMINISH
THROUGH SUNDAY MORNING AND AFTERNOON AS THE LLJ LIFTS NORTH AND
EAST OF THE REGION.
TRENDS FOR A SUNDAY AFTERNOON SEVERE WEATHER THREAT, WITH THE
POSSIBILITY OF AN ISOLATED TORNADO FOR MOST OF THE NC AND VA
PIEDMONT IS INCREASING WITH MODELS NOW HINTING AT HIGH PRESSURE
RETREATING ENOUGH TO ALLOW FOR A BRIEF PERIOD OF DESTABILIZATION
ALONG A TRIPLE POINT IN CENTRAL VIRGINIA. STRONG ADVECTION OF
MOISTURE DUE TO THE LLJ WILL RAISE DEWPOINTS ENOUGH ACROSS THE
AREA TO ALLOW FOR MINOR DESTABILIZATION TO OCCUR ACROSS THIS
MENTIONED REGION. ALONG WITH THE MINOR DESTABILIZATION, THE LLJ
MAY SUPPORT ROTATING LOW-TOPPED SUPERCELLS GIVEN 0-1KM SRH
EXCEEDING 200M2S2 AND BULK SHEAR VALUES OF 40-50KTS.
BY LATE MONDAY, ALL REMNANTS OF ISAIAS LOOK TO BE WELL EAST OF
THE REGION, WITH DRY CONDITIONS RETURNING AREAWIDE ONCE AGAIN. A
POSSIBLE DRY FRONTAL PASSAGE BY THE TUESDAY NIGHT TIMEFRAME
LOOKS TO DROP TEMPERATURES SLIGHTLY THROUGH THE MIDDLE OF THE
WORK WEEK. OVERALL, THE REGION WILL LIKELY NOT SEE ANY RAIN
CHANCES THROUGH MOST OF NEXT WEEK AFTER THE REMNANTS FROM
ISAIAS MOVE THROUGH OVER THE WEEKEND.
AVIATION /18Z FRIDAY THROUGH WEDNESDAY/
BROKEN TO OVERCAST SKIES WILL CONTINUE AS CLOUD DEBRIS FROM
HURRICANE ISAIAS MOVE IN. VFR SKIES ARE LIKELY FOR THE REST OF TODAY
AND INTO SATURDAY MORNING. WINDS WILL BE LIGHT UNTIL FRIDAY
AFTERNOON BUT OVERNIGHT FOG IS UNLIKELY GIVEN EXTENSIVE CLOUD
CONDITIONS AND THE ASSIMILATION OF MID-LEVEL CLOUDS FROM ISAIAS. THE
OUTER RAIN BANDS OF ISAIAS MAY START AS EARLY AS NOON SATURDAY IN
THE NORTH CAROLINA COUNTIES AND MAY BRING LOWER VISIBILITIES AND
RAIN TO KBLF, KDAN, AND KBCB BY 15Z.
EXTENDED AVIATION OUTLOOK...
SUB-VFR CONDITIONS ARE LIKELY THROUGH THIS WEEKEND AS THE REMNANTS
OF ISAIAS MAKE ITS WAY THROUGH THE MID-ATLANTIC. RAIN WILL REDUCE
VISIBILITIES AT ALL TERMINALS AND LOW LEVEL CLOUDS MAY REACH BELOW
1000 FT SATURDAY NIGHT INTO SUNDAY MONDAY. THERE MAY BE A BRIEF
PERIOD OF INSTABILITY SUNDAY AFTERNOON TO ALLOW SOME THUNDERSTORMS
AT KDAN AND KLYH BUT THE CHANCES OF SEVERE WEATHER REMAIN LOW. THE
CENTER OF WHAT'S LEFT OF ISAIAS WILL TO THE EAST BY MONDAY BUT
UPSLOPE RAIN AND LOW LEVEL CLOUDS WILL STILL GIVE SUB-VFR CONDITIONS
FOR KBLF AND KLWB. BY MONDAY AFTERNOON, THE REST OF THE TERMINALS
SHOULD BE CLEARING OUT AND ALL AIRPORTS SHOULD BE BACK TO VFR BY
TUESDAY.
IN ADDITION TO THE STORM THREAT, WIND SHEAR AND GUSTY WINDS ARE
GOING TO BE AN ISSUE. AS ISAIAS TRANSITIONS TO A EXTRATROPICAL
CYCLONE, A EASTERLY/SOUTHEASTERLY LOW LEVEL JET WILL PASS THROUGH
THE SOUTHWESTERN APPALACHIANS. THIS JET IS FORECAST TO BE RATHER
POTENT AND SEND STRONG LOW LEVEL WIND SHEAR UP TO 60 KNOTS TO THE
WESTERN PORTION OF THE FORECAST AREA. WIND SHEAR VALUES AT THE
TERMINALS MAY NOT REACH AS HIGH BUT WIND SHEAR VALUES OF 45-55 KNOTS
ARE STILL LIKELY AT KLWB, KBLF, AND KBCB. KDAN AND KLYH MAY BE TOO
FAR EAST FROM THE JET, BUT SPOTS OF LOW LEVEL WIND SHEAR VALUES OF
35-45 KNOTS MAY BE IN THE VICINITY OF KDAN. THE DURATION OF THE WIND
SHEAR LOOKS TO START AS EARLY AS 15Z SATURDAY AND ENDING AS LATE AS
15Z SUNDAY. BECAUSE OF MIXING AND DOWNSLOPING WINDS, SURFACE WIND
GUSTS UNDER THE JET ARE EXPECTED TO INCREASE AND MAY REACH AS HIGH
AS 30-40 KNOTS ALONG THE APPALACHIAN MOUNTAINS. A WIND ADVISORY HAS
BEEN ISSUED FOR COUNTIES ALONG THIS AREA, INCLUDING KBLF. THE REST
OF THE TERMINALS MAY ONLY HAVE GUSTS OF 25-35 KNOTS. WHILE THE WINDS
RELATED TO THE JET DISSIPATE BY SUNDAY EVENING, WINDS WILL SHIFT TO
NORTHWESTERLY AS ISAIAS'S REMAINS MOVES TO OUR EAST, BRINGING GUSTY
WINDS OF 25-40 KNOTS ALONG AND WEST OF THE BLUE RIDGE EARLY NEXT
WEEK.
RNK WATCHES/WARNINGS/ADVISORIES
VA...WIND ADVISORY FROM 5 PM SATURDAY TO 11 AM EDT SUNDAY FOR
VAZ007-009-015.
NC...WIND ADVISORY FROM 5 PM SATURDAY TO 11 AM EDT SUNDAY FOR
NCZ001-018.
WV...WIND ADVISORY FROM 5 PM SATURDAY TO 11 AM EDT SUNDAY FOR
WVZ042-043-508.
DISCUSSION...EB
AVIATION...CG
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