Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000
FXUS61 KRNK 310902
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
502 AM EDT FRI OCT 31 2014

.SYNOPSIS...
WEATHER CONDITIONS WILL RAPIDLY DETERIORATE LATER THIS AFTERNOON
AND EVENING AS A FAST MOVING DISTURBANCE FROM CANADA MOVES
SOUTHEAST ACROSS THE OHIO VALLEY...THEN ACROSS THE SOUTHERN
APPALACHIANS TONIGHT AND SATURDAY. WINTER STORM CONDITIONS ARE
LIKELY IN THE HIGH COUNTRY OF NORTH CAROLINA...AND INTO THE HIGHER
ELEVATIONS OF FAR WESTERN VIRGINIA VICINITY OF MOUNT ROGERS
TONIGHT AND SATURDAY. ELEVATIONS ABOVE 3000 FEET WILL SEE THE
GREATEST WINTRY IMPACT.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 400 AM EDT THURSDAY...

TRICK OR TREAT. THE LAST DAY OF OCTOBER...ALTHOUGH QUIET AND NEAR
NORMAL FEELING AT THE MOMENT...WILL CHANGE INTO A DIFFERENT
COSTUME BEFORE THE END OF THE DAY. SKIES WILL START OFF RELATIVELY
BRIGHT PER LINGERING HIGH PRESSURE...BUT AS THE HIGH FADES TO OUR
EAST...SKIES WILL DARKEN FROM THE WEST AS LOW PRESSURE APPROACHES
FROM THE NORTHWEST. CLOUDS WILL THICKEN AND LOWER THIS AFTERNOON
WITH ONSET OF LIGHT RAIN ANTICIPATED OVER THE MOUNTAINS AFTER 2PM
AND THEN MOVING EAST OF THE MOUNTAINS THIS EVENING. TEMPERATURES
TODAY WILL BE SEASONALLY COOL...BUT WILL FALL 5 TO 8 DEGREES SHORT
OF OUR NORMAL HIGH FOR THE DATE.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
AS OF 500 AM EDT FRIDAY...

IF YOU ARE LOOKING FOR THE GREAT PUMPKIN I THINK YOU ARE IN FOR A
TRICK INSTEAD OF A TREAT. THE WEATHER PATTERN THIS WEEKEND WILL BE
WEARING A SCARY COSTUME...COURTESY OF THE MANITOBA MAULER (LOW
PRESSURE COMING FROM THE CANADIAN PROVINCE OF MANITOBA). THIS FAST
MOVING AREA OF LOW PRESSURE IN THE UPPER LEVELS OF THE ATMOSPHERE
WILL DIVE SOUTH FASTER THAN A HEADLESS HORSEMAN TOWARD THE
SOUTHERN APPALACHIANS BY SATURDAY MORNING. THIS WILL RESULT IN
THE DEVELOPMENT OF A HIGHLY AMPLIFIED TROUGH OVER THE EAST COAST
AND A STRONG SURFACE LOW DEVELOPING OFFSHORE. IN TERMS OF SENSIBLE
WEATHER IMPACTS, EXPECT MUCH COLDER WEATHER BY SATURDAY WITH
RAIN IN THE LOWER ELEVATIONS AND ACCUMULATING SNOW IN THE HIGHER
ELEVATIONS OF THE NORTH CAROLINA HIGH COUNTRY AND INTO THE
MOUNTAINS OF FAR SOUTHWESTERN VIRGINIA. WINTER STORM WARNINGS HAVE
BEEN POSTED WITH POTENTIAL FOR SEVERAL INCHES OF SNOW...ESPECIALLY
FOR ELEVATIONS ABOVE 3000 FEET. MODELS INDICATE THE CHANGE FROM
RAIN TO SNOW AT THESE HIGHER ELEVATIONS WILL TAKE PLACE AROUND THE
WITCHING HOUR TONIGHT. BOO.

WITH THE UPPER LOW HOVERING OVERHEAD SATURDAY...GOOSE BUMPS WILL
BE COMMON AS MUCH COLDER AIR GETS UNLEASHED VIA BRISK NORTHWEST
WINDS. 85H TEMPS PLUNGE TO NEAR M6 DEG C IN THE MOUNTAINS OF NORTH
CAROLINA WHERE A WINTRY PRANK WILL PLAY OUT DURING THE DAY WITH
THE HIGHER ELEVATION LANDSCAPE BECOMING MASKED IN A LAYER OF
WHITE. THE STRONGEST UPPER LEVEL FORCING IS PROGGED TO PASS
DIRECTLY OVER THE HIGH COUNTRY OF NC AND THIS SHOULD BE GROUND
ZERO FOR SNOW WHICH WILL ACCUMULATE 3 TO 6 INCHES BEFORE ALL IS
SAID AND DONE SATURDAY NIGHT. OUTSIDE OF THIS HIGHER IMPACT
AREA...SNOW AMOUNTS WILL BE CONSIDERABLY LESS. WITH THE EXCEPTION
OF THE HIGHER MOUNTAINS OF SOUTHWEST VA INCLUDING MOUNT
ROGERS...WHICH MAY RECEIVE SIMILAR ACCUMULATIONS OF SNOW...THE
REMAINDER OF THE FORECAST AREA APPEARS TO BE TOO WARM TO PARTAKE
IN MUCH IF ANY ACCUMULATION. SOME LIGHT ACCUMULATIONS OF SNOW ARE
POSSIBLE IN THE HIGHLANDS OF WEST VIRGINIA AND INTO THE ALLEGHANY
HIGLANDS OF VA...BUT NOT UNTIL THE COLDER AIR ARRIVES LATER
SATURDAY AND INTO SATURDAY NIGHT. FLURRIES AND SNOW SHOWERS CAN BE
EXPECTED ACROSS ALL MOUNTAIN ZONES SATURDAY NIGHT. EAST OF THE
MOUNTAINS...ACROSS THE FOOTHILLS AND PIEDMONT...THICKNESSES REMAIN
ABOVE CRITICAL SUPPORTING NOTHING BUT A COLD RAIN FOR THE DURATION
OF THE EVENT. RAIN WILL COME TO AN END EAST OF THE MOUNTAINS AS
STRONG DOWNSLOPE DRYING BEGINS PER INCREASING NORTHWEST WINDS
IN THE WAKE OF THE STORM SYSTEM. LIQUID EQUIVALENT QPF FOR THE
EVENT IS EXPECTED TO RANGE FROM ABOUT A QUARTER /0.25/ OF AN INCH
IN THE NORTHEAST CWA (LYNCHBURG-BUCKINGHAM)...TO NEAR ONE INCH
/1.00/ IN THE SOUTHWEST (BLUEFIELD-BOONE).

A WINTER SHIVER WILL BE FELT THROUGHOUT THE MID ATLANTIC SATURDAY
NIGHT...READINGS DIPPING INTO THE L-M20S IN THE HIGHER ELEVATIONSAND
LOWER TO MID 30S ACROSS THE FOOTHILLS AND PIEDMONT. TEMPERATURES
WILL STRUGGLE SUNDAY IN SPITE OF ANY CLEARING...AND SET THE STAGE
FOR A WIDER-SPREAD KILLING FREEZE SUNDAY NIGHT...TEMPERATURES
DIPPING AT OR BELOW 32 FOR THE ENTIRE CWA.

WINDS THIS WEEKEND WILL BE THE STRONGEST IN THE WAKE OF THE
DEPARTING LOW PRESSURE...RAMPING UP SATURDAY AFTERNOON AND
CONTINUING INTO THE DAY SUNDAY BEFORE DIMINISHING LATER SUNDAY.
ADVISORY SORT OF GUSTS...NEAR 40 KTS...ARE LIKELY VCNTY OF THE
BLUE RIDGE SATURDAY EVENING. WIND TRAJECTORIES FROM 340 DEGREES
ALSO SUGGEST STRONG CROSS WINDS LIKELY ALONG I-77 VCNTY OF FANCY
GAP.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 400 PM EDT THURSDAY...

RIDGE OF HIGH PRESSURE WILL BUILD OVER THE REGION EARLY NEXT
WEEK...HEIGHTS RISING AT 500 MB MONDAY AND TUESDAY RESULTING IN A
RETURN TO SEASONABLY NORMAL TEMPERATURES. FLOW PATTERN DURING THE
WEEK THEN EVOLVES INTO A SPLIT FLOW PATTERN ACROSS THE UNITED
STATES BY WEDNESDAY WHICH MAY BRING A SHORT WAVE THROUGH THE
NORTHERN STREAM. SURFACE HIGH PRESSURE REMAINS OVER THE SOUTHEAST
MONDAY AND TUESDAY WITH FLOW OFF THE GULF OF MEXICO INCREASING AS
THE HIGH MOVES OFFSHORE WEDNESDAY AND THURSDAY. MODELS SHOWING A
BOUNDARY APPROACHING THE FORECAST AREA FROM THE WEST ON WEDNESDAY.
WILL BE INCREASING THE PROBABILITY OF PRECIPITATION ON WEDNESDAY
AND WEDNESDAY NIGHT. TEMPERATURES THROUGH THE PERIOD WILL BE NEAR
OR JUST ABOVE NORMAL.

&&

.AVIATION /07Z FRIDAY THROUGH TUESDAY/...
AS OF 200 AM EDT FRIDAY...

EXPECT VFR AT ALL PRIMARY TAF SITES THIS MORNING...THOUGH SOME
MODELS HINTING AT A FEW HOURS OF MVFR IN THE MTNS OF WV VCNTY OF
KLWB EARLY THIS MORNING.

OVERALL TREND WILL BE FOR INCREASING CLOUDS TODAY. A STRONG UPPER
LEVEL DISTURBANCE WILL DROP SOUTHEAST THROUGH THE OHIO VALLEY
TODAY AND IS PROGGED BY ALL MODELS TO LEAD TO SURFACE CYCLOGENESIS
LEE OF THE NORTH CAROLINA MOUNTAINS TONIGHT...THIS FEATURE
DEEPENING RAPIDLY AS IT PASSES OFF THE NORTH CAROLINA COAST
SATURDAY.

LOOK FOR THICKENING AND LOWERING OF CLOUD BASES TODAY WITH ONSET
OF RAIN IN THE MOUNTAINS AFTER 18Z/2PM...SPREADING EAST OF THE
MOUNTAINS INTO THE PIEDMONT BY 00Z/8PM THIS EVENING. RAIN WILL
BECOME MODERATE AT TIMES WITH CIGS LOWERING THROUGH MVFR CATEGORY
BETWEEN 18Z/2PM TO 00Z/8PM TIME FRAME...THEN INTO THE IFR CATEGORY
TONIGHT. THIS VIGOROUS STORM SYSTEM WILL RESULT IN LOWERING
FREEZING LEVELS WITH TIME...PRECIPITATION CHANGING TO SNOW OVER
THE HIGHER ELEVATIONS TONIGHT.

DURING THE OVERNIGHT...PRIMARILY AFTER MIDNIGHT...HIGH CONFIDENCE
THAT PTYPE CHANGE WILL OCCUR OVER THE MOUNTAINS NEAR THE
APPALACHIAN DIVIDE...FROM BLUEFIELD WV (KBLF) TO BOONE NORTH
CAROLINA (KTNB). THIS AREA WILL BE IMPACTED BY THE MAJORITY OF THE
WINTRY PRECIPITATION WHICH WILL PLAY OUT LATE FRIDAY NIGHT INTO
SATURDAY...WITH HEAVY SNOW ACCUMULATIONS EXPECTED FOR THE NC/TN
MTNS ALL THE WAY DOWN TO THE SMOKIES. LIFR CONDITIONS ARE LIKELY
OVER THE MOUNTAINOUS TERRAIN TONIGHT AND SATURDAY.

AS CYCLOGENESIS TAKES PLACE AND THE STORM MOVES TO THE COAST
SATURDAY...STRONG PRESSURE RISES IN THE WAKE OF THE SYSTEM WILL
RESULT IN INCREASING WIND SPEEDS. GUSTS OF 25 TO 40 KTS ARE
POSSIBLE VCNTY OF THE MTNS SATURDAY AFTERNOON AND EVENING...WITH
STRONG GUSTS CONTINUING INTO THE DAY SUNDAY.

VFR CONDITIONS WILL RETURN TO THE AREA SUNDAY...WINDS GRADUALLY
DIMINISHING. FAIR WEATHER IS EXPECTED MONDAY AND TUESDAY AS
AS HIGH PRESSURE PASSES OVER THE AREA...CONDITIONS REMAINING VFR.

&&

.EQUIPMENT...
THE AC UNITS FOR THE RADAR SHELTER ARE BAD. RADAR OPERATION WILL
BE INTERMITTENT UNTIL SUCH TIME THE AC UNITS ARE FIXED.
IF SHELTER TEMPERATURES RISE ABOVE CRITICAL LEVELS WE WILL PLACE
THE RADAR INTO STANDBY TO AVOID DAMAGE TO THE TRANSMITTER.

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...WINTER STORM WARNING FROM 8 PM THIS EVENING TO 8 PM EDT
     SATURDAY FOR VAZ007-009-015.
NC...WINTER STORM WARNING FROM 8 PM THIS EVENING TO 8 PM EDT
     SATURDAY FOR NCZ001-018.
WV...NONE.

&&

$$
SYNOPSIS...PM
NEAR TERM...PM
SHORT TERM...PM
LONG TERM...AMS
AVIATION...PM
EQUIPMENT...PM



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