Area Forecast Discussion
Issued by NWS Blacksburg, VA

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FXUS61 KRNK 240342
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
1042 PM EST FRI JAN 23 2015

.SYNOPSIS...
AN AREA OF LOW PRESSURE WILL MOVE NORTHEAST FROM THE GULF OF
MEXICO TOWARD THE MID-ATLANTIC COAST THROUGH SATURDAY BRINGING A
VARIETY OF SNOW...SLEET...AND FREEZING RAIN TO AREAS WEST OF THE
BLUE RIDGE AND RAIN TO THE EAST. GUSTY WINDS AND SNOW SHOWERS ARE
EXPECTED IN THE MOUNTAINS SATURDAY AS THE DEEP AREA OF LOW
PRESSURE MOVES NORTHEAST ALONG THE COAST. AN ALBERTA CLIPPER WILL
BRING ANOTHER CHANCE OF SNOW AND COLDER TEMPERATURES TO THE AREA
BY EARLY NEXT WEEK.

&&

.NEAR TERM /THROUGH SATURDAY/...
AS OF 1035 PM EST FRIDAY...

WINTER BE LEAVING WEATHER ADVISORIES INTACT WITH THIS ISSUANCE AND
CONTINUE THEM THROUGH 10AM SATURDAY MORNING.

00Z/7PM SOUNDING FROM RNK HAD A WARM NOSE AT 3500-4000FT AGL OF
39F/4C. REST OF THE SOUNDING BELOW 2500FT AGL WAS BELOW FREEZING.
SO LITTLE TO NO SLEET OR SNOW EXPECTED AT THIS POINT UNTIL SURFACE
LOW MOVES OFF THE EAST COAST AND LOW LEVEL WINDS TURN TO THE NORTH
AND NORTHWEST BRINGING DEEPER COLD AIR BACK INTO THE REGION. LARGEST
ICING AMOUNTS STILL EXPECTED ALONG THE BLUE RIDGE FROM FLOYD
COUNTY AND BENT MOUNTAIN NORTH TO MONTEBELLO.

LIGHT TO MODERATE PRECIPITATION HAS BEEN ENDING FROM SOUTHWEST TO
NORTHEAST SINCE 9PM AS THE DRY SLOT HAS ADVANCED INTO THE FORECAST
AREA. BUT LOCAL WRF AS WELL AS HRRR KEEP LOW LEVELS WINDS FROM THE
SOUTHEAST UNTIL 09Z/4AM. NOT AS MUCH ACCUMULATION OF ICE IN THE
AREAS BELOW FREEZING IN THE DRY SLOT BUT STILL UPSLOPE AND LOW
LEVEL MOISTURE FOR FREEZING DRIZZLE AND FOG...ESPECIALLY ALONG
AND JUST EAST OF THE BLUE RIDGE SOUTH OF ROANOKE.

03Z/10PM MSAS ANALYSIS SHOWED BEST PRESSURE FALLS HAVE
TRANSITIONED INTO SOUTHEAST VIRGINIA AND THE DELMARVA. THE PRIMARY
SURFACE LOW WAS OVER SOUTHEAST GEORGIA AND WILL MOVE TO THE MID
ATLANTIC COAST EARLY SATURDAY MORNING. ONCE THE LOW IS OFF THE
COAST AND WINDS BECOME NORTH TO NORTHWEST...EASTERN UPSLOPE ENDS
AND WESTERN UPSLOPE BEGINS. COLDER AIR WILL COME IN ON THE WEST
SIDE OF THE LOW...CHANGING THE PRECIPITATION BACK TO SNOW IN THE
MOUNTAINS.

THE REST OF SATURDAY WILL SEE LINGERING FLURRIES FOR THE
FAR WESTERN SLOPES...IMPROVING CONDITIONS EAST OF THE RIDGE...AND
STRONG GUSTY NORTHWEST WINDS FOR ALL. WITH GOOD DOWNSLOPING EAST
OF THE RIDGE TEMPS SHOULD REBOUND NICELY INTO THE MIDDLE 40S FOR
HIGHS SATURDAY AFTERNOON.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
AS OF 330 PM EST FRIDAY...

NORTHERN JET STREAM WILL BE ACTIVE EARLY NEXT WEEK. MEAN LONG WAVE
TROF OF LOW PRESSURE WILL ALIGN N-S OVER THE EASTERN CONUS WITH
MULTIPLE SHORT WAVES PASSING THROUGH THE FLOW.  FIRST
DISTURBANCE...OR ALBERTA CLIPPER...WILL APPROACH THE FORECAST AREA
SUNDAY...MOVING FROM IOWA SUNDAY MORNING TO NORTHERN KENTUCKY SUNDAY
EVENING...THEN PASS ACROSS THE MID ATLANTIC MONDAY MORNING. A SECOND
SYSTEM WILL MOVE ACROSS THE GREAT LAKES AND INTO THE NORTHERN MID
ATLANTIC LATE MONDAY NIGHT INTO TUESDAY.

MODELS ARE IN AGREEMENT THAT A DISTINCT WARM NOSE...850 H TEMPS OF +3
DEG C...WILL PREVAIL UNTIL THE ALBERTA CLIPPER PASSES OVERHEAD EARLY
MONDAY.  AS SUCH...ANY PRECIP THAT ARRIVES AHEAD OF THE SYSTEM
SUNDAY OR SUNDAY NIGHT WILL MOSTLY LIKELY BE RAIN. ONCE THE WAVE
PASSES OVERHEAD LATE SUNDAY NIGHT/EARLY MONDAY...THE WARM NOSE WOULD
THEN BE SQUASHED WITH THE FREEZING LEVEL RETURNING CLOSES ENOUGH TO
THE GROUND TO SUPPORT A P-TYPE OF SNOW.

MODELS MAINTAIN THE HIGHEST QPF TO THE NORTH OF THE TRACK OF THE
SURFACE CYCLONE.  THIS SUGGESTS THE BEST CHANCE FOR MEASURABLE
PRECIPITATION DURING THE SUNDAY-TUESDAY TIME FRAME WILL PRIMARILY BE
NORTH OF OUR CWA...WV...NRN VA...AND INTO PENNSYLVANIA. EVEN
SO...THERE IS STILL THE OPPORTUNITY FOR SOME ACCUMULATING SNOW
ACROSS OUR CWA MONDAY INTO TUESDAY...WITH THE MAIN FOCUS ACROSS OUR
NORTHERN CWA...THE INTERSTATE 64 CORRIDOR...AND ALONG OUR FAVORED
WESTERN SLOPES FROM WESTERN GREENBRIER SOUTHWEST INTO THE HIGH
COUNTRY OF NC.  ATTM...THINKING 1-3 INCHES OF SNOW FOR THESE
LOCATIONS...BUT THERE COULD BE A LITTLE MORE FOR NORTHWESTERN
GREENBRIER PENDING THE TRACK OF THE SECOND REINFORCING SHORT WAVE
EARLY TUESDAY.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 330 PM EST THURSDAY...

A HIGH AMPLITUDE UPPER TROF ACROSS THE EAST COAST TUESDAY WILL MOVE
EAST AND LIFT OUT LATE WEDNESDAY INTO WEDNESDAY NIGHT. A WEAK
NORTHERN STREAM SYSTEM ZIPS THROUGH THE GREAT LAKES THURSDAY...WITH
LIMITED MOISTURE.

UPSLOPE SNOW SHOWERS IN THE WEST WILL CONTINUE TUESDAY WITH COLD AIR
ADVECTION AND WEAK SHORTWAVES RIDING DOWN THE WEST SIDE OF THE UPPER
TROF. THE GFS SOLUTION IS A LITTLE WETTER THAN ECMWF WITH MOUNTAINS
SNOW SHOWERS. HIGH TEMPERATURES WILL REMAIN BELOW NORMAL TUESDAY
WITH READINGS FROM THE THE MID 20S IN THE NORTHWEST MOUNTAINS TO THE
THE LOWER 40S IN THE PIEDMONT. ALLOWED FOR ISOLATED SNOW
SHOWERS/SNOW FLURRIES IN THE NORTHWEST MOUNTAINS TUESDAY NIGHT AS A
1033 MB HIGH PRESSURE BUILDS EAST FROM THE OHIO VALLEY. LOW
TEMPERATURES TUESDAY NIGHT WILL VARY FROM THE LOWER TEENS IN THE
NORTHERN MOUNTAINS TO THE LOWER 20S IN THE PIEDMONT. AS THE HIGH
PRESSURE CENTER MOVES EAST ACROSS THE REGION WEDNESDAY...THE LOW
LEVEL WINDS BACK AROUND WEDNESDAY BRINGING AN END TO ANY LINGERING
UPSLOPE SNOW SHOWERS WITH TEMPERATURES MODERATING. HIGH TEMPERATURES
WEDNESDAY WILL VARY FROM THE UPPER 20S IN THE MOUNTAINS TO LOWER 40S
IN THE PIEDMONT. LOW TEMPERATURES WEDNESDAY NIGHT WILL GENERALLY BE
FROM THE UPPER TEENS TO THE UPPER 20S. A COLD FRONT WILL TRAVEL EAST
ACROSS OUR REGION THURSDAY AFTERNOON INTO FRIDAY. HIGH TEMPERATURES
THURSDAY WILL WARM INTO THE MID 30S IN THE NORTHWEST MOUNTAINS TO
THE UPPER 40S IN THE PIEDMONTS. LOW TEMPERATURES WILL MODERATE TO
THE MID 20S TO LOWER 30S THURSDAY NIGHT INTO FRIDAY. ALLOWED FOR
ISOLATED POPS IN THE WEST FRIDAY...AS WEAK SHORTWAVE TRAVELS EAST
ACROSS THE REGION.

&&

.AVIATION /04Z SATURDAY THROUGH WEDNESDAY/...
AS OF 645 PM EST FRIDAY...

POOR FLYING CONDITIONS TONIGHT INTO SATURDAY WITH IFR/LIFR
PREVAILING THIS EVENING INTO TONIGHT WITH SIGNIFICANT IMPROVEMENT
HOLDING OFF UNTIL SATURDAY MORNING.

COMPLICATED PTYPE SCENARIO UNDERWAY ACROSS THE REGION WITH WINTRY
MIXTURE OF RAIN...SNOW...SLEET AND FREEZING RAIN WITH POCKETS OF
DRIZZLE AND FREEZING DRIZZLE...AN AREA OF LOW PRESSURE MOVES
NORTHEAST FROM THE GULF OF MEXICO TOWARD THE MID-ATLANTIC COAST
THROUGH SATURDAY.

FOR KLYH AND KDAN...EXPECTING WARMER AIR MOVING IN ALOFT TO
CHANGE PCPN OVER TO ALL RAIN. WITH TEMPERATURES NEAR FREEZING AT
KLYH...PILOTS WILL HAVE TO WATCH FOR POCKETS OF FREEZING DRIZZLE.

KBCB AND KROA WILL HOLD ON TO SOME COLDER AIR NEAR THE SURFACE
HOLD ON A BIT LONGER TONIGHT. WINTRY MIX OF RAIN...FREEZING
RAIN...SLEET AND SNOW WILL TRANSITION TO SOME SNIZZLE OR FREEZING
DRIZZLE AT KBCB WITH JUST A PLAIN DRIZZLE AT KROA.

AT KBLF...COMBINATION OF RAIN...FREEZING RAIN WILL TRANSITION TO
SNOW AND FREEZING DRIZZLE AND DRIZZLE OVERNIGHT INTO SATURDAY.
KLWB WILL SEE THE MOST FROZEN/FREEZING PCPN AS THE COLDER AIR
STAYS AROUND THE LONGEST.

AS THE LOW CENTER STARTS TO PULL AWAY ON SATURDAY...WINDS WILL
PICK UP FROM THE NORTHWEST AND TRAILING BAND OF SYNOPTIC PCPN
WILL SWING THROUGH THE AREA WITH UPSLOPE LOCATIONS FROM THE BLUE
RIDGE WEST TRANSITIONING BACK TO SNOW SHOWERS AND STAYING IN PCPN
THROUGH THE LATTER PORTION OF THE TAF PERIOD.

MEDIUM CONFIDENCE ON CEILINGS...AND VISIBILITIES. MEDIUM TO
HIGH CONFIDENCES ON WINDS DURING THE TAF PERIOD.


EXTENDED AVIATION DISCUSSION...
SUNDAY THROUGH TUESDAY....PERSISTENT UPSLOPE CLOUDS AND POSSIBLE
SUB VFR CIGS AT BLF/LWB ALONG WITH PERIODS OF SNOW SHOWERS. AN
ALBERTA CLIPPER WILL BRING MORE A MORE WIDESPREAD CHANCE OF SNOW
TO THE ENTIRE REGION LATE SUNDAY INTO MONDAY. GENERALLY MVFR TO
VFR CONDITIONS ALONG AND EAST OF THE BLUE RIDGE WITH A CHANCE OF
RAIN OR SNOW THERE CONFINED TO MONDAY. ON TUESDAY...A FEW SNOW
FLURRIES MAY LINGER IN WESTERN GREENBRIER COUNTY. HIGH PRESSURE
BUILD EAST ACROSS THE AREA ON WEDNESDAY.

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...WINTER WEATHER ADVISORY UNTIL 10 AM EST SATURDAY FOR
     VAZ010>020-022>024-034-035.
NC...WINTER WEATHER ADVISORY UNTIL 10 AM EST SATURDAY FOR NCZ001-
     002-018.
WV...WINTER WEATHER ADVISORY UNTIL 10 AM EST SATURDAY FOR
     WVZ042>044-507-508.

&&

$$
SYNOPSIS...MBS
NEAR TERM...AMS/MBS
SHORT TERM...PM
LONG TERM...KK
AVIATION...KK/MBS/RAB


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