Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 232057 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 357 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 330 PM EST FRIDAY... WINTER BE LEAVING WEATHER ADVISORIES INTACT WITH THIS ISSUANCE AND CONTINUE THEM THROUGH 10AM SATURDAY MORNING. LOW PRESSURE CONTINUES TO DEVELOP AS IT MOVES OUT OF THE GULF AND WILL HEAD UP THE COAST ON SATURDAY. WARM AIR HAS BEEN MOVING IN ALOFT AS THE PCPN ENTERED SPREAD INTO THE REGION FROM THE SOUTHWEST...SO MANY LOCATIONS STARTED OFF WITH SOME SNOW/SLEET THEN WENT TO A MIXED BAG WITH MAINLY RAIN EAST OF THE BLUE RIDGE. THE OVERALL FLAVOR OF THIS WILL CONTINUE INTO TONIGHT WITH MIXED PRECIPITATION FOR THE MOUNTAINS AND RAIN TO THE EAST. UPSTREAM RADAR COVERAGE WAS A BIT PATCHY EARLIER BUT SATELLITE WATER VAPOR IMAGERY SHOWS A GOOD SUPPLY OF MOISTURE YET TO HEAD IN OUR DIRECTION AND THE RADAR HAS BEEN FILLING IN NICELY. GLAZING FROM FREEZING RAIN WILL BE AN INCREASING CONCERN AS WE HEAD INTO TONIGHT AND THE BOUNDARY LAYER COOLS A BIT WHILE THE PRONOUNCED WARM NOSE REMAINS. WARM SURFACE TEMPS SHOULD HELP REDUCE SIGNIFICANT ICING OF THE GROUND WITH THE MAIN ICE ACCRETION ON TREES/CARS ETC BUT SLICK SPOTS SHOULD BE EXPECTED...ESPECIALLY THE NORMAL TROUBLE SPOTS FROM FLOYD COUNTY UP TO BENT MOUNTAIN...APPROACHING AFTON MOUNTAIN...AND WESTERN GREENBRIER COUNTY. SYNOPTIC DRY SLOT WILL BE SET TO MOVE IN FROM THE SOUTHWEST THIS EVENING AND SHOULD BE BISECTING THE REGION BY DAYBREAK. THEN AS THE LOW PULLS AWAY AND STRONG NORTHWEST WINDS DEVELOP...WE WILL SEE SOME UPSLOPE ENHANCEMENT OF THE TRAILING DEFORMATION PRECIPITATION AS IT SWINGS THROUGH LATE TONIGHT INTO SATURDAY MORNING. 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 THURSDAY/... 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 /20Z FRIDAY THROUGH WEDNESDAY/... AS OF 1230 PM EST FRIDAY... IFR/LIFR CONDITIONS SETTING IN ALL SITES FOR THIS EVENING WITH SIGNIFICANT IMPROVEMENT HOLDING OFF UNTIL SATURDAY MORNING. COMPLICATED PTYPE SCENARIO UNDERWAY ACROSS THE REGION FOR THE EARLY PORTION OF THE TAF PERIOD. FOR KLYH AND KDAN...EXPECTING WARMER AIR MOVING IN ALOFT TO CHANGE PCPN OVER TO ALL RAIN IN THE NEAR FUTURE. WHILE THERE MAY BE SOME MIXED PCPN EARLY ON BELIEVE THIS WILL BE QUITE EPHEMERAL SO WILL JUST GO WITH LIQUID AS EXPECTING THIS TO BECOME THE DOMINANT PTYPE. KBCB AND KROA WILL SEE SOME COLDER AIR NEAR THE SURFACE HOLD ON A BIT LONGER FOR A DECENT AMOUNT OF SLEET MIXING IN EARLY. WITH TIME WE WILL START TO LOSE DENDRITIC GROWTH IN THE CLOUDY LAYER AS THE DRY SLOT MOVES IN THIS EVENING. THIS WILL TRANSITION PCPN OVER TO SOME SNIZZLE OR FREEZING DRIZZLE AT KBCB WITH JUST A PLAIN DRIZZLE AT KROA. KBLF WILL BE WARMING TO MOSTLY RAIN THEN TO DRIZZLE...BUT KLWB WILL SEE THE MOST FROZEN/FREEZING PCPN AS THE COLDER AIR STAYS AROUND LONGER. AS THE LOW STARTS TO PULL AWAY ON SATURDAY...WINDS WILL PICK UP FROM THE NW 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. 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. && .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...MBS SHORT TERM...PM LONG TERM...KK AVIATION...MBS/RAB

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