Area Forecast Discussion
Issued by NWS Blacksburg, VA

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309 FXUS61 KRNK 110145 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 845 PM EST WED FEB 10 2016 .SYNOPSIS... A STRONG UPPER LOW CENTERED OVER THE OHIO VALLEY WILL MOVE EAST TONIGHT INTO THURSDAY. WEAK UPPER SHORTWAVES WILL MOVE ACROSS THE MOUNTAINS THROUGH TONIGHT RESULTING IN SCATTERED SNOW SHOWERS AND SNOW FLURRIES. A CLIPPER SYSTEM WILL CROSS OUR REGION ON FRIDAY WITH SOME LIGHT SNOW ACCUMULATIONS...ESPECIALLY IN THE MOUNTAINS. && .NEAR TERM /THROUGH THURSDAY/... AS OF 840 PM EST TUESDAY... OVERALL...SNOW SHOWER COVERAGE HAS BEEN SCATTERED OVER THE WEST...BUT WITH ANOTHER STREAMWISE VORT TO PUSH NEWD INTO THE AREA OVERNIGHT EXPECT ANOTHER WRN SLOPE INCREASE IN COVERAGE. SHOULD SEE ANOTHER 1-3 INCHES OVER WRN GREENBRIER TO FLATOP WV...MAYBE UP TO 4 INCHES IN NW GREENBRIER. FLURRIES WILL BE MAKING IT AS FAR EAST AS THE NEW RIVER VALLEY AND BLUE RIDGE. WINDS WILL BE GUSTY AND AT TIMES AT/NEAR ADVISORY LEVELS OVER THE NC MTNS AS STRONG COLD ADVECTION CONTINUES AND ANOTHER SUBSIDENCE BAND BEHIND DEPARTING SHORTWAVE MOVES BY 12Z THU. NO CHANGES TO HEADLINES. PREVIOUS VALID DISCUSSION... A BROAD AND COLD UPPER LEVEL LOW WILL TRACK EAST FROM THE OHIO VALLEY THROUGH THE PERIOD. COLD AIR WILL CONTINUE TO PUSH INTO THE REGION TONIGHT WITH LOWS BETWEEN 10F-20F. BLUSTERY CONDITIONS ARE LIKELY EAST OF THE BLUE RIDGE WITH WIND CHILL VALUES IN THE SINGLE DIGITS THURSDAY MORNING. HIGH PRESSURE WILL MOVE OVER THE OHIO VALLEY THURSDAY AFTERNOON...SHUTTING DOWN WINDS AND UPSLOPE SNOW SHOWERS. UNDER MOSTLY SUNNY SKIES THURSDAY AFTERNOON...TEMPERATURES WILL REBOUND INTO THE 20S WEST TO 30S EAST. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/... AS OF 230 PM EST WEDNESDAY... 00Z ECMWF IS FARTHER SOUTH WITH THE SHORT WAVE ON FRIDAY...WHILE THE 12Z NAM AND GFS HAVE THIS FEATURE CROSSING THE INTO SOUTHERN VIRGINIA FRIDAY AFTERNOON. WINDS BACK TO THE SOUTHWEST AHEAD OF THE SHORT WAVE ON THURSDAY NIGHT. NAM IS SLOWER THAN THE GFS BRINGING MOISTURE BACK INTO THE COUNTY WARNING AREA LATE THURSDAY. BY THE END OF THE DAY FRIDAY...BULK OF MOISTURE WILL HAVE MOVED EAST AND UPSLOPE SNOW SHOWERS WILL BE BACK IN FULL SWING INTO EARLY SATURDAY MORNING. DEPTH OF MOISTURE BECOMES TOO SHALLOW...AND WINDS TOO LIGHT TO SUPPORT UPSLOPE BY SATURDAY EVENING. LOOKING AT PRECIPITATION AMOUNTS LESS THAN 0.25 INCHES LIQUID ON FRIDAY...AND EVEN LIGHTER AMOUNTS OF UPSLOPE ON FRIDAY NIGHT. BUT WITH HIGH SNOW RATIOS...THIS STILL HAS A DECENT POTENTIAL FOR LIGHT SNOW ACCUMULATIONS. PLAN ON GOING BELOW GUIDANCE FOR TEMPERATURES THURSDAY NIGHT THROUGH SATURDAY NIGHT BUT TEMPERATURES MAY BE MARGINALLY TOO WARM ACROSS THE SOUTHERN COUNTY WARNING AREA FOR MUCH MORE THAN LIGHT SNOW OR A MIX ON FRIDAY. FRIDAY NIGHT AND SATURDAY MODELS BRINGING SECOND SURGE OF ARCTIC AIR INTO THE REGION. 850MB TEMPERATURES LOWER INTO THE -18 TO -22 RANGE BY THE END OF THE DAY SATURDAY. A LOW LEVEL JET OF 40 TO 50 KNOTS WILL MEAN GUSTY SURFACE WINDS AND DANGEROUSLY COLD WIND CHILLS. GFS PRESSURE RISES LATE FRIDAY NIGHT ALSO SUPPORT GUSTY WINDS. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... AS OF 150 PM EST WEDNESDAY... SUNDAY THE VERY DEEP POLAR LONG WAVE TROF MOVES NORTHEAST...LEAVING THE MID ATLANTIC REGION IN WEAK 500 MB RIDGING. THE NEXT SYNOPTIC SCALE SHORT WAVE DIGS INTO THE TENNESSEE VALLEY ON MONDAY THEN CROSSES THE EASTERN UNITED STATES ON TUESDAY. HOWEVER...THERE WAS STILL QUITE A LARGE SPREAD IN MODEL SOLUTIONS...ESPECIALLY ON MONDAY THROUGH WEDNESDAY. WPC WAS LEANING TOWARD ENSEMBLE SOLUTIONS WHICH FAVOR A SURFACE LOW IN THE CAROLINAS ON TUESDAY MORNING. MONDAY AND MONDAY NIGHT LOOKING MORE LIKE A POSSIBLE MIXED PRECIPITATION EVENT BUT CONFIDENCE WAS TOO LOW TO INCLUDE MORE THAN RAIN OR SNOW AT THIS TIME. TIMING IN THE MODELS WAS ALSO CHANGING...SLOWER THAN PAST COUPLE OF RUNS. WHENEVER THE STORM SYSTEM DOES GO THROUGH...LIFT LOOKS IMPRESSIVE ON ISENTROPIC LEVELS AS DOES THE WARM AIR ADVECTION. HAVE INCREASED PROBABILITY OF PRECIPITATION IN THE MONDAY AND MONDAY NIGHT TIME FRAME AND WILL KEEP MENTION OF WINTER STORM THREAT IN THE HAZARDOUS WEATHER OUTLOOK. && .AVIATION /02Z THURSDAY THROUGH MONDAY/... AS OF 0700 PM EST WEDNESDAY... SNOW SHOWERS...COLD AND WINDS WILL HINDER AVIATION OPERATIONS OVERNIGHT WITH IMPROVING CONDITIONS THROUGH THE DAY THURSDAY. BKN/OVC MVFR CLOUDS WITH IFR CONDITIONS POSSIBLE IN CONTINUING NW FLOW SNOW SHOWERS...ESPECIALLY ALONG WESTERN SLOPES THROUGH EARLY MORNING HOURS ON WEDNESDAY. KBLF HAS THE BEST CHANCE OF GOING IFR IN HEAVIER SNOW SHOWERS...WITH LESSER PROBABILITIES THAT KLWB WILL WITNESS THE LOWER CATEGORY. SNOW SHOWERS WILL BE MAINLY CONFINED TO THE WESTERN SLOPES...BUT LIGHT SNOW SHOWERS OR FLURRIES COULD BREACH THE NEW RIVER AND ROANOKE VALLEYS. WINDS WILL STAY GUSTY WITH SUSTAINED WINDS OUT OF THE WEST NORTHWEST AT 10 TO 18 KTS WITH GUSTS EXPECTED OVER 20 KTS AT KBLF/KLWB/KBCB/KROA EARLY TONIGHT. PRESSURE RISES WILL CONTRIBUTE TO INCREASE GUSTS UP TO 35 KTS ALONG THE BLUE RIDGE WHILE VALLEYS WINDS WEAKEN SOME. AN ADDITIONAL INCREASE IN GUST POTENTIAL ARRIVES DURING THE DAY TOMORROW AT ALL TAF SITES. MEDIUM-HIGH CONFIDENCE IN CEILINGS...WITH SLIGHTLY LOWER CONFIDENCE IN VISIBILITIES AND WINDS DURING THE TAF PERIOD. EXTENDED DISCUSSION... CONDITIONS SHOULD BRIEFLY RETURN TO MAINLY VFR THURSDAY NIGHT AS WEAK HIGH PRESSURE BUILDS IN AND MOISTURE DECREASES ACROSS THE REGION. ANOTHER CLIPPER SYSTEM POSES TO MOVE ACROSS THE AREA FRIDAY...BRINGING THE POTENTIAL FOR SUB-VFR CONDITIONS TO THE WEST. VFR CONDITIONS SHOULD RETURN FOR MUCH OF THE WEEKEND...PRIOR TO THE ARRIVAL OF AN ADDITIONAL WEATHER SYSTEM...BRINGING THE THREAT FOR SUB VFR CONDITIONS AGAIN MONDAY AND TUESDAY. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 10 AM EST THURSDAY FOR VAZ007-009>020-022>024. WINTER WEATHER ADVISORY UNTIL 7 AM EST THURSDAY FOR VAZ007- 009>012-015-019-020. NC...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 10 AM EST THURSDAY FOR NCZ001-002-018. WINTER WEATHER ADVISORY UNTIL 7 AM EST THURSDAY FOR NCZ001-018. WV...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 10 AM EST THURSDAY FOR WVZ042>044-507-508. WINTER WEATHER ADVISORY UNTIL 7 AM EST THURSDAY FOR WVZ042>044- 507. WINTER STORM WARNING UNTIL 7 AM EST THURSDAY FOR WVZ043-508. && $$ SYNOPSIS...RCS NEAR TERM...RCS/WP SHORT TERM...AMS LONG TERM...AMS AVIATION...JM/RCS

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