Area Forecast Discussion
Issued by NWS Blacksburg, VA

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674 FXUS61 KRNK 091757 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 1257 PM EST TUE FEB 9 2016 .SYNOPSIS... A STRONG CYCLONE IN THE UPPER LEVELS OF THE ATMOSPHERE IS CENTERED OVER THE OHIO VALLEY. THIS FEATURE WILL REMAIN NEARLY STATIONARY THROUGH WEDNESDAY BEFORE SLOWLY MOVING EAST. WEAK UPPER LEVEL IMPULSES WILL MOVE ACROSS THE MOUNTAINS THROUGH WEDNESDAY NIGHT RESULTING IN PERSISTENT SNOW SHOWER AND FLURRY ACTIVITY. TEMPERATURES WILL REMAIN BELOW NORMAL FOR THE REMAINDER OF THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1000 AM EST TUESDAY... HAVE LOWERED MAXIMUM TEMPERATURES A FEW DEGREES...MAINLY OVER THE MOUNTAINS BASED ON CURRENT OBSERVATIONS AND THE LATEST LAV AND MAV GUIDANCE FOR THE REST OF THE DAY. COLD UPPER LEVEL LOW IS CENTERED OVER OHIO WITH WIDESPREAD SNOW SHOWER ACTIVITY OCCURRING FROM THE GREAT LAKES TO THE SOUTHERN APPALACHIANS. THIS UPPER LOW IS PROGGED TO REMAIN NEARLY STATIONARY OVER THE NEXT 24 HOURS RESULTING IN A PERSISTENT STREAM OF MOISTURE INTO THE WESTERN SIDE OF THE APPALACHIAN MOUNTAINS. THIS WILL PROVIDE THE WEST SIDE OF THE MOUNTAINS WITH PERIODS OF MODERATE ACCUMULATING SNOW. AS THE AIR PASSES OVER THE MOUNTAINS...THE AIR WILL DRY OUT...RESULTING IN A MORE SCATTERED NATURE TO THE SNOW SHOWERS WITH LITTLE OR NO ACCUMULATION EAST OF THE BLUE RIDGE. MODELS CONTINUE TO FAVOR THE HEAVIEST SNOW ACCUMULATIONS ALONG THE WEST FACING SLOPES OF THE WEST VIRGINIA HIGHLANDS WITH MULTIDAY SNOW TOTALS UPWARDS OF 8 TO 12 INCHES IN WESTERN GREENBRIER COUNTY. LESSER BUT RESPECTABLE AMOUNTS WILL BE OBSERVED FARTHER SOUTHWEST THROUGH SUMMERS AND MERCER WEST VIRGINIA...TAZEWELL...SMYTH...AND WESTERN GRAYSON VIRGINIA...AND INTO ASHE AND WATAUGA COUNTIES IN NORTH CAROLINA. EAST OF THESE COUNTIES...AMOUNTS WILL TAPER TO JUST AN INCH OR TWO...WITH ONLY TRACE AMOUNTS EAST OF THE BLUE RIDGE. WILL NOT MAKE ANY CHANGES TO THE CURRENT WARNING AND ADVISORY CONFIGURATION...MAINTAINING A WINTER STORM WARNING FROM WESTERN GREENBRIER COUNTY TO NEAR FLAT TOP WEST VIRGINIA...AND WINTER WEATHER ADVISORIES FROM THE VA/WV BORDER SOUTHWEST THROUGH THE WESTERN NEW RIVER VALLEY AND INTO THE MOUNTAINS OF NORTHWEST NORTH CAROLINA. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 400 AM EST TUESDAY... BROAD UPPER TROUGH WILL SLOWLY MOVE EAST ALONG THE EAST COAST WEDNESDAY INTO THURSDAY NIGHT. THERE REMAINS DIFFERENCES IN THE STRENGTH OF THE UPPER TROUGH...AND IN THE SPEED AND LOCATION OF SHORTWAVES EMBEDDED IN THE LARGE UPPER TROF. THE NAM AND ECMWF ARE DEEPER WITH THE UPPER TROUGH COMPARED TO THE GFS. THIS TRANSLATES TO A FURTHER SOUTH PLACEMENT AND TRACK OF THE ROBUST SHORTWAVE WEDNESDAY WHICH ROTATES EAST AROUND UPPER TROUGH WEDNESDAY NIGHT INTO THURSDAY. SNOW SHOWERS AND SNOW FLURRIES CONTINUE WEDNESDAY INTO WEDNESDAY NIGHT WITH THE NORTHWEST FLOW AND COLD ADVECTION. THE BEST CHANCES FOR SNOW WILL OCCUR IN THE MOUNTAINS AND WESTERN SLOPES. HIGH TEMPERATURES WEDNESDAY WILL RANGE FROM THE LOWER TEENS IN THE NORTHWEST MOUNTAINS TO THE MID 30S IN THE PIEDMONT. 850 MB TEMPERATURES WILL DROP TO -18 TO -20 BY 12Z/7AM THURSDAY. THIS WILL MAKE SNOW SHOWERS IN THE WESTERN MOUNTAINS QUITE EFFICIENT WITH SNOW TO LIQUID RATIOS OF 25:1 POSSIBLE WEDNESDAY NIGHT. IN GENERAL...ADDITIONAL SNOW ACCUMULATIONS WEDNESDAY AND WEDNESDAY NIGHT WILL VARY FROM A COATING TO NEAR 3 INCHES ALONG THE WESTERN FACING SLOPES ESPECIALLY IN GREENBRIER COUNTY OF SOUTHEAST WEST VIRGINIA. LOW TEMPERATURES WEDNESDAY NIGHT WILL RANGE FROM AROUND ZERO IN THE NORTHWEST MOUNTAINS TO NEAR 20 DEGREES IN THE PIEDMONT. THE COMBINATION OF WIND AND TEMPERATURES WILL MAKE WIND CHILLS AS COLD AS 5 BELOW TO 20 BELOW ZERO WEDNESDAY NIGHT INTO THURSDAY MORNING IN THE MOUNTAINS. THERE IS ENOUGH DRY AIR AND DOWNSLOPING ON THURSDAY TO CREATE SOME CLEARING EAST OF THE BLUE RIDGE. WHILE IN THE WEST...ISOLATED TO SCATTERED SNOW SHOWERS WILL CONTINUE ESPECIALLY IN THE NORTHWEST. AROUND AN INCH OR SO SNOW ACCUMULATION MAY BE POSSIBLE WITH A HEAVIER SNOW SHOWER THURSDAY. HIGH TEMPERATURES ON THURSDAY WILL BE IN THE TEENS IN THE MOUNTAINS TO THE LOWER 30S IN THE PIEDMONT. ON THURSDAY NIGHT...THE UPPER TROUGH AXIS PULLS NORTHEAST AND MOST OF SNOW SHOWERS AND SNOW FLURRIES SHOULD TAPER OFF. LOW TEMPERATURES THURSDAY NIGHT WILL RANGE FROM THE SINGLE DIGITS TO THE TEENS. WIND CHILLS MAY STILL BE NEAR WIND CHILL LEVELS FOR THE NORTHWEST MOUNTAINS THURSDAY NIGHT INTO FRIDAY MORNING. && .LONG TERM /FRIDAY THROUGH MONDAY/... AS OF 250 PM EST MONDAY... EASTERN UPPER TROF GETS RE-ENFORCED FRIDAY NIGHT AND SATURDAY...THEN TROF AXIS MOVES OF THE COAST ON SUNDAY. BOTH THE ECMWF AND GFS BRING A CLIPPER ACROSS THE CENTRAL UNITED STATES MONDAY THEN INTO THE MID ATLANTIC REGION BY TUESDAY. WPC SUGGESTED THE TRACK OFF THE ECMWF MAY BE TOO FAR SOUTH. SOME 850 MB WARM AIR ADVECTION AND LOW LEVEL CONVERGENCE ALONG THE LEADING EDGE OF THE NEXT SURGE OF ARCTIC AIR. BEST LIFT LOOKS TO BE ON FRIDAY WITH SOME UPPER DIFFLUENCE. SNOW SHOULD BE MORE WIDESPREAD THAN JUST UPSLOPE. THEN GUSTY WINDS AND VERY LOW WIND CHILL VALUES ON FRIDAY NIGHT THROUGH SATURDAY NIGHT WITH NORTHWEST 850 MB WINDS APPROACHING 50 KNOTS. WIND CHILLS WILL AGAIN BE IN ADVISORY CRITERIA...BETWEEN -5 TO -19 IN THE MOUNTAINS ON SATURDAY NIGHT. A ROUGHLY 1045 MB SURFACE HIGH WILL BUILD INTO THE AREA FRIDAY NIGHT AND SATURDAY. THIS FEATURE WILL BE CENTERED OVER THE MID ATLANTIC REGION MONDAY MORNING. WINDS WILL DIMINISH ENOUGH WITH THE APPROACH OF THIS HIGH...AND WITH THE ASSOCIATED DRY AIR...TO END UPSLOPE SNOW SHOWERS IN THE MOUNTAINS SUNDAY. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... AS OF 1255 AM EST TUESDAY... SNOW SHOWERS WILL PERSIST WEST OF THE BLUE RIDGE THROUGH THE PERIOD WITH A PERSISTENT ACCUMULATING SNOW ALONG THE WESTERN SLOPES OF THE APPALACHIANS. MVFR AND OCCASIONAL IFR CIGS AND VSBYS WILL BE FOUND ACROSS THE MOUNTAINS WITH MAINLY VFR CONDITIONS EAST OF THE BLUE RIDGE. CAN`T RULE OUT STRAY SNOW SHOWERS OR FLURRIES MAKING IT EAST OF THE BLUE RIDGE ASSOCIATED WITH LOCAL MVFR...BUT COVERAGE DOES NOT WARRANT INCLUSION IN THE KLYH OR KDAN TAF ATTM. CURRENT WEATHER PATTERN WILL PERSIST THROUGH WEDNESDAY PER NEARLY STATIONARY UPPER LEVEL LOW WHICH IS CENTERED OVER THE OHIO VALLEY. WINDS DURING THE PERIOD WILL PRIMARILY BE OUT OF THE WEST TO NORTHWEST...MAGNITUDES OF 8 TO 15 KTS SUSTAINED WITH OCCASIONAL GUSTS OF 15 TO 25 KTS. EXTENDED DISCUSSION... SUB-VFR SHOULD BECOME MORE CONFINED TO THE MOUNTAINS AND WESTERN SLOPES WEDNESDAY INTO THURSDAY WITH PRIMARY AREA OF MVFR/IFR CONDITIONS CONFINED TO THE WEST...UPSLOPE...SIDE OF THE APPALACHIAN MOUNTAINS. THIS WILL PRIMARILY IMPACT KBLF/KLWB WITH MAINLY VFR CONDITIONS EAST OF THE HIGHER MOUNTAIN RIDGES INTO CENTRAL AND EASTERN VA/NC. CONDITIONS SHOULD BRIEFLY RETURN TO MAINLY VFR THURSDAY/THURSDAY NIGHT AS WEAK HIGH PRESSURE BUILDS IN AND MOISTURE DECREASES. ANOTHER SYSTEM MOVING ACROSS THE SOUTH MAY BRING SUB VFR CONDITIONS WITH WINTRY PRECIP FRIDAY INTO FRIDAY NIGHT. AFTER THAT...ANOTHER ARCTIC FRONT CROSSES BY SAT MORNING WITH GUSTY WINDS AND UPSLOPE SNOW SHOWERS AND SUB VFR IN THE MTNS. && .EQUIPMENT... AS OF 1030 AM EST TUESDAY... KFCX RADAR IS BACK IN SERVICE. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...WINTER WEATHER ADVISORY UNTIL 7 AM EST THURSDAY FOR VAZ007- 009>012-015-019-020. NC...WINTER WEATHER ADVISORY UNTIL 7 AM EST THURSDAY FOR NCZ001-018. WV...WINTER WEATHER ADVISORY UNTIL 7 AM EST THURSDAY FOR WVZ042>044- 507. WINTER STORM WARNING UNTIL 7 AM EST THURSDAY FOR WVZ043-508. && $$ SYNOPSIS...PM NEAR TERM...AMS/PM SHORT TERM...KK LONG TERM...AMS AVIATION...RCS EQUIPMENT...AMS

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