Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 270528 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 1228 AM EST TUE JAN 27 2015 .SYNOPSIS... LOW PRESSURE OVER VIRGINIA WILL DEVELOP INTO A MAJOR WINTER STORM AS IT MOVES NORTHEAST ALONG THE NEW ENGLAND COAST TONIGHT AND TUESDAY. THIS STORM WILL INFLUENCE OUR WEATHER THROUGH TUESDAY WITH MOUNTAIN SNOW SHOWERS AND GUSTY NORTHWEST WINDS. && .NEAR TERM /THROUGH TODAY/... AS OF 715 PM EST MONDAY... NO CHANGES PLANNED TO CURRENT WINTER WEATHER ADVISORIES. AREA RADARS SHOWING SCATTERED SHOWERS MOVING THROUGH THE REGION ALONG A COLD FRONT BEING ENHANCED A BIT BY A WEAK UPPER LEVEL SHORT WAVE. MESO MODELS SEEM TO HAVE BEEN HANDLING THE EVOLUTION OF THIS WELL AND INDICATE IT WILL CONTINUE TO DISSIPATE AS IT MOVES INTO THE PIEDMONT. THEREFORE WILL BE LOWERING POPS OUT EAST. EXPECT THE UPSLOPE SNOW SHOWERS TO CONTINUE IN THE BLUSTERY NW FLOW BEHIND THE FRONT FOR THE FAR WESTERN SLOPES OF THE BLUE RIDGE...AND A MORE VIGOROUS SHORT WAVE DIVING DOWN THE BACKSIDE OF THE UPPER TROF SHOULD ENERGIZE THE ACTIVITY FROM THE NORTH CAROLINA MTNS UP INTO THE GRAYSON HIGHLANDS WHERE THE WINTER WEATHER ADVISORY CONTINUES THROUGH NOON TOMORROW. PREVIOUS AFD... LOW PRESSURE IS CURRENTLY PASSING OVER CENTRAL VIRGINIA WITH UPPER TROF AXIS AND COLDER AIR SPILLING OVER THE APPALACHIAN MOUNTAINS. TEMPERATURES ARE FALLING ACROSS THE MOUNTAINS...AND THIS COLD AIR ADVECTION WILL CAUSE FALLING TEMPERATURES FARTHER EAST AS WE PROGRESS THROUGH THE EVENING. TEMPERATURES HAVE ALREADY DROPPED INTO THE 20S IN THE MOUNTAINS. READINGS IN THE 40S WERE FOUND OVER THE PIEDMONT OF NC AND INTO SOUTHSIDE VA...BUT THESE NUMBERS WILL TAKE A TUMBLE TONIGHT. THROUGH 4PM TODAY...LITTLE OR NO SNOW HAD ACCUMULATED ANYWHERE WITHING THE CWA...WITH MAINLY A MIX OF RAIN/SNOW OVER THE MOUNTAINS AND RAIN EAST OF THE BLUE RIDGE. AS TEMPERATURES FALL THIS EVENING...ANY LINGERING RAIN WILL CHANGE TO SNOW. THE DEFORMATION ZONE ON THE NORTHWEST SIDE OF THE LOW IS EXPECTED TO PRODUCE A PERIOD OF SNOW OVER THE MOUNTAINS THIS EVENING. HIGHEST ACCUMULATIONS THIS EVENING ARE EXPECTED TO BE IN THE WV HIGHLANDS WHERE 1 TO 3 INCHES OF ACCUMULATION IS ANTICIPATED BEFORE MIDNIGHT. LATER TONIGHT THERE WILL BE A SECONDARY SURGE OF MOISTURE ASSOCIATED WITH AN UPPER LEVEL SHORT WAVE CROSSING THE NORTH CAROLINA MOUNTAINS. THIS WILL LIKELY RESULT IN ACCUMULATING SNOW FOR THE NORTH CAROLINA HIGH COUNTRY AND MOUNT ROGERS IN VIRGINIA. SNOW TO LIQUID RATIOS WILL ALSO BEGIN TO COME INTO PLAY LATE TONIGHT AS TEMPERATURES DIP BELOW 20 DEG F...WILDING 2 TO 1. AS SUCH...THINK IT IS FEASIBLE TO SEE 2 TO 4 INCHES OF SNOW OVER THE NC HIGH COUNTRY...POSSIBLY MORE AT ELEVATIONS ABOVE 4000 FT. OVERALL THIS IS NOT EXPECTED TO BE A BIG SNOW PRODUCER FOR THE CENTRAL APPALACHIANS. THE MAIN MEDIA FOCUS WILL BE ON COASTAL NEW ENGLAND WHERE THIS AREA OF LOW PRESSURE WILL WRAP UP INTO A MAJOR WINTER STORM. FOR THE CENTRAL APPALACHIANS...WE GET TO DEAL WITH THE BACKLASH WINDS AND MOUNTAIN SNOW SHOWERS. THEIR IS SOME POTENTIAL FOR WRAP AROUND MOISTURE FROM THE COASTAL STORM TO PENETRATE AS FAR SOUTH AS OUR NORTHEASTERN CWA LATE TONIGHT...SO WILL HAVE TO MONITOR THIS CLOSELY AS THERE MAY BE A NEED FOR WINTER WEATHER HEADLINES FOR AREAS NORTHEAST OF LYNCHBURG... SPECIFICALLY APPOMATTOX...BUCKINGHAM AND POINTS NORTH AND EAST. EVEN THOUGH WE ARE NOT ADVERTISING MUCH PRECIP WITHIN OUR LOCAL FORECAST AREA...THIS WEATHER SYSTEM IS VERY DYNAMIC...LOTS OF ENERGY ALOFT THAT WILL CAUSE THIS STORM TO DEEPEN QUICKLY AS IT MOVES UP THE EAST COAST. HAVE EVEN SEEN A FEW LIGHTNING STRIKES WITHIN THE SHOWERS OVER THE NORTH CAROLINA PIEDMONT TODAY WHICH IS AN INDICATOR OF HOW UNSTABLE THIS ATMOSPHERE IS BECOMING AND THE POTENTIAL ENERGY THAT IS BUILDING UP FOR THIS THING TO FEED OFF OF ONCE IT GETS EAST OF OUR FORECAST AREA AND CERTAINLY SETTING THE STAGE FOR COASTAL BOMBOGENESIS TONIGHT. MODELS HAVE BEEN STRUGGLING WITH QPF...AND IT WAS A BIT INTERESTING TO SEE ALL THE QPF THE GFS MODEL PAINTING OVER OUR CWA THIS MORNING...YET NOT MUCH WAS OCCURRING...CONVECTIVE FEEDBACK IN THE MODEL. WHAT REALLY MADE IT HUMOROUS WAS THE MODEL THEN TOOK THE 4-6 TENTHS OF AN INCH OF QPF AND CONVERTED IT TO ALL SNOW. ANYONE ISSUING FORECASTS AND BLINDLY FOLLOWING GUIDANCE THIS MORNING WOULD HAVE THEN EXPERIENCED A GOOD TASTE OF METEOROLOGICAL/MODEL CANCER...A GARBAGE IN...GARBAGE OUT SORT OF FORECAST. QPF ISSUES ASIDE...THE IMPACT FROM THIS STORM FOR OUR LOCAL AREA WILL BE MINOR COMPARED TO OUR NEIGHBORS TO THE NORTH. I.E. NOTHING WE HAVN`T SEE BEFORE. IN SUMMARY...A PERIOD OF SNOW IS LIKELY FOR OUR MOUNTAINS TONIGHT WITH FLURRIES AND SCATTERED SNOW SHOWERS LINGERING INTO TUESDAY. IT WILL BECOME BLUSTERY WITH NORTHWEST WINDS OF 10 TO 20MPH...AND GUSTS OF 25 TO 30 MPH. A 40 MPH GUST OVER THE NC/VA/WV HIGHLANDS IS CERTAINLY POSSIBLE. COLDER AIR SPILLING INTO THE AREA TONIGHT WILL PUSH TEMPERATURES INTO THE TEENS ACROSS THE HIGHLANDS...TO NEAR 30 IN THE PIEDMONT. TEMPERATURES WILL MOVE VERY LITTLE ON TUESDAY...REMAINING IN THE 20S MOUNTAINS...AND 30S TO NO MORE THAN 40 EAST OF THE BLUE RIDGE. && .SHORT TERM /TONIGHT THROUGH THURSDAY/... AS OF 400 PM EST MONDAY... TUESDAY NIGHT OUR REGION WILL CONTINUE TO BE WITHIN A NORTHWEST FLOW REGIME ON THE BACKSIDE OF THE DEEPENING LOW PRESSURE SYSTEM OFF THE NEW ENGLAND COAST. NORTHWEST FLOW...WITH A ORIGIN ACROSS LAKE ERIE...WILL BRING MOISTURE UPSLOPE ACROSS THE SOUTHEAST WEST VIRGINIA MOUNTAINS...SOUTH INTO THE NORTHERN MOUNTAINS OF NORTH CAROLINA. ANTICIPATE LIGHT ACCUMULATIONS OF SNOW ALONG THE PREFERRED WESTERN SLOPES. AMOUNTS WILL BE GREATEST IN WESTERN GREENBRIER COUNTY WHERE LESS THAN INCH OF NEW MEASURABLE SNOW IS EXPECTED. ELSEWHERE...THE SNOW WILL LIKELY BE IN THE FORM OF FLURRIES...OR ACCUMULATING SNOW THAT PRODUCES A DUSTING ON SURFACES. WINDS WILL GUST ACROSS THE MOUNTAINS IN THE 20 TO 30 MPH RANGE WITH LESSER MAGNITUDES ACROSS THE PIEDMONT. BY WEDNESDAY...HIGH PRESSURE WILL BE BUILDING INTO THE AREA AND LOW LEVEL WINDS WILL WEAKEN AND VEER MORE NORTHERLY...THUS TURNING OFF THE UPSLOPE SNOW MACHINE. ANTICIPATE A TREND TOWARD LITTLE OR NO CLOUD COVER AND WEAKENING WINDS. WEDNESDAY NIGHT INTO THURSDAY...THE CENTER OF THE SURFACE HIGH WILL SHIFT EAST OF THE REGION WHILE OUR NEXT CLIPPER SYSTEM HEADS SOUTHEAST THROUGH THE GREAT LAKES REGION. LOOK FOR WINDS TO BACK SOUTHWEST AND INCREASE THROUGH THIS TIME PERIOD...ALONG WITH AN ONSET OF WARM AIR ADVECTION. CLOUD COVER WILL START TO INCREASE FROM WEST TO EAST WEDNESDAY NIGHT SO THAT BY DAYBREAK THURSDAY MOSTLY CLOUDY TO CLOUDY CONDITIONS ARE EXPECTED ACROSS THE ENTIRE FORECAST REGION. OUR NEXT CHANCE OF PRECIPITATION WILL ARRIVE IN THE WEST BY MIDDAY THURSDAY AS THE CLIPPER SYSTEM HEADS INTO THE OHIO VALLEY. THE ONSET OF PRECIPITATION LOOKS AT THIS TIME TO BE A RAIN/SNOW MIX IN THE WEST. AS PRECIPITATION SPREADS EAST DURING THE...MILDER AIR WILL ALLOW FOR THE VAST MAJORITY OF THE PRECIPITATION TO TRANSITION TO PLAIN RAIN. TEMPERATURES WILL MODERATE DURING THIS TIME PERIOD...ESPECIALLY ACROSS WESTERN PARTS OF THE AREA ONCE WARM AIR ADVECTION STARTS WEDNESDAY NIGHT INTO THURSDAY. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... AS OF 400 PM EST MONDAY... BELOW NORMAL TEMPERATURES TRENDING TO MUCH BELOW THROUGH THE EXTENDED...ALONG WITH STRONG NORTHWEST WINDS THURSDAY NIGHT/FRIDAY AND AGAIN SUNDAY NIGHT/MONDAY. UPPER LEVELS WILL BE EVOLVING TO MORE OF A DOMINANT NORTHERN STREAM. THE LATEST INDICATIONS POINT TO A COLDER MORE AMPLIFIED EASTERN TROF DEVELOPING AS PER THE ECMWF...AND SPLIT FLOW OUT WEST WITH A RIDGE FOR THE PACIFIC NW AND A CUTOFF LOW REGENERATING OVER THE BAJA PENINSULA. THURSDAY NIGHT STARTS OUT WITH A COLD FRONT PUSHING THROUGH FOLLOWED BY UPSLOPE SNOW SHOWERS FOR THE WESTERN SLOPES OF THE APPALACHIANS WITH BLUSTERY NORTHWEST WINDS. THE SNOW SHOWERS AND BLUSTERY CONDITIONS WILL CONTINUE INTO FRIDAY. HIGH PRESSURE THEN BUILDS IN WITH FAIR WEATHER AND COLD TEMPERATURES FOR THE START OF THE WEEKEND. IT NOW APPEARS THAT A COLD FRONT WILL BE APPROACHING FROM THE WEST ON SUNDAY...BRINGING A GOOD CHANCE OF PRECIPITATION TO THE REGION. THE FRONT WILL PUSH THROUGH SUNDAY NIGHT...ALLOWING VERY STRONG NORTHWEST WINDS TO USHER IN A SHOT OF ARCTIC AIR AND COLD TEMPERATURES FOR THE START OF NEXT WEEK. THE ECMWF HAS BEEN CONSISTENT WITH THIS MESSAGE AND NAEFS ANOMALIES NOW SUPPORT THE GFS TREND TOWARD THIS SOLUTION SO CONFIDENCE IS GROWING IN THIS COLD OUTBREAK. && .AVIATION /05Z TUESDAY THROUGH SATURDAY/... AS OF 1200 AM EST TUESDAY... DEEP COASTAL LOW PRESSURE AREA THE MAIN FOCUS FOR THIS TAF VALID CYCLE. THE MAIN EFFECTS OF THIS STORM WILL BE FOR THE BIG CITIES IN THE NORTHEAST. FOR US...WE WILL DEAL WITH A COUPLE OF BANDS OF SNOW...A DEFORMATION ZONE ASSOCIATED WITH THE COASTAL LOW IMPACTING THE EASTERN PARTS OF THE PIEDMONT INCLUDING LYH/DAN...WHILE IN THE WEST IS A STRONG UPPER-LEVEL DISTURBANCE TRACKING SSE FROM THE OH/TN VALLEY TOWARD EASTERN TN/WESTERN NC...THAT WILL MAINLY IMPACT EASTERN TN/FAR SOUTHWEST VA/NORTHWEST NC OVERNIGHT/EARLY TUE. THIS WOULD PRINCIPALLY IMPACT TNB...BUT COULD IMPACT LWB/BLF/BCB TO SOME EXTENT...SO HAVE INCLUDED -SN WITH IFR- LIFR CIGS AND MVFR- IFR VSBYS WITH THIS ACTIVITY. IN ADDITION...THERE WILL BE MVFR-IFR CIGS WILL LIKELY PERSIST MOST OF THE NIGHT ACROSS EASTERN WV...WITH MVFR CIGS REMAINING IN PLACE EAST OF THE BLUE RIDGE IN ASSOCIATION WITH THE DEFORMATION ZONE. WINDS NOW NW IN ALL AREAS WITH SPEEDS 8-12KTS AND GUSTS 20-22KTS MANY SITES. WINDS SPEEDS ARE EXPECTED TO INCREASE OVERNIGHT AS THE COASTAL LOW INTENSIFIES TO 9-13KTS WITH GUSTS 17-25KTS. AS THE LOW PULLS NORTHEAST AWAY FROM THE AREA DURING THE DAY TUE...WINDS WILL GRADUALLY SUBSIDE...BUT AT LEAST LOW END GUSTS ARE EXPECTED THROUGHOUT THE DAY. MEDIUM CONFIDENCE IN CIGS THROUGH THE TAF VALID PERIOD. MEDIUM TO HIGH CONFIDENCE IN VSBYS THROUGH THE TAF VALID PERIOD. HIGH CONFIDENCE IN WIND DIR/SPD THROUGH THE TAF VALID PERIOD. EXTENDED DISCUSSION... HIGH PRESSURE ON WEDNESDAY WILL PROVIDE A QUIET DAY WITH VFR CONDITIONS ACROSS ALL TAF LOCATIONS. ANOTHER CLIPPER SYSTEM ARRIVES ON THURSDAY...BRINGING A CHANCE OF SUB-VFR CIGS AND VSBYS...WITH A CHANCE FOR -SHRA...-SHSN IN THE MOUNTAINS. && .EQUIPMENT... HINTON ALL HAZARDS RADIO...162.425MHZ WAS OFF THE AIR THIS MORNING. TECHNICIANS INDICATE THERE IS QUITE A BIT OF TREE DAMAGE FROM ICE IN THE AREA AND THE RADIO WILL CONTINUE EXPERIENCE INTERMITTENT OUTAGES DUE TO POWER INTERRUPTIONS IN THE AREA. THE ROANOKE TRANSMITTER...POOR MOUNTAIN 162.475 MHZ...IS ALSO EXPERIENCING PROBLEMS WITH INTERMITTENT OUTAGES. SIMILAR CONDITIONS EXIST ON POOR MOUNTAIN WITH THE POWER BEING INTERRUPTED BY TREE DAMAGE FROM ICE. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR VAZ015. NC...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR NCZ001-018. WV...NONE. && $$ SYNOPSIS...PM NEAR TERM...MBS/PM SHORT TERM...DS LONG TERM...MBS AVIATION...PM/RAB EQUIPMENT...PM

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