Area Forecast Discussion
Issued by NWS Blacksburg, VA

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654 FXUS61 KRNK 130048 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 748 PM EST FRI FEB 12 2016 .SYNOPSIS... AN UPPER LEVEL DISTURBANCE WILL PASS EAST OF THE AREA THIS EVENING. A SURGE OF ARCTIC AIR FOLLOWS THIS SYSTEM OVERNIGHT RESULTING IN VERY WINDY CONDITIONS AND BITTERLY COLD TEMPERATURES...ALONG WITH SOME ADDED SNOW SHOWERS FOR THE FAR WESTERN SLOPES OF THE APPALACHIANS INTO SATURDAY. BY MONDAY ANOTHER WINTER STORM SYSTEM WILL BEGIN TO AFFECT THE REGION WITH THE POTENTIAL FOR SNOW AND MIXED PRECIPITATION THROUGH THE FIRST PART OF NEXT WEEK. && .NEAR TERM /THROUGH SATURDAY/... AS OF 200 PM EDT FRIDAY... SHORTWAVE PASSING TO THE SOUTH WILL FINALLY LINK WITH THE SURFACE COASTAL LOW IN TURN TAKING THE LAST BATCH OF SYNOPTIC SNOW SHOWERS OUT OF THE AREA BY THIS EVENING. SHOULD THEN SEE A BRIEF BREAK AFTER SUNSET BEFORE THE TRUE UPSTREAM ARCTIC AIR ARRIVES ON INCREASING NW WINDS LATE THIS EVENING THROUGH SATURDAY AS DEEP 5H TROFFINESS CARVES OUT ACROSS THE EAST. THIS ALONG WITH INCREASING LAPSES...DEEP MOISTURE AND STRONG UPSLOPE WILL ALLOW FOR BANDS OF HEAVIER SNOW SHOWERS TO DEVELOP OVER THE FAR WEST WITH ANOTHER 1-3 INCHES OF SNOW LIKELY ACROSS THE FAVORED AREAS...AND FLURRIES OUT TO THE BLUE RIDGE. EXPECT DOWNSLOPE CLEARING TO DEVELOP OUT EAST OVERNIGHT SO DRY AFTER ANY LATE DAY SNOW SHOWERS END BY EARLY THIS EVENING. OTRW WINDS AND COLD THE MAIN CONCERNS WITH GUIDANCE SHOWING A 50+ KNOT 85H JET PLOWING IN ON VERY STRONG SUBSIDENCE AND 85H TEMPS FALLING TO BELOW -20C OVERNIGHT. MAY BE STRONG ENOUGH FOR WARNING CRITERIA WIND SPEEDS TO BE REACHED OVER THE NW NC MOUNTAINS WITH WIDESPREAD ADVISORY LEVELS OUT TO THE BLUE RIDGE. THEREFORE BUMPED UP WIND SPEEDS WHILE KEEPING THIS ROLLED UP INTO THE GOING WINTER WEATHER ADVISORY FOR ADDED SNOW WEST AND WIND CHILLS OUT TO THE FOOTHILLS. SINCE MOS NOT QUITE AS COLD AS BEFORE UNDER LOTS OF MIXING...STAYED A LITTLE ABOVE THE COLDEST LOWS BUT STILL OVERALL SINGLE DIGITS/TEENS TO AROUND 20 WITH CHILLS AT ADVISORY OR COLDER LEVELS IN SPOTS WEST. ARCTIC HIGH SLOWLY BUILDS IN FROM THE NW DURING SATURDAY ALLOWING SOME MID/LATE AFTERNOON DROP OFF IN WINDS BUT STILL FRIGID WITH HIGHS SINGLE DIGITS/TEENS MOUNTAINS AND 20S TO NEAR 30 FROM THE BLUE RIDGE EAST. LOW LEVEL UPSLOPE MOISTURE LOOKS TO SLOWLY WANE SATURDAY AFTERNOON BUT STILL ENOUGH FOR HIGH POPS DURING THE MORNING...TAPERING TO CHANCE COVERAGE LATER IN THE DAY. CLOUDS SHOULD ALSO SLOWLY FADE FROM EAST TO WEST AS THE VERY DRY ARCTIC AIR SPILLS IN ALLOWING FOR MORE SUN FROM THE BLUE RIDGE EAST AND BECOMING PC FAR WEST LATE. STILL APPEARS THAT WIND CHILL ADVISORY CRITERIA COULD LINGER INTO THE AFTERNOON SO FEW CHANGES WITH GOING HEADLINES. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/... AS OF 300 PM EST FRIDAY... ARCTIC HIGH PRESSURE WILL MOVE FROM THE OHIO VALLEY SATURDAY NIGHT THEN OVER THE MID ATLANTIC REGION SUNDAY. OVERNIGHT LOWS WILL DROP DOWN INTO THE SINGLE DIGITS ACROSS THE MOUNTAINS TO A RANGE OF 10F- 15F IN THE EAST. EVEN WITH LIGHT WINDS...WIND CHILL VALUES WILL BE BELOW ZERO SUNDAY MORNING. TEMPERATURES AND WIND CHILLS WILL MODERATE THROUGH THE DAY SUNDAY WITH HIGHS ONLY PEAKING IN THE 20S. AN AREA OF LOW PRESSURE BEGINS TO DEVELOP OVER EASTERN TEXAS SUNDAY NIGHT. AS THIS LOW TRACKS EAST AND DEEPENS THROUGH THE DAY MONDAY...A WARM FRONT WILL GLIDE OVER THE ARCTIC HIGH...PRODUCING LIGHT SNOW ACROSS THE REGION. AS THIS LOW APPROACHES THE TENNESSEE VALLEY...A WARM NOSE WILL BEGIN TO ENTER THE AREA...POSSIBLY CHANGING SNOW OVER TO A WINTRY MIX OF SLEET, RAIN OR FREEZING RAIN. CONFIDENCE IS HIGH ON A WINTER STORM FOR THE AREA BEGINNING MONDAY...HOWEVER P-TYPE REMAINS THE BIGGEST QUESTION. MODELS CONTINUE TO JUMP AROUND WITH THE TRACK OF THE LOW. IF THE LOW TRACKS NORTH FROM THE TENNESSEE VALLEY AND REMAINS WEST OF THE APPALACHIANS...P-TYPE WILL CHANGE FROM SNOW TO SLEET TO RAIN MONDAY AFTERNOON AND NIGHT. IF THE TRACK IS FARTHER SOUTH AND EAST OF THE APPALACHIANS...A LONGER DURATION OF SNOW IS EXPECTED WITH A CHANGE OVER TO SLEET/RAIN OCCURRING LATER MONDAY NIGHT. DYNAMICS AND LIFT WITH THIS SYSTEM ARE VERY IMPRESSIVE...ESPECIALLY AS THE LOW APPROACHES THE AREA. UPWARDS OF AN INCH OF LIQUID IS LIKELY...BUT AT WHAT P-TYPE IT FALLS AS IS ANOTHER QUESTION TO ANSWER. FOR THIS FORECAST PACKAGE...WE WILL KEEP P-TYPE SIMPLE WITH RAIN/SNOW. WE WILL ALSO KEEP SNOWFALL LIGHT TO MODERATE AND NOT SPECULATE ON AMOUNTS AT THIS TIME. && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 245 PM EST FRIDAY... EARLY TUESDAY MORNING A SURFACE LOW PRESSURE SYSTEM WILL MOVE ACROSS THE CWA...WITH THE CENTER OF THE SYSTEM TRACKING TO THE SOUTHEAST AND THEN SHIFTING TO MOVE ALONG THE EAST COAST. THE FURTHER SOUTHEAST THE SYSTEM MOVES THE MORE LIKELY THE PRECIPITATION WILL FALL AS SNOW. THERE IS SOME UNCERTAINTY AT THIS TIME WHETHER THE PRECIPITATION WILL FALL COMPLETELY AS SNOW...RAIN...OR WINTRY RAIN MIX. THE MODELS DAYTIME SURFACE TEMPERATURES STAY WARM ENOUGH TO FAVOR RAIN FOR MAJORITY OF THE CWA ESPECIALLY IN THE PIEDMONT. HOWEVER...SNOW COULD BE POSSIBLE IN THE HIGHER ELEVATIONS AND ALONG THE WESTERN SLOPES OF THE BLUE RIDGE AS THE RIDGES STAY COLDER AND THE LOW PRESSURE BRINGS IN A COLDER WRAP AROUND MOISTURE. WEDNESDAY A CLIPPER SYSTEM STARTS TO MOVE INTO THE CWA BRINGING AN ADDITIONAL CHANCE FOR SNOW AND COLD TEMPERATURES. THE GFS AND EURO ARE IN DISAGREEMENT HOW MUCH MUCH SNOW BUT MODELS TEND TO AGREE THAT THE WESTERN SLOPES WILL SEE SOME ACCUMULATIONS. A HIGH PRESSURE THEN BUILDS IN DURING THE DAY THURSDAY AND TEMPERATURES WILL START TO WARM UP. && .AVIATION /01Z SATURDAY THROUGH WEDNESDAY/...
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AS OF 1150 AM EST FRIDAY... MAIN CONCERN OVERNIGHT AND INTO EARLY SATURDAY WILL BE LOW LEVEL TURBULENCE GENERATED FROM STRONG NORTHWEST WINDS. AN ARCTIC FRONT WILL MOVE ACROSS THE APPALACHIAN MOUNTAINS FROM NORTHWEST TO SOUTHEAST OVERNIGHT. PASSAGE OF THE FRONT WILL BRING ONSET OF MODERATE TO STRONG NORTHWEST WINDS...SUSTAINED VALUES NEAR 20 KTS ATTMS WITH GUSTS OF 30 TO 35 KTS. GUSTS NEAR 45 KTS ARE POSSIBLE EARLY SATURDAY MORNING VCNTY OF KROA/KBCB/KTNB WHERE AIRFLOW WILL BE THE STRONGEST OVER THE RIDGE CRESTS...SIMILAR TO WATER FLOWING OVER A DAM. IN ADDITION TO THE WIND...ANTICIPATE MVFR CIGS/VSBYS OVER THE MOUNTAINS DUE TO SCATTERED SNOW SHOWERS. NARROW CORRIDOR OF IFR WILL EXIST ALONG THE NORTHWEST FACING SLOPES OF THE APPALACHIAN DIVIDE FROM EKN-BLF-TNB WHERE VSBYS/CIGS MAY OBSCURE THE RIDGE TOPS. EAST OF THE MOUNTAINS...THE NORTHWEST WIND WILL RESULT IN DOWNSLOPE DRYING WITH CLOUD BASES DISSOLVING AND RESULTING IN VFR. WINDS WILL DIMINISH SATURDAY EVENING AND INTO SATURDAY NIGHT...WITH NEAR CALM CONDITIONS BY SUNDAY AS HIGH PRESSURE SETTLES OVERHEAD. MAIN CONCERN SATURDAY NIGHT INTO SUNDAY WILL BE THE BITTER COLD...TEMPERATURES DROPPING INTO THE SINGLE DIGITS. EXTENDED DISCUSSION... WINTER STORM IS EXPECTED TO IMPACT THE AREA EARLY NEXT WEEK WITH ONSET OF WINTRY PRECIPITATION BEGINNING SUNDAY NIGHT. CONFIDENCE IS HIGH THAT POOR FLYING CONDITIONS WILL EXIST FROM SUNDAY NIGHT THROUGH TUESDAY. THIS WINTER STORM WILL PRODUCE A VARIETY OF WINTRY PRECIPITATION...STARTING AS SNOW SUNDAY NIGHT...THEN TRANSITIONING TO SLEET AND FREEZING RAIN MONDAY. AFTER THE EARLY WEEK WINTER STORM...THERE IS ANOTHER WEAK CLIPPER SYSTEM THAT MAY IMPACT THE AREA FOR MID WEEK...POSSIBLY RESULTING IN THE CONTINUATION OF POOR FLYING CONDITIONS THROUGH WEDNESDAY.
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&& .CLIMATE... COLDEST AIR OF THE SEASON ARRIVES THIS WEEKEND. SEVERAL RECORD LOW MAX TEMPERATURES AND LOW TEMPERATURES ARE POSSIBLE. BELOW ARE THE CURRENT RECORDS FOR SATURDAY 2/13 AND SUNDAY 2/14. SATURDAY 02/13/2016 SITE MINT YEAR LOMAX YEAR KBLF 4 1988 19 1988 KDAN 11 1955 32 1981 KLYH 5 1979 9 1899 KROA 8 1917 18 1914 KRNK -4 1969 14 1955 SUNDAY 02/14/2016 SITE MINT YEAR LOMAX YEAR KBLF 5 1971 16 1960 KDAN 15 1986 32 1986 KLYH 4 1899 24 1905 KROA 10 1943 26 1986 KRNK -2 1969 24 1986 && .RNK WATCHES/WARNINGS/ADVISORIES... VA...WIND CHILL ADVISORY FROM 11 PM THIS EVENING TO 10 AM EST SUNDAY FOR VAZ007-009>020-022>024-032>035. WINTER WEATHER ADVISORY UNTIL 7 AM EST SATURDAY FOR VAZ007-009- 015. NC...WIND CHILL ADVISORY FROM 11 PM THIS EVENING TO 10 AM EST SUNDAY FOR NCZ001-002-018. WINTER WEATHER ADVISORY UNTIL 7 AM EST SATURDAY FOR NCZ001-018. WV...WIND CHILL ADVISORY FROM 11 PM THIS EVENING TO 10 AM EST SUNDAY FOR WVZ042>044-507. WINTER WEATHER ADVISORY UNTIL 7 AM EST SATURDAY FOR WVZ042-043- 508. WIND CHILL WARNING FROM 11 PM THIS EVENING TO 10 AM EST SUNDAY FOR WVZ508. && $$ SYNOPSIS...JH/MBS NEAR TERM...JH SHORT TERM...RCS LONG TERM...RCS AVIATION...PM CLIMATE...CF

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