Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 192350 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 650 PM EST FRI DEC 19 2014 .SYNOPSIS... HIGH PRESSURE BUILDS SOUTHEAST ACROSS THE AREA RESULTING IN OVERALL DRY WEATHER INTO EARLY TONIGHT. A WEAK AREA OF LOW PRESSURE WILL DEVELOP ALONG THE GULF COAST STATES LATE TONIGHT AND MOVE EAST OVER THE SOUTHEAST STATES ON SATURDAY. THIS SYSTEM WILL BRING A PERIOD OF LIGHT WINTRY PRECIPITATION TO MAINLY SOUTHERN AND WESTERN AREAS SATURDAY. ANOTHER LOW DEVELOPS ACROSS THE SOUTHEAST SUNDAY NIGHT MOVING UP THE COAST TO THE TIDEWATER OF VIRGINIA BY MONDAY AFTERNOON. && .NEAR TERM /THROUGH SATURDAY/... AS OF 145 PM EST FRIDAY... UPPER TROUGH AND SHORTWAVE MOVING OUT OF TEXAS INTO THE LOWER AND MID MISSISSIPPI VALLEY WILL SHIFT TOWARD OUR REGION OVERNIGHT INTO SATURDAY. MODELS SEEM TO BE AGREEING ON A NON-EVENT...MEANING NO ADVISORIES OR WARNINGS AS THE SYSTEM MOVES BY FAIRLY QUICK PREVENTING SUFFICIENT MOISTURE INFLOW TO ADVANCE NWD. THIS SYSTEM HAS ENOUGH DYNAMICS ALOFT TO GIVE A LIGHT COATING OF SNOW TO AS MUCH AS 1-2 INCHES...BUT OVERALL SPEED WILL AGAIN LIMIT THIS. FORECAST FROM PREVIOUS SHIFT WAS NOT THAT DIFFERENT FROM HOW THE 12Z MODELS DEPICT THINGS. ONLY ADJUSTMENTS WERE TO LOWER POPS FURTHER NORTH FROM ROUGH LEWISBURG TO ROANOKE TO LYNCHBURG. FEEL MODELS HIGHLIGHT BEST LIFT AND MOISTURE CONVERGENCE WITH THE SHORTWAVE ACROSS THE NC/VA BORDER...SO KEPT LIKELY POPS FROM THE GRAYSON HIGHLANDS AND NC MTNS EAST TOWARD DANVILLE/MARTINSVILLE AND REIDSVILLE...TAPERING TO SLIGHT CHANCE NORTH OF HIGHWAY 460. QPF WILL BE LESS THAN A TENTH OF AN INCH...WHICH TRANSLATES TO LESS THAN 1 INCH OF SNOW...THOUGH POSSIBLE NARROW AXIS OF HEAVIER BAND COULD BRING AN INCH OR TWO THE HIGHER TERRAIN OF NC SAT MORNING. AT ISSUE EARLY WILL BE THE EVER INCREASING HIGH CLOUDS AND HOW COOL WILL WE GET BEFORE CLOUDS BLANKET THE SKIES SLOWING THE FALL. TEMPS AT THE SFC AND ALOFT BASED ON THE FORECAST SOUNDINGS LEAD TO SNOW/SOME SLEET STARTING LATE TONIGHT IN THE SOUTH THEN TRANSITIONING TO RAIN BY LATE MORNING...EXCEPT THE MTNS WHERE IT WILL STAY MIXED AND NEAR THE 0C ISOTHERM. LOWS GIVEN INCREASING CLOUDS WILL RANGE FROM TEH MID 20S OVER THE ALLEGHANY HIGHLANDS...TO UPPER 20S SW VA/SRN WV AND PIEDMONT NORTH OF DANVILLE...WITH LOWER 30S NC MTNS-ROANOKE...SOUTHSIDE VA...INTO THE NC FOOTHILLS. TEMPS WILL NOT RISE TOO MUCH SATURDAY WITH PRECIP AROUND...THINKING MID TO UPPER 30S MOUNTAINS...TO LOWER 40S EAST. DEEP MOISTURE BEGINS TO LIFT OUT BY MID-LATE AFTERNOON SUCH THAT PRECIP SHOULD TAPER OFF. IN SUMMARY...NO ADVISORIES OR WARNINGS...BUT MAY NEED A SPECIAL WEATHER STATEMENT FOR THE SW MTNS OF VA INTO NC LATER AS SNOW COMING IN BEFORE DAWN WILL STICK TO UNTREATED ROADS...THOUGH INTENSITY/RATE OF SNOWFALL DOES NOT LOOK ALL THAT IMPRESSIVE. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... AS OF 320 PM EST FRIDAY... 500 MB PATTERN SATURDAY NIGHT AND SUNDAY HAD SLIGHTLY RISING HEIGHTS AND WEAK RIDGING. THEN HIGHER AMPLITUDE LONG WAVE TROF BEGINS DIGGING IN THE CENTRAL UNITED STATES. WPC IS FAVORING THE TIMING OFF THE ECMWF FOR THE NEXT SOUTHERN STREAM SHORT WAVE WHICH CROSSES THE FORECAST AREA ON MONDAY. WILL KEEP HIGHEST PROBABILITY OF PRECIPITATION ON MONDAY. 850 MB TEMPERATURES RISE ABOVE ZERO ON SUNDAY. BY MONDAY STRONGER SURFACE WEDGE WILL BE IN PLACE AS LOW PRESSURE DEVELOPS OFF THE CAROLINA COAST. BY MONDAY MORNING...WARM NOSE ABOVE WEDGE REACHES TEMPERATURES WARM ENOUGH TO MELT ANY FROZEN PRECIPITATION. POCKET OF STRONGER WIND SPEEDS AT 850 MB WILL ENHANCE UPSLOPE ON EASTERN SIDE OF THE BLUE RIDGE ON MONDAY. BUFKIT SOUNDINGS SHOWED THE POTENTIAL FOR FREEZING RAIN AT LEWISBURG AND HOT SPRINGS. AMOUNT OF PRECIPITATION THAT FAR NORTHWEST OF THE STORM WAS STILL UNCERTAIN. HIGHEST AMOUNTS WILL BE CLOSER TO THE COAST. WILL STAY CLOSE TO GUIDANCE FOR TEMPERATURES SATURDAY NIGHT THROUGH SUNDAY NIGHT. MONDAY WILL HAVE LITTLE TO NO TEMPERATURE RISE SINCE REGION WILL BE IN A WELL ESTABLISHED RIDGE WITH PRECIPITATION AND PLENTY OF CLOUDS. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... AS OF 240 PM EST FRIDAY... WEAK CAD EVENT WITH OVERRUNNING PRECIPITATION WILL CONTINUE MONDAY NIGHT INTO TUESDAY. LIGHT RAIN...POSSIBLY WITH A FEW POCKETS OF SLEET OR FREEZING RAIN EXPECTED. WITH CLOUDS AND PRECIPITATION KEPT LOW TEMPERATURES COOLER THAN MOS WITH READINGS FROM AROUND FREEZING TO THE UPPER 30S IN THE SOUTHEAST. A DEEP LONGITUDINAL TROUGH DEVELOPS FROM GREAT LAKES SOUTH TO THE GULF OF MEXICO ON TUESDAY WITH INCREASING SOUTHERLY LOW LEVEL FLOW ACROSS OUR REGION...ACCOMPANIED BY INCREASING MOISTURE ADVECTION. TEMPERATURES WILL WARM TUESDAY AHEAD OF THE COLD FRONT WITH HIGHS FROM THE MID 40S IN THE MOUNTAINS TO THE LOWER 50S IN THE PIEDMONT. MODEL CONSENSUS OF GFS AND ECMWF IS THAT A SYNOPTIC UPPER TROUGH OVER THE MISSISSIPPI VALLEY WILL AMPLIFY TUESDAY AND THEN EJECT NEGATIVELY TILTED THROUGH THE SOUTHEAST U. S. TUESDAY NIGHT INTO WEDNESDAY. WITH THE POSITION OF THE ASSOCIATED SURFACE OCCLUDED FRONT AND THE TRIPLE POINT PASSING SOMEWHERE NEAR OR JUST SOUTH OF OUR REGION....THERE IS THE POTENTIAL FOR OUR REGION TO HAVE ACTIVE WEATHER LATE TUESDAY NIGHT INTO WEDNESDAY WITH PLENTY OF SHOWERS...PERHAPS VERY GUSTY WINDS AND A FEW THUNDERSTORMS. LOOKS LIKE THE AXIS OF BETTER INSTABILITY MAY BE A LITTLE FURTHER SOUTH ON THE 12Z MODEL RUN. COLD AIR PUSHES INTO THE REGION TUESDAY NIGHT INTO WEDNESDAY ALLOWING FOR SOME RAIN AND SNOW SHOWERS. IF ENOUGH COLD AIR ARRIVES QUICKLY...THERE COULD BE SOME ACCUMULATING SNOW IN THE WESTERN MOUNTAINS. LOW TEMPERATURES TUESDAY NIGHT WILL RANGE FROM THE LOWER 30S IN THE MOUNTAINS TO THE LOWER 40S IN THE SOUTHEAST. A COLD FRONT WILL MOVE EAST ACROSS OUR REGION WEDNESDAY INTO WEDNESDAY NIGHT. HIGHS ON WEDNESDAY WILL WARM INTO THE LOWER 40S IN THE WEST TO THE LOWER 50S IN THE EAST. RAIN AND SNOW SHOWERS WILL CHANGEOVER TO SNOW SHOWERS AND SNOW FLURRIES IN THE WEST WEDNESDAY NIGHT. LOW TEMPERATURES WEDNESDAY NIGHT WILL DROP INTO THE MID 20S IN THE MOUNTAINS TO THE LOWER 30S IN THE PIEDMONT. WEST TO NORTHWEST UPPER FLOW WILL CONTINUE INTO THURSDAY WITH HIGHS FROM THE UPPER 20S IN THE MOUNTAINS TO AROUND 50 IN PIEDMONT. WINDS WILL BE QUITE STRONG ON THURSDAY AS A 50 TO 55 KNOT 850MB JET PIVOTS ACROSS THE REGION. THE UPPER FLOW SHIFTS TO THE SOUTHWEST THURSDAY NIGHT INTO FRIDAY AS TROF CURVES OUT IN THE CENTRAL US WITH SFC INFLECTION OF LOW PRESSURE DEVELOPING OVER THE TENNESSEE VALLEY BY FRIDAY MORNING. MOISTURE SLOWLY RETURN FRIDAY NIGHT INTO SATURDAY AS THE HIGH CENTER SLIDE OFF THE COAST. && .AVIATION /00Z SATURDAY THROUGH THURSDAY/...
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AS OF 650 PM EST FRIDAY... VFR CONDITIONS EXPECTED THIS EVENING INTO TONIGHT. HIGH CLOUDS INCREASE THIS EVENING...THEN LOWER TO A MID DECK AROUND MIDNIGHT. A LIGHT SNOW EVENT ON TAP SATURDAY FOR OUR REGION. LIGHT SNOW WILL BEGIN ALONG THE SOUTHERN BLUE RIDGE BETWEEN 4-7 AM AND SPREAD NORTHWARD IN OUR AREA. SOME LIGHT SNOW/FLURRIES EXPECTED AT ALL SITES BEFORE 18Z...WITH HIGHEST IMPACT FOR AVIATION LOOKING TO STAY SOUTH OF A TRI-FVX LINE...SO WENT WITH MVFR VSBYS/CIGS AT DAN AROUND 15Z...WITH POSSIBLE MVFR CIGS AT BLF. THIS SYSTEM MOVES OUT FAIRLY QUICK WITH PRECIPITATION ENDING SATURDAY AFTERNOON INTO SATURDAY EVENING. MEDIUM CONFIDENCE ON VISIBILITIES...WINDS AND CEILINGS DURING THE TAF PERIOD. EXTENDED DISCUSSION... ONCE THIS FEATURE EXITS WILL SEE THE NEXT WAVE ALONG THE COAST BRING ANOTHER ROUND OF SUB-VFR CONDITIONS FOR LATER SUNDAY NIGHT INTO MONDAY. RAIN WILL BE THE PRIMARY PRECIPITATION TYPE WITH THE POTENTIAL FOR POCKETS OF FREEZING RAIN LATE SUNDAY NIGHT INTO MONDAY MORNING ACROSS COLDER NORTHERN PORTIONS OF FORECAST AREA WHICH MIGHT IMPACT LWB IF TEMPERATURES ARE COLD ENOUGH. RAIN WILL IMPACT AREAS ALONG AND EAST OF THE BLUE RIDGE...WITH YET ANOTHER SYSTEM SLATED FOR LATE TUESDAY INTO WEDNESDAY AHEAD OF A STRONG COLD FRONT. THESE SYSTEMS ARE EXPECTED TO BRING A PERIOD MAINLY RAIN BUT COULD BE SOME WINTRY WX AS WELL ESPECIALLY IN THE MOUNTAINS WITH THE SUNDAY NIGHT/MONDAY EVENT. EXPECT POTENTIAL LOW LEVEL WIND SHEAR AS WELL AND POOR FLYING WEATHER FOR EARLY NEXT WEEK. RAIN AND SNOW SHOWERS WILL CONTINUE INTO WEDNESDAY. GUSTY NORTHWEST WINDS ARE POSSIBLE WEDNESDAY INTO THURSDAY. MOUNTAIN SNOW SHOWERS AND SNOW FLURRIES EXPECTED WEDNESDAY NIGHT INTO CHRISTMAS.
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&& .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...JH/WP NEAR TERM...WP SHORT TERM...AMS LONG TERM...KK AVIATION...JH/KK/WP

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