Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 200238 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 938 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 945 PM EST FRIDAY... MOSAIC OF NWS DOPPLER RADARS INDICATES LEADING EDGE OF PRECIP EXPANDING INTO SOUTHEAST TN...AND CENTRAL GA. HOWEVER...SFC OBS SUGGEST MOST OF THE LEADING RADAR RETURNS ARE NOT REACHING THE GROUND...AS SFC OBS SHOW PRECIP REPORTED IN ALABAMA. HRRR...RUC/RAP...AND HI-RES ARW MODELS ALL ARE IN THE BALLPARK ON WHERE PRECIP IS FALLING AT 02Z...AND NONE OF THESE MODELS BRING LIGHT PRECIP INTO OUR FORECAST AREA UNTIL AFTER 09Z. COMBINE THIS WITH THE FACT THAT THE OOZ SOUNDINGS FROM RNK AND GSO SHOW A TREMENDOUS DRY LAYER (PWATS 0.25 AND 0.31 RESPECTFULLY) BELOW 400MB...AND CHANCES FOR MEANINGFUL MEASURABLE PRECIP WITH THIS SYSTEM ARE DIMINISHING. AS A RESULT...DELAYED THE ARRIVAL OF PRECIP FROM THE SOUTHWEST. REDUCED POPS...ESPECIALLY NORTH OF 460...AND LOWERED QPF/SNOWFALL AMOUNTS. HIGH CLOUDINESS IS GRADUALLY OVERSPREADING THE REGION...BUT POCKETS OF CLEARNING HAVE ALLOWED TEMPS IN SOME AREAS LIKE DAN AND HSP TO FALL FASTER THAN ANTICIPATED. THEREFORE LOWERED TEMPS A FEW DEGREES...BUT TEMP FALL SHOULD SLOW AS CLOUDS THICKEN. TEMPS WILL NOT RISE TOO MUCH SATURDAY WITH PRECIP AROUND...THINKING MID TO UPPER 30S MOUNTAINS...TO LOWER 40S EAST. MOISTURE BEGINS TO LIFT OUT BY MID-LATE AFTERNOON SUCH THAT PRECIP SHOULD TAPER OFF. && .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 /03Z SATURDAY THROUGH WEDNESDAY/... 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. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...JH/WP NEAR TERM...PH/WP SHORT TERM...AMS LONG TERM...KK AVIATION...JH/KK/WP

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