Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 272039 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 339 PM EST TUE JAN 27 2015 .SYNOPSIS...
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AN UPPER LEVEL DISTURBANCE WILL DROP SOUTHEAST ACROSS THE REGION TONIGHT BRINGING CONTINUED GUSTY WINDS ALONG WITH SOME MOUNTAIN SNOW SHOWERS OR FLURRIES. HIGH PRESSURE BUILDS IN ON WEDNESDAY...FOLLOWED BY ANOTHER CLIPPER AREA OF LOW PRESSURE FOR THURSDAY. COLD HIGH PRESSURE SHOULD AGAIN FOLLOW THIS SYSTEM WITH ANOTHER ROUND OF COLDER AIR INCLUDING STRONG NORTHWEST WINDS AND MOUNTAIN SNOW SHOWERS FOR THE END OF THE WEEK.
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&& .NEAR TERM /THROUGH WEDNESDAY/...
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AS OF 222 PM EST TUESDAY... MOST OF THE AREA REMAINS IN BETWEEN FEATURES THIS AFTERNOON AND WITHIN A SMALL REGION OF WEAK SUBSIDENCE/DRY AIR PER LATEST VISIBLE IMAGES. EXPECT THIS TO LINGER INTO EARLY THIS EVENING BEFORE THE LAST PIECE OF CHANNELED VORTICITY BEHIND THE EXITING COASTAL UPPER TROUGH PIVOTS THROUGH TOWARD MORNING. HOWEVER DESPITE A RENEWED SURGE OF 85H COLD ADVECTION THIS EVENING...LOW LEVEL MOISTURE/LIFT APPEARS LACKING TO PRODUCE TOO MUCH IN THE WAY OF UPSLOPE SNOW SHOWERS EXCEPT OVER THE FAR NW WHERE KEEPING DECENT CHANCE POPS GOING. COULD SEE ANOTHER INCH OR TWO PERHAPS WESTERN GREENBRIER WITH A PERIOD OF FLURRIES FARTHER SOUTH ALONG THE UPSLOPE REGION OVERNIGHT. OTHERWISE WILL SEE LOW CLOUDS RETURN OVER THE WEST WHILE DOWNSLOPING SHOULD KEEP THINGS MAINLY CLEAR IN THE EAST FOR THE MOST PART. A PERIOD OF STRONGER NW WINDS ALSO LOOKS TO DEVELOP THIS EVENING WITH THE WAVE AND INCREASING COLD ADVECTION. HOWEVER PRESSURE RISES AND HEIGHT OF THE INVERSION DO NOT SUPPORT ENOUGH FOR AN ADVISORY ALTHOUGH MAY CHANNEL ENOUGH FOR ISOLATED 45+ MPH GUSTS OVER THE NORTH CAROLINA MOUNTAINS. THUS KEEPING MENTION IN THE HWO. APPEARS MIXING AND MORE CLOUDS MOUNTAINS TO HELP HOLD TEMPS UP SOME OVERNIGHT SO STAYING JUST ABOVE MOST MOS GUIDANCE ALTHOUGH STILL QUITE COLD WITH LOWS 15-20 WEST AND LOW/MID 20S EAST. HIGH PRESSURE FINALLY SLIDES IN FROM THE NW WEDNESDAY UNDER BUILDING 5H HEIGHTS ALLOWING FOR SUNNY SKIES AND DIMINISHING WINDS. WITH VERY DRY AIR IN PLACE AND GRADUAL 85H WARMING...EXPECT HIGHS TO BE CLOSER TO THE WARMER MAV MOS ESPECIALLY EAST WHERE SOME MID/UPPER 40S LIKELY...WITH MID 30S TO AROUND 40 WEST.
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&& .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
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AS OF 330 PM EST TUESDAY... THINGS TO REMAIN VERY PROGRESSIVE FOR THE MIDDLE OF THE WEEK WITH THE UPPER RIDGE CROSSING THE AREA WEDNESDAY NIGHT AHEAD OF THE NEXT FAST MOVING CLIPPER APPROACHING FROM THE UPPER MIDWEST. EXPECT INCREASING WARM ADVECTION ALOFT AHEAD OF THIS SYSTEM TO SPREAD A MID/HIGH CLOUD CANOPY IN FROM THE NW ALONG THE UPPER JET ESPECIALLY MOUNTAINS OVERNIGHT BUT DRY. SURFACE HIGH SLIDING EAST IN COMBINATION WITH CLOUDS SHOULD ACT TO HOLD TEMPS UP OUTSIDE THE DEEPER VALLEYS WITH LOWS MOSTLY IN THE 20S INCLUDING A FEW TEENS NW PENDING CLOUD COVERAGE. CENTER OF THE LOW PRESSURE SYSTEM PROGGED TO PASS WELL TO THE NORTH LATER THURSDAY WHILE SWINGING ANOTHER FAST MOVING COLD FRONT INTO THE REGION THURSDAY AFTERNOON. GIVEN BEST DYNAMICS AND LIFT HEADING BY TO THE NORTH...EXPECT MOISTURE TO BE LIMITED UNDER ONLY BRIEF/WEAK RETURN LOW LEVEL FLOW SO PRECIP CHANCES LOOK IFFY OUTSIDE THE MOUNTAINS. HOWEVER DOES APPEAR THAT A BAND OF SNOW/RAIN WILL ARRIVE OVER THE FAR WEST BY MIDDAY AND THEN PERHAPS CLIP THE NORTHERN BLUE RIDGE UPON ATTEMPTING TO CROSS THE RIDGES UNDER A QUICKLY VEERING WESTERLY FLOW. PTYPE LIKELY TO START AS LIGHT SNOW MOUNTAINS BEFORE SWITCHING TO MORE LIQUID NATURE AS BOTH 85H AND BOUNDARY LAYER WARMING TAKE OVER. THUS KEEPING A NARROW SWATH OF LIKELY POPS NW THURSDAY WITH CHANCES ELSEWHERE WEST...BUT MAINLY SLIGHT POPS SOUTH AS WELL AS THE EASTERN THIRD. SNOWFALL AMOUNTS OF PERHAPS AN INCH OR SO WESTERN GREENBRIER WITH OVERALL QPF OF LESS THAN A TENTH OF AN INCH...MAINLY WEST. EXPECTING HIGH TEMPS TO GET A BOOST THURSDAY AFTERNOON GIVEN THE SLOWING FRONT AND PERHAPS MORE SUN OUT EAST WHERE COULD SEE VALUES AROUND 50. THINK ONLY THE FAR NW AND HIGHER ELEVATIONS TO REMAIN IN THE 30S...PENDING TIMING OF CLOUDS AND ANY PRECIP. HOWEVER COULD SEE MOST PUSH INTO THE 40S...AS USUALLY WARMER JUST SOUTH OF THESE CLIPPERS PASSING WAY NORTH WITH MODELS TOO WET...AND TOO COLD SO STAYED ABOVE MOS FOR HIGHS. COLD FRONT FROM THE CLIPPER SCOOTING BY TO OUR NORTH WILL MOVE THROUGH THE REGION EARLY THURSDAY NIGHT...USHERING IN MUCH COLDER AIR FOR THE END OF THE WORKWEEK AND INTO THE WEEKEND. THIS WILL SET UP WHAT LOOKS TO BE PRETTY DECENT NW FLOW SNOW SHOWERS WEST OF THE BLUE RIDGE. ACCUMULATIONS FOR THE FAR WESTERN SLOPES LOOK TO BE AN INCH OR TWO...BUT WESTERN GREENBRIER COUNTY SHOULD PICK UP A TOTAL OF AROUND 5 INCHES BEFORE THINGS START TO WIND DOWN FRIDAY MORNING INTO FRIDAY AFTERNOON. IF LATER MODEL RUNS ARE AS ROBUST WITH THE QPF AND SNOW THIS WILL REQUIRE A WINTER WEATHER ADVISORY AT LEAST FOR WESTERN GREENBRIER THURSDAY NIGHT/FRIDAY MORNING. THE OTHER BIG STORY WILL BE THE VERY STRONG WINDS DEVELOPING THURSDAY NIGHT AND CONTINUING INTO FRIDAY. THE LOW LEVEL FLOW WILL VEER AROUND FROM WEST TOP NORTHWEST AND INCREASE TO 50KTS OR MORE PER THE LATEST GFS. NAM SOUNDINGS ON BUFKIT SHOW THE INVERSION LOWERING TO AROUND 850MB BY FRIDAY MORNING WITH 50KT WINDS RIGHT AT THE TOP OF THE SHALLOW MIXED LAYER BELOW THE INVERSION. IF THIS SCENARIO PLAYS OT AS CURRENTLY ADVERTISED BY THE MODELS IT WILL PRODUCE WIND GUSTS AROUND 50MPH...POSSIBLY HIGHER. WE WILL BE KEEPING A CLOSE EYE ON THIS IN LATER MODEL RUNS TO SEE IF A HIGH WIND WATCH IS NECESSARY FOR THE THURSDAY NIGHT/FRIDAY TIME FRAME. WITH THE COMBINED WIND AND COLD WILL ALSO BE LOOKING AT SOME WIND CHILL VALUES IN THE TEENS TO SINGLE DIGITS WEST OF THE BLUE RIDGE.
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&& .LONG TERM /SATURDAY THROUGH TUESDAY/...
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AS OF 330 PM EST TUESDAY... BELOW NORMAL TEMPERATURES TRENDING TO MUCH BELOW THROUGH THE EXTENDED...ALONG WITH POSSIBILITY OF MORE STRONG NORTHWEST WINDS SUNDAY NIGHT THROUGH MONDAY. UPPER LEVEL PATTERN FOR THE EXTENDED WILL BE SPLIT FLOW WITH A DOMINANT NORTHERN STREAM TROF IN THE EAST AND RIDGE FOR THE PAC NW. THERE IS ENOUGH GENERAL AGREEMENT BETWEEN THE GFS AND ECMWF MEMBERS...WHICH ARE SUPPORTED BY NAEFS ANOMALIES...TO BUY OFF ON THIS WHICH WILL BE A COLD SOLUTION. SATURDAY LOOKS LIKE FAIR WEATHER UNDER COLD HIGH PRESSURE. NEXT SYSTEM DEVELOPS TO OUR WEST AND TRACKS INTO NEW ENGLAND WITH A TRAILING COLD FRONT SWEEPING THROUGH THE REGION SUNDAY NIGHT. WILL NOT SPLIT HAIRS ABOUT PTYPE THIS FAR OUT BUT THE GENERAL TRACK TO OUR WEST AND NORTH WILL KEEP US ON THE WARM SIDE OF THE STORM. POSSIBLE HYBRID WEDGE IN PLACE AT THE ONSET MAY HELP COOL THINGS FOR WINTRY MIX AT ONSET GOING TO RAIN FOR THE BULK OF SUNDAY THEN BACK TO WINTRY AS PCPN TAPERS OFF...THOUGH TYPICAL NW FLOW UPSLOPE SNOW SHOWERS WEST OF THE BLUE RIDGE BECOME ESTABLISHED IN THE COLD AIR BEHIND THE COLD FRONT. MAY ALSO BE LOOKING AT ANOTHER STRONG NW WIND EVENT AS WE GO THROUGH SUNDAY NIGHT AND INTO MONDAY BUT THERE IS PLENTY OF TIME TO WATCH THIS AND SEE HOW LATER MODEL RUNS HANDLE THE EVOLUTION OF LOW LEVEL WINDS.
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&& .AVIATION /21Z TUESDAY THROUGH SUNDAY/... AS OF 1143 AM EST TUESDAY... VFR EXPECTED TO PREVAIL THIS AFTERNOON UNDER SCATTERED CLOUDS AND STRONGER NORTHWEST WINDS THAT MAY GUST UP TO 25-30 KNOTS AT TIMES. ANOTHER DISTURBANCE CROSSES THE REGION THIS EVENING WITH ANOTHER SURGE IN NW WINDS EXPECTED WITH SOME GUSTS TO 35 KNOTS POSSIBLE ESPECIALLY ALONG THE ROA-HLX-TNB CORRIDOR. NEXT ROUND OF UPSLOPE CLOUDS MAY ALSO DEVELOP OVER THE WEST DURING THE PASSAGE OF THE CORE OF THE COLDEST AIR ALOFT WITH PERHAPS MVFR CIGS AT KBLF/KLWB AND POSSIBLY KBCB. SOME SPOTTY SNOW SHOWERS OR FLURRIES ALSO LIKELY OVER THE WEST SOME INCLUDING A MENTION A VFR MENTION AT KBLF OVERNIGHT. HIGH PRESSURE ON WEDNESDAY WILL PROVIDE A QUIET DAY WITH VFR CONDITIONS UNDER MAINLY CLEAR SKIES ACROSS ALL TAF LOCATIONS. EXTENDED DISCUSSION... ANOTHER CLIPPER SYSTEM ARRIVES ON THURSDAY...BRINGING A CHANCE OF SUB-VFR CIGS AND VSBYS...WITH A CHANCE FOR -SHRA...-SHSN IN THE MOUNTAINS. MVFR CIGS LIKELY TO LINGER OVER THE MOUNTAINS THURSDAY NIGHT INTO FRIDAY IN THE WAKE OF THIS SYSTEM WITH STRONG NW WINDS ALSO PERSISTING INTO FRIDAY EVENING. ANOTHER AREA OF HIGH PRESSURE SHIFTS EAST INTO THE AREA SATURDAY WITH VFR EXPECTED INTO SATURDAY NIGHT. THE NEXT LOW PRESSURE SYSTEM HEADING OUT OF THE SW STATES WILL BRING A RETURN OF CLOUDS AND SOME PRECIPITATION ON SUNDAY WITH WIDESPREAD MVFR TO IFR LIKELY. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...JH NEAR TERM...JH SHORT TERM...JH/MBS LONG TERM...MBS AVIATION...JH/PM/RAB/WP

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