Area Forecast Discussion
Issued by NWS Blacksburg, VA

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KRNK 260910 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 410 AM EST WED NOV 26 2014 .SYNOPSIS... LOW PRESSURE WILL MOVE NORTHEAST AND DEEPEN ALONG THE CAROLINA COAST THIS MORNING BEFORE PASSING EAST OF THE VIRGINIA CAPES THIS AFTERNOON. A CLIPPER TYPE LOW PRESSURE SYSTEM WILL MOVE SOUTHEAST TOWARD THE REGION LATER TODAY AND WILL CROSS THE MID ATLANTIC STATES LATER TONIGHT. HIGH PRESSURE WILL COVER THE REGION THURSDAY NIGHT AND FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 220 AM EST WEDNESDAY... PRECIP CONTINUING TO OVERSPREAD THE REGION EARLY THIS MORNING WITH SURFACE LOW PRESSURE TRACKING QUICKLY NNE ALONG THE SOUTH CAROLINA COAST SIMILAR TO THE LATEST GFS/EC INITS. HOWEVER PRECIP GIVEN SUCH A WARM BOUNDARY LAYER AND LACK OF HIGHER RATES...HAS BEEN SLOW TO TRANSITION TO SNOW EXCEPT ON THE HIGHER PEAKS FROM BEECH MTN UP TO MT ROGERS ATTM. LATEST REGIONAL RADAR TRENDS SHOW HEAVIER PRECIP TO THE SOUTH AND EXPECT THIS AXIS TO PIVOT INTO THE REGION TOWARD DAYBREAK BEFORE QUICKLY SLIDING EAST BY MIDDAY AS THE SURFACE LOW TRACKS TO NEAR VA BEACH AROUND 18Z. ALTHOUGH GUIDANCE IN GENERAL AGREEMENT ON HEAVIER QPF ESPCLY BLUE RIDGE EAST...STILL LOTS OF UNCERTAINTY IN REGARDS TO PTYPE AS THE NAM REMAINS QUITE COLD WITH MORE WIDESPREAD SNOW PER LOW PRESSURE SLIGHTLY FARTHER EAST...WHILE THE GFS/EC STAYING WARMER THROUGH 12Z BEFORE PIVOTING IN COLDER THICKNESS AS THE COASTAL STARTS TO WIND UP THIS MORNING. THIS TIMING AND HEIGHT OF THE SNOW LEVEL CRITICAL TO SEEING 3-6 INCHES IN SPOTS ON THE RIDGES AND LITTLE OR NO ACCUMULATION IN OTHERS AS THE BEST FRONTOGENETIC FORCING LOOKS TO SET UP ALONG THE BLUE RIDGE THIS MORNING. APPEARS BEST LIFT...DYNAMIC COOLING AND COLD ADVECTION TO ALL COINCIDE BETWEEN ABOUT 10-15Z ACROSS THE WESTERN HALF JUST AHEAD OF THE MAIN SHORTWAVE ALOFT AND WITHIN A BELT OF MORE LOW LEVEL NORTHERLY FLOW BEHIND THE SURFACE LOW. THIS IS WHEN AN INCH/HOUR TYPE SNOWFALL RATES POSSIBLE AS GUIDANCE INDICATES SOME CSI BANDING ESPCLY AS BEST LIFT DEVELOPS WITHIN THE DENDRITIC GROWTH ZONE AND SNOW LEVELS CHASE DOWN THE RIDGES ABOVE 2500 FEET AND INTO THE VALLEYS. HOWEVER THIS LOOKING MORE AND MORE UNCERTAIN GIVEN THE WARM BOUNDARY LAYER BUT STILL A CLOSE CALL. OTRW WILL CONTINUE TO FOLLOW A MORE BLENDED/CONSENSUS APPROACH AND KEEP AMOUNTS GENERALLY CLOSE TO GOING VALUES FOR NOW. ONLY EXCEPTIONS TO LOWER AT THE ONSET SW...AND BY AFTERNOON GIVEN EXITING MOISTURE. FARTHER EAST...DEGREE OF ACCUMULATION INTO THE NEW RIVER VALLEY AND POINTS NE DEPENDENT UPON GETTING SNOW ON THE GROUND PRIOR TO THE DAYLIGHT HOURS AND RATE OF FALL. THUS FEW CHANGES TO GOING HEADLINES FOR NOW ALTHOUGH SOME ADJUSTS MAY BE NEEDED ONCE THINGS START TO CHANGEOVER FROM WEST TO EAST PRIOR TO 12Z. SHOULD SEE POPS QUICKLY TAPER FROM SW TO NE BY 21Z/4PM WITH SOME REDEVELOPMENT OF RAIN/SNOW SHOWERS OVER THE WEST AS THE FLOW TURNS MORE NW LATE. HIGH TEMPS IFFY WITH READINGS TO FALL WITH PRECIP EARLY...THEN PERHAPS REBOUND A BIT MORE THIS AFTERNOON AS MOISTURE EXITS SO BUMPED UP HIGHS A NOTCH ESPCLY GIVEN CURRENT WARMER READINGS. && .SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/... AS OF 400 AM EST WEDNESDAY... EXPECT A BREAK IN PRECIPITATION BEGINNING EARLY THIS EVENING AS THE COASTAL LOW MOVES TOWARD NEW ENGLAND. THE BREAK WILL BE SHORT LIVED HOWEVER AS ANOTHER LOW PRESSURE SYSTEM ENTERS THE CENTRAL APPALACHIANS AFTER MIDNIGHT. WHILE MOISTURE WILL BE LIMITED AS DRIER AIR BUILDS INTO THE REGION...THIS LOW WILL BE SUPPORTED ALOFT BY A VIGOROUS UPPER TROUGH AND...WHEN COMBINED WITH UPSLOPE FLOW AS THE ENERGY ENCOUNTERS THE MOUNTAINS...SHOULD BE ENOUGH TO SQUEEZE OUT 2 TO 3 INCHES ACROSS THE NORTH CAROLINA HIGHLANDS INTO THE MOUNTAIN EMPIRE...POSSIBLY AS FAR NORTH AS WESTERN GREENBRIER COUNTY. BECAUSE OF THE POTENTIAL IMPACT TO HOLIDAY TRAVEL...WILL ISSUE A WINTER WEATHER ADVISORY FOR THANKSGIVING FOR THESE LOCATIONS RUNNING FROM MIDNIGHT TO NOON. GREATEST AMOUNTS WILL BE FOUND IN THE HIGHER TERRAIN/COLDER AIR ALOFT. ELSEWHERE ACROSS THE MOUNTAINS...MAY SEE UP TO AN INCH OF SNOW IN SPOTS...BUT MAINLY ON GRASSY SURFACES. EAST OF THE BLUE RIDGE...LOW LEVEL TEMPERATURES WILL REMAIN SUFFICIENTLY WARM TO KEEP PRECIPITATION AS LIQUID. THE LOW WILL PASS TOWARD THE COASTAL PLAIN DURING EARLY AFTERNOON...ENDING PRECIPITATION IN THE EAST AND LEAVING ONLY DIMINISHING UPSLOPE SNOW SHOWERS ALONG THE RIDGES IN THE WEST THAT WILL LINGER INTO LATE EVENING. HIGH PRESSURE WILL PASS ACROSS THE REGION ON FRIDAY...MAKING FOR MOSTLY CLEAR SKIES AND LIGHT WINDS. AFTERNOON TEMPERATURES WILL BE ON THE CHILLY SIDE...WITH HIGHS RANGING FROM THE LOW/MID 30S IN THE WEST TO THE MID 40S IN THE EAST. AS THE HIGH SHIFTS EAST FRIDAY EVENING...WILL SEE A RETURN OF SOUTHWESTERLY WIND FLOW THAT WILL CARRY WARMER AIR NORTHWARD ALONG THE APPALACHIAN CHAIN. AS SUCH...EXPECT WARMER TEMPERATURES FOR SATURDAY...WITH HIGHS IN THE MID 40S TO LOW 50S. MAY SEE A FEW SHOWERS DEVELOP SATURDAY EVENING IN THE WEST AS A WARM FRONT LIFTS NORTH ACROSS THE OHIO RIVER VALLEY. && .LONG TERM /SUNDAY THROUGH TUESDAY/... AS OF 400 AM EST WEDNESDAY... THE WARMING TREND THAT STARTED ON SATURDAY WILL CONTINUE ON SUNDAY AND MONDAY...WITH READINGS SOME 10 TO 15 DEGREES ABOVE NORMAL FOR THAT TIME. TEMPERATURES WILL COOL TO NEAR NORMAL READINGS BEHIND THE PASSAGE OF A COLD FRONT ACROSS OUR AREA ON TUESDAY. && .AVIATION /09Z WEDNESDAY THROUGH SUNDAY/... AS OF 1230 AM EST WEDNESDAY... DEVELOPING LOW PRESSURE OFF THE SE COAST OVERNIGHT WILL CONTINUE TO SPREAD DEEP MOISTURE BACK INTO THE REGION FROM THE SOUTH THROUGH EARLY WEDNESDAY WITH RAPID DETERIORATING FLIGHT CONDITIONS ANTICIPATED FROM SOUTH TO NORTH ACROSS THE MID ATLANTIC AFTER MIDNIGHT. THIS STORM SYSTEM WILL PRODUCE MAINLY RAIN EAST OF THE BLUE RIDGE...WITH SNOW ALONG AND WEST OF THE BLUE RIDGE. EVENING RNK SOUNDING PROFILE INDICATED ABOVE FREEZING TEMPERATURES THROUGH ABOUT 9KFT AGL. THIS LAYER IS EXPECTED TO COOL RAPIDLY WITH ONSET OF PRECIPITATION AFTER MIDNIGHT WITH THE FREEZING LEVEL DROPPING TO WITHIN 1-3KFT OF THE SURFACE BEFORE DAYBREAK WEDNESDAY. FOR THE MOUNTAIN TERMINALS WHICH INCLUDE KBLF/KLWB/KBCB ONSET OF PRECIPITATION IS EXPECTED BETWEEN 1AM AND 3AM. INITIAL P-TYPE WILL BE RAIN BUT THEN CHANGE TO SNOW BEFORE DAYBREAK AS THE FREEZING LEVEL DROPS TO WITHIN 1KFT OF THE SURFACE. SOME ACCUMULATIONS LIKELY AT THESE THREE AIRPORTS THROUGH MIDDAY WEDNESDAY...WITH PLOWABLE SNOW MOST LIKELY AT KBLF/KLWB...PERHAPS AT KBCB. BETWEEN 8AM AND NOON...SNOWFALL RATES OF AN INCH AN HOUR ARE POSSIBLE. FARTHER EAST...CLOSER TO THE BLUE RIDGE VCNTY OF KROA...RAIN IS ALSO EXPECTED AT THE ONSET...THEN MIXING WITH AND POSSIBLY CHANGING TO SNOW BEFORE ENDING. FREEZING LEVEL AT KROA IS EXPECTED TO DROP TO WITHIN 2KFT OF THE SURFACE...CERTAINLY ALLOWING FOR ACCUMULATING SNOW ON THE SURROUNDING RIDGES...BUT LESS CONFIDENT ON MUCH IN THE WAY OF ACCUMULATION AT THE AIRPORT DUE TO THE WARMER VALLEY TEMPERATURES. IN SPITE OF THE WARM GROUND TEMPERATURES...IT IS STILL POSSIBLE THAT DE-ICING PROCEDURES WILL BE NEEDED FOR A FEW HOURS AT KROA WED MORNING. SNOW MAY MIX WITH RAIN AT KLYH AS WELL...BUT FOR BOTH KLYH AND KDAN DO NOT EXPECT ANY IMPACT FROM SNOW ON RUNWAY SURFACES AT THIS TIME...WITH PRIMARILY RAIN OCCURRING AT BOTH KLYH AND KDAN...THE FREEZING LEVEL ONLY DROPPING TO WITHIN 3KFT OF THE SURFACE. DEVELOPMENT OF WIDESPREAD MVFR CONDITIONS IS ANTICIPATED AT ALL LOCATIONS BY 09Z/3AM WEDNESDAY...WITH AREAS OF IFR/LIFR IN SNOW FROM KBCB WEST FROM ABOUT 10Z/5AM - 16Z/NOON. THIS STORM SYSTEM IS EXPECTED TO MOVE RAPIDLY NORTHEAST IMPACTING NUMEROUS FLIGHT TERMINALS EAST OF THE APPALACHIAN MOUNTAINS AND ALONG THE NEW ENGLAND COAST. FOR THE LOCAL REGION...THIS STORM SYSTEM SHOULD EXIT THE AREA BY MID/LATE WEDNESDAY AFTERNOON 18-21Z...ONLY TO BE FOLLOWED BY A FAST MOVING CLIPPER TYPE AREA OF LOW PRESSURE...UPPER LEVEL DISTURBANCE...WEDNESDAY NIGHT INTO EARLY THURSDAY. THIS SECOND WEATHER FEATURE HAS THE POTENTIAL TO BRING WIDESPREAD SUB-VFR WEDNESDAY NIGHT WITH MVFR/IFR VSBY RESTRICTIONS IN LIGHT SNOW OVERNIGHT. LIGHT ACCUMULATIONS OF UP TO 2 INCHES ARE LIKELY AT KBLF/KLWB/KBCB...AND WITH A DUSTING TO AN INCH POSSIBLE FARTHER EAST BY THURSDAY MORNING. EXTENDED DISCUSSION... LOW CLOUDS AND SNOW SHOWERS/FLURRIES MAY PERSIST AT KBLF/KLWB INTO THURSDAY NIGHT WITH MVFR CIGS POSSIBLE. OTRW EXPECTING DOWNSLOPE DRYING TO BRING A RETURN TO VFR FROM THE BLUE RIDGE EAST AS HIGH PRESSURE STARTS TO BUILD IN AND DRIER AIR WINS OUT. THIS HIGH PRESSURE SYSTEM SHOULD BUILD ACROSS THE REGION AND TO THE EAST BY THE WEEKEND RESULTING IN MORE WIDESPREAD VFR TO END THE WEEK. BY LATE SUNDAY OR MONDAY...A WEAK FRONTAL BOUNDARY COULD SLIDE DOWN FROM THE NORTH BRINGING THE NEXT CHANCE FOR LIGHT PRECIP AND SUB-VFR CONDITIONS TO THE REGION...BUT ANY PRECIP LOOKS TO BE IN THE FORM OF RAIN. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR VAZ007-009>018. WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR VAZ019- 020-024-035. WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO NOON EST THURSDAY FOR VAZ007-009-015. WINTER STORM WARNING UNTIL 4 PM EST THIS AFTERNOON FOR VAZ015. WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR VAZ020. NC...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR NCZ001-002-018. WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO NOON EST THURSDAY FOR NCZ001-018. WINTER STORM WARNING UNTIL 4 PM EST THIS AFTERNOON FOR NCZ001- 018. WV...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR WVZ042>044. WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR WVZ507. WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO NOON EST THURSDAY FOR WVZ508. WINTER STORM WARNING UNTIL MIDNIGHT EST TONIGHT FOR WVZ508. && $$ SYNOPSIS...AMS/JH NEAR TERM...JH SHORT TERM...AMS/NF LONG TERM...DS AVIATION...JH/PM

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.