Area Forecast Discussion
Issued by NWS Blacksburg, VA

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156 FXUS61 KRNK 111657 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 1157 AM EST THU FEB 11 2016 .SYNOPSIS... HIGH PRESSURE WILL GRADUALLY BUILD EAST INTO THE AREA THIS AFTERNOON ALLOWING FOR DRIER WEATHER ALONG WITH DIMINISHING WINDS. A CLIPPER SYSTEM WILL CROSS OUR REGION ON FRIDAY WITH SOME LIGHT SNOW ACCUMULATIONS...ESPECIALLY IN THE MOUNTAINS. GENERALLY QUIET WEATHER IS EXPECTED FOR THE WEEKEND WITH MORE SNOW SHOWERS WEST OF THE BLUE RIDGE ALONG THE FAR WESTERN SLOPES. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1000 AM EST THURSDAY... UPDATED TO LET THE GOING HEADLINES EXPIRE WITH ONLY FAR WESTERN GREENBRIER COUNTY LIKELY TO SEE ADDED SNOWFALL INTO EARLY AFTERNOON...WHILE WIND CHILLS SLOWLY RECOVER AS TEMPS EDGE UP AND WINDS DIMINISH WITH HIGH PRESSURE BUILDING IN. HOWEVER WILL STILL BE COLD WITH CHILLS OVER THE MOUNTAINS STAYING IN THE SINGLE DIGITS AND TEENS...WITH SOME OF THE HIGHER ELEVATIONS PERSISTING BELOW ZERO ALTHOUGH TOO ISOLATED TO KEEP A HEADLINE GOING. WILL ALSO LIKELY COVER THE LINGERING SNOW WITH A SPS UNTIL DRIER AIR FINALLY WINS OUT AS SEEN OFF LATEST SHORT RANGE GUIDANCE AND LATEST VISIBLE PICS. OTHERWISE LOWERED HIGHS SLIGHTLY OVER THE WEST BASED ON CURRENT OBS AND ONLY SLOW RECOVERY AT 85H THIS AFTERNOON DESPITE INCREASING INSOLATION. EXPECT AREAS EAST OF THE BLUE RIDGE TO SEE A LITTLE BUMP GIVEN DOWNSLOPE BUT MOSTLY LOW/MID 30S OUT TO THE PIEDMONT. GUSTY WINDS SHOULD PERSIST INTO EARLY AFTERNOON BEFORE THE SURFACE HIGH FINALLY NOSES EAST AND THE LOW LEVEL JET FADES AS DEEP COLD ADVECTION STARTS TO BRIEFLY WANE. PREVIOUS DISCUSSION AS OF 430 AM EST THURSDAY... COLD NORTHWEST WINDS WILL CONTINUE TO BRING SNOW SHOWERS TO LOCATIONS WEST OF THE BLUE RIDGE...ESPECIALLY THE FAR WESTERN SLOPES OF THE APPALACHIANS...THROUGH THIS MORNING. THANKFULLY SYNOPTIC MOISTURE WILL START TO WANE AS THE UPPER TROF FINALLY PULLS THROUGH THE REGION AND ALLOWS HIGH PRESSURE TO BUILD IN FROM THE MIDWEST. THIS WILL ALLOW THE SNOW SHOWERS TO TAPER OFF TO LINGERING FLURRIES BY THIS AFTERNOON. THE CURRENT WATCH/WARNING SITUATION IS COMPLICATED AS THERE LOOKS TO BE ONE LAST BURST OF SNOW RIGHT AROUND 12Z THAT MAY BRING AN ADDITIONAL INCH OR SO TO THE WARNING AREAS AND POSSIBLY A LOCALIZED LIGHT ACCUMULATION IN A SNOWBANK EAST TO THE BLUE RIDGE. WITH THIS IN MIND IT APPEARS THE BEST COURSE OF ACTION WILL BE TO CONTINUE THE WARNINGS UNTIL THEY EXPIRE AT 7AM AND FOLLOW THEM WITH AN ADVISORY THROUGH 10AM. IT WILL BE A LAST MINUTE DECISION AS TO WHETHER THE CURRENT ADVISORY AREA WILL BE EXTENDED BEYOND THE CURRENT EXPIRATION TIME OF 7AM. THE JOSTLING OF THE PRODUCTS ASIDE...THE MAIN POINT IS THAT AN ADDITIONAL LIGHT ACCUMULATIONS OF SNOW IS POSSIBLE THROUGH THE MORNING RUSH HOUR. TEMPERATURES THIS MORNING REMAIN COLD AND COMBINED WITH THE GUSTY NORTHWEST WINDS...THE CURRENT WIND CHILL ADVISORY WILL REMAIN IN TACT UNTIL 10AM. THEREAFTER...EXPECT ANOTHER COLD DAY WITH HIGHS WEST OF THE RIDGE GENERALLY IN THE LOW/MID 20S AND MID/UPPER 30S TO THE EAST. TEMPERATURES TONIGHT WILL DROP EARLY...THEN BEGIN TO RISE AS CLOUDS MOVE IN FROM THE WEST AHEAD OF THE NEXT SYSTEM BRINGING SOME UPPER SHORT WAVE ENERGY AND ISENTROPIC LIFT TO THE REGION. CURRENT INDICATIONS ARE THAT PRECIPITATION WILL HOLD OFF UNTIL FRIDAY SO WILL RUN WITH A DRY FORECAST THURSDAY NIGHT WITH JUST SOME LOW CHANCE POPS FAR WEST TOWARD DAYBREAK FRIDAY. && .SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/... AS OF 445 AM EST THURSDAY... MULTIPLE WINTER CONCERNS TO CONTINUE THROUGH THE PERIOD. FRIDAY...ALBERTA CLIPPER SYSTEM RACES THROUGH THE FORECAST AREA...REACHING THE WESTERN DOORSTEP AROUND DAYBREAK...THEN TRANSLATING TO THE COAST BY EVENING. TRACK OF BEST LIFT AND MOISTURE SEEMS TO BE JUST SOUTH OF THE CWA ACROSS NE TN INTO NW NC...THEN RELOCATING TO THE COAST PLAIN AS LOW PRESSURE IS INDUCED OFF THE SC/NC COAST IN RESPONSE TO THE UPPER SHORT WAVE. QPF STILL IN THE 0.1 TO 0.2 RANGE WITHIN THIS BAND...WITH AMOUNTS MOSTLY LESS THAN 0.10 ACROSS THE BULK OF THE RNK CWA...EXCEPT FOR THE FAR SOUTHWEST SECTIONS. WITH A VERY COLD AIR MASS AND HIGH SNOW TO LIQUID RATIO...THESE COULD EQUATE TO 1 TO 3 INCHES OF SNOW. THIS EVENT ALONE WILL NOT MEET ADVISORY CRITERIA EXCEPT IN A FEW ISOLATED SPOTS...PERHAPS HIGHER ELEVATIONS OF WATAUGA AND ASHE. HOWEVER...AS THE ALBERTA CLIPPER PASSES...WE MOVE BACK INTO A PERIOD OF ENHANCED UPSLOPE SNOW SHOWERS ALONG THE WESTERN SLOPES OF THE MOUNTAINS FRIDAY NIGHT INTO SATURDAY MORNING. THIS COULD PUSH SNOW AMOUNTS ACROSS SOME OF THE SOUTHWESTERN AND WESTERN AREAS INTO THE LOW END OF ADVISORY CRITERIA. WITH ONGOING HEADLINES...ISSUING SOMETHING FOR THIRD/FOURTH PERIOD...ESPECIALLY CONSIDERING THE LOW END NATURE OF THE EVENT AT THIS POINT...WOULD JUST ADD CONFUSION AT THIS POINT. UPSLOPE SNOW SHOULD WIND DOWN A LITTLE MORE QUICKLY THAN WITH THE CURRENT EVENT...GENERALLY TAPERING OFF TO FLURRIES BY SATURDAY EVENING. THE ALBERTA CLIPPER WILL INITIATE ANOTHER STRONG AND EVEN MORE SIGNIFICANT SURGE OF ARCTIC AIR INTO THE REGION. WHILE THE CORE OF THE ARCTIC AIR MASS...-40C...WILL TRACK FROM THE CENTRAL GREAT LAKES TOWARD NEW ENGLAND AND THE NORTHERN MID- ATLANTIC...WE WILL CERTAINLY SEE OUR SHARE OF BITTER COLD AIR HERE AS WELL. 850MB TEMPS WILL FALL BELOW -20C BY LATE SATURDAY MORNING IN THE NORTHERN PART OF THE CWA AND REMAIN THERE UNTIL EARLY SUNDAY AFTERNOON...WITH SOUTHERN AREAS BOTTOMING OUT AROUND -18C AND NORTHERN AREAS AROUND -22C. IN 2014 AND 2015...OUR COLDEST MORNINGS...BELOW ZERO IN MANY AREAS WEST OF THE BLUE RIDGE...CAME WHEN THE 850MB TEMPS WERE AROUND -25C. IT APPEARS WE WILL FALL JUST SHORT OF THAT. HOWEVER...STRONG NORTHWEST WINDS WILL COMBINE WITH THE BITTER COLD TEMPERATURES TO PRODUCE WIND CHILLS BELOW ZERO JUST ABOUT EVERYWHERE WEST OF THE BLUE RIDGE...WITH -20 TO -25C WIND CHILLS IN WESTERN GREENBRIER...AND OTHER HIGHER ELEVATIONS OF BATH DOWN TOWARD WATAUGA. WIND CHILL ADVISORIES AND EVEN A WIND CHILL WARNING...WILL BE NEEDED IN MANY AREAS WEST OF THE BLUE RIDGE FOR FRIDAY NIGHT/SATURDAY. AGAIN...THIS WILL NEED TO BE ISSUED ONCE THE CURRENT SET OF ADVISORIES/WARNINGS EXPIRES. MAX TEMPS SATURDAY WILL BE HARD PRESSED TO RISE ABOVE 10 IN THE WESTERN MOUNTAINS AND REMAIN IN THE 20S ACROSS THE PIEDMONT. SUNDAY WILL BE DRY AND VERY COLD...WITH ONLY A SLIGHT RECOVERY IN THE AFTERNOON FROM BITTER COLD TEMPS SUNDAY MORNING...AS LOW AS -5F ACROSS THE WESTERN MOUNTAINS. && .LONG TERM /MONDAY THROUGH WEDNESDAY/... AS OF 515 AM EST THURSDAY... SUNDAY THE VERY DEEP POLAR LONG WAVE TROUGH LIFTS NORTHEAST AS THE ARCTIC SURFACE HIGH SETTLES SQUARELY OVER THE REGION. AT THIS POINT...THE ATTENTION THEN TURNS TO A COMBINATION OF VIGOROUS SHORT WAVES DESTINED TO MERGE INTO A SINGLE STRONGER SYSTEM ALONG THE SOUTHEAST U.S. COAST. THE LATEST GFS HAS TRENDED TOWARD THE ECMWF...MEANING A FURTHER NORTHWARD TRACK...WHILE THE ECMWF HAS GENERALLY REMAINED CONSISTENT WITH THE TRACK...BUT HAS TRENDED COLDER. GIVEN THE ANTECEDENT AIR MASS IN PLACE WILL BE BITTER COLD AND DRY...THE COLDER TEMPERATURE SOLUTION OF THE GFS SEEMS PLAUSIBLE. THE MODELS HAVE ALSO TRENDED STRONGER WITH THIS SYSTEM AS THE ENERGY FROM TWO SHORT WAVES MERGES IN THE GA/SC AREA...NOW DEPICTING A DEEPER COASTAL LOW AND POTENTIAL MILLER A TYPE SCENARIO. AS WPC HAS NOTED...THE THREAT IS THERE FOR A SIGNIFICANT WINTER STORM IN THE EAST...AND THIS DOES INDEED APPEAR TO BE THE CASE. SIGNIFICANT SNOW AMOUNTS ARE INDICATED VIA BOTH THE GFS AND ECMWF ACROSS THE RNK CWA...WEST OF THE BLUE RIDGE...WITH STRONG POTENTIAL FOR MIXED PRECIPITATION...SNOW/SLEET/FREEZING RAIN ACROSS THE PIEDMONT AS THE WARM NOSE INVADES THAT REGION MONDAY NIGHT. HAVE ADVERTISED LIKELY POPS FOR THE ENTIRE CWA MON-MON NIGHT AND CONFINED TO ALL SNOW WEST OR A RAIN/SNOW MIX PIEDMONT GIVEN UNCERTAINTY WITH COLD AIR DEPTH ACROSS THE PIEDMONT. ALL INTERESTS ACROSS THE REGION SHOULD MONITOR FUTURE FORECASTS CLOSELY REGARDING THIS POSSIBLE WINTER STORM EARLY NEXT WEEK. THERE ARE SOME INDICATIONS THAT TEMPERATURES MAY MODERATE TOWARD THE MID-WEEK PERIOD...BUT SNOWFALL MON-TUE MAY DETERMINE THAT TO A GREAT DEGREE. WITH NORTHWEST FLOW ALOFT...WOULD BE VERY CAUTIOUS ABOUT JUMPING ON ANY SIGNIFICANT WARMING TRENDS AT THIS POINT. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... AS OF 1145 AM EST THURSDAY... PERIODS OF LINGERING MVFR WILL PERSIST IN THE VICINITY OF KBLF/KLWB INTO EARLY THIS AFTERNOON BEFORE DRIER AIR CAUSES ANY REMAINING LOW DECK TO SCATTER OUT. OTHERWISE LOOKING AT OVERALL VFR CONDITIONS THROUGH THE AFTERNOON WITH GUSTY NORTHWEST WINDS SLOWLY DIMINISHING AND BECOMING LIGHT OVERNIGHT. VFR CONDITIONS WILL CONTINUE OVERNIGHT WITH INCREASING MID CLOUDS LIKELY LATE THIS EVENING OVER THE FAR WEST AND ELSEWHERE AFTER MIDNIGHT. HOWEVER APPEARS THAT KBLF/KLWB SHOULD REMAIN WITH VFR CIGS OVERNIGHT ALTHOUGH BASES WILL BE QUICKLY LOWERING BY DAYBREAK FRIDAY. FAST MOVING LOW PRESSURE ASSOCIATED WITH THIS INCREASING MOISTURE WILL PASS TO THE SOUTH DURING FRIDAY REACHING THE COAST DURING THE AFTERNOON. QUICK SHOT OF DEEPER MOISTURE UNDER THE PASSING UPPER SUPPORT LIKELY TO YIELD A PERIOD OF MVFR/IFR CIGS/VSBYS FROM THE NC BORDER NORTH INTO SOUTHEAST WEST VA THROUGH EARLY AFTERNOON FRIDAY BEFORE ENERGY JUMPS TO THE COAST. THINK COULD SEE A QUICK BURST OF SNOW ESPCLY AROUND KBLF WITH SOME OF THESE LOWER CIGS/VSBYS HEADING OUT TO KBCB BEFORE MOISTURE CUTS OFF CROSSING THE BLUE RIDGE. COULD SEE SOME LIGHT SNOW REACH KROA BUT THINKING STILL VFR THERE AND POINTS EAST WHERE WILL KEEP THINGS VFR/DRY THROUGH THE VALID TAF PERIOD. EXTENDED DISCUSSION... NEXT ROUND OF NW FLOW KICKS IN BEHIND THE EXITING WAVE BY FRIDAY EVENING WITH UPSLOPE BRINGING MVFR/IFR CIGS TO KBLF/KLWB INTO SAT MORNING...BEFORE GOING VFR AGAIN BY LATE SATURDAY. WINDS WILL BE GUSTY AGAIN WITH ANOTHER SURGE OF ARCTIC AIR POURING IN SATURDAY. SHOULD BE VFR SUNDAY THEN ANOTHER SYSTEM SEEMS POISED TO BRING WINTRY WX TO THE AREA AS EARLY AS SUNDAY NIGHT WITH SUB-VFR EXPECTED REGION WIDE MONDAY INTO AT LEAST PART OF TUESDAY. TRACK OF THIS SYSTEM WILL DETERMINE PTYPE AND WHERE OVER THE MID ATLANTIC AND SOUTHEAST...BUT FOR OUR AREA SOME WINTRY PRECIP LOOKS LIKELY. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...JH/MBS NEAR TERM...JH/MBS SHORT TERM...AMS/RAB LONG TERM...AMS/RAB AVIATION...JH/MBS/WP

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