Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 111030 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 530 AM EST THU FEB 11 2016 .SYNOPSIS... HIGH PRESSURE WILL MOVE INTO THE REGION FROM THE MIDWEST AND GRADUALLY BRING AN END TO OUR UPSLOPE SNOW SHOWERS TODAY. THEN...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 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 /10Z THURSDAY THROUGH MONDAY/... AS OF 1140 PM EST WEDNESDAY... MVFR CIGS AT BLF/LWB EARLY ON WILL START TO GET TO VFR BY 12-15Z WITH SNOW SHOWERS/FLURRIES ENDING. NOT PUTTING ANY VSBY ISSUES AT THIS TIME..THINKING THE BEST SNOW SHOWERS MAY PUSH ACROSS BLF BETWEEN 05-06Z. WINDS WILL STAY GUSTY THROUGH MOST OF THE TAF PERIOD...SUSTAINED 10-15 KTS WITH GUSTS TO 30 KTS POSSIBLE AT BCB/ROA THROUGH 15Z. HIGH PRESSURE BUILDS IN THIS AFTERNOON/EVENING ALLOWING WINDS TO RELAX AND SKIES TO CLEAR. HIGH CONFIDENCE IN ALL PARAMETERS...BUT LOWER EARLY IN BLF/LWB PER SNOW SHOWER THREAT. EXTENDED DISCUSSION... VFR THURSDAY NIGHT AS WEAK HIGH PRESSURE BUILDS IN. LOW PRESSURE PASSES SOUTH OF US FRIDAY AND MAY THROW SOME MVFR CIGS TOWARD THE NC/VA BORDER WITH LIGHT SNOW POSSIBLE...THEN NW FLOW BEHIND THIS IS GOING TO BRING MVFR CIGS TO BLF/LWB INTO SAT MORNING...BEFORE GOING VFR AGAIN BY LATE SATURDAY. WINDS WILL BE GUSTY AGAIN WITH ANOTHER SURGE OF ARCTIC AIR POURING IN SATURDAY. ANOTHER CLIPPER SYSTEM POSES TO MOVE ACROSS THE AREA SHOULD BE VFR SUNDAY THEN ANOTHER SYSTEM SEEMS POISED TO BRING WINTRY WX TO THE AREA AS EARLY AS MONDAY WITH SUB-VFR EXPECTED REGION WIDE. TRACK OF THIS SYSTEM WILL DETERMINE PTYPE AND WHERE OVER THE MID ATLANTIC AND SOUTHEAST...BUT FOR OUR AREA WINTRY PRECIP LOOKS FAVORABLE. STAY TUNED. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...WIND CHILL ADVISORY UNTIL 10 AM EST THIS MORNING FOR VAZ007- 009>020-022>024. WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR VAZ007- 009>012-015-019-020. NC...WIND CHILL ADVISORY UNTIL 10 AM EST THIS MORNING FOR NCZ001- 002-018. WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR NCZ001- 018. WV...WIND CHILL ADVISORY UNTIL 10 AM EST THIS MORNING FOR WVZ042>044-507-508. WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR WVZ042- 044-507. WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR WVZ508. WINTER STORM WARNING UNTIL 7 AM EST THIS MORNING FOR WVZ043- 508. WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR WVZ043. && $$ SYNOPSIS...MBS NEAR TERM...MBS SHORT TERM...AMS/RAB LONG TERM...AMS/RAB AVIATION...JM/RCS/WP

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