639  
FXUS61 KRNK 141756  
AFDRNK  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BLACKSBURG VA  
1256 PM EST THU DEC 14 2017  
   
SYNOPSIS
 
 
A LOW PRESSURE SYSTEM SLIDING BY TO OUR NORTH WILL BRING STRONG  
GUSTY WINDS TO THE APPALACHIANS AND CENTRAL MID ATLANTIC REGION,  
ALONG WITH UPSLOPE SNOW SHOWERS FOR THE HIGHER ELEVATIONS WEST  
OF THE BLUE RIDGE. HIGH PRESSURE WILL THEN BUILD OVER THE  
EASTERN PART OF THE COUNTRY AND BRING US FAIR WEATHER WITH A  
WARMING TREND AS WE HEAD INTO THE WEEKEND. A LOW PRESSURE SYSTEM  
WILL THEN MOVE OUT OF THE LOWER MISSISSIPPI VALLEY LATE IN THE  
WEEKEND AND BRING A CHANCE OF RAIN TO THE FORECAST FOR SUNDAY.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
AS OF 1255 PM EST THURSDAY...UPDATE TO EXPIRE THE WIND  
HEADLINES IN EFFECT. EVEN GUSTS AT THIS POINT ARE BECOMING LESS  
FREQUENT, THOUGH STILL GUSTING TO 25 MPH AT ROANOKE FROM THE  
NORTHWEST. ALSO INCREASED TEMPERATURES IN THE PIEDMONT AND  
SOUTHSIDE AREAS BY 2 DEGREES. THIS RAISES HIGHS IN THESE AREAS  
INTO THE UPPER 40S TO LOW 50S. OTHERWISE, FORECAST ESSENTIALLY  
UNCHANGED WITH THE EARLY-AFTERNOON UPDATE.  
 
PREVIOUS DISCUSSION ISSUED AT 220 AM THURSDAY...  
 
CLIPPER TYPE LOW PRESSURE SYSTEM WILL SLIDE BY TO OUR NORTH  
EARLY THIS MORNING. THE LOW LEVEL WIND FIELD ASSOCIATED WITH  
THIS SYSTEM IS QUITE ROBUST AND LOOKS LIKE IT WILL PEAK JUST  
BEFORE DAYBREAK, ABOUT THE TIME COLD AIR ADVECTION BECOMES  
ESTABLISHED AND HELPS FORCE HIGHER MOMENTUM AIR FROM THE  
HILLTOPS TO THE LOWER ELEVATIONS. THIS WILL RESULT IN STRONG  
GUSTY WINDS PRIMARILY AT THE HIGHER ELEVATIONS ALONG AND WEST OF  
THE BLUE RIDGE THROUGH EARLY THIS MORNING WHERE A WIND ADVISORY  
IS IN EFFECT UNTIL NOON. A HIGH WIND WARNING IS IN EFFECT FROM  
THE MOUNTAINS OF NC INTO THE GRAYSON HIGHLANDS OF VA WHERE GUSTS  
TO 60 MPH HAVE BEEN COMMON. THE WIND FIELD WILL GRADUALLY  
SLACKEN AND THE HIGH WIND THREAT WILL DIMINISH BY NOONTIME.  
 
THE BRISK WIND FLOW WILL ALSO RESULT IN UPSLOPE CLOUDS AND SNOW  
SHOWERS WEST OF THE RIDGE. SOME OF THE HIGHER ELEVATIONS MAY  
PICK UP A FRESH COATING OF SNOW WITH A COUPLE OF INCHES POSSIBLE  
FOR WESTERN GREENBRIER COUNTY. THIS WILL COMBINE WITH THE WIND  
TO CREATE SOME AREAS OF BLOWING SNOW EARLY THIS MORNING. MOISTURE  
ABATES AFTER DAYBREAK WITH JUST SOME LINGERING FLURRIES LATE  
THIS MORNING. MUCH QUIETER EAST OF THE RIDGE WITH GENERALLY  
FAIR AND BLUSTERY CONDITIONS FOR TODAY. HIGH TEMPERATURES TODAY  
WILL GENERALLY BE IN THE MIDDLE 40S EAST TO LOW/MID 30S WEST.  
 
HIGH PRESSURE WILL SETTLE OVER THE REGION TONIGHT WITH QUIET  
WEATHER EXPECTED, THOUGH THERE APPEARS TO BE ENOUGH MOISTURE TO  
KEEP SOME CLOUDINESS AROUND ESPECIALLY WEST OF THE RIDGE. THIS  
WILL KEEP TEMPERATURES TONIGHT FROM REACHING THEIR FULL  
POTENTIAL. LOWS TONIGHT WILL BE IN THE MIDDLE 20S EAST TO  
TEENS/LOWER 20S WEST, THOUGH IF CLOUD COVER IS LESS THAN  
EXPECTED THESE TEMPERATURES MAY BE ADJUSTED DOWNWARD.  
 

 
   
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/
 
 
AS OF 245 AM EST THURSDAY...  
 
SPLIT FLOW FRIDAY WILL FEATURE PASSAGE OF NORTHERN/SOUTHERN  
STREAM ENERGY. THESE FEATURES ARE FORECAST TO REMAIN OUT OF  
PHASE WITH DEEPER MOISTURE REMAINING TO THE EAST FRIDAY WITH A  
SURFACE WAVE DEVELOPING OFFSHORE, WHILE JUST AHEAD OF THE  
NORTHERN SHORTWAVE TROUGH. GUIDANCE SHOWING LOTS OF MID/HIGH  
CLOUDS FROM FRIDAY BUT WITH LITTLE PRECIP. FORECAST WILL REFLECT  
SPOTTY UPSLOPE SNOW SHOWERS AND FLURRIES FAR NORTHWEST SECTIONS  
FRIDAY NIGHT, BUT ONLY 20ISH POP FOR NOW GIVEN LACK OF MOISTURE  
WITH THIS SYSTEM. MOS IS COOLER THAN NORMAL FRIDAY GIVEN  
PROGGED CLOUDS FOR MUCH OF THE DAY WHICH SHOULD HOLD THE  
MOUNTAINS IN THE 30S AND LOW 40S EAST.  
 
FAST WEST/NORTHWEST FLOW TO CONTINUE BEHIND THIS SYSTEM INTO THE  
WEEKEND WITH SLOWLY BUILDING HEIGHTS BY SATURDAY AS THE 850 MB COLD  
POOL STARTS TO LIFT OUT. THIS WARM ADVECTION WONT DEEPEN ENOUGH TO  
BE REALIZED AT THE SURFACE UNTIL SATURDAY AFTERNOON WITH  
SUNSHINE HELPING TO PUSH HIGHS INTO THE 40S TO PERHAPS AROUND 50  
SOUTHEAST. SOME INCREASE IN HIGH CLOUDS POSSIBLE SATURDAY NIGHT  
BUT LIKELY THIN ENOUGH TO STILL ALLOW LOWS TO REACH THE 20S TO  
AROUND 30.  
 

 
   
LONG TERM /SUNDAY THROUGH WEDNESDAY/
 
 
AS OF 324 PM EST WEDNESDAY...  
 
WARMING TREND WILL CONTINUE LATE IN THE WEEKEND INTO EARLY NEXT WEEK  
AS WEAK SOUTHEAST RIDGING KEEPS A MORE ZONAL TRAJECTORY IN PLACE  
UNTIL WEDNESDAY WHEN A PASSING TROUGH ALOFT DIGS BACK INTO THE  
REGION. HOWEVER WITH THE WARM ADVECTION WILL SEE MOISTURE RETURN  
PERHAPS BY LATE SUNDAY BUT MORESO SUNDAY NIGHT INTO EARLY MONDAY  
WITH A RESIDUAL UPPER LOW EJECTING NORTHEAST ACROSS THE GULF STATES.  
APPEARS MUCH OF THIS PRECIP WOULD BE LIGHT AND MOSTLY LIQUID GIVEN  
WESTERLY FLOW AND WELL ABOVE FREEZING 850 MB TEMPS. MODELS THEN  
DIVERGE ON WHETHER OR NOT THIS FEATURE HELPS DEVELOP A WEAK LOW  
OFFSHORE, AIDED BY YET ANOTHER SHORTWAVE HEADED OUT OF THE  
SOUTHWEST STATES, OR THINGS REMAIN MORE PROGRESSIVE AND DRIER  
INTO TUESDAY. GIVEN SOMEWHAT WETTER TRENDS WILL CONTINUE CHANCE  
POPS SUNDAY AFTERNOON INTO MONDAY WHILE LEAVING IN LOW POPS  
NORTHWEST MONDAY NIGHT/TUESDAY FOR SHOWERS AHEAD OF THE NEXT  
FRONT AND OVER THE SOUTH PER LINGERING SHORTWAVE ENERGY. DRIER  
AND COLDER AIR SHOULD FOLLOW THE FRONT FOR WEDNESDAY AS DEEPER  
NORTHWEST FLOW KICKS IN. OTHERWISE LOOKING AT HIGHS REBOUNDING  
TO ABOVE NORMAL SUNDAY-TUESDAY AND WELL INTO THE 50S EAST FOR  
EARLY NEXT WEEK.  
 

 
   
AVIATION /18Z THURSDAY THROUGH TUESDAY/
 
 
AS OF 1256 PM EST THURSDAY...  
 
GENERAL MIX OF VFR/MVFR CEILINGS ACROSS THE TAFS, THOUGH MVFR  
UPSLOPE STRATUS MAINLY FOR LEWISBURG AND BLUEFIELD. CEILING  
TRENDS SHOULD CONTINUE THROUGH MIDNIGHT. NORTHWEST WINDS  
INITIALLY 6-12 KTS GUSTS TO 20 KTS ABATE THROUGH EARLY EVENING  
TO LIGHT AND VARIABLE AS BOUNDARY LAYER WINDS EASE. UNTIL THEN,  
POTENTIAL FOR MOUNTAIN WAVE CLOUDS/TURBULENCE IN AND AROUND THE  
BLUE RIDGE.  
 
AVIATION FORECAST THEN TRENDS LESS CERTAIN LOOKING INTO THE  
OVERNIGHT AND MIDDAY FRIDAY PERIOD. ANOTHER MID-LEVEL  
DISTURBANCE TRAVERSES THE REGION AROUND 07Z. RECENT 12Z GFS AND  
NAM SOLUTIONS ARE AT ODDS IN TERMS OF PRECIPITATION AS THIS  
UPPER-LEVEL SYSTEM RIPPLES THROUGH OUR AREA. THE NAM IS THE  
WETTEST, AND EXAMINATION OF FORECAST SOUNDINGS SUPPORT POTENTIAL  
FOR LIGHT SNOW/FLURRIES OR FREEZING DRIZZLE BETWEEN 07-15Z  
ALONG THE BLUE RIDGE AND ADJACENT TERMINALS. HAVE SIDED TOWARD  
THE WORST-CASE NAM WITH -FZDZ INDICATED IN MOST TAFS EXCEPT  
BLUEFIELD AND DANVILLE. FREEZING DRIZZLE WOULD PRODUCE SLICK  
RUNWAYS AND GREATER MIXED-ICE ACCUMULATION ON WINGS. CEILINGS  
TREND MVFR MOST TAFS EXCEPT AT DANVILLE WHERE VFR CONDITIONS  
SHOULD PREVAIL. LIGHT AND VARIABLE WINDS, TENDING LIGHT  
EAST/NORTHEAST THROUGH THE REST OF THE TAF PERIOD.  
 
HIGH CONFIDENCE IN AVIATION ELEMENTS THROUGH MIDNIGHT. MEDIUM  
CONFIDENCE ON CEILINGS AND WINDS AFTER MIDNIGHT, MEDIUM TO LOW  
CONFIDENCE ON WEATHER TYPE AND VISBYS AFTER MIDNIGHT.  
 
EXTENDED DISCUSSION...  
 
SHOULD SEE CONDITIONS IMPROVING TOWARD VFR LATE FRIDAY AFTERNOON  
INTO THE EVENING AS AFOREMENTIONED UPPER DISTURBANCE/WEAK  
SURFACE LOW MOVES OFF THE ATLANTIC COAST. VFR CONDITIONS SHOULD  
PREVAIL UNTIL SUNDAY NIGHT. A BETTER SHOT EXISTS FOR SUB- VFR  
CONDITIONS FROM A SYSTEM SYSTEM FORECAST TO EMANATE FROM THE  
MID-MISSISSIPPI VALLEY MONDAY INTO TUESDAY.  
 

 
   
RNK WATCHES/WARNINGS/ADVISORIES
 
 
VA...NONE.  
NC...NONE.  
WV...NONE.  
 

 
 

 
SYNOPSIS...MBS  
NEAR TERM...AL/MBS  
SHORT TERM...JH/PM  
LONG TERM...JH  
AVIATION...AL  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab VA Page
The Nexlab WV Page
The Nexlab NC Page Main Text Page