Area Forecast Discussion
Issued by NWS Blacksburg, VA

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227
FXUS61 KRNK 130525
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
1225 AM EST SAT FEB 13 2016

.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE WILL PASS EAST OF THE AREA THIS
EVENING. A SURGE OF ARCTIC AIR FOLLOWS THIS SYSTEM OVERNIGHT
RESULTING IN VERY WINDY CONDITIONS AND BITTERLY COLD
TEMPERATURES...ALONG WITH SOME ADDED SNOW SHOWERS FOR THE FAR
WESTERN SLOPES OF THE APPALACHIANS INTO SATURDAY. BY MONDAY
ANOTHER WINTER STORM SYSTEM WILL BEGIN TO AFFECT THE REGION WITH
THE POTENTIAL FOR SNOW AND MIXED PRECIPITATION THROUGH THE FIRST
PART OF NEXT WEEK.

&&

.NEAR TERM /THROUGH TODAY/...
AS OF 1030 PM EDT FRIDAY...

BITTER COLD AIR IS INBOUND. WINDS HAVE SWITCHED AROUND TO THE
NORTHWEST AND NOW ITS JUST A MATTER OF TIME BEFORE THE ARCTIC AIR
INFILTRATES THE FORECAST AREA FROM THE NORTHWEST. REGIONAL RADARS
INDICATE SOME INTENSE SNOW SHOWERS OVER THE MOUNTAINS. THESE SNOW
SHOWERS WILL LIKELY PRODUCE A QUICK BURST OF SNOW WITH SNOWFALL
RATES OF A HALF INCH TO AN INCH IN LESS THAN 30 MINUTES.
DELINEATION OF THE TRUE ARCTIC AIR RESIDES UPSTREAM OF THE LAST
NE-SW ORIENTED BAND OF SNOW SHOWERS THAT YOU SEE ON RADAR.
TEMPERATURES FALL AT LEAST 10 DEGREES EITHER SIDE OF THIS
BOUNDARY...FROM THE MID 20S TO THE MID TEENS.

ARCTIC AIR WILL FLOW INTO THE AREA THROUGH SATURDAY AS DEEP 5H
TROFFINESS CARVES OUT ACROSS THE EAST. ACCUMULATING SNOW SHOWERS
ARE LIKELY OVERNIGHT TONIGHT WEST OF THE BLUE RIDGE WITH 1-3
INCHES OF SNOW LIKELY FROM THE WV HIGHLANDS SOUTHWEST THROUGH THE
WESTERN NEW RIVER VALLEY AND INTO THE MOUNTAINS OF NORTHWEST NORTH
CAROLINA...AND FLURRIES OUT TO THE BLUE RIDGE FOOTHILLS.

ASIDE FROM THE SNOW SHOWER THREAT...THE MAIN HAZARD WILL BE THE
COMBINATION OF THE COLD AND WIND...MODELS INDICATING A 50+ KNOT
85H JET PLOWING IN ON VERY STRONG SUBSIDENCE AND 85H TEMPS FALLING
TO BELOW -20C OVERNIGHT. THIS IS STRONG ENOUGH FOR NEAR WARNING
CRITERIA WIND SPEEDS TO BE REACHED OVER THE NW NC MOUNTAINS WITH
WIDESPREAD ADVISORY LEVELS OUT TO THE BLUE RIDGE. OF MOST CONCERN
THOUGH IS THE DANGEROUS WIND CHILL...SO PREFER TO USE ONE
HEADLINE AND HAVE THE STRONG WIND SPEEDS CONTAINED WITHIN THE
WINTER WEATHER ADVISORY. ATTM THINKING SATURDAYS SUNRISE
TEMPERATURE WILL BE IN THE SINGLE DIGITS/TEENS IN THE MOUNTAINS TO
AROUND 20 IN THE PIEDMONT WITH CHILLS WELL BELOW ZERO IN THE
MOUNTAINS AND BETWEEN ZERO AND 5 ABOVE IN THE PIEDMONT.

ARCTIC HIGH SLOWLY BUILDS IN FROM THE NW DURING SATURDAY ALLOWING SOME
MID/LATE AFTERNOON DROP OFF IN WINDS BUT STILL FRIGID WITH HIGHS SINGLE
DIGITS/TEENS MOUNTAINS AND 20S TO NEAR 30 FROM THE BLUE RIDGE EAST. LOW
LEVEL UPSLOPE MOISTURE LOOKS TO SLOWLY WANE SATURDAY AFTERNOON BUT
STILL ENOUGH FOR HIGH POPS DURING THE MORNING...TAPERING TO
CHANCE COVERAGE LATER IN THE DAY. CLOUDS SHOULD ALSO SLOWLY FADE
FROM EAST TO WEST AS THE VERY DRY ARCTIC AIR SPILLS IN ALLOWING
FOR MORE SUN FROM THE BLUE RIDGE EAST AND BECOMING PC FAR WEST
LATE. STILL APPEARS THAT WIND CHILL ADVISORY CRITERIA COULD LINGER
INTO THE AFTERNOON SO FEW CHANGES WITH GOING HEADLINES.

&&

.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
AS OF 300 PM EST FRIDAY...

ARCTIC HIGH PRESSURE WILL MOVE FROM THE OHIO VALLEY SATURDAY NIGHT
THEN OVER THE MID ATLANTIC REGION SUNDAY. OVERNIGHT LOWS WILL DROP
DOWN INTO THE SINGLE DIGITS ACROSS THE MOUNTAINS TO A RANGE OF 10F-
15F IN THE EAST. EVEN WITH LIGHT WINDS...WIND CHILL VALUES WILL BE
BELOW ZERO SUNDAY MORNING. TEMPERATURES AND WIND CHILLS WILL
MODERATE THROUGH THE DAY SUNDAY WITH HIGHS ONLY PEAKING IN THE 20S.

AN AREA OF LOW PRESSURE BEGINS TO DEVELOP OVER EASTERN TEXAS SUNDAY
NIGHT. AS THIS LOW TRACKS EAST AND DEEPENS THROUGH THE DAY
MONDAY...A WARM FRONT WILL GLIDE OVER THE ARCTIC HIGH...PRODUCING
LIGHT SNOW ACROSS THE REGION. AS THIS LOW APPROACHES THE TENNESSEE
VALLEY...A WARM NOSE WILL BEGIN TO ENTER THE AREA...POSSIBLY
CHANGING SNOW OVER TO A WINTRY MIX OF SLEET, RAIN OR FREEZING RAIN.
CONFIDENCE IS HIGH ON A WINTER STORM FOR THE AREA BEGINNING
MONDAY...HOWEVER P-TYPE REMAINS THE BIGGEST QUESTION.
MODELS CONTINUE TO JUMP AROUND WITH THE TRACK OF THE LOW. IF THE LOW
TRACKS NORTH FROM THE TENNESSEE VALLEY AND REMAINS WEST OF THE
APPALACHIANS...P-TYPE WILL CHANGE FROM SNOW TO SLEET TO RAIN MONDAY
AFTERNOON AND NIGHT. IF THE TRACK IS FARTHER SOUTH AND EAST OF THE
APPALACHIANS...A LONGER DURATION OF SNOW IS EXPECTED WITH A CHANGE
OVER TO SLEET/RAIN OCCURRING LATER MONDAY NIGHT. DYNAMICS AND LIFT
WITH THIS SYSTEM ARE VERY IMPRESSIVE...ESPECIALLY AS THE LOW
APPROACHES THE AREA. UPWARDS OF AN INCH OF LIQUID IS LIKELY...BUT AT
WHAT P-TYPE IT FALLS AS IS ANOTHER QUESTION TO ANSWER. FOR THIS
FORECAST PACKAGE...WE WILL KEEP P-TYPE SIMPLE WITH RAIN/SNOW. WE
WILL ALSO KEEP SNOWFALL LIGHT TO MODERATE AND NOT SPECULATE ON
AMOUNTS AT THIS TIME.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 245 PM EST FRIDAY...

EARLY TUESDAY MORNING A SURFACE LOW PRESSURE SYSTEM WILL MOVE ACROSS
THE CWA...WITH THE CENTER OF THE SYSTEM TRACKING TO THE SOUTHEAST
AND THEN SHIFTING TO MOVE ALONG THE EAST COAST. THE FURTHER
SOUTHEAST THE SYSTEM MOVES THE MORE LIKELY THE PRECIPITATION WILL
FALL AS SNOW. THERE IS SOME UNCERTAINTY AT THIS TIME WHETHER THE
PRECIPITATION WILL FALL COMPLETELY AS SNOW...RAIN...OR WINTRY
RAIN MIX. THE MODELS DAYTIME SURFACE TEMPERATURES STAY WARM ENOUGH
TO FAVOR RAIN FOR MAJORITY OF THE CWA ESPECIALLY IN THE PIEDMONT.
HOWEVER...SNOW COULD BE POSSIBLE IN THE HIGHER ELEVATIONS AND
ALONG THE WESTERN SLOPES OF THE BLUE RIDGE AS THE RIDGES STAY
COLDER AND THE LOW PRESSURE BRINGS IN A COLDER WRAP AROUND
MOISTURE.

WEDNESDAY A CLIPPER SYSTEM STARTS TO MOVE INTO THE CWA BRINGING AN
ADDITIONAL CHANCE FOR SNOW AND COLD TEMPERATURES. THE GFS AND EURO
ARE IN DISAGREEMENT HOW MUCH MUCH SNOW BUT MODELS TEND TO AGREE THAT
THE WESTERN SLOPES WILL SEE SOME ACCUMULATIONS. A HIGH PRESSURE THEN
BUILDS IN DURING THE DAY THURSDAY AND TEMPERATURES WILL START TO
WARM UP.

&&

.AVIATION /05Z SATURDAY THROUGH WEDNESDAY/...
AS OF 1215 AM EST SATURDAY...

MAIN AVIATION CONCERNS THIS PERIOD WILL BE STRONG WINDS AND SNOW
SHOWERS.

EXPECT SNOW SHOWERS WITH MVFR TO OCCASION IFR CIGS/VSBYS TO MAINLY
IMPACT BLF/LWB EARLY POSSIBLY ENTERING BCB/ROA...BUT IT WILL BE
ISOLATED HERE.

THE WINDS WILL STAY OUT OF NW AT 10-20KTS WITH GUSTS OVER 30 TO 40
KTS POSSIBLE...MAINLY IN THE HIGHER TERRAIN. TYPICAL GUSTS TO 30
KTS WILL OCCUR AT ROA/BCB. WINDS WILL START TO WIND DOWN SOME LATE
SATURDAY AFTERNOON. SNOW SHOWERS AND CLOUD COVER WILL ALSO LESSEN
BY MIDDAY SATURDAY...WITH EVERYONE GOING VFR THROUGH SAT
AFTERNOON.

WINDS WILL DIMINISH SATURDAY EVENING AND INTO SATURDAY
NIGHT...WITH NEAR CALM CONDITIONS BY SUNDAY AS HIGH PRESSURE
SETTLES OVERHEAD. MAIN CONCERN SATURDAY NIGHT INTO SUNDAY WILL BE
THE BITTER COLD...TEMPERATURES DROPPING INTO THE SINGLE DIGITS.

EXTENDED DISCUSSION...

WINTER STORM IS EXPECTED TO IMPACT THE AREA EARLY NEXT WEEK WITH
ONSET OF WINTRY PRECIPITATION BEGINNING SUNDAY NIGHT.  CONFIDENCE
IS HIGH THAT POOR FLYING CONDITIONS WILL EXIST FROM SUNDAY NIGHT
THROUGH TUESDAY. THIS WINTER STORM WILL PRODUCE A VARIETY OF WINTRY
PRECIPITATION...STARTING AS SNOW SUNDAY NIGHT...THEN TRANSITIONING
TO SLEET AND FREEZING RAIN MONDAY. AFTER THE EARLY WEEK WINTER
STORM...THERE IS ANOTHER WEAK CLIPPER SYSTEM THAT MAY IMPACT THE
AREA FOR MID WEEK...POSSIBLY RESULTING IN THE CONTINUATION OF
POOR FLYING CONDITIONS THROUGH WEDNESDAY.

&&

.CLIMATE...
COLDEST AIR OF THE SEASON ARRIVES THIS WEEKEND. SEVERAL RECORD LOW
MAX TEMPERATURES AND LOW TEMPERATURES ARE POSSIBLE. BELOW ARE THE
CURRENT RECORDS FOR SATURDAY 2/13 AND SUNDAY 2/14.

SATURDAY 02/13/2016
SITE   MINT YEAR  LOMAX YEAR
KBLF     4 1988     19 1988
KDAN    11 1955     32 1981
KLYH     5 1979      9 1899
KROA     8 1917     18 1914
KRNK    -4 1969     14 1955


SUNDAY 02/14/2016
SITE   MINT YEAR  LOMAX YEAR
KBLF     5 1971     16 1960
KDAN    15 1986     32 1986
KLYH     4 1899     24 1905
KROA    10 1943     26 1986
KRNK    -2 1969     24 1986

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...WIND CHILL ADVISORY UNTIL 10 AM EST SUNDAY FOR VAZ007-009>020-
     022>024-032>035.
     WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR VAZ007-
     009-015.
NC...WIND CHILL ADVISORY UNTIL 10 AM EST SUNDAY FOR NCZ001-002-018.
     WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR NCZ001-
     018.
WV...WIND CHILL ADVISORY UNTIL 10 AM EST SUNDAY FOR WVZ042>044-507.
     WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR WVZ042-
     043-508.
     WIND CHILL WARNING UNTIL 10 AM EST SUNDAY FOR WVZ508.

&&

$$
SYNOPSIS...JH/MBS
NEAR TERM...JH/PM
SHORT TERM...RCS
LONG TERM...RCS
AVIATION...PM/WP
CLIMATE...CF



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