Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000
FXUS61 KRNK 142025
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
325 PM EST SUN FEB 14 2016

.SYNOPSIS...
COLD HIGH PRESSURE MOVES EAST AND OFF THE MID ATLANTIC COAST TONIGHT.
A WARM FRONTAL BOUNDARY WORKS TOWARD THE TENNESSEE VALLEY BY THIS
EVENING WITH SNOW MOVING INTO THE MOUNTAINS. BY MONDAY...LOW
PRESSURE WORKS FROM THE LOWER MISSISSIPPI VALLEY TO THE SOUTHERN
APPALACHIANS. WITH COLD AIR IN PLACE EXPECT SNOW CHANGING TO A
WINTRY MIX MONDAY INTO MONDAY NIGHT. THIS SYSTEM MOVES EAST BY
TUESDAY AFTERNOON.

&&

.NEAR TERM /THROUGH MONDAY/...
AS OF 325 PM EST SUNDAY...

WINTER STORM WARNINGS REMAIN IN EFFECT UNTIL NOON ON TUESDAY.

ARCTIC HIGH PRESSURE WILL TRAVEL EAST TONIGHT...AS A LONGWAVE TROUGH
DEVELOPS OVER THE CENTRAL UNITED STATES. WARM AND MOIST AIR FROM
THE ATLANTIC AND GULF OF MEXICO WILL OVERRUN THE ARCTIC AIR
RESULTING IN SNOW TONIGHT.

LIGHT SNOW HAS STARTED IN THE MOUNTAINS THIS AFTERNOON AND WILL
INCREASE IN COVERAGE AND SPREAD EASTWARD TONIGHT. PTYPE WILL STAY AS
ALL SNOW TONIGHT BECAUSE AIRMASS IS VERY COLD WITH THERMAL PROFILE
STAYING BELOW ZERO THROUGH 12Z MONDAY. SHAPED EVENING POPS TOWARDS A
BLEND OF HRRR AND HIRESW-ARW-EAST...THEN LEANED TOWARDS GFS. NAM
SOLUTION WAS TOO SLOW AND TOO DEEP WITH THE STORM...THUS FOLLOWED
WPC WEIGHTING MORE TOWARDS GFS. MODELS FAVOR A MOUNTAIN EMPIRE TO
WESTERN GREENBRIER CORRIDOR FOR HEAVIER SNOW BAND POTENTIAL BY
MIDNIGHT TONIGHT. SMALLER BANDS OF SNOW SHOULD SLIDE EAST TO THE
PIEDMONT THROUGH THE NIGHT.  USED A SNOW TO LIQUID RATIOS CLOSE A
20:1 RANGE EARLY TONIGHT...THEN DROPPING TOWARD 15:1 BY 12Z MONDAY.
LOW TEMPERATURES TONIGHT WILL RANGE FROM THE LOWER TEENS IN THE
NORTHWEST MOUNTAINS TO THE LOWER 20S IN THE PIEDMONT.

AN UPPER LEVEL TROUGH WILL AMPLIFY OVER THE MISSISSIPPI RIVER VALLEY
TONIGHT AND MONDAY. SEVERAL SHORTWAVES WILL ROTATE AROUND THE UPPER
TROUGH. WARMER AIR WILL PUSH IN ALOFT AND MIX IN SLEET AND FREEZING
RAIN ON MONDAY. THE COLDER AIR WILL HOLD IN THE NORTH THE LONGEST.
TEMPERATURES WILL CLIMB IN THE LOWER TO MID 30S WEST OF I77 MONDAY
AFTERNOON...AND WARM AIR WILL ALSO PUSH NORTH INTO SOUTHEAST
PORTIONS OF FORECAST AREA MONDAY AFTERNOON. USED A TOPDOWN APPROACH
FOR WEATHER TYPE WITH PRIMARY MODEL GFS. ICE ACCUMULATIONS OF TWO-
TENTHS OF AN INCH OR LESS EXPECTED IN MOST AREAS THROUGH MONDAY
NIGHT. SNOW ACCUMULATIONS WILL VARY GREATLY BECAUSE OF THE WINTRY
MIX FROM 2 INCHES IN NORTH CAROLINA PIEDMONT TO AS MUCH AS 5 TO 10
INCHES IN NORTHWEST GREENBRIER BY MONDAY NIGHT.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
AS OF 322 PM EST SUNDAY...

MAY INIT WITHIN A LULL IN HEAVIER PRECIP AS A DRY SLOT REMAINS IN
BETWEEN THE DEPARTING NORTHERN STREAM SYSTEM AND THE AXIS OF BETTER
LIFT ASSOCIATED WITH THE ACTUAL SURFACE LOW APPROACHING FROM THE SW.
THIS MAINLY BETWEEN 00Z AND 06Z BEFORE THE NEXT SLUG OF DEEPER MOISTURE
ARRIVES OVER THE FAR WEST AROUND OR SHORTLY AFTER MIDNIGHT. WITH MODEL
CONSENSUS IN TRACKING THE MAIN WAVE EITHER OVER THE MOUNTAINS OR JUST
TO THE WEST...WILL CONTINUE TO SEE VERY STRONG WARM ADVECTION ALOFT.
THIS SEEN VIA MOST GUIDANCE SHOWING 50+ KTS AT 85H FROM THE SOUTH WHILE
TEMPS WITHIN THAT LAYER SURGE TO +4C TO +6C IN THE WARM NOSE. HOWEVER
THROUGH MIDNIGHT WILL STILL SEE MUCH OF THE REGION HAVE SURFACE TEMPS
NEAR OR JUST BELOW FREEZING MAKING FOR CONTINUED LIGHT FREEZING RAIN IN
ALL EXCEPT THE FAR WEST AND SE. APPEARS ADDED QPF THOUGH WILL BE LIGHT
AND MAINLY SUPPORTED BY WEAK LOW LEVEL ISENTROPIC LIFT BLUE RIDGE.

BIGGER CONCERN DEVELOPS AFTER MIDNIGHT WHEN THE HEAVIER BAND OF PRECIP
ALONG THE SURFACE TROUGH/WAVE SHIFTS EAST REACHING THE PIEDMONT
OVERNIGHT. MODELS SHOW CONTINUED WARMING IN THE BOUNDARY LAYER UNDER
THIS HEAVIER PRECIP AXIS AS COMBO OF THE DEEPENING WARMING ALOFT AND
PERHAPS PRECIP FALLING THROUGH THAT LAYER HELP TO BUMP MOST TO ABOVE
FREEZING FROM AFTER MIDNIGHT UNTIL EARLY TUESDAY. SINCE THIS MAY BE
SLOWER TO ERODE OVER THE EARLIER SNOW PACK...SLOWLY TRANSITIONING THE
PTYPE FROM FREEZING RAIN TO ALL RAIN FROM SOUTH TO NORTH BY MORNING.
THUS RUNNING WITH SOME LIGHT ADDED SNOW FAR NW EARLY ON...FOLLOWED BY
MORE SIGNIFICANT ICING ESPCLY BLUE RIDGE AND POINTS NORTH/EAST OF ROUTE
460 WHERE COULD SEE UP TO A QUARTER INCH OF ICE IN THE LATE EVENING TO
SHORTLY AFTER MIDNIGHT TIME FRAME. KEPT TEMPS NEAR FREEZING OR JUST
BELOW EARLY ON WITH SLOW RISES BY MORNING WHEN MOST SHOULD BE NEAR OR
JUST ABOVE FREEZING EXCLUDING THE VALLEYS UP NORTH. ALSO IF TEMPS END
UP WARMER AND QPF IS MORE THEN POTENTIAL FOR FLOODING ESPCLY EAST AS
MODELS SHOW A GOOD INCH OF QPF BLUE RIDGE EAST OVERNIGHT ON TOP OF
EARLIER SNOW/ICE AND FROZEN GROUND. THEREFORE ADDED MENTION TO THE HWO
FOR POSSIBLE FLOOD WATCH CONCERNS ON THE HEELS OF THE WINTER STORM
HEADLINES BY TUESDAY.

SYSTEM GOES NEGATIVE TILT AND QUICKLY EXITS BY TUESDAY AFTERNOON
ALLOWING COLD ADVECTION TO KICK BACK IN ESPCLY MOUNTAINS WHERE MAY
SWITCH TO SNOW SHOWERS WESTERN SLOPES. ELSEWHERE AFTER EARLY HIGH POPS
EAST EXPECT A BREAK UNDER WEAK SUBSIDENCE AHEAD OF YET ANOTHER DIGGING
UPSTREAM CLIPPER THAT WILL BE APPROACHING THE WEST LATE IN THE DAY.
COULD ALSO SEE SOME BREAKS DEVELOP THAT SHOULD ALLOW TEMPS TO RECOVER
BACK INTO THE 30S/40S MOUNTAINS AND POSSIBLY LOW 50S PIEDMONT.

THE CLIPPER GLIDES IN FROM THE WEST ON THE TAIL OF THE DEPARTING SYSTEM
TUESDAY NIGHT WITH TEMPS ALOFT COLD ENOUGH FOR A PERIOD OF SNOW
MOUNTAINS AND RAIN/SNOW EAST OVERNIGHT. LATEST MODELS SUGGEST AN INCH
OR TWO OF SNOW COULD OCCUR ACROSS THE HIGHER WESTERN ELEVATIONS BUT
LITTLE ELSEWHERE AS TEMPS MARGINAL HEADING EAST OF THE BLUE RIDGE. THUS
INCLUDING SOME HIGH CHANCE POPS WEST...AND LOW POPS TO JUST EAST OF THE
MOUNTAINS FOR NOW. LOWS MAINLY UPPER 20S TO LOW/MID 30S EAST.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 1230 PM EST SUNDAY...

UPPER TROUGH WILL LINGER WEDNESDAY BEHIND A DEPARTING CLIPPER THAT
SHOULD CONTINUE TO DRIVE UPSLOPE FLOW...PRIMARILY ACROSS THE WESTERN
SLOPES WEDNESDAY INTO WEDNESDAY NIGHT. THIS SUPPORTS KEEPING ADDED SNOW
SHOWERS OVER THE WEST ESPCLY WEDNESDAY BEFORE TAPERING OFF WEDNESDAY
NIGHT AS WEAK HIGH PRESSURE BUILDS IN. THUS KEEPING CHANCE POPS OVER
THE FAR WEST INTO LATE WEDNESDAY NIGHT. SHORTWAVE RIDGING STARTS TO
TAKE SHAPE THURSDAY AS CHILLY HIGH PRESSURE SHIFTS TO THE NORTH AND
MUCH DRIER AIR WORKS IN. THIS WILL KEEP TEMPS CLOSER TO NORMAL LEVELS
BY THURSDAY ALTHOUGH STILL WELL INTO THE 20S AT NIGHT.

A MUCH MORE TRANQUIL AND NEEDED WARMER SCENARIO TO UNFOLD FROM FRIDAY
INTO THE WEEKEND WITH OVERALL ZONAL FLOW IN PLACE AS THE MAJORITY OF
ANY COLD AIR REMAINS TO THE NORTH. WILL SEE A WEAK COOL FRONT SNEAK
THROUGH WITH PERHAPS A FEW MOUNTAIN RAIN SHOWERS FRIDAY NIGHT INTO
SATURDAY...AND AHEAD OF ANOTHER FRONT SUNDAY...OTHERWISE KEEPING THINGS
DRY. THIS ALONG WITH MUCH WARMER 85H TEMPS SUPPORTS HIGHS 50-55
FRIDAY...50S TO NEAR 60 PIEDMONT SATURDAY...AND OVERALL 50S ON SUNDAY.




&&

.AVIATION /21Z SUNDAY THROUGH FRIDAY/...
AS OF 1234 PM EST SUNDAY...

POOR FLYING CONDITIONS EXPECTED DURING THE TAF PERIOD BECAUSE OF WINTER
STORM WITH SNOW MIXED WITH SLEET AND FREEZING RAIN. GUSTY
SOUTHEAST WINDS ARE ALSO POSSIBLE ALONG THE RIDGES. PILOTS SHOULD
WATCH FOR MOUNTAIN OBSCURATIONS.

VFR CEILINGS THIS AFTERNOON WILL LOWER TO MVFR IN CLOUDS AND
SNOW LATE THIS AFTERNOON INTO TONIGHT. WARM FRONT AND SNOW WILL
MOVE INTO THE WESTERN AREAS BY 22Z...AND SHIFT EAST TONIGHT. LOOK
FOR VSBYS/CIGS TO DROP TO MVFR AND LOWER ESPECIALLY WEST OF THE
BLUE RIDGE BY 06Z...WITH IFR CIGS/VSBYS SPREADING EAST OVERNIGHT.

LIGHT WINDS WILL BECOME SOUTHEAST THIS AFTERNOON INTO TONIGHT
WITH SOME GUSTS OVER BLF TO 20KTS AFTER 00Z MONDAY. EXPECT SNOW
SWITCHING TO SLEET/FREEZING RAIN MONDAY WITH THIS MIX INTO MONDAY
NIGHT AND EARLY TUESDAY. MVFR TO IFR CIGS/VSBYS TO REMAIN. SOME
RAIN IS EXPECTED AT LEAST DAN/BLF AS WARMER SURGE OF AIR RIDES IN
TUESDAY.

MEDIUM CONFIDENCE IN CEILINGS...VISIBILITIES AND WINDS DURING THE
TAF PERIOD.

EXTENDED DISCUSSION...

THIS STORM EXITS TUESDAY AFTERNOON...BUT IS FOLLOWED QUICKLY BY A CLIPPER
SYSTEM THAT MAY IMPACT THE AREA FOR TUESDAY NIGHT-WEDNESDAY...POSSIBLY
RESULTING IN THE CONTINUATION OF POOR FLYING CONDITIONS.

HIGH PRESSURE BUILDS IN THURSDAY WITH VFR RETURNING.

&&

.CLIMATE...
COLDEST AIR OF THE SEASON HAS SETTLED OVER THE MID ATLANTIC
REGION. ROANOKE...DANVILLE...AND BLUEFIELD SET RECORD LOW
TEMPERATURES SUNDAY MORNING. SEE RECORD EVENT REPORT (RER) FOR
MORE DETAILS. SEVERAL CLIMATE SITES MAY BREAK RECORDS FOR LOW
MAXIMUM TEMPERATURES TODAY. THE CURRENT RECORDS ARE LISTED BELOW.

SUNDAY 02/14/2016
SITE   LOMAX YEAR
KBLF    16 1960
KDAN    32 1986
KLYH    24 1905
KROA    26 1986
KRNK    24 1986

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...WINTER STORM WARNING UNTIL NOON EST TUESDAY FOR VAZ007-009>020-
     022>024-032>035-043>047-058-059.
NC...WINTER STORM WARNING UNTIL NOON EST TUESDAY FOR NCZ001>006-
     018>020.
WV...WINTER STORM WARNING UNTIL NOON EST TUESDAY FOR WVZ042>044-507-
     508.

&&

$$
SYNOPSIS...JH/WP
NEAR TERM...KK
SHORT TERM...JH
LONG TERM...JH
AVIATION...KK/WP
CLIMATE...CF


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