FXUS61 KRNK 052017
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
317 PM EST SAT DEC 5 2009

.SYNOPSIS...
LOW PRESSURE WILL DEVELOP AND MOVE RAPIDLY ALONG THE SOUTHEAST
COAST TODAY...REACHING THE OUTER BANKS OF NORTH CAROLINA
BY LATE THIS AFTERNOON...AND EXITING THE MID ATLANTIC COAST AREA
BY THIS EVENING. COLD HIGH PRESSURE WILL BUILD IN BEHIND THE
SYSTEM FOR OVERNIGHT.

&&

.NEAR TERM /THROUGH SUNDAY/...
RADAR/SATELLITE LOOPS SHOWS PRECIP ENDING FAIRLY QUICKLY ACROSS
THE FAR WRN CWA. WILL BE ABLE TO END ADVISORIES/WARNINGS SOONER
THAN EXPECTED MOST AREAS...BUT NOT ALL AREAS BY 400 PM...SO HAVE
OPTED TO ISSUE THE AFTERNOON PACKAGE BY 300 PM WITH A REST OF THIS
AFTERNOON SECTION BEFORE TONIGHT. WILL PULL THE SW MTNS AND NC
MTNS OUT OF THEIR ADVISORIES...AND HAVE TRIMMED THE REST OF THE
MTNS ADVISORIES...NRV MAINLY...TO END AT 500 PM. REST OF THE
ADVISORIES AND WARNINGS WILL END AT 700 PM. WILL JUST NEED TO
UPDATE THE FORECAST BY 500 PM- MAY HAVE MOST OF THE CWA CLEAR OF
ACCUMULATING SNOW BY AROUND THEN. SNOW ACCUMS HAVE BEEN HIGHLY
VARIABLE BY ELEVATION AS EXPECTED. SO FAR...LITTLE OR NO ACCUM ROA
AND LYH...BUT THEY MAY SEE SOME BETWEEN 400 PM AND 700 PM AS THE
SNOW TAPERS OFF. 

MAIN CONCERN OF THE FCST TURNS TO THE RAPID DROP IN TEMPS EXPECTED
TONIGHT IN THE MTNS. WHERE SNOW HAS FALLEN AND MAY STILL BE ON
ROADS...IT WILL PROBABLY QUICKLY FREEZE AS COLDER AIR POURS INTO
THE REGION ON THE NORTHWEST WINDS BEHIND THE STORM. BY 700
PM...TEMPS WILL LIKELY BE IN THE MID TO UPPER 20S ACROSS THE
MTNS...AND WITH THE SNOW COVER...CLEARING SKIES AND WEAKENING
WINDS...WILL DROP INTO THE TEENS OVERNIGHT. 

SUNDAY WILL FEATURE LOTS OF SUN AND LIGHT WINDS...BUT WITH A COLD
AIRMASS IN PLACE AND SNOW COVER IN THE MTNS...I HAVE GONE WITH
HIGH ON THE COOL SIDE OF GUIDANCE.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
RIDGING AT THE SURFACE AND ALOFT WILL PUSH EAST OVER THE ATLANTIC 
OVERNIGHT SUNDAY. MODELS HAVE BEEN SLOWER WITH A WEAK SHORTWAVE 
PUSHING ACROSS THE FORECAST AREA. A SOUTHERLY FLOW WILL BRING IN 
MOISTURE AHEAD OF THIS FEATURE INCREASING CLOUD COVER MONDAY. THE 
LATEST MODEL RUNS HAVE MINOR DIFFERENCES ON THE TIMING OF THE 
PRECIP. HAVE LEANED TOWARD THE SLOWER SOLUTION HAVING SLIGHT CHANCE 
ALONG AND WEST OF THE BLUE RIDGE MOUNTAINS BEGINNING AT 18Z MONDAY. 
HOWEVER...WOULD NOT BE SURPRISED TO SEE THIS SLOW DOWN A BIT IN 
LATER RUNS. 

TEMPERATURES WILL NOT BE QUITE AS COLD SUNDAY NIGHT AS THE PREVIOUS 
NIGHT...AS 850MB TEMPERATURES SEEM TO RISE A BIT WITH A LIGHT 
SOUTHERLY FLOW PUSHING SLIGHTLY WARMER AIR INTO THE COUNTY WARNING 
AREA. HOWEVER...CLOUD COVERAGE WILL BE LOW AND WINDS WILL REMAIN 
LIGHT WHICH WILL ALLOW TEMPERATURES TO FALL INTO THE MID TO UPPER 20 
RANGE ACROSS THE BOARD. 

EXPECT THE SLIGHT CHANCE POPS IN THE WEST CONTINUING THROUGH TUESDAY 
MORNING THEN INCREASING TO CHANCE FOR THE AFTERNOON. WITH WARM AIR 
ADVECTION CONTINUING...TEMPERATURES WILL RISE INTO THE MID TO UPPER 
40S ACROSS THE FORECAST AREA. 

MOST OF THE ENERGY LOOKS TO APPROACH THE AREA TUESDAY NIGHT THUS 
HAVE MAINTAINED THE LIKELY POPS LATE. COLD AIR ADVECTION WILL BE 
FILTERING IN BRIEFLY FROM THE NORTHWEST TUESDAY NIGHT WITH A WIDE 
RANGE OF 850MB TEMPS RANGING FROM PLUS 5 TO MINUS 7 FROM
SOUTHEAST TO NORTHWEST RESPECTIVELY. BUFKIT SOUNDINGS SUPPORT NEAR
TO BELOW FREEZING TEMPERATURES FROM THE UPPER LEVELS DOWN TO THE
SURFACE AT MOST ALL OF OUR SITES...WITH THE EXCEPTION OF DANVILLE
AND LYNCHBURG WHICH WILL HOVER CLOSE TO FREEZING AT THE SURFACE.
EXPECT RAIN CHANGING TO SNOW AFTER SUNSET TUESDAY AND WITH A WARM
NOSE ADVECTING IN NEAR 850MB...THE PRECIP WILL THEN CHANGE TO A
WINTRY MIX ENCOMPASSING SNOW...SLEET AND FREEZING RAIN. DANVILLE
AND THE PIEDMONT AREAS OF VIRGINIA AND NORTH CAROLINA WILL BE THE
AREAS MOST LIKELY TO SEE ALL RAIN UNTIL JUST BEFORE SUNRISE BEFORE
ANY FREEZING RAIN BEGINS. LYNCHBURG WILL ALSO REMAIN MOSTLY RAIN
BUT HAS A HIGHER PROBABILITY OF SEEING A MIX OF SLEET AND FREEZING
RAIN TOWARD DAWN.

HAVE LEANED TOWARD THE MOS GUIDANCE FOR TEMPERATURES TUESDAY NIGHT 
DUE TO THE COLD AIR ADVECTION PUSHING OVER THE AREA BUT MOST OF THE 
COLDER AIR WILL BANK UP AGAINST THE APPALACHIANS OF SOUTHEAST WEST 
VIRGINIA. 

&&

.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
A HYBRID DAMMING EVENT IS POSSIBLE TUESDAY NIGHT INTO WEDNESDAY. GFS 
WAS INDICATING SOME WINTRY MIXTURE OF SLEET...FREEZING RAIN AND RAIN 
FOR EARLY WEDNESDAY BECOMING A COLD RAIN. THE ECMWF IS WARMER AND 
DEPICTS ONLY RAIN ACROSS THE ENTIRE CWA.  WILL ALLOW FOR SOME WINTRY 
MIX EARLY WEDNESDAY WITH THE CONSISTENCY OF THE MODELS.

HIGH PRESSURE OVER THE REGION ON TUESDAY INTO WEDNESDAY SLIDES 
EAST...WHILE STRONG LOW PRESSURE WILL TRACK FROM THE PLAINS 
NORTHEASTWARD OVER THE GRTLKS/OH VALLEY REGION. AS THE LOW LIFTS 
NORTHEAST A COLD FRONT WILL PUSH EAST ACROSS OUR REGION WEDNESDAY 
AND INTO THE ATLANTIC OCEAN ON WEDNESDAY NIGHT. KEEP THE BEST POPS 
CHANCE IN THE NORTH WESTERN MOUNTAINS WEDNESDAY NIGHT INTO THURSDAY. 
HIGH PRESSURE WILL BUILD EAST INTO THE AREA FROM THE TENNESSEE 
VALLEY ON THURSDAY INTO THURSDAY NIGHT. KEPT SOME CHCY POPS IN THE 
WEST WITH THE PASSAGE OF A WARM FRONT ON FRIDAY.

&&

.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
SNOW AT ALL TAF SITES EXCEPT FOR DANVILLE...WILL TAPER OFF FROM
WEST TO EAST BETWEEN 05/20Z AT BLF...AND 06/02Z AT LYH. IFR
CONDITIONS WILL GRADUALLY RISE TO VFR OVERNIGHT. CLOUDS WILL
BECOME SCATTERED EAST OF THE BLUE RIDGE AFTER 00Z TO 02Z WITH
ROA...LYH AND DAN ALL VFR BY 04Z. THE CLEARING WILL BE SLOWER AT
BLF AND LWB DUE TO A WEST TO NORTHWEST LOW LEVEL WIND AND
RESIDUAL LOW LEVEL MOISTURE. ALL SITES SHOULD BECOME VFR BETWEEN
06Z AND 10Z SUNDAY.

HIGH PRESSURE WILL CONTINUE THE VFR CONDITIONS INTO MONDAY.
A WEAK COLD FRONT MAY BRING BRIEF MVFR CONDITIONS IN CLOUDS AND
POSSIBLY LIGHT PRECIP BY MONDAY NIGHT INTO TUESDAY IN THE MOUNTAINS. IFR
CONDITIONS MAY BE POSSIBLE TUESDAY NIGHT AND WEDNESDAY WITH A
LARGER LOW PRESSURE SYSTEM DEVELOPING IN THE SOUTHERN PLAINS.

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR VAZ018.
     WINTER STORM WARNING UNTIL 11 PM EST THIS EVENING FOR VAZ019-
     020-023-024.
     WINTER WEATHER ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR 
     VAZ010>014-016-017.
     WINTER WEATHER ADVISORY UNTIL 11 PM EST THIS EVENING FOR 
     VAZ022-034-035-045>047.
NC...NONE.
WV...WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR WVZ044-
     045.
     WINTER WEATHER ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR 
     WVZ042-043.

&&

$$
SYNOPSIS...JJ
NEAR TERM...JJ
SHORT TERM...REB
LONG TERM...KK
AVIATION...AMS/JJ