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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KRNK 051005
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
505 AM EST WED MAR 5 2014

.SYNOPSIS...
-- Changed Discussion --
HIGH PRESSURE ACROSS QUEBEC TODAY WILL BE RIDGING SOUTHWARD INTO
OUR AREA. STORM SYSTEM MOVING ALONG THE GULF COAST STATES SHOULD
TRACK OVER THE SOUTHEAST COAST BY THURSDAY NIGHT INTO
FRIDAY...SPREADING MOISTURE OUR WAY...SOME OF WHICH WILL BE WINTRY
PRECIPITATION.
-- End Changed Discussion --

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
AS OF 245 AM EST WEDNESDAY...

TRICKY FORECAST TODAY IN TERMS OF CLOUD COVER AND AFFECT ON TEMPS.
THE NAMDNG AND CMC SEEM TO ALWAYS HANDLE CIRRUS IN THE WINTER MONTHS
BETTER THAN THE GFS/MOSGUIDE...ALTHOUGH THE NAM CAN OVERDUE
OPAQUENESS. THIS MORNING WE STILL ARE SEEING DENSE CIRRUS FROM ERN
KY TO MID TN EWD. MODELS SHOW MID LEVEL VORT PASSING ACROSS THE
CAROLINAS THIS MORNING NUDGING THE WRN SHIELD OF CLOUDS EASTWARD BY
MIDDAY. THINK WILL SEE MORE SUNSHINE TODAY IN THE WEST.
HOWEVER...THINK THE SOUTHEAST CWA WILL HANG ONTO CLOUDS THROUGH MID
AFTERNOON. LOW LVL WINDS TURN MORE TO THE NORTH AND NORTHEAST AND 8H
TEMP ADVECTION IS GENERALLY NEUTRAL WITH SOME CAA ARRIVING LATE IN
THE NORTHERN CWA. ALL MODELS FAVOR WARMER TEMPS TODAY...AND AGREE
SOMEWHAT BUT CUT HIGHS A DEGREE TO 3 UNDER MOS GUIDANCE...WITH LOWER
40S OVER THE ALLEGHANY HIGHLANDS TO UPPER 40S ACROSS THE NEW RIVER
VALLEY AND PIEDMONT...WHILE SOME DOWNSLOPE WIND FROM THE NORTH MAY
INCREASE TEMPS SOUTH OF THE BLUE RIDGE ALONG PATRICK COUNTY INTO THE
NC FOOTHILLS INTO THE LOWER TO MID 50S.

TONIGHT...COLD ADVECTION CONTINUES AS HIGH PRESSURE OVER SOUTHERN
QUEBEC WEDGES SOUTHWARD INTO THE REGION. MODELS ARE SHOWING EAST
FLOW TURNING SE LATE TONIGHT ALLOWING FOR SOME INCREASE IN LOW LEVEL
MOISTURE. MODEL SOUNDINGS SUGGEST ABOUT A 1-2 KFT LAYER AT MOST.
POTENTIAL FOR SOME FREEZING DRIZZLE EXISTS MAINLY OVER THE HIGHER
ELEVATIONS OF THE BLUE RIDGE NORTH OF ROANOKE AND INTO THE MOUNTAINS
OF BATH. HOWEVER...THE COVERAGE IS MINUSCULE...FOR ANY HEADLINES.

WITH INCREASED CLOUD COVER AND COLDER AIR ADVECTION LOW TEMPS WILL
STAY COOL BUT NOT FRIGID...WITH 20S MOST LOCATIONS...FROM LOWER 20S
IN THE ALLEGHANY HIGHLANDS AND GREENBRIER COUNTY TO UPPER 20S TO
AROUND 30 SOUTHSIDE VA INTO NORTH CAROLINA.
-- End Changed Discussion --

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
-- Changed Discussion --
AS OF 500 AM EST WEDNESDAY...

COMPLEX WEATHER PATTERN WITH A STRONG RIDGE WEDGING DOWN THE EAST
COAST AND A SOUTHERN STREAM CLOSED LOW/GULF WAVE TRACKING TO OUR
SOUTH. ALL MODELS HAVE COME IN SLOWER WITH THE ARRIVAL OF
OVERRUNNING PRECIPITATION. PRECIPITATION IS NOT EXPECTED TO ENTER
RNK NORTH CAROLINA COUNTIES UNTIL THURSDAY EVENING...THEN SPREADS
NORTH OVERNIGHT. I TOOK POPS OUT THURSDAY MORNING...AND TRENDED DOWN
FOR THE AFTERNOON BASED ON LATEST MODEL RUNS. RAMPED UP POPS
STARTING THURSDAY EVENING AS ISENTROPIC LIFT AND MOISTURE ADVECTION
INCREASES RAPIDLY. WITH THE SLOWER ARRIVAL...THERE IS ALSO A SLOWER
EXIT. THE ECM PULLS PRECIPITATION OUT OF THE AREA AROUND 00Z
SATURDAY. THE NAM HANGS ON TO PRECIPITATION THROUGH 12Z SATURDAY. AS
WAS THE CASE WITH THE 12Z GFS...THE 00Z GFS REMAINS AN OUTLIER. THE
00Z GFS HAS LIGHT PRECIPITATION ACROSS SOUTHSIDE FRIDAY
MORNING...EXITING BY NOON.

P-TYPE IS THE BIGGEST CONCERN THURSDAY NIGHT INTO FRIDAY MORNING.
BOUNDARY LAYER SHOULD REMAIN WARM ENOUGH THURSDAY AFTERNOON THAT IF
ANY PRECIPITATION SNEAKS IN EARLY...IT WILL FALL AS A COLD RAIN. AS
RAIN MOVES IN OVERNIGHT AND FALLS INTO SURFACE DEWPOINTS IN THE
20S...SURFACE BOUNDARY LAYER WILL BECOME COLD ENOUGH TO SUPPORT
SLEET AND THEN FREEZING RAIN. THERMAL PROFILES SUGGEST COLD BOUNDARY
LAYER WILL BE THICK ENOUGH...ESPECIALLY NORTH OF HIGHWAY 460...FOR
MOSTLY A SLEET EVENT THURSDAY NIGHT. AS THE STORM SYSTEM MOVES OVER
THE SOUTHEASTERN US...THE COLD BOUNDARY LAYER WILL BECOME SHALLOW
ENOUGH TO SUPPORT FREEZING RAIN...PARTICULARLY ACROSS NORTHWEST
NORTH CAROLINA AND SOUTHSIDE VIRGINIA FRIDAY MORNING. THROUGH THE
DAY FRIDAY...THE WEDGE WILL ERODE AND TEMPERATURES WARM TO HAVE
PRECIPITATION ENDING AS RAIN.

AMOUNTS OF SLEET AND ICE WILL REMAIN LIGHT BUT MAY BE ENOUGH FOR
ADVISORIES. SLEET AMOUNTS MAY BE AS MUCH AS A HALF INCH NORTH OF 460
FROM ROANOKE TO LYNCHBURG. IF SLEET TURNS OUT TO BE SNOW...1-2
INCHES ARE POSSIBLE FROM THE GREENBRIER AND ROANOKE VALLEYS TO
LYNCHBURG. A LIGHT GLAZING OF ICE IS POSSIBLE FOR ALL COUNTIES...BUT
MAINLY ALONG AND EAST OF THE BLUE RIDGE. EASTERLY UPSLOPE MAY BRING
UP TO 0.2 OF AN INCH OF ICE TO THE NORTHWEST NORTH CAROLINA AND
SOUTHWEST VIRGINIA BLUE RIDGE. FORECASTED TEMPERATURES ACROSS THE
SOUTH WILL BE NEAR FREEZING. THIS SHOULD KEEP ANY ICE ACCRETIONS
BELOW WARNING CRITERIA. WITH TEMPERATURES RIGHT AROUND FREEZING AND
CONSIDERING THE ERRATIC NATURAL OF THE MODELS THE PAST COUPLE OF
DAYS...CONFIDENT IS NOT HIGH ENOUGH TO POST ANY HEADLINE WITH THIS
PACKAGE.

RAINFALL AMOUNTS OF A QUARTER TO A HALF INCH ARE POSSIBLE DURING
THIS EVENT. THE NAM DOES HAVE HIGHER AMOUNTS...NOT ONLY BECAUSE OF A
LONGER EVENT...BUT WITH AN EASTERLY 40-50 KT LOW LEVEL JET. THE NAM
FOCUSES THIS JET ACROSS THE SOUTHERN APPALACHIANS WHICH INCLUDES RNK
NORTH CAROLINA HIGH COUNTRY. SOMETHING THAT WILL NEED TO BE
WATCHED.

SINCE PRECIPITATION LOOKS TO HOLD OFF MOST OF THE DAY
THURSDAY...WARMED TEMPERATURES A FEW DEGREES...BUT WILL REMAIN
AROUND 10F COLDER THAN NORMAL. SURFACE TEMPERATURES DROP INTO THE
MID 20S ACROSS THE NORTH TO AROUND FREEZING IN THE SOUTH THURSDAY
NIGHT. TEMPERATURES WARM UP QUICKLY AS RAIN EXITS AND WEDGE ERODES.
TEMPERATURES FRIDAY AFTERNOON COULD BE IN THE 50S IN SOUTHWESTERN
VIRGINIA. IF THE WEDGE HOLDS ON...THE PIEDMONT MAY WARM INTO THE MID
40S.
-- End Changed Discussion --

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 300 PM EST TUESDAY...

A 1020MB SFC HIGH OVER THE SOUTHEAST WILL RIDGE NORTH INTO OUR AREA
SATURDAY AHEAD OF AN APPROACHING COLD FRONT TO OUR WEST ACROSS THE
OHIO VALLEY. HIGH TEMPERATURES SATURDAY WILL BE MILD WITH VALUES
FROM AROUND 50 DEGREES IN THE MOUNTAINS TO THE MID 60S IN THE
PIEDMONT. AS THE HIGH CENTER PUSHES EAST INTO THE ATLANTIC
OCEAN...THE COLD FRONT WILL DROP SOUTHEAST INTO THE MOUNTAINS
SATURDAY NIGHT INTO SUNDAY. DECREASED POPS FOR SATURDAY NIGHT WITH
BEST CHANCES IN THE NORTHWEST. LOW TEMPERATURES WILL RANGE FROM  THE
LOWER 30S IN THE MOUNTAINS TO AROUND 40 DEGREES IN THE PIEDMONT.

THE COLD FRONT WITH LIMITED MOISTURE WILL TRAVEL EAST ACROSS OUR
REGION BY SUNDAY NIGHT. HIGHS ON SUNDAY WILL BE A COUPLE OF DEGREES
COOL THAN SATURDAY FROM THE MID 40S IN THE MOUNTAINS TO AROUND 60
DEGREES IN THE SOUTHEAST. REMOVED LIGHT POPS FROM SUNDAY NIGHT IN
THE WEST...AS HIGH PRESSURE BUILDS EAST OUT OF KENTUCKY. LOWS WILL
DROP TO MID 20S IN THE NORTHWEST MOUNTAINS TO MID 30S IN THE EAST.
HIGH PRESSURE WILL MOVE EAST ACROSS OUR REGION ON MONDAY. A WEST
FLOW WILL ALLOW TEMPERATURES TO MODERATE ON MONDAY. LOW PRESSURE
CENTER DEVELOPS IN THE GULF MONDAY NIGHT AND TRAVELS EAST ON
TUESDAY. MEANWHILE...ANOTHER COLD FRONT DROPS SOUTHEAST ACROSS THE
REGION. UNSETTLED WEATHER EXPECTED TUESDAY WITH PERIODS OF
RAIN...LEANING TOWARDS THE GLOBAL ENSEMBLE MEANS.

&&

.AVIATION /10Z WEDNESDAY THROUGH SUNDAY/...
AS OF 1217 AM EST WEDNESDAY...

ADVERTISING VFR THROUGH WEDNESDAY NIGHT WITH HIGH PRESSURE IN
CONTROL. THERE WILL BE SOME HIGH CLOUDS ABOVE 10KFT ASSOCIATED
WITH SOME DISTURBED WEATHER MOVING EAST ALONG THE GULF COAST...BUT
THIS SYSTEM IS FORECAST TO KEEP ITS DISTANCE FROM THE CENTRAL
APPALACHIANS IN THE NEAR TERM. WINDS THROUGH THE TAF PERIOD ARE
EXPECTED TO AVERAGE LESS THAN 10 KNOTS.

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


EXTENDED AVIATION CONCERNS...
LOW PRESSURE WILL MOVE ALONG OR JUST OFF THE SOUTHEAST COAST
THURSDAY INTO FRIDAY WITH MVFR OR WORSE CIGS AND POSSIBLY MVFR/IFR
VSBYS EXTENDING AS FAR WEST AS BLF-ROA...WITH ICE OR SNOW
POSSIBLE EAST OF THE BCB-ROA LINE. THIS SYSTEM WILL BE EXITING BY
FRIDAY EVENING AND VFR WILL RETURN SATURDAY. ANOTHER SYSTEM MAY
IMPACT THE AREA SATURDAY NIGHT INTO SUNDAY WITH SCATTERED MVFR
SHOWERS. HIGH PRESSURE BUILDS IN FOR SUNDAY NIGHT INTO MONDAY.

&&

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

&&

$$
SYNOPSIS...PM/WP
NEAR TERM...WP
SHORT TERM...RCS
LONG TERM...KK
AVIATION...KK/RCS