-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KRNK 140516
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
116 AM EDT FRI MAR 14 2014

.SYNOPSIS...
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HIGH PRESSURE WILL SHIFT TO THE SOUTHEAST COAST FRIDAY. LOW
PRESSURE PASSING ACROSS THE GREAT LAKES WILL DRAG A COLD FRONT
ACROSS THE AREA LATER FRIDAY NIGHT AND SATURDAY. A LARGER LOW
PRESSURE SYSTEM WILL BRING PRECIPITATION BACK TO THE REGION FOR
SUNDAY AND MONDAY.
-- End Changed Discussion --
&&

.NEAR TERM /THROUGH TODAY/...
AS OF 945 PM EDT WEDNESDAY...

EXPECT MAINLY CLEAR SKIES OVERNIGHT...THOUGH SOME MID LEVEL CLOUDS
UPSTREAM OVER NRN KY/OHIO VERY WELL COULD SNEAK INTO SE WV AND
EAST INTO THE ALLEGHANY HIGHLANDS AFTER MIDNIGHT. AIRMASS IS VERY
DRY THOUGH...SO NOT EXPECTING A LOT OF THESE CLOUDS TO HOLD
TOGETHER.

NOT MUCH CHANGE TO THE OVERNIGHT FORECAST. THERE ARE A COUPLE OF
CENTERS OF HIGH PRESSURE FROM THE FL PANHANDLE COAST TO WV. THIS
HIGH WILL SHIFT EAST OVERNIGHT. WINDS STILL UP THIS EVENING BUT
EXPECT MOST LOCATIONS TO DECOUPLE OVERNIGHT. THE WINDS MAY SHIFT
AROUND TO THE SW LATE...BUT THINK THE VALLEY TO RIDGE VARIANCE
WILL BE LESS IN THE WEST.

PREVIOUS VALID DISCUSSION...

FRIDAY...HIGH PRESSURE WILL SHIFT TO THE COAST OF THE
CAROLINAS...ALLOWING WINDS ACROSS OUR REGION TO SHIFT MORE
SOUTHWESTERLY. THESE SOUTHWESTERLY WINDS WILL DRAW SIGNIFICANTLY
WARMER AIR INTO THE AREA...ALLOWING AFTERNOON HIGHS TO REBOUND
SOME 20 TO 25 DEGREES OVER HIGHS ON THURSDAY. WIND SPEEDS WILL
ALSO BEGIN TO INCREASE DURING THE AFTERNOON AS A LOW PRESSURE
SYSTEM PASSES ACROSS THE GREAT LAKES. WILL START THE DAY OFF WITH
CLEAR SKIES...WITH HIGH CLOUDS INCREASING DURING THE AFTERNOON
FROM THE WEST.

&&

.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
AS OF 330 PM EDT THURSDAY...

A SURFACE WAVE WILL TRACK FROM THE GREAT LAKES ACROSS
SOUTHEASTERN CANADA FRIDAY NIGHT AND SATURDAY. THIS WAVE WILL PUSH
A COLD FRONT ACROSS THE OHIO VALLEY FRIDAY NIGHT. THIS FRONT WILL
THEN MOVE OVER THE CENTRAL APPALACHIAN MOUNTAINS SATURDAY MORNING
AND STALL NEAR THE VA/NC BORDER SATURDAY AFTERNOON. WITH AVAILABLE
MOISTURE...LIGHT RAIN/SPRINKLES ARE POSSIBLE ACROSS THE WESTERN
SLOPES OF SE WV/SW VA SATURDAY MORNING. HIGH PRESSURE BUILDS IN
FROM THE NORTH SATURDAY AFTERNOON AND NIGHT. MOISTURE WILL BEGIN
TO ENTER FROM THE SOUTHWEST LATE SATURDAY NIGHT AS A WAVE OF LOW
PRESSURE TRACKS EAST OVER THE SOUTHERN MISSISSIPPI VALLEY. BOTH
THE NAM AND ECM KEEP THE AREA DRY OVERNIGHT WHILE THE GFS BRINGS
IN LIGHT PRECIPITATION IN AROUND MIDNIGHT. CONFIDENCE IS LOW FOR
MEASURABLE PRECIPITATION SATURDAY NIGHT...THEREFORE WILL ONLY HAVE
20-30 POPS IN RNK SW QUADRANT. SATURDAY HIGH TEMPERATURES WILL RUN
BETWEEN 50F-60F ACROSS THE MOUNTAINS AND 65F-70F IN THE EAST.
CLOUDS WILL INCREASE DURING THE EVENING...TRAPPING THIS
WARMTH...KEEPING SATURDAY NIGHT LOWS ABOVE FREEZING. PRECIPITATION
COMING IN BY SUNRISE WILL FALL AS RAIN.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 355 PM EDT THURSDAY...

AN UPPER LEVEL TROUGH WILL BE DIGGING ACROSS THE CENTRAL US SUNDAY
WITH A SURFACE LOW OVER THE SOUTHERN MISSISSIPPI VALLEY. WARM MOIST
AIR AHEAD OF THE SURFACE LOW WILL MOVE OVER THE AREA AND OVER A
SHALLOW WEDGE TO INCREASE THE CHANCES FOR RAIN ACROSS THE AREA
SUNDAY AFTERNOON AND NIGHT. THICKNESSES AND 85H TEMPERATURES COOL
THROUGH THE AFTERNOON BUT WILL REMAIN WARM ENOUGH FOR SUNDAY
PRECIPITATION TO FALL AS RAIN. OVERNIGHT SUNDAY INTO MONDAY...A
STRONGER AREA OF HIGH PRESSURE WILL WEDGE DOWN THE EAST COAST.
THERMAL PROFILES BEGIN TO COOL NORTH TO SOUTH WITH RAIN CHANGING TO
A WET SNOW. LOW LEVEL THICKNESSES SUGGEST WEDGE MAY BE SHALLOW TO
KEEP MOST FROZEN PRECIPITATION EAST OF THE BLUE RIDGE.
HOWEVER...WITH AN EASTERLY FLOW...AREAS ALONG THE BLUE RIDGE WILL
ALSO GET IN ON THIS SNOW ACTION. SNOWFALL AMOUNTS STILL IN QUESTION
AS BEST ISENTROPIC LIFT AND MOISTURE EXITS AS THE COLDER AIR DIVES
SOUTH MONDAY MORNING. WITH CONFIDENCE LOW ON TIMING COLD AIR WILL
KEEP HOURLY TEMPERATURES WITH A NORMAL DIURNAL CURVE AS HIGHS
APPROACH 40F. MODELS ARE SUGGESTING TEMPERATURES ALONG AND EAST OF
THE BLUE RIDGE WILL DROP OR REMAIN STEADY IN THE LOW TO MID 30S.
AREAS OUTSIDE OF THE WEDGE SHOULD WARM WITH A NORMAL DIURNAL CURVE
INTO THE LOW TO MID 40S WITH PRECIPITATION BEING MOSTLY RAIN.

THE AMOUNT OF PRECIPITATION MONDAY INTO TUESDAY WILL DEPEND ON THE
TRACK OF A CLOSED LOW OVER THE GULF STATES. THE 12Z ECM TRACKS THIS
LOW INLAND AND ACROSS THE SOUTHEASTERN US MONDAY INTO TUESDAY. THE
12Z GFS TRACKS THE CLOSED LOW JUST OFF THE GULF COAST THEN OFF THE
SOUTHEAST COAST TUESDAY MORNING. BOTH OF THESE MODELS KEEP BULK OF
PRECIPITATION ALONG THE SOUTHEAST COAST...LIMITING SNOW/RAIN AMOUNTS
OVER THE AREA MONDAY NIGHT INTO TUESDAY MORNING. DURING THE DAY
TUESDAY...WRAP-AROUND MOISTURE WITH THE CLOSED LOW MAY BRING AN
INCREASING CHANCE FOR RAIN AND/OR SNOW TO THE FOOTHILLS AND PIEDMONT
COUNTIES AS IT TRACKS OFF THE NC/VA COAST. FOR NOW...USED HPCGUIDE
WITH LESS THAN 20 POPS TUESDAY IN THE EAST. WE WILL REVISIT THIS
SCENARIO TOMORROW IF THE MODELS REMAIN CONSISTENT. WILL ALSO NEED TO
REVISIT TEMPERATURES FOLLOWING THE EXIT OF THIS LOW TUESDAY NIGHT
INTO THURSDAY. MODELS ARE HANGING ON TO WEDGE UNTIL THE NEXT FRONT
SWEEPS ACROSS THE REGION WEDNESDAY (GFS) OR THURSDAY (ECM).
&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
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AS OF 100 AM EDT FRIDAY...

VFR CIGS/VSBYS EXPECTED THROUGH THE TAF VALID PERIOD. WESTERLY
WINDS WILL CONTINUE TO DIMINISH OVERNIGHT BUT REMAIN GUSTY ON THE
RIDGES AS WARMER AIR ALOFT RETURNS. A WEAK COLD FRONT APPROACHING
FROM THE NW WILL BEGIN TO SPREAD A HIGH CLOUD CANOPY IN FROM THE
WEST THIS AFTERNOON WITH SOME INCREASE IN MID DECK ESPCLY ACROSS
THE SE WVA SITES THIS EVENING. HOWEVER GIVEN SUCH DRY AIR IN PLACE
SHOULD NOT SEE MUCH IN THE WAY OF PRECIP OVER THE FAR NW THROUGH
MIDNIGHT FRIDAY NIGHT. SURFACE RIDGING WILL DEPART OFF TO THE SE
FRIDAY MAKING FOR A QUICK TURNAROUND IN SW FLOW. THIS COMBINED
WITH HEATING SHOULD CAUSE AN ABRUPT INCREASE IN WIND SPEEDS DURING
THE AFTERNOON WITH GUSTS OVER 20 KTS LIKELY...AND PERHAPS 25-30
KTS FROM KBLF-KROA BY MID OR LATE AFTERNOON.

.EXTENDED AVIATION DISCUSSION...

A WEAK COLD FRONT WILL MOVE THROUGH THE REGION FRI NIGHT/SAT WITH
UPSLOPE CLOUDS AND POSSIBLE RAIN/SNOW SHOWERS ACROSS THE SE WVA
SITES...OTHERWISE MOSTLY VFR EXPECTED ELSEWHERE THROUGH SAT. A
SOUTHERN STREAM SYSTEM WILL PHASE WITH A NORTHERN STREAM SYSTEM
SUNDAY THROUGH MONDAY BRINGING WIDESPREAD RAIN TO THE AREA BY SUN
AFTERNOON ALONG WITH MVFR-IFR CIGS/VSBYS. AS COLD AIR SPREADS
SOUTH DOWN THE EAST SIDE OF THE APPALACHIANS SUN
NIGHT/MON...PRECIP WILL LIKELY CHANGE TO SNOW NORTH AND A WINTRY
MIX SOUTH. ACCUMULATING SNOW APPEARS POSSIBLE EARLY MON. WINDS
WILL ALSO LIKELY BE STRONG AND GUSTY IN ASSOCIATION WITH THIS
WEATHER SYSTEM. IT COULD BE TUE OR WED BEFORE CONDITIONS IMPROVE
TO VFR.
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&&

.FIRE WEATHER...
WIND SPEEDS CONTINUE TO WEAKEN THIS AFTERNOON...AND WITH
TEMPERATURES SOON TO BEGIN FALLING AS THE SUN SETS...RH VALUES
WILL BEGIN TO INCREASE FOR THE EVENING...DECREASING THE FIRE
WEATHER CONCERNS FOR THE REMAINDER OF THE DAY.

FIRE WEATHER CONCERNS WILL BE HIGH AGAIN ON FRIDAY. WINDS WILL
SHIFT SOUTHWESTERLY OVERNIGHT...ALLOWING WARMER AIR TO ENTER THE
REGION. WITH NO RETURN OF GULF/ATLANTIC MOISTURE EXPECTED...
AFTERNOON RH VALUES WILL AGAIN FALL BELOW CRITICAL LEVELS. THE
WARM AND DRY CONDITIONS...COMBINED WITH ABUNDANT SUNSHINE...WILL
ALLOW THE FINE FUELS TO CONTINUE TO DRY...FALLING AOB 8GM IN SOME
AREAS. WIND SPEEDS WILL INCREASE AGAIN DURING THE AFTERNOON AS
LOW PRESSURE PASSES ACROSS THE GREAT LAKES...BUT SOME QUESTION
REMAINS AS TO WHETHER SUSTAINED SPEEDS WILL REACH CRITICAL LEVELS.
CURRENTLY HAVE A FIRE WEATHER WATCH IN EFFECT FOR FRIDAY...AND
WILL REEXAMINE CONDITIONS THIS EVENING AND OVERNIGHT TO DETERMINE
IF A RED FLAG WARNING IS NEEDED OR IF A SPECIAL WEATHER STATEMENT
WILL BE SUFFICIENT.

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
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VA...FIRE WEATHER WATCH FROM 11 AM EDT THIS MORNING THROUGH THIS
     AFTERNOON FOR VAZ011>020-022>024-032>035-043>047-058-059.
NC...FIRE WEATHER WATCH FROM 11 AM EDT THIS MORNING THROUGH THIS
     AFTERNOON FOR NCZ002>006-019-020.
WV...NONE.
-- End Changed Discussion --

&&

$$
SYNOPSIS...NF/WP
NEAR TERM...NF/WP
SHORT TERM...RCS
LONG TERM...RCS
AVIATION...JH/RAB
FIRE WEATHER...NF