-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KRNK 171351
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
951 AM EDT THU APR 17 2014

.SYNOPSIS...
A LARGE AREA OF HIGH PRESSURE WILL REMAIN OVER THE NORTHEASTERN
U.S. THROUGH FRIDAY KEEPING A RELATIVELY COOL AIR MASS ACROSS THE
REGION. AN AREA OF LOW PRESSURE WILL MOVE VERY SLOWLY THROUGH THE
SOUTHEASTERN STATES INTO SATURDAY...WHICH WILL BRING CLOUDS TO THE
ENTIRE AREA AND A CHANCE OF RAIN TO NORTH CAROLINA AND FAR
SOUTHERN VIRGINIA. A STRONGER COLD FRONT WILL APPROACH THE REGION
FROM THE WEST EARLY NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
AS OF 940 AM EDT THURSDAY...

ONLY MINOR CHANGES MADE TO THE FORECAST AS DRY HIGH PRESSURE OVER
NEW ENGLAND CONTINUES TO DOMINATE OUR REGION. INCREASED CLOUD
COVER SLIGHTLY AS HIGH CLOUDS SHOWN ON VISIBLE SATELLITE WERE
DRIFTING OVER AREAS SOUTH OF HIGHWAY 460 THIS MORNING. CANADIAN
MODEL FORECAST SHOWS THESE CLOUDS WILL THIN DURING THE AFTERNOON.

OTHERWISE...FORECAST TEMPS RUNNING JUST A TAD COOLER THAN 13Z
OBSERVATIONS...SO ADJUSTED READINGS UP A COUPLE OF DEGREES CLOSER
TO THE ADJUSTED NAM MOS GUIDANCE.

LOW PRESSURE DEVELOPING ACROSS THE SOUTHEAST STATES/EASTERN GULF
LATE IN THE PERIOD WILL REMAIN SUFFICIENTLY FAR SOUTH THROUGH THIS
TIME FRAME TO HAVE NO IMPACT ON THE REGION THROUGH THIS TIME
FRAME. A NORTHERN STREAM UPPER SHORT WAVE APPROACHING FROM THE
NORTHWEST WILL ALSO HAVE LITTLE IMPACT OTHER THAN ALSO SOME HIGH
CLOUDS LATE IN THE PERIOD. MAIN CONCERN THROUGH THIS TIME FRAME
WILL ONCE AGAIN BE FREEZING TEMPERATURES AND FROST POTENTIAL.  FOR
FRIDAY MORNING...ANY FREEZING TEMPERATURES LOOK VERY SPOTTY AS AIR
MASS CONTINUES TO SLOWLY MODIFY. MORE IMPORTANTLY...HOWEVER...WILL
BE STRENGTHENING EASTERLY FLOW IN RESPONSE TO DEVELOPING LOW
PRESSURE IN THE SOUTHEAST. THE EXTENT OF THIS WIND FLOW IS NOT
TOTALLY CLEAR AT THIS POINT...BUT ENOUGH CONFIDENCE THAT WEST OF
THE BLUE RIDGE IN THE SOUTHERN SHENANDOAH VALLEY THAT ENOUGH
DECOUPLING WILL EXIST FOR DEVELOPMENT OF WIDESPREAD FROST AS
TEMPERATURES DROP INTO THE LOWER AND MID 30S AFTER LATE
TONIGHT/EARLY FRIDAY. THUS...HAVE GONE AHEAD AND ISSUED A FROST
ADVISORY FOR BOTETOURT...AMHERST...AND ROCKBRIDGE...THE MAIN AREA
OF CONCERN AT THIS POINT. DAY SHIFT MAY NEED TO CONSIDER EXPANDING
THIS FURTHER EAST AND SOUTH DEPENDING ON DEGREE OF CONFIDENCE IN
DECOUPLING ALLOWING FOR FROST FORMATION. GROUND IS QUITE
MOIST...SO IF WINDS REMAIN LIGHT...TEMPERATURES SHOULD BE COLD
ENOUGH FOR FROST TO DEVELOP.
-- End Changed Discussion --

&&

.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM EDT THURSDAY...

FRIDAY INTO FRIDAY NIGHT...A COLD AIR DAMMING RIDGE WILL BE IN PLACE
ACROSS THE LEE OF THE APPALACHIANS. PROGRESSIVELY INCREASING
MOISTURE OFF THE ATLANTIC WILL PROGRESS INTO THE AREA ON SOUTHEAST
WINDS...ROUNDING THE BASE OF THE RIDGE. ANTICIPATE AT LEAST A MOSTLY
CLOUDY SKY ON FRIDAY WITH INCREASING CLOUD COVER FRIDAY NIGHT.
ANOTHER FEATURE ALSO WILL BE CONTRIBUTING TO INCREASED CLOUD
COVER TO AREA IN GENERAL...AND POTENTIALLY SOME PRECIPITATION TO THE
SOUTHERN AND SOUTHEASTERN PORTION OF THE REGION. 00Z/8PM GUIDANCE
AMONG THE GFS...ECMWF...AND CANADIAN SOLUTIONS BRING A CLOSED LOW
SLOWLY NORTHEAST THROUGH THE GULF COAST STATES WITH THE NORTHERN
EXTENT OF ITS PRECIPITATION SHIELD BRUSHING OUR SOUTHERN TIER
COUNTIES BY FRIDAY EVENING...CONTINUING THROUGH THE NIGHT...AND
CONCLUDING INTO SATURDAY MORNING. THE LOW ITSELF IS PROGGED TO
CONTINUE A SLOW NORTHEAST TRACK AND EXIT THE U.S. OFF THE GA/SC
COAST AROUND SATURDAY EVENING.

WHILE THESE THREE SOLUTIONS ARE SIMILAR...THEY ARE A SHIFT NORTH
AS COMPARED TO THEIR EARLIER COUNTERPARTS THAT HAD DRY
SOLUTIONS...AND THE 00Z/8PM NAM SOLUTION HAS MAINTAINED A MORE
SOUTHERLY...AND THUS DRIER AND WARMER SOLUTION FOR OUR REGION. GIVEN
THIS...WILL OFFER NO MORE THAN A SLIGHT CHANCE OF LIGHT RAIN FROM
THE NORTHERN MOUNTAINS OF NC EASTWARD ALONG THE NC/VA BORDER DURING
THE FRIDAY EVENING/NIGHT TIME FRAME...AND GREATER CLOUD COVER...AND
COOLER TEMPERATURES ACROSS THE FORECAST AREA AS A WHOLE.

WILL REFRAIN FROM CONTINUING THE SLIGHT CHANCE INTO SATURDAY AT THIS
POINT...AND ALLOW OUR FORECAST TO CONTINUE FORWARD NEARLY UNCHANGED
THROUGH THE REMAINDER OF THE WEEKEND. THIS SOLUTION IS ONE THAT
KEEPS THE REGION WITHIN A ZONE OF DRY...HIGH PRESSURE...WITH EVER
SLOWLY RISING HEIGHTS THROUGH THE PERIOD...WHILE THE CLOSED LOW
SPINS OFF THE COAST OF THE SOUTHEAST U.S.

&&

.LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 330 PM EDT WEDNESDAY...

UPPER RIDGING BUILDING BEHIND A CLOSE UPPER LOW OFF THE SOUTHEAST
COAST WILL PROVIDE A NICE BOOST IN TEMPS FOR MUCH OF THE LONG
TERM. DESPITE CLOUDS AHEAD OF ANOTHER WEAK SYSTEM APPROACHING FROM
THE GREAT LAKES...WARM SW FLOW SHOULD SHOVE +10C H85 AIR OUR WAY
INTO TUESDAY. H8H TEMPS ARE ONLY SLIGHTLY COOLED BY THIS BOUNDARY
WITH SHOWERS PROBABLY CONFINED TO TUESDAY NIGHT OR WEDNESDAY
MORNING. HEIGHTS BUILD QUICKLY BEHIND THIS DISTURBANCE IN RESPONSE
TO A CLOSED LOW AND DIGGING NEGATIVELY TILTED TROUGH THROUGH THE
ROCKIES...WITH THE WARM PATTERN CONTINUING THROUGH THE END OF THE
FORECAST.

&&

.AVIATION /14Z THURSDAY THROUGH MONDAY/...
AS OF 730 AM EDT THURSDAY...

VFR CIGS/VSBYS EXPECTED TO CONTINUE THROUGH THE PERIOD AS A LARGE
COLD...DRY HIGH PRESSURE AREA ANCHORS ACROSS THE NORTHEASTERN U.S.
THROUGH THE PERIOD. LOW PRESSURE ALOFT WILL BE DEEPENING ACROSS
THE EASTERN GULF SE GA/SC/NORTHERN FL THROUGH THE PERIOD...WHICH
WILL PROLONG THE E-NE SFC FLOW INTO THE REGION FOR SEVERAL DAYS.
AS THE FLOW BECOMES MORE ESE-SE THU NIGHT INTO FRI AND INCREASED
MARITIME FLOW...SOME LOW CLOUDS MAY BEGIN TO DEVELOP ACROSS THE
PIEDMONT...ESPECIALLY IN UPSLOPE AREAS ALONG THE BLUE RIDGE...BUT
THIS SHOULD REMAIN BEYOND THIS VALID TAF PERIOD. A FEW HIGH CLOUDS
WILL SKIRT THE AREA FROM THE WEST TODAY...BUT HIGH CLOUDS WILL
INCREASE CONSIDERABLY OVERNIGHT AND AFT 06Z COULD BECOME BKN-OVC
IN MOST AREAS AT 250. WINDS ENE- ESE THROUGH THE PERIOD AT
6-9KTS...WITH LOW END GUSTS POSSIBLE LYH/ROA DURING THE DAYTIME.
BLF CONTINUES TO EXHIBIT TYPICALLY GUSTY SE WINDS FOR SYNOPTIC
PATTERN...AND THIS SHOULD CONTINUE THROUGH MUCH OF THE TAF VALID
PERIOD WITH PERIODIC GUSTS TO 20KTS POSSIBLE.

HIGH CONFIDENCE IN VFR CIGS/VSBYS THROUGH THE TAF VALID PERIOD.
MEDIUM TO HIGH CONFIDENCE IN WIND SPD/DIR THROUGH THE TAF VALID
PERIOD.

EXTENDED AVIATION DISCUSSION...
THE NEXT COLD FRONT APPROACHES FROM THE WEST FRIDAY WHILE ANOTHER
SYSTEM STAYS OFF THE SOUTHEAST COAST. THERE IS POTENTIAL FOR
INCREASE CLOUDS FRIDAY-SATURDAY OVER THE SOUTHEAST BUT MOST PLACES
SHOULD STAY VFR...POTENTIALLY MVFR EARLY FRI ACROSS THE PIEDMONT.
VFR FOR SUNDAY WITH HIGH PRESSURE REMAINING ACROSS THE NORTHEAST
AND MID ATLANTIC. THE NEXT SYSTEM TO BRING MVFR TO POTENTIALLY IFR
CIGS AND -SHRA TO THE AREA DOES NOT ARRIVE UNTIL EARLY TO MID PART
OF NEXT WEEK.

&&

.CLIMATE...
AS OF 1000 AM EDT WEDNESDAY...

RECORD LOWS AT BLACKSBURG...BLUEFIELD AND LEWISBURG THIS MORNING

BLACKSBURG TIED THEIRS AT 24...BLUEFIELD TIED THEIRS AT 23 AND
LEWISBURG BROKE THEIRS AT 23.


APRIL 17TH RECORD LOWS

ROANOKE 27F 1980......FORECASTED LOW 31F.
LYNCHBURG 27F 1904....FORECASTED LOW 30F.
DANVILLE 28F 1962.....FORECASTED LOW 30F.
BLUEFIELD 25F 2001....FORECASTED LOW 32F.
BLACKSBURG 20F 1974...FORECASTED LOW 26F.
LEWISBURG 25F 2001....FORECASTED LOW 20F.

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
VA...FROST ADVISORY FROM 4 AM TO 9 AM EDT FRIDAY FOR VAZ023-024-035.
NC...NONE.
WV...NONE.
-- End Changed Discussion --

&&

$$
SYNOPSIS...RAB
NEAR TERM...PH/RAB
SHORT TERM...DS
LONG TERM...KM
AVIATION...KK/RAB
CLIMATE...JC/KM