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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KRNK 121644
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
1244 PM EDT SUN MAY 12 2013

.SYNOPSIS...
COLD FRONT WHICH BROUGHT YESTERDAYS SHOWERS HAS MOVED EAST TO
ALONG THE MID ATLANTIC COAST. A SECOND COLD FRONT WILL CROSS THE
AREA THIS MORNING. MUCH COLDER...DRIER AIR...ALONG WITH BRISK
NORTHWEST WINDS WILL FOLLOW TODAYS FRONTAL PASSAGE. COLD HIGH
PRESSURE...ORIGINATING FROM CANADA...WILL SETTLE OVER THE AREA
FROM FOR MONDAY AND TUESDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
AS OF 1230 PM EDT SUNDAY...

HAVE MADE SOME MINOR ADJUSTMENTS TO THE HIGH TEMPERATURE FORECAST
FOR TODAY. IN THE FAR WEST...THE COMBINATION OF PARTLY TO MOSTLY
CLOUDY SKIES AND STRONG COLD AIR ADVECTION IS LIMITING THE RATE OF
TEMPERATURE INCREASE. HAVE UNDERCUT HIGH TEMPERATURES BY TWO TO
THREE DEGREES FROM THE EARLIER FORECAST IN ANTICIPATION OF THIS
SLOW RATE OF INCREASE TO CONTINUE. IN ACROSS THE EASTERN PART OF
THE FORECAST AREA...TEMPERATURES ARE RISING SLIGHTLY FASTER THAN
FORECAST DUE TO PLENTY OF SUN AND DOWNSLOPING COMPRESSIONAL
WARMING COUNTERING THE AFFECTS OF THE COLD AIR ADVECTION MORE THAN
ANTICIPATED. WE EXPECT THIS TREND TO CONTINUE THROUGH THE
AFTERNOON AND RAISED HIGHS BY ROUGHLY TWO TO THREE DEGREES.

HAVE ALSO ADJUSTED HOURLY TEMPERATURE...DEW POINT AND SKY COVER
BASED UPON THE LATEST OBSERVATIONS AND EXPECTED TRENDS THROUGH THE
AFTERNOON. THE BIGGEST ADJUSTMENT WITHIN THESE CATEGORIES IS THE
DEW POINT. VALUES ARE DECREASING QUICKER THAN EXPECTED...ALREADY
INTO THE MID 20S OVER PARTS OF SOUTHEAST WEST VIRGINIA.

AS OF 955 AM EDT SUNDAY...

A STIFF NORTHWEST WINDS WILL CONTINUE TO ADVECT COLDER AND DRIER
AIR INTO THE REGION. THE REMAINDER OF THE DAY IS EXPECTED TO BE
PRECIPITATION FREE...WITH LIMITED CLOUD COVER ACROSS THE REGION.
THE MOST CLOUD COVER WILL BE OVER SOUTHEAST WEST VIRGINIA WHERE
UPSLOPE FLOW AND WHAT LIMITED LOW LEVEL MOISTURE THAT REMAINS WILL
HELP PROMPT SOME SCATTERED CUMULUS CLOUDS. GUSTS TO AROUND 30 MPH
WILL BE COMMON AT THE RIDGE TOPS.

AS OF 730 AM EDT SUNDAY...

LIGHT SHOWER ACTIVITY ASSOCIATED WITH COLD FRONT CROSSING THE
MOUNTAINS HAS DISSIPATED. FRONT HAS MOVED TO ALONG THE BLUE RIDGE
AND WILL MAKE ITS WAY ACROSS THE FOOTHILLS AND INTO THE PIEDMONT
B4 NOON TODAY. PASSAGE OF THE FRONT WILL BRING ONSET OF BRISK
NORTHWEST WINDS WITH GUSTS OF 20 TO 30 MPH FROM LATE MORNING
THROUGH THE AFTERNOON. SOME LINGERING CLOUDINESS IS POSSIBLE IN
THE MOUNTAINS THIS MORNING...BUT THE OVERALL TREND WILL BE FOR
CLEARING SKIES TODAY WITH MOSTLY SUNNY CONDITIONS FOR THE
AFTERNOON. DEWPOINTS WILL TAKE A BIG TUMBLE WITH READINGS FALLING
INTO THE 30S AND POSSIBLY THE UPPER 20S BY THE END OF THE DAY.
TEMPERATURES TODAY WILL STRUGGLE PER FALLING THICKNESSES BEHIND
THE FRONT...READINGS DOWN 10 TO 15 DEGREES COMPARED TO YESTERDAY.
COMBINE THIS WITH THE FALLING DEWPOINTS AND BRISK NORTHWEST
WINDS...CONDITIONS WILL FALL SHY OF ANYTHING IDEAL FOR A MOTHERS
DAY PICNIC. ADVICE IS TO CELEBRATE INDOORS...UNLESS YOU WANT TO
WEAR A JACKET AND CHASE WIND DRIVEN PAPER PRODUCTS.

FOR TONIGHT...WINDS WILL DIMINISH SOMEWHAT...BUT NOT COMPLETELY.
BRISK WINDS WILL CONTINUE ALONG THE RIDGE TOPS AND TO A MUCH
LESSER DEGREE IN THE VALLEYS. SURFACE HIGH PRESSURE...ORIGINATING
FROM CANADA...WILL BE CENTERED WEST OF THE APPALACHIANS...SO A
PRESSURE GRADIENT WILL STILL EXIST OVER THE MTNS. WITH DEWPOINTS
HEADED INTO THE 20S TONIGHT...LOOK FOR SURFACE TEMPERATURES TO
SLIP INTO THE 30S...POSSIBLY THE UPPER 20S IN SOME OF THE HIGHER
MOUNTAIN LOCATIONS...SUPPORTED BY MODEL FCST 85H TEMPS OF M2 TO M4
DEG. FREEZE WATCH IS IN EFFECT FOR TONIGHT...ALL AREAS THAT HAVE A
GOOD CHANCE AT TESTING 32 DEG F...PRIMARILY ELEVATIONS ABOVE 2500
FEET. WINDS SHOULD REMAIN STRONG ENOUGH TO PREVENT FROST
FORMATION. CAN`T RULE OUT SOME PATCHY FROST IN THE SHELTERED
MOUNTAIN VALLEYS...BUT THINK WE WILL HAVE TO WAIT UNTIL THE
HIGH PRESSURE SYSTEM PASSES OVHD MONDAY NIGHT TO KILL OFF THE
WINDS ENOUGH TO PROMOTE FROST FORMATION IN ADDITION TO ANOTHER
CHANCE AT TESTING THE FREEZING MARK.
-- End Changed Discussion --

&&

.SHORT TERM /MONDAY THROUGH TUESDAY/...
AS OF 310 AM EDT SUNDAY...

HIGH PRESSURE WILL BUILD INTO OUR AREA MONDAY. WITH A DEEP MID/UPPER
LEVEL TROUGH...COLD AIR ALOFT COMES OVER THE FORECAST AREA. USED A
BLEND OF THE CANADIAN AND GFS FOR CLOUD COVER. THE COMBINATION OF
MOISTURE AND A LARGE ENOUGH LAPSE RATES MAY RESULT IN A LAYER OF
STRATOCUMULUS IN THE NORTHWEST UPSLOPE AREAS. KEPT HIGH TEMPERATURES
ON THE COOL SIDE/BELOW NORMAL WITH READINGS CLOSE TO THE ADJMETBC
FROM THE UPPER 40S IN THE MOUNTAINS TO THE LOWER 60S IN THE
SOUTHEAST. MONDAY NIGHT INTO TUESDAY MORNING...THE  1025 SURFACE
HIGH IS CENTERED OVER THE AREA. HOWEVER...HIGH CLOUDS IN ADVANCE OF
THE WARM FRONT CROSSING THROUGH THE OHIO VALLEY MAY REACH THE
FORECAST AREA BEFORE 12Z TUESDAY MORNING. IF THE CLOUDS HOLD OFF
TEMPERATURES WILL STILL BE PLENTY COLD WITH LIGHTER WINDS FOR
ANOTHER NIGHT WITH FROST AND FREEZES ESPECIALLY IN THE MOUNTAINS.
WITH THIS BEING FOURTH PERIOD...WILL ADD THE MENTION TO THE HWO.
HIGH PRESSURE CONTINUES TO SLIDE EAST ON TUESDAY INTO TUESDAY NIGHT.
ELECTED TO RAISE HIGHS TUESDAY UP A FEW DEGREES AS SUPPORT BY MOS
GUIDANCE...WITH READINGS FROM THE THE UPPER 50S IN THE MOUNTAINS TO
AROUND 70 IN THE PIEDMONTS. THE ECMWF WAS MORE ROBUST COMPARED TO
THE GFS WITH POPS ACROSS THE NORTH TUESDAY NIGHT. ALLOWED FOR
ISOLATED  SHOWER ACROSS EXTREME NORTHWEST. HELD ON TO LOW
TEMPERATURES TUESDAY NIGHT FROM THE MID 40S TO THE LOWER 50S.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 130 PM EDT SATURDAY...

PATTERN BECOME LESS AMPLIFIED THIS TIME FRAME. A WARM FRONT AND
LOWER LEVEL MOISTURE APPROACHES ON TUESDAY NIGHT AND WEDNESDAY.
MODELS SHOWING STRONG WARM AIR ADVECTION AND ENOUGH MOISTURE TO KEEP
THE PROBABILITY OF PRECIPITATION IN THE FORECAST.

THE WARM FRONT IS LEADING MUCH WARMER AIR INTO THE REGION. 850 MB
TEMPERATURES REMAIN IN THE +12 TO +16 RANGE FOR THE REST OF THE
WEEK. EAST TO WEST ORIENTED FRONT REMAINS NORTH OF THE FORECAST
AREA. SOUTHERN STREAM SHORT WAVE WILL BE SOMEWHERE OVER THE
TENNESSEE VALLEY OF SOUTHEAST UNITED STATES ON FRIDAY. THIS LOOKS  TO
BE THE DAY WITH BETTER AREAL COVERAGE/GREATER PROBABILITY OF
PRECIPITATION. OTHERWISE NOTHING ORGANIZED SO JUST EXPECTING TYPICAL
OROGRAPHICALLY INDUCED AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS.

TEMPERATURES WILL BE NEAR NORMAL TO ABOVE NORMAL THROUGH THE PERIOD.
NO REASON TO STRAY FAR FROM CURRENT GUIDANCE.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 800 AM EDT SUNDAY...

VFR CONDITIONS TODAY.  GUSTY NORTHWEST WINDS THROUGH SUNSET.

A COLD FRONT ALONG THE BLUE RIDGE AT 12Z/8AM WILL MOVE RAPIDLY
EAST...CLEARING DANVILLE VIRGINIA BY NOON TODAY. SURFACE WINDS
WILL INCREASE FROM THE NORTHWEST BEHIND THIS COLD FRONT WITH GUSTS
AROUND 2O T0 25 KTS AFTER 14Z/10AM SUNDAY. ALL AREAS CAN EXPECT
VFR CONDITIONS WITH ANY LINGERING CLOUDINESS THIS
MORNING DISSIPATING FOR THE AFTERNOON. CLEAR SKIES AND
DIMINISHING WINDS CAN BE EXPECTED TONIGHT.

MAINLY VFR CONDITIONS ARE EXPECTED THROUGH THE UPCOMING WORK
WEEK...THROUGH THURSDAY. COLD HIGH PRESSURE WILL PROMPT SOME
PATCHY FROST WHERE WINDS BECOME NEAR CALM AS THE CENTER OF THE
HIGH MOVES OVERHEAD. THE MOST LIKELY MORNING TO FIND FROST ON
AIRCRAFT WILL BE LATE MONDAY NIGHT INTO EARLY TUESDAY MORNING.

THE NEXT CHANCE FOR RAIN AND WIDESPREAD SUB VFR CONDITIONS IS NOT
EXPECTED UNTIL THE END OF THE WEEK...THURSDAY/FRIDAY TIME FRAME.

&&

.CLIMATE...
LOW TEMPERATURES MONDAY AND TUESDAY MORNING WILL FLIRT WITH RECORD
LOW TEMPERATURES AT ALL CLIMATE LOCATIONS WITH THE BEST CHANCE FOR
BREAKING ANY RECORDS BEING TUESDAY MORNING. THE FOLLOWING ARE THE
CURRENT RECORD LOW TEMPERATURES FOR MAY 13 AND MAY 14 ALONG WITH
THE YEAR OF THAT RECORD.

MAY 13                MAY 14
ROA...35...1917       ROA...37...1996
LYH...35...1969       LYH...33...1997
RNK...26...1969       RNK...31...1996
DAN...38...1960       DAN...38...2007
BLF...33...1996       BLF...33...1996

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
VA...FREEZE WATCH FROM MIDNIGHT EDT TONIGHT THROUGH MONDAY MORNING
     FOR VAZ007-009>011-015-018>020.
NC...FREEZE WATCH FROM MIDNIGHT EDT TONIGHT THROUGH MONDAY MORNING
     FOR NCZ001-018.
WV...FREEZE WATCH FROM MIDNIGHT EDT TONIGHT THROUGH MONDAY MORNING
     FOR WVZ042>045.
-- End Changed Discussion --

&&

$$
SYNOPSIS...PM
NEAR TERM...DS/PM
SHORT TERM...KK
LONG TERM...AMS
AVIATION...PM
CLIMATE...CF