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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KRNK 150147
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
947 PM EDT TUE MAY 14 2013

.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO SLIDE EAST OFF THE SOUTH CAROLINA
COAST TONIGHT...WHILE A DEEP LOW PRESSURE SYSTEM PASSES ACROSS THE
NORTHERN GREAT LAKES. A WARM FRONT ASSOCIATED WITH THE LOW WILL
PASS JUST NORTH OF OUR AREA...TRIGGERING ISOLATED SHOWERS NORTH
OF THE HIGHWAY 460 CORRIDOR TONIGHT. A FRONTAL BOUNDARY WILL
APPROACH THE AREA ON THURSDAY AND STALL OVER OR NEAR THE REGION
INTO THE START OF THE WEEKEND.

&&

.NEAR TERM /UNTIL 7 AM WEDNESDAY MORNING/...
AS OF 712 PM EDT TUESDAY...

H5 HEIGHTS RISE QUICKLY OVERNIGHT AS A CHUNK OF THE IMPRESSIVE
HEAT ACROSS THE MIDWEST DARTS EAST. WITH CLEAR SKIES AND WINDS NOT
KICKING UP UNTIL MORNING...SOME OF THE VA/NC PIEDMONT SITES COULD
DECOUPLE AND FALL A FEW DEGREES BELOW GUIDANCE INT OTHE MID 40S.
SUCH A QUICK TURN IN TEMPERATURE BETWEEN TODAY AND TOMORROW MEANS
SOME GUSTY WINDS AHEAD OF THE STRONG WAA...SUCH THAT PARTS OF NW
NC AND SE WEST VA MAY GUST TO 35 KTS NEAR DAWN.

&&

.SHORT TERM /7 AM WEDNESDAY MORNING THROUGH FRIDAY NIGHT/...
AS OF 330 PM EDT TUESDAY...

THE WARMUP REALLY KICKS IN FOR WEDNESDAY AS THE UPPER RIDGE
SETTLES ACROSS THE AREA AND WE FALL INTO A STRONG WEST TO
SOUTHWESTERLY WIND FLOW. EXPECT A FEW AFTERNOON CLOUDS...WITH
HIGHS APPROACHING THE UPPER 70S TO LOW 80S ACROSS THE
MOUNTAINS...AND REACHING INTO THE UPPER 80S FURTHER EAST.

AIR MASS MODERATES BY THURSDAY WITH MORE TYPICAL MAXIMUM TEMPERATURES.

SOUTHERN STREAM SHORT WAVE REACHES THE TENNESSEE VALLEY THURSDAY
NIGHT THEN WEAKENS AS IT MOVES INTO THE SOUTHERN APPALACHIANS
FRIDAY. FRONT OVER THE MID ATLANTIC REGION DROPS SOUTH THROUGH
VIRGINIA ON THURSDAY NIGHT THEN RETREATS BACK NORTH OF THE
FORECAST AREA ON FRIDAY. COMBINATION OF BOTH THE SHORT WAVE AND
FRONT WILL BRING THE MORE WIDESPREAD SHOWERS AND THUNDERSTORMS
INTO THE AREA THURSDAY NIGHT AND FRIDAY.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 330 PM EDT TUESDAY...

SEEING SIGNIFICANT DIFFERENCES BETWEEN THE 00Z/14 ECMWF AND GFS BY
SUNDAY WITH THE LONG WAVE TROF IN THE CENTRAL UNITED STATES. ECMWF
SHOWED A DISTINCT SOUTHERN PIECE OF THE TROF AND WAS MUCH SLOWER
THAN THE GFS.

STARTING OUT FRIDAY NIGHT WITH THE SURFACE FRONT FROM WISCONSIN INTO
NORTHWESTERN VIRGINIA. BY SUNDAY THE FRONT HAS MOVED BACK NORTH.
LEANING TOWARD THE SLOWER ECMWF KEEPS THE FORECAST AREA DEEP IN THE
WARM UNSTABLE AIR THROUGH TUESDAY.

MODELS ALSO ARE TAKING THE UPPER LOW OVER SAN FRANCISCO THIS MORNING
ACROSS THE ROCKIES ...THEN THE TENNESSEE VALLEY...THEN INTO THE
SOUTHERN APPALACHIANS SUNDAY NIGHT. SUSPECT THE DETAILS MAY NOT BE
CORRECT THIS FAR OUT BUT IDEA OF A SHORT WAVE CUTTING INTO THE
EASTERN UPPER RIDGE IS REASONABLE. MAY HAVE ENHANCED PROBABILITY
OF PRECIPITATION WITH ANY FEATURE LIKE THIS SATURDAY THROUGH
TUESDAY.

&&

.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --
AS OF 1000 PM EDT TUESDAY...

HIGH PRESSURE SHIFTED TO THE SOUTH CAROLINA COAST...ALLOWING
SURFACE WINDS TO BECOME SOUTHWESTERLY. FORECAST MODELS STILL
PROGGING A WARM FRONT ASSOCIATED WITH LOW TO PASS ACROSS THE
NORTHERN THIRD OF THE AREA TONIGHT. A LARGER ISSUE OVERNIGHT WILL
BE THE POSSIBILITY OF WIND SHEAR...AS WINDS NEAR THE SURFACE WILL
DIMINISH THIS EVENING BUT INCREASE ALOFT AS A SURGE OF MUCH WARMER
AIR ARRIVES. LATEST MODELS SHOW A 40KT TO 45KT JET JUST OFF THE
SURFACE AFTER MIDNIGHT...AND HAVE INCLUDED A PERIOD OF LLWS FOR
ALL TAF SITES THROUGH AROUND SUNRISE.

OUR NEXT CHANCE OF ORGANIZED PRECIPITATION AND AREAS OF SUB-VFR
CONDITIONS WILL BE LATE THURSDAY THROUGH SATURDAY WHEN A FRONTAL
SYSTEM MOVES INTO AND THEN STALLS NEAR THE REGION.
-- End Changed Discussion --

&&

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

&&

$$
SYNOPSIS...NF
NEAR TERM...KM
SHORT TERM...AMS/NF
LONG TERM...AMS
AVIATION...JC/NF