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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KRNK 150756
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
356 AM EDT WED MAY 15 2013

.SYNOPSIS...
-- Changed Discussion --
HIGH PRESSURE WILL SLIDE EAST AND OFFSHORE THE SOUTHEAST COAST
TODAY ALLOWING FOR A RETURN SOUTHWEST FLOW OF VERY WARM AIR INTO
THIS AFTERNOON. DEEP LOW PRESSURE PASSING ACROSS THE NORTHERN
GREAT LAKES WILL LIFT AN ASSOCIATED WARM FRONT NORTH OF THE AREA
LATER TODAY WITH AN ASSOCIATED COLD FRONT APPROACHING FROM THE
NORTH BY EARLY THURSDAY. THIS FRONTAL BOUNDARY WILL DROP SOUTH
INTO THE REGION LATER THURSDAY BEFORE STALLING OVER OR NEAR THE
AREA INTO THE WEEKEND.
-- End Changed Discussion --
&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
AS OF 300 AM EDT WEDNESDAY...

WINDS ACROSS THE SW CONTINUE TO INCREASE EARLY THIS MORNING WITH
SPEEDS ALREADY TOPPING ADVISORY LEVELS AT ELEVATIONS ABOVE 3500
FEET. SINCE EXPECT THE STRONGEST WINDS OVER THE NEXT FEW HOURS
AND PERHAPS AT A BIT LOWER ELEVATION...WENT AHEAD WITH A WIND
ADVISORY FOR A FEW CTYS ACROSS THE SW THROUGH MIDDAY. ALTHOUGH THE
BEST JET EXITS SHORTLY AFTER SUNRISE...APPEARS THE ONSET OF DEEP
MIXING WITH THE VERY WARM AIR ARRIVING MAY KEEP STRONGER GUSTS
GOING A WHILE LONGER.

OTRW THE ABRUPT SHOT OF VERY WARM AIR THE MAIN ISSUE TODAY AS A
PIECE OF THE HOT AIR THAT HAS BEEN OVER THE CENTRAL STATES RACES
EAST INTO THE REGION TODAY ON THE WESTERLY JET ALOFT AND IN
WAKE OF THE WARM FRONT PASSING NORTH. MODELS CONTINUE TO SHOW AN
AXIS OF +18- 19C 85H AIR ARRIVING BY AFTERNOON WITH AIDED
COMPRESSION/DOWNSLOPE OUT EAST AND STRONG INSOLATION AFTER SOME
MORNING MID DECK IN SPOTS. THIS SHOULD ALLOW ALL LOCATIONS OUTSIDE
OF THE HIGHER ELEVATIONS TO PUSH ABOVE 80 TODAY AND PERHAPS AROUND
90 IN SPOTS FROM ROANOKE EAST ESPCLY GIVEN THE WELL MIXED WESTERLY
FLOW THAT COULD ALLOW FOR A LATE AFTERNOON TEMP JUMP AT SPOTS LIKE
ROA. THUS BUMPED UP HIGHS A LITTLE AS WELL AS WINDS WITH QUITE A
BREEZY/WINDY AND HOT AFTERNOON IN SPOTS FOR MID MAY GIVEN THE
STRONG RETURN FLOW AROUND HIGH PRESSURE OFFSHORE AND STRONG UPPER
RIDGING.

5H HEIGHTS WILL BEGIN TO SLOWLY FALL OVERNIGHT AS A COLD FRONT
TO THE NORTH SAGS SOUTH HELPING TO FLATTEN THE UPPER RIDGE IN
PLACE. WINDS ABOVE THE SURFACE AHEAD OF THE FRONT WILL AGAIN
INCREASE AS A WEAK MID LEVEL TROF SWINGS BY TO THE NE OVERNIGHT.
HOWEVER SOUNDINGS SHOW LESS MIXING DOWN ACROSS THE HIGHER
ELVATIONS WITH MORE MOISTURE IN PLACE SO NOT EXPECTING A REPEAT OF
THE CURRENT GUSTS OVER THE SW. OTRW CLOUDS AHEAD OF THE BOUNDARY
WILL INCREASE SOME FROM NW TO SE LATE WITH PERHAPS A THIN BAND OF
SHRA NEARING THE FAR NW LATE. SINCE LATEST MODELS SLOWER GIVEN THE
STRONG RIDGING...ONLY KEPT A VERY LOW POP EXTREME NW...AND LEFT
ELSW DRY WITH SKIES MAINLY CLEAR OVER THE SOUTHERN HALF THRU
MORNING AND BECOMING PC ELSW. QUITE A WARM AND ALMOST MUGGY NIGHT
WITH DEWPOINTS JUMPING INTO THE 50S AND LIGHT MIXING/WARM
ADVECTION KEEPING LOWS 60-65 RIDGES AND SE WITH ONLY THE VALLEYS
SEEING SOME 50S.
-- End Changed Discussion --
&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
-- Changed Discussion --
AS OF 400 AM EDT WEDNESDAY...

UNSETTLED PERIOD WITH FRONTAL BOUNDARY TRAVELING ACROSS
OUR REGION. WITH BROAD MID LEVEL RIDGING OVER THE AREA
INITIALLY...SLOWED DOWN THE ADVANCE OF POPS THURSDAY
MORNING. BY THURSDAY AFTERNOON...H5 TROUGH WILL ROLL
ACROSS THE MISSISSIPPI RIVER VALLEY. FRONTAL BOUNDARY
WILL SLOW DROP SOUTH THURSDAY. PLACED THE HIGHEST POPS
ACROSS THE NORTHWEST ON THURSDAY. HIGH TEMPERATURES ON
THURSDAY WILL BE COOLER THAN TODAY BECAUSE OF ADDITIONAL
CLOUD COVER WITH READINGS FROM THE UPPER 60S IN THE
NORTHWEST TO THE MID 80S IN THE SOUTHEAST.

A WEAKENING AREA OF LOW PRESSURE WILL TRAVEL EAST ACROSS THE
TENNESSEE VALLEY THURSDAY NIGHT...THEN MOVES INTO THE SOUTHERN
APPALACHIANS FRIDAY. MOISTURE WILL INCREASE AND CLOUDS THICKEN
AND LOWER THURSDAY NIGHT. KEPT THE HIGHER POPS IN THE WEST.
EXPECT A MILD THURSDAY NIGHT WITH CLOUDS AND SOUTHERLY
FLOW...WITH LOWS FROM LOWER 50S IN THE WEST TO LOWER 60S IN THE
EAST.

ON FRIDAY...A SHORTWAVE ROTATING THROUGH THE UPPER TROUGH OVER
NEW ENGLAND WILL PUSH THE FRONTAL BOUNDARY SOUTH...THEN IT
RETREATS BACK NORTHWARD BY FRIDAY NIGHT. COMBINATION OF BOTH THE
SHORT WAVE AND FRONT WILL BRING THE MORE WIDESPREAD SHOWERS AND
THUNDERSTORMS INTO THE AREA. HIGHS ON FRIDAY WILL VARY FROM
UPPER 60S IN THE NORTHWEST TO LOWER TO MID 80S IN THE SOUTHEAST.
HARD TO PIN POINT POPS FOR FRIDAY NIGHT...BUT SHAPE TOWARDS
ECMWF/GFS BLEND WITH HIGHER POPS IN THE EAST. ANOTHER MILD AND
HUMID NIGHT WITH LOWS IN MID 50S TO LOWER 60S.
-- End Changed Discussion -- &&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
-- Changed Discussion --
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 SATURDAY MORNING 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 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.
-- End Changed Discussion -- &&

.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
AS OF 108 AM EDT WEDNESDAY...

VFR WILL PREVAIL ACROSS THE REGION OVERNIGHT INTO WEDNESDAY NIGHT
WITH ONLY SOME PASSING MID DECK LIKELY AT TIMES. OTRW THE MAIN
ISSUES REMAIN WITH LOW LEVEL WIND SHEAR OVERNIGHT INTO EARLY
WEDNESDAY...AND THEN GUSTY SURFACE WINDS ESPCLY ACROSS THE
WESTERN LOCATIONS WEDNESDAY AFTERNOON AS MIXING ENHANCES. LATEST
MODELS SHOW A 40 TO 50 KT JET JUST OFF THE SURFACE AFTER
MIDNIGHT...SO KEPT A PERIOD OF LLWS FOR ALL TAF SITES WITH THE
EXCEPTION OF KBLF WHERE SHOULD STAY MORE MIXED THROUGH THE COLUMN
INTO MID MORNING WEDNESDAY. CONTINUED STRONG JET ALOFT SHOULD
ALSO SUPPORT SOME SURFACE GUSTS TO 25-30 KTS WEDNESDAY AFTERNOON
BEFORE DIMINISHING WEDNESDAY EVENING.

OUR NEXT CHANCE OF ORGANIZED PRECIPITATION AND AREAS OF SUB-VFR
CONDITIONS WILL BE LATE THURSDAY THROUGH SUNDAY WHEN A FRONTAL
SYSTEM MOVES INTO AND THEN STALLS NEAR THE REGION. APPEARS THE
AFTERNOON AND EARLY EVENING HOURS WOULD HAVE THE BEST CHANCE OF
SEEING PERIODS OF MVFR/IFR IN SHRA/TSRA ESPCLY FRIDAY INTO SUNDAY
AFTERNOON WITH SOME PATCHY FOG DURING THE OVERNIGHTS.

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
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VA...WIND ADVISORY UNTIL NOON EDT TODAY FOR VAZ015.
NC...WIND ADVISORY UNTIL NOON EDT TODAY FOR NCZ001-018.
WV...NONE.
-- End Changed Discussion --

&&

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