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000
FXUS61 KRNK 170004
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
804 PM EDT THU MAY 16 2013

.SYNOPSIS...
A COLD FRONT WILL CONTINUE TO SINK FROM THE OHIO RIVER VALLEY
THROUGH THE EVENING...AND WILL SETTLE ACROSS THE EASTERN HALF OF
THE FORECAST AREA BY FRIDAY AFTERNOON. THE FRONT WILL REMAIN IN
THE AREA THROUGH THE WEEKEND...PROVIDING THE FOCUS FOR SPOTTY
SHOWER AND THUNDERSTORM ACTIVITY...MAINLY DURING THE AFTERNOON
AND EVENING HOURS.

&&

.NEAR TERM /THROUGH FRIDAY/...
AS OF 400 PM EDT THURSDAY...

RADAR INDICATES A BAND OF SHOWERS AND THUNDERSTORMS ACROSS OUR
NORTHERN TIER OF COUNTIES THIS AFTERNOON...A FEW OF WHICH HAVE
BECOME STRONG TO BORDERLINE SEVERE. EXPECT THESE SHOWERS AND
THUNDERSTORMS TO SINK SOUTH ACROSS THE AREA THROUGH THE
EVENING...BUT TO WEAKEN AFTER SUNSET WITH THE LOSS OF DAYTIME
HEATING. TOWARD SUNSET...BELIEVE WESTERLY WINDS WILL DIMINISH IN
SPEED...WHICH WILL ERODE THE CAP OVERHEAD AND ALLOW A FEW MORE
SHOWERS/THUNDERSTORMS TO DEVELOP FURTHER SOUTH ACROSS THE
AREA...BUT THIS ACTIVITY SHOULD REMAIN SHORTLIVED. BY
MIDNIGHT...EXPECT ONLY LINGERING SHOWER ACTIVITY MAINLY NORTH OF
THE HIGHWAY 460 CORRIDOR.

CLOUD COVER WILL REMAIN WIDESPREAD THROUGH THE NIGHT...AND WITH
MOISTURE/WARM AIR CONVERGENCE AHEAD OF THE FRONT...WILL BE LOOKING
AT A WARM/MUGGY NIGHT WITH TEMPERATURES MAINLY UPPER 50S TO LOWER
60S. MODELS PROG THE COLD FRONT SINKING SOUTHWARD...EAST OF THE
BLUE RIDGE...BY LATE FRIDAY MORNING...BRINGING A LIGHT NORTHEASTERLY
WINDFLOW ACROSS THE AREA. MAY SEE PATCHY FOG DEVELOP IN THE MORE
STABLE AIRMASS ACROSS THE PIEDMONTS...WHICH WILL BURN OFF SHORTLY
AFTER SUNRISE.

SHOWER ACTIVITY WILL BE MORE WIDESPREAD DURING THE AFTERNOON AND
EVENING WITH THE FRONT SITUATED ACROSS THE AREA. INCREASED CLOUD
COVER WILL ALSO LIMIT AFTERNOON HEATING...KEEPING HIGHS CONFINED
TO THE UPPER 70S WEST AND THE LOW 80S EAST.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
AS OF 300 PM EDT THURSDAY...

A RATHER OBNOXIOUS PATTERN SHAPING UP THROUGH THE FORECAST
PERIOD. UPPER TROF OVER THE MID WEST WILL BE OPENING UP AS BITS OF
ENERGY GET EJECTED TOWARD US. DIFFUSE FRONTAL BOUNDARY AT THE SFC
WILL ALSO BE WAFFLING BACK AND FORTH WITH NO BIG KICKER TO PUSH IT
CLEAR WHILE HIGH PRESSURE BEGINS TO WEDGE DOWN THE ERN SEABOARD.

EXPECT CONVECTION THAT FIRES TOMORROW WILL LINGER INTO THE
EVENING BEFORE GRADUALLY DIMINISHING OVERNIGHT AS HIGH PRESSURE
WEDGES DOWN THE EAST COAST. EXPECTING ENHANCED POPS ALONG THE BLUE
RIDGE AS E/SELY FLOW SETS UP. AFTER A BRIEF LULL EARLY SATURDAY
MORNING...EXPECT MORE CONVECTION TO DEVELOP WITH DIFFUSE FRONT IN
THE AREA AND WEAK LOW PRESSURE APPROACHING FROM THE WEST.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 300 PM EDT THURSDAY...

MODELS BEGIN TO DIVERGE IN THE EXTENDED AS THE EURO DEVELOPS AN
OMEGA BLOCK AND DIGS A CUTOFF OVER THE EAST COAST. THE GFS HAS
SIMILAR MORPHOLOGY BUT IS MUCH LESS AGGRESSIVE WITH THE TROF IN
THE EAST. WILL LEAN TOWARD A EURO SOLUTION FOR THE FORECAST.
EXPECT THE WEDGE SITUATION TO REMAIN IN PLACE THROUGH MONDAY WITH
DIURNAL TRENDS LEADING TO CHC/LKLY POPS WITH THUNDER THROUGH
MONDAY. IT LOOKS LIKE THE HIGH WILL FINALLY EDGE FAR ENOUGH TO THE
EAST LATE MONDAY TO NUDGE THE FRONT NORTH THROUGH OUR AREA AND GET
US INTO THE WARM SECTOR. BELIEVE TUESDAY WILL BE OUR BEST BET TO
AVOID PCPN WITH FRONT TO OUR NORTH AND SOME SHORT WAVE
RIDGING...THOUGH LOCAL MOUNTAIN EFFECTS MAY STILL COOK UP SOME
ISOLATED CONVECTION. NEXT FRONT WILL BE APPROACHING FROM THE WEST
ON WEDNESDAY SO EXPECT INCREASING CHC OF THUNDER AS WE GET INTO
WEDNESDAY AFTERNOON. THE FRONT WANTS TO PUSH THROUGH AND CLEAR THE
AREA FOR THURSDAY...THOUGH WAVE DEVELOPMENT ON THE FRONT MAY SLOW
IT DOWN AND DO NOT HAVE A GREAT DEAL OF CONFIDENCE WITH FRONTAL
POSITION THIS FAR OUT WITH MODELS STILL SORTING THINGS OUT.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
AS OF 800 PM EDT THURSDAY...

SCT-BKN BAND OF SHOWERS WITH EMBEDDED THUNDERSTORMS WILL CONTINUE
TO WORK ITS WAY ACROSS THE AREA EARLY THIS EVENING AND WEEKEND.
STRONGEST SFC GUSTS THAT WE HAVE OBSERVED FROM ANY OF THIS
ACTIVITY HAS BEEN ABOUT 30 KTS. RISK WILL CONTINUE FOR A FEW MORE
HOURS...THROUGH ABOUT 02Z/10PM...B4 ACTIVITY FADES TO JUST AN
AREA OF MID/UPPER LEVEL CLOUDINESS. OUTSIDE OF THE AREA OF
SHRA/TSTM ACTIVITY...CONDITIONS WERE PRIMARILY VFR. THESE VFR
CONDITIONS SHOULD PERSIST UNTIL SKIES CLEAR TOWARD MORNING. WITH
ANY CLEARING...EXPECT AREAS OF FOG...ESP AREAS WHICH RECEIVED
RAIN...SUCH AS KLWB.

DURING THE OVERNIGHT...A COLD FRONT WILL PUSH SOUTHWARD FROM
NORTHERN VIRGINIA...PASSING ACROSS LYH AND DAN...AND ADVANCING
CLOSE TO ROA. WITH THE WEAKLY STABLE AIRMASS IN PLACE...EXPECT A
LIGHT NORTHEASTERLY FLOW. ON FRIDAY...WITH DAYTIME HEATING...THE
FRONTAL BOUNDARY DRAPED ACROSS OUR AREA WILL PROVIDE THE FOCUS FOR
SCATTERED SHOWERS AND THUNDERSTORMS...BUT MAINLY DURING THE
AFTERNOON.

THE FRONT WILL LINGER ACROSS THE AREA THROUGH THE WEEKEND AND INTO
EARLY NEXT WEEK...RESULTING IN A PERSISTENT PATTERN OF SCATTERED
AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS AS WEAK IMPULSES
PASS ACROSS THE FRONTAL BOUNDARY...OFFERING UPPER LEVEL SUPPORT.
PERIODS OF MVFR/IFR ARE EXPECTED TO BE ASSOCIATED WITH THE
SHOWER AND THUNDERSTORM ACTIVITY. PATCHY EARLY MORNING FOG CAN
ALSO BE EXPECTED.

&&

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

&&

$$
SYNOPSIS...NF
NEAR TERM...NF
SHORT TERM...MBS
LONG TERM...AMS/MBS
AVIATION...PM