-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KRNK 162011
AFDRNK

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

.SYNOPSIS...
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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.
-- End Changed Discussion --

&&

.NEAR TERM /THROUGH FRIDAY/...
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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.
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&&

.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
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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.
-- End Changed Discussion --

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
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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.
-- End Changed Discussion --

&&

.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
AS OF 200 PM EDT THURSDAY...

CONDITIONS STILL VFR THIS AFTERNOON...ALTHOUGH CLOUDS CONTINUE TO
LOWER AS A COLD FRONT AND ASSOCIATED CONVECTION SINKS IN FROM THE
NORTH. BEST CHANCES FOR SHOWER AND THUNDERSTORM ACTIVITY THIS
EVENING WILL BE AT LWB...WITH SLIGHT CHANCE FOR BLF...BCB...ROA
AND LYH. STILL LOOKING FOR WESTERLY DOWNSLOPE WINDFLOW TO KEEP
CONVECTION CAPPED THROUGH SUNSET UNTIL WINDS DIE DOWN...AT WHICH
POINT EXPECT TO SEE SHOWERS AND A FEW THUNDERSTORMS BECOME MORE
SPREAD ACROSS THE FORECAST AREA. THAT SAID...CONVECTION SHOULD BE
SHORTLIVED WITH THE LOSS OF DAYTIME HEATING...WITH ONLY SPOTTY
SHOWER ACTIVITY LINGERING AFTER MIDNIGHT. ANY LOCATIONS WHERE
THUNDERSTORM ACTIVITY DOES PASS CAN EXPECT BRIEF PERIODS OF
IFR CONDITIONS...WITH VISIBILITIES DROPPING TO 1/4SM OR LESS IN
HEAVY RAIN.

OVERNIGHT...THE COLD FRONT WILL PUSH SOUTHWARD EAST OF THE BLUE
RIDGE...PASSING ACROSS LYH AND DAN...AND ADVANCING CLOSE TO ROA.
WITH THE WEAKLY STABLE AIRMASS IN PLACE...EXPECT A LIGHT
NORTHEASTERLY FLOW...WITH PATCHY FOG DEVELOPING ACROSS THE AREA.
WITH DAYTIME HEATING...THE FRONTAL BOUNDARY DRAPED ACROSS OUR AREA
WILL PROVIDE THE FOCUS FOR SCATTERED SHOWERS DURING THE
MORNING...WITH SOME INTENSIFYING INTO THUNDERSTORMS BY EARLY
AFTERNOON. MAIN AREAS TO WATCH WILL BE WHERE SUNSHINE BREAKS DOWN
TO THE SURFACE. WHILE SKIES WILL BE MOSTLY CLOUDY TO START THE
DAY...EXPECT TO SEE A FEW LOCATIONS BREAK OUT DURING THE
MORNING...ALLOWING SURFACE TEMPERATURES TO SPIKE UP QUICKLY.

THE FRONT WILL LINGER ACROSS THE AREA INTO EARLY NEXT WEEK...
RESULTING IN A PERSISTENT PATTERN OF SCATTERED AFTERNOON AND
EVENING SHOWERS AND THUNDERSTORMS AS WEAK IMPULSES PASS
ACROSS...OFFERING UPPER LEVEL SUPPORT. PERIODS OF MVFR/IFR ARE
EXPECTED DURING ANY SHOWERS AND THUNDERSTORMS. 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...JH/NF