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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KRNK 170520
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
120 AM EDT FRI MAY 17 2013

.SYNOPSIS...
-- Changed Discussion --
A COLD FRONT WILL CONTINUE TO SINK SOUTH TOWARD THE REGION
OVERNIGHT BEFORE SETTLING 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 SHOWER AND
THUNDERSTORM ACTIVITY...MAINLY DURING THE AFTERNOON AND EVENING
HOURS.
-- End Changed Discussion --
&&

.NEAR TERM /THROUGH TODAY/...
AS OF 1100 PM EDT THURSDAY...

PRECIP HAS PRETTY MUCH ENDED FOR THE OVERNIGHT. CAN`T RULE OUT A
LATE NIGHT SHOWER PER LINGERING ELEVATED INSTABILITY (CAPE)...AND
WILL MAINTAIN LOW CHC POP TO ACCOUNT FOR THIS. SOME LATE NIGHT FOG
IS ALSO A GOOD POSSIBILITY FOR AREAS WHICH RECIEVED RAINFALL...ESP
THE GREENBRIER VALLEY OF WV.

MODELS ARE PROGGING A COLD FRONT TO SINK SOUTHWARD...EAST OF THE
BLUE RIDGE...BY LATE FRIDAY MORNING...BRINGING A LIGHT NORTHEASTERLY
WINDFLOW ACROSS THE AREA.

FOR FRIDAY...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 /TONIGHT 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 /05Z FRIDAY THROUGH TUESDAY/...
-- Changed Discussion --
AS OF 104 AM EDT FRIDAY...

EXPECTING OVERALL VFR OUTSIDE OF THE NW VALLEYS WHERE WILL SEE
AREAS OF IFR/LIFR IN FOG STRATUS DEVELOP THROUGH EARLY FRIDAY
MORNING. COULD SEE KLWB EVEN LOWER TO VLIFR BY DAYBREAK. OTRW
MAINLY SCTD/BKN HIGH/MID CLOUDS INTO EARLY FRIDAY MORNING WITH
SPOTS OF LOWER VSBYS AND PERHAPS SOME STRATUS TAKING SHAPE AROUND
KLYH AND KBCB THAT WERE IN PROXIMITY TO EVENING SHRA/TSRA.

WEAK BACKDOOR COLD FRONT TO THE NORTH WILL DRIFT SOUTH/SW ON
FRIDAY BEFORE STALLING NEAR THE BLUE RIDGE LATE IN THE DAY. THIS
COMBINED WITH INCREASING MOISTURE...HEATING AND OROGRAPHICS WILL
PROVIDE THE FOCUS FOR ADDED SHRA/TSRA BY EARLY AFTERNOON WITH SOME
OF THIS COVERAGE LINGERING AND SPREADING NE BY EVENING. APPEARS
THE SW TIER OF THE AREA WILL HAVE THE INITIAL BEST SHOT OF SEEING
CONVECTION BUT CANT RULE OUT AT LEAST CLUSTERS OF STORMS ACROSS
THE REGION BY LATE IN THE DAY. THUS WILL MAINTAIN THE GOING
VCSH/VCTS MENTION FROM KBCB/KROA WESTWARD EARLY FRIDAY AFTERNOON
AND THEN INCLUDE A PREVAILING MVFR MENTION OF TSRA AT MOST SITES
MAINLY DURING THE 19-00Z/2-8PM PERIOD. THINK EASTERN LOCATIONS
SUCH AS KLYH MAY SEE LESS OF A THREAT EARLY ON SO DELAYED
INCLUSION OF CONVECTION A FEW HOURS THERE. EXPECT COVERAGE TO
DIMINISH WITH LOSS OF HEATING FRIDAY EVENING BUT STILL ENOUGH
INSTABILITY AROUND ESPCLY SOUTH/SW SECTIONS TO KEEP -SHRA GOING A
WHILE LONGER INTO THE EARLY OVERNIGHT.

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.
-- End Changed Discussion --

&&

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

&&

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