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000
FXUS61 KRNK 171437
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
1037 AM EDT FRI MAY 17 2013

.SYNOPSIS...
A COLD FRONT WILL CONTINUE TO SINK SOUTH TOWARD THE REGION
TODAY BEFORE SETTLING ACROSS THE EASTERN HALF OF THE FORECAST
AREA BY THIS EVENING. THE FRONT WILL STALL OVER NORTH CAROLINA
OVERNIGHT INTO SATURDAY NIGHT BEFORE LIFTING BACK NORTHEAST AS A
WARM FRONT BY EARLY NEXT WEEK. A WEAK UPPER LEVEL DISTURBANCE
WILL RIDE EAST ALONG THE FRONT ENHANCING THE THREAT FOR SHOWERS
AND THUNDERSTORMS ESPECIALLY OVER THE WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 AM EDT FRIDAY...

PLENTY OF SUNSHINE REACHING THE SURFACE THIS MORNING FOR MUCH OF
THE AREA OUTSIDE OF PORTIONS OF THE ALLEGHANY HIGHLANDS AND THE
SHENANDOAH VALLEY. THE INCREASED HEATING IS ALREADY LEADING TO A
FEW CU POPPING UP ALONG THE RIDGELINES...AND WILL HAVE TO MONITOR
THROUGH THE MORNING FOR THE DEVELOPMENT OF SHOWER ACTIVITY...AND
THUNDERSTORMS LATER IN THE DAY. MAINTAINING THE PREVIOUS FORECAST
PHILOSOPHY FOR TODAY...WHICH IS FOR SPOTTY SHOWERS AND
THUNDERSTORMS TO DEVELOP BY EARLY AFTERNOON ALONG THE RIDGES AS
SOUTHEASTERLY WINDS LEAD TO STRONGER LOW LEVEL CONVERGENCE...AND
THEN THUNDERSTORM ACTIVITY WILL BECOME MORE WIDESPREAD ACROSS THE
PIEDMONTS DURING THE EVENING AHEAD OF A FRONT THAT WILL BE SINKING
ACROSS THE AREA. BELIEVE THAT THUNDERSTORM ACTIVITY WILL BE MORE
PULSE LIKE IN NATURE...AND MAY BE SLOW MOVING DUE TO WEAK WINDS
ALOFT. AS SUCH...MAY SEE LOCALLY HEAVY RAIN IN A FEW AREAS IF
CELLS LINGER LONG ENOUGH OR IF THEY BEGIN TO TRAIN.

LINGERING INSTABILITY WILL GET SHOVED BACK TO ALONG AND WEST OF
THE BLUE RIDGE OVERNIGHT AS THE FRONT PASSES INTO THE FAR SOUTHERN
AREAS BY DAYBREAK. WILL HAVE CONTINUED HIGH POPS DURING THE
EVENING PENDING WHERE MORE ORGANIZED THUNDERSTORM ACTIVITY TAKES
SHAPE...THEN DECREASING BY MIDNIGHT ESPECIALLY EAST IN THE WAKE
OF THE BOUNDARY. WESTERN AREAS MAY SEE SHOWERS INCREASE AGAIN
LATE AHEAD OF THE APPROACHING UPPER LOW BUT IFFY...SO ONLY KEEPING
CHANCE POPS GOING THERE. OTHERWISE MOSTLY CLOUDY AND MUGGY WITH
LOWS IN THE 50S TO LOWER 60S FOR OVERNIGHT LOWS.

&&

.SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/...
AS OF 349 AM EDT FRIDAY...

BOUNDARY JUST TO OUR NORTH WILL SINK SOUTH OVER THE WEEKEND...IN A
BACKDOOR FASHION AS HIGH PRESSURE SLIPS OVER NEW ENGLAND. THIS
BOUNDARY IN COMBINATION WITH SOUTHEAST UPSLOPE WINDS AGAINST THE
BLUE RIDGE...AND AN UPPER WAVE MOVING ACROSS TN...SHOULD PRODUCE A
SOMEWHAT COOL AND DAMP WEEKEND. SUNDAY APPEARS TO BE THE WETTEST DAY
WITH THE UPPER DISTURBANCE RIGHT ON OUR DOORSTEP THEN MOVING INTO
VIRGINIA DURING THE DAY. PWATS START OUT FAIR SATURDAY BUT REALLY
INCREASE SUNDAY TO 1.5" THROUGH THE PIEDMONT. WITH DEAD FLOW
ALOFT AND WEAK MBE VELOCITIES...STORMS MAY BE SLOW MOVING AND
LATCHED ONTO THE BLUE RIDGE...POSSIBLY LEADING TO SOME WATER
PROBLEMS. INSTABILITY ISN`T THE STRONGEST...AS SUNSHINE WILL BE
LIMITED BY ABUNDANT CLOUDS...BUT COOLING ALOFT THANKS TO THE UPPER
WAVE COULD LEAD TO A MINIMAL STRONG STORM THREAT...ALTHOUGH NOT
TOO THRILLED ABOUT SEVERE WEATHER. SURFACE WINDS VEER ON
MONDAY...MORE OF A S TO SSW WIND AS THE SHORTWAVE MOVES
EAST...THUS ONLY CHC POPS AND WARMER AFTERNOON TEMPS...ESPECIALLY
WEST OF THE BLUE RIDGE WITH LESS CLOUDS.

&&

.LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 315 AM EDT FRIDAY...

FRONT LIFTS TO OUR NORTH TUESDAY WHICH SHOULD BE OUR BEST BET TO
AVOID PCPN GIVEN 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 /15Z FRIDAY THROUGH TUESDAY/...
AS OF 615 AM EDT FRIDAY...

FOG EARLY THIS MORNING REMAINS LIMITED TO MAINLY THE VALLEYS
ACROSS THE NORTH/NW THAT EXPERIENCED HEAVY RAINFALL YESTERDAY
EVENING. OTRW EXPECTING MAINLY VFR OUTSIDE OF KLWB WHERE WILL SEE
AREAS OF LIFR/VLIFR IN FOG/STRATUS THROUGH MID MORNING. ELSW MAINLY
SCTD/BKN MID CLOUD CANOPY TO INIT WITH ONLY SPOTTY LOWER VSBYS
AND PERHAPS SOME STRATUS KLYH/KBCB VICINITY THAT WERE IN
PROXIMITY TO EVENING SHRA/TSRA.

WEAK BACKDOOR COLD FRONT TO THE NORTH WILL DRIFT SOUTH/SW TODAY
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 THIS EVENING BUT STILL ENOUGH
INSTABILITY AROUND ESPCLY WESTERN LOCATIONS 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.

&&

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

&&

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