-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KRNK 111301
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
901 AM EDT FRI JUL 11 2014

.SYNOPSIS...
WEAK HIGH PRESSURE WILL SPILL SOUTH INTO THE REGION TODAY AND
CONTINUE TO EXTEND INTO THE AREA FROM OFF THE MID ATLANTIC COAST
INTO SATURDAY. DEEPER MOISTURE WILL RETURN LATER SUNDAY INTO
EARLY NEXT WEEK AHEAD OF A STRONG COLD FRONT THAT WILL BE PASSING
THROUGH THE REGION TUESDAY INTO TUESDAY NIGHT. HIGH PRESSURE
FOLLOWING THE FRONT SHOULD BRING MUCH DRIER AND COOLER AIR FOR THE
MIDDLE AND END OF NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 900 AM EDT FRIDAY...

VERY MINOR UPDATE TO HOURLY GRIDS TO LINGER SOME FOG IN MTN
VALLEYS JUST A BIT LONGER AND BETTER MATCH CURRENT AREAS INTO
SHENANDOAH VALLEY...AND ALSO ADJUST SKY COVER TO BETTER MATCH OBS
AND MORE CLEARING THIS MORNING BEFORE CU FILL BACK IN MIDDAY.
OTHERWISE NO OTHER CHANGES AT THIS TIME AS MEX TEMP AND GENERALLY
SLIGHT CHC PRECIP FOR HIGHER TERRAIN STILL LOOKS GOOD.

PREV DISCUSSION AS OF 240 AM EDT FRIDAY...

FAINT SURFACE FRONT BASICALLY REMAINS EAST-WEST ALONG THE HIGHWAY
460 CORRIDOR ATTM AS MOST SHOWERS HAVE FADED PER LOSS OF
INSTABILITY AND ARRIVAL OF DRIER AIR ALOFT SEEN OFF THE LATEST
VAPOR LOOP. HOWEVER WITH DEEPER MOISTURE STILL SOUTH OF THE
BOUNDARY AND MSAS SHOWING LINGERING HIGHER THETA-E...WILL LEAVE IN
A TOKEN POP ACROSS THE SE EARLY THIS MORNING GIVEN OUTFLOW AROUND.

OTRW FRONT TO SLIDE A BIT MORE TO THE SE TODAY AS MORE OF THE DRIER
AIR ALOFT TO THE NW ARRIVES IN THE WAKE OF THE PASSING 5H TROF
AXIS JUST OFF TO THE EAST. THIS ALONG WITH SLIGHTLY LOWER
DEWPOINTS/PWATS...AND LACK OF UPPER SUPPORT SHOULD BRING ABOUT A
DRIER DAY WITH FORECAST SOUNDINGS SHOWING EXTENSIVE DRYING ABOVE A
RATHER LARGE MID LEVEL CAP THIS AFTERNOON. MODELS DO SHOW SOME
WEAK LOW LEVEL CONVERGENCE DEVELOPING MAINLY FAR SW LATER ON AS
THE BOUNDARY LAYER FLOW TURNS MORE SE AND SOME RETURN IN 85H
THETA-E RETURNS. HOWEVER THIS LOOKS TO FOCUS MORE WITH OROGRAPHIC
SUPPORT AND DIFF HEATING AND LESS OUT EAST WHERE A DRIER NE
TRAJECTORY WILL OCCUR. MOST GUIDANCE BASICALLY IN LINE WITH SOME
ISOLATED POP UP CONVECTION WITH SHOTGUN NATURE COVERAGE MAINLY
BLUE RIDGE AND FAR NW GIVEN MODEST CAPE/INSTABILITY. THUS WILL RUN
WITH MORE CHANCE POPS IN THESE SPOTS WITH A BROAD 20ISH POP
COVERAGE ELSW EXCEPT THE SE AND FAR WESTERN SLOPES FOR NOW. DRIER
AIR UNDER INCREASING SUN...AFTER EARLY LOW CLOUDS/FOG...ALONG WITH
WARMING ALOFT WEST SHOULD BALANCE OUT HIGHS IN THE LOW/MID 80S
OVERALL.

WEAK SURFACE HIGH WILL BRIDGE IN FROM THE NE OVERNIGHT WHICH SHOULD
KEEP WEAK SUBSIDENCE IN PLACE UNDER THE LEADING EDGE OF THE STRONGER
5H RIDGE TO THE WEST. MAY SEE ISOLATED SHRA/TSRA CONTINUE FOR A
BIT DURING THE EVENING BEFORE FADING TO MORE FOG OVERNIGHT AS A
PERIOD OF CLEARING TAKES SHAPE. HOWEVER FLOW...ALBEIT
WEAK...TURNING AROUND TO A MORE S/SE COMPONENT IN THE 8-9H LAYER
MAY TEND TO REDEVELOP SOME STRATO-CU ESPCLY SOUTHERN BLUE RIDGE
WHERE TRAPPED MOISTURE FROM THE EVENING MAY LINGER. OTRW MOSTLY
CLEAR TO PC. KEPT TEMPS CLOSER TO THE WARMER MET MOS AS MAV
DEWPOINTS LOOK TOO DRY BY MORNING EVEN IF SKIES ARE TOTALLY CLEAR.

&&

.SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/...
AS OF 320 AM EDT FRIDAY...

WEAK HIGH PRESSURE WILL RIDGE ACROSS OUR REGION ON SATURDAY.
SCATTERED DIURNAL CONVECTION IS EXPECTED TO DEVELOP OVER THE
MOUNTAINS AND ADJACENT FOOTHILLS SATURDAY AFTERNOON INTO SATURDAY
NIGHT WITH LIGHT UPSLOPE FLOW AND LIGHT LOW LEVEL CONVERGENCES
FOCUSED ON THE MOUNTAINS. SWODY2 PLACED THE SLIGHT RISK OF SEVERE
THUNDERSTORMS ACROSS THE MIDWEST WITH BETTER INSTABILITY AND
LIFT. FELT THAT THE ADJMAV CAPTURED THE SATURDAY HIGH
TEMPERATURES WITH READINGS FROM AROUND 80 DEGREES IN THE MOUNTAINS
TO THE LOWER 90S IN THE PIEDMONT. KEPT THE LIGHT POPS GOING IN THE
WEST UNTIL 06Z SUNDAY THEN DRY OUT INTO SUNDAY MORNING. LOW
TEMPERATURES SATURDAY NIGHT REMAIN MILD WITH VALUES FROM THE LOWER
60S IN THE WEST TO AROUND 70 DEGREES IN THE EAST.

AS THE RIDGES SLIDE EAST SUNDAY...WINDS BECOME SOUTHWEST
SLOWLY INCREASING MOISTURE. THE GFS IS MORE ROBUST WITH COVERAGE OF
SHOWERS AND THUNDERSTORMS SUNDAY AFTERNOON COMPARED TO THE ECMWF.
STORMS WILL BE A LITTLE MORE WIDESPREAD COMPARED TO SATURDAY BUT
STILL MAINTAINED CHC CATEGORY WITH NO FORCING. STILL NOT SEEING
ENOUGH INSTABILITY OR ANY FORCING FOR MUCH IN THE WAY OF SEVERE
THREAT.

BECAUSE OF THE WESTERLY COMPONENT OF THE FLOW...QUESTIONS REMAIN
ABOUT HOW FAR EAST THUNDERSTORMS MAY DEVELOP OR SHIFT TO LATER IN
THE DAY. MUCH MORE ORGANIZED AND POSSIBLY SEVERE STORMS WELL
UPSTREAM CLOSER TO NEXT FRONTAL BOUNDARY SHOULD REMAIN WELL TO THE
WEST THROUGH THE NIGHT.

HIGH TEMPERATURES ON SUNDAY WILL BE SEASONABLE FROM THE LOWER
80S IN THE WEST TO THE LOWER 90S IN THE EAST. GFS MOS IS
HINTING THAT WE COULD SEE A FEW MID 90S IN THE SOUTHEAST
DEPENDING ON THE CLOUD COVER AND STRENGTH OF THE DOWNSLOPE.

A COLD FRONT APPROACHING FROM THE WEST ON MONDAY WILL CREATE
A WARM AND HUMID AIRMASS WITH PLENTY OF INSTABILITY TO
SET OFF SOME AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS.
RAISED POPS TO INCLUDE THE MENTION OF LIKELY IN THE NORTHWEST.
HIGH TEMPERATURES ON MONDAY WILL VARY FROM THE MID 80S IN THE WEST
TO THE MID 90S IN THE EAST. LOWS MONDAY WILL GENERALLY BE FROM THE
LOWER 60S IN THE MOUNTAINS TO AROUND 7O DEGREES IN THE PIEDMONT.

&&

.LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 1230 PM EDT THURSDAY...

WAVES OF UPPER LEVEL ENERGY ASSOCIATION WITH AN UPPER LEVEL TROF
AND ASSOCIATED CUT OFF LOW OVER THE NORTHERN GREAT LAKES WILL
BRING ADDITIONAL SHOWERS AND THUNDERSTORMS AHEAD OF THE FRONT ON
TUESDAY. TIMING DIFFERENCES REMAIN ON WHEN EXACTLY THE COLD FRONT
WILL CROSS OUR REGION...HOWEVER IT WILL HAPPEN EITHER LATE TUESDAY
OR EARLY WEDNESDAY.

BEHIND THE COLD FRONT...HIGH PRESSURE BUILDS IN AND A NOTICEABLE
DROP IN HUMIDITY WILL BE FELT AS DEWPTS CRASH INTO THE 40S AND 50S.
HIGH TEMPS WEDNESDAY AND THURSDAY WILL BE SEVERAL DEGREES BELOW
NORMAL. THIS MEANS MID TO UPPER 70S ACROSS THE MOUNTAINS AND LOW 80S
EAST OF THE BLUE RIDGE. DEPENDING ON CLOUD COVER...WOULD NOT BE
SURPRISED TO SEE A FEW MOUNTAIN LOCATIONS DROP INTO THE MID TO UPPER
40S FOR NIGHT TIME LOWS ESPECIALLY ON THURSDAY.

&&

.AVIATION /13Z FRIDAY THROUGH TUESDAY/...
AS OF 650 AM EDT FRIDAY...

PATCHY DENSE FOG THE MAIN ISSUE EARLY THIS MORNING WITH IFR/LIFR
EXPECTED TO PERSIST AT KLWB/KBCB AND PERHAPS KDAN UNTIL AROUND
13Z/9AM BEFORE QUICKLY IMPROVING AS FOG DISSIPATES WITH HEATING.
COULD SEE A BRIEF PERIOD OF MVFR AROUND KLYH AND KROA AS WELL BUT
WONT INCLUDE IN THE TAFS FOR NOW.

A BIT DRIER AIR WILL FINALLY WORK IN TODAY AND HELP SCOUR OUT
FOG/LOW CLOUDS BY MID MORNING AND LIMIT THE COVERAGE OF AFTERNOON
CONVECTION FOR THE MOST PART. LATEST BUFKIT SOUNDINGS DO SHOW VFR
CU CIGS DEVELOPING ESPCLY MOUNTAINS BY MIDDAY BUT MOST BASES ABOVE
4K FT. AN ISOLATED SHRA/TSRA ALSO STILL POSSIBLE MAINLY ALONG THE
BLUE RIDGE BUT TOO IFFY TO INCLUDE AT THIS POINT. OTRW KEEPING VFR
UNDER LIGHT EAST TO SE WINDS AFTER EARLY LOW CONDITIONS IMPROVE.
MORE FOG LIKELY LATER TONIGHT IF LEFTOVER CU FADES QUICK ENOUGH
BUT AGAIN MOSTLY CONFINED TO THE VALLEYS WHERE A LATE NIGHT PERIOD
OF MVFR/IFR POSSIBLE ESPCLY KLWB/KBCB/KDAN.

EXTENDED AVIATION DISCUSSION...

CONTINUED LOW PROBABILITY OF SHRA/TSRA SATURDAY...AS WEAK HIGH
PRESSURE EXTENDS IN FROM THE NORTHEAST WITH A RELATIVE DRY AIR
MASS IN PLACE.

MOISTURE AND MORE WIDESPREAD SHRA/TSRA LIKELY TO RETURN FOR THE
END OF THE WEEKEND AND EARLY NEXT WEEK AS A BROAD UPPER TROUGH
DIGS INTO THE GREAT LAKES REGION AND RESULTANT CYCLONIC FLOW
PROVIDES INCREASINGLY UNSTABLE/UNSETTLED CONDITIONS ACROSS THE
REGION. APPEARS BEST SHOT AT WIDESPREAD MVFR/IFR NOW ON TUESDAY
WITH THE PASSAGE OF A STRONG COLD FRONT FOR MID JULY WITH OCNL
MVFR IN PASSING AFTERNOON/EVENING TSRA IN ADVANCE OF THE BOUNDARY
ON MONDAY. PATCHY LATE NIGHT/EARLY MORNING FOG WILL RESULT IN
LOCAL MVFR TO IFR CONDITIONS DURING THE LATE NIGHTS AND EARLY
MORNINGS...ESPECIALLY IN VALLEY LOCATIONS AND WHERE EARLIER
AFTERNOON RAINFALL OCCURRED.

&&

.HYDROLOGY...
AS OF 1000 AM EDT THURSDAY...

US DROUGHT MONITOR ISSUED JULY 10 2014...SHOWS EXPANSION OF
D0...ABNORMALLY DRY CATEGORY...ACROSS MUCH OF NEW RIVER VALLEY AND
OVER PARTS OF THE VA AND NC PIEDMONT...CENTERED AROUND DANVILLE.
PULASKI COUNTY VA APPEARS TO BE NEAR THE EPICENTER OF THE
DEVELOPING CONDITIONS OVER THE NEW RIVER VALLEY WITH MUCH OF THAT
COUNTY RECEIVING LESS THAN 50 PERCENT OF NORMAL RAINFALL SINCE
EARLY MAY.

&&

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

&&

$$
SYNOPSIS...JH/SK
NEAR TERM...JH/SK
SHORT TERM...KK
LONG TERM...CF/KK
AVIATION...JH/RAB
HYDROLOGY...PC