Area Forecast Discussion
Issued by NWS Blacksburg, VA

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FXUS61 KRNK 300558
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
158 AM EDT TUE JUN 30 2015

.SYNOPSIS...
HIGH PRESSURE WILL MOVE EAST OF THE REGION OVERNIGHT ALL WHILE A
WARM FRONT LIFTS NORTH THROUGH THE OHIO VALLEY. TUESDAY INTO TUESDAY
NIGHT...A COLD FRONT WILL APPROACH THE REGION AND BRING AN INCREASED
CHANCE OF SHOWERS AND STORMS TO THE REGION. WEDNESDAY THROUGH THE
UPCOMING WEEKEND...OUR AREA WILL BE IN LINE FOR ADDITIONAL ACTIVE
WEATHER PATTERNS TO HEAD SOUTHEAST INTO AND TROUGH THE REGION...WITH
THURSDAY INTO FRIDAY HAVING THE BEST CHANCES.

&&

.NEAR TERM /THROUGH TODAY/...
AS OF 850 PM EDT MONDAY...

BAND OF BROKEN CONVECTION CONTINUES TO APPROACH THE WESTERN SLOPES
THIS EVENING ASSOCIATED WITH A RESIDUAL OUTFLOW AXIS THAT HAS PROPAGATED
EAST ALONG THE LEADING EDGE OF HIGHER RETURN THETA-E. LATEST SPC ANALYSIS
SHOWING MOST REMAINING CAPE ALONG THE FAR WESTERN SLOPES WITH THE LATEST
00Z SOUNDINGS INDICATING A STRONG MID LEVEL CAP ABOVE SOME SHALLOW LOW
LEVEL INSTABILITY OVER CLOSER TO THE BLUE RIDGE. HOWEVER DEWPOINTS CONTINUE
TO SLOWLY INCREASE UNDER WEAK RETURN FLOW WHICH COMBINED WITH THE PASSING
WARM FRONT/SHORTWAVE MAY BE ENOUGH TO BRING A FEW SHOWERS FARTHER EAST
THAN MOST GUIDANCE SHOWS DESPITE VERY DRY AIR ALOFT. THEREFORE WILL
EDGE LOW POPS A LITTLE FARTHER EAST ESPCLY OVER THE SW WHERE MORE IN
LINE WITH AN UPSTREAM AXIS OF DEEPER CONVECTION HEADING SE INTO NE TN
ATTM. OTRW PLAN TO KEEP THINGS DRY EAST OF THE MOUNTAINS AS SUPPORTED
BY THE LATEST HRRR IN CUTTING MOISTURE OFF UPON HEADING EAST OF THE
SLOPES. ALSO BEEFING UP CLOUD COVER ESPCLY GIVEN THE LARGE SWATH OF
DEBRIS CANOPY SEEN OFF IR PICS TO THE WEST. THIS SHOULD ACT TO HOLD
LOW TEMPS UP SOME AS WELL AS KEEPING FOG LIMITED FOR THE MOST PART.

PREVIOUS DISCUSSION AS OF 230 PM EDT MONDAY...

AN AREA OF LOW PRESSURE WAS MAKING ITS WAY EASTWARD FROM OHIO INTO
PENNSYLVANIA. ITS ASSOCIATED WARM FRONT IS EXPECTED TO HEAD NORTHEAST
TONIGHT FROM WEST VIRGINIA INTO NORTHERN VIRGINIA. ITS PROXIMITY TO
OUR REGION WILL ALLOW FOR ISOLATED TO SCATTERED SHOWERS TO MOVE INTO
THE AREA FROM THE WEST...AND ALSO DEVELOP LATE THIS AFTERNOON DURING
THE PEAK HEATING OF THE DAY ACROSS THE WESTERN PORTIONS OF THE
FORECAST AREA. ANTICIPATE ISOLATED SHOWERS TO WORK MAKE THEIR WAY AS
FAR EAST AS A BOONE TO BLACKSBURG TO HOT SPRINGS LINE BY MIDNIGHT.
AFTER THIS TIME...COVERAGE WILL GRADUALLY DECREASE AGAIN WITH ONLY
ISOLATED SHOWERS OVER SOUTHEAST WEST VIRGINIA BY DAYBREAK TUESDAY.
LOW TEMPERATURES WILL BE MILDER THAN THOSE REALIZED THIS MORNING
THANKS TO INCREASING DEW POINTS AND CLOUD COVER. THE UPPER 50S TO
LOWER 60S ARE EXPECTED ACROSS THE MOUNTAINS WITH LOWER 60S ACROSS
THE PIEDMONT.

ON TUESDAY THE AXIS OF THE PARENT UPPER TROUGH WILL DEEPEN ACROSS
THE OHIO AND TENNESSEE VALLEY REGION. LOOK FOR INCREASED JET
DYNAMICS ACROSS THE REGION ON TUESDAY AND BETTER SURFACE BASED
INSTABILITY. THE RESULT WILL BE A GREATER COVERAGE OF SHOWERS AND
STORMS ACROSS THE AREA AND AN EARLIER IGNITION TIME. BY THE LATE
AFTERNOON...SHOWERS AND STORMS WILL BE LIKELY ACROSS THE SOUTHWEST
PORTION OF THE AREA WITH SCATTERED COVERAGE ELSEWHERE. THE STORM
PREDICTION CENTER HAS A MARGINAL CHANCE OF SEVERE WEATHER ACROSS THE
AREA. A FEW OF THE STORMS MAY HAVE STRONG TO SEVERE WINDS AND HAIL.
HIGH TEMPERATURES WILL RANGE FROM THE UPPER 70S TO AROUND 80 ACROSS
THE MOUNTAINS WITH MID TO UPPER 80S ACROSS THE PIEDMONT.

&&

.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
AS OF 305 PM EDT MONDAY...

5H TROUGH DEEPENS OVER THE EAST ALLOWING BY WEDNESDAY A SERIES OF
UPPER DISTURBANCES TO SLIDE SE OVER THE AREA. EXPECT SOME STORMS
STICKING AROUND EARLY TUESDAY EVENING BEFORE WEAKENING/ENDING
OVERNIGHT...THOUGH THE LATEST ECMWF SUGGEST SOME ORGANIZED
CONVECTION GOING FROM INDIANA/OHIO/KENTUCKY TUESDAY EVENING INTO THE
MOUNTAINS BY MIDNIGHT BEFORE WEAKENING. WILL STICK WITH HIGHER
CHANCES IN THE WEST IN THE EVENING.

WEDNESDAY...ANOTHER WAVE WORKS IN FROM THE NW LATER IN THE DAY BUT
NOT SEEING A GREAT THREAT OF STORMS...MAINLY 30/40 POPS HIGHER IN
THE MOUNTAINS. HIGHS TO BE CLOSER TO NORMAL...WITH MID TO UPPER 70S
WEST...TO MID TO UPPER 80S EAST.

SFC FRONT TO SLIDE SWD INTO THURSDAY WITH ANOTHER STRONGER WAVE
ALOFT HEADING FROM THE MID MS VALLEY INTO THE VIRGINIAS/CAROLINAS.
THE 12Z GFS SHOWING A FURTHER NWD ARC TO THIS SYSTEM AS OPPOSED TO
THE 12Z ECMWF. THE DISTRIBUTION BETWEEN THE MODELS STILL FAVOR A
BETTER THREAT OF STORMS THURSDAY AND WILL HAVE LIKELY POPS WEST TO
HIGH CHANCE EAST. THINGS WEAKEN/FADE THURSDAY NIGHT.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 300 PM EDT MONDAY...

THE PATTERN REMAINS THE SAME THIS PERIOD...WITH SOME RISING HEIGHTS
THIS WEEKEND RETURN MORE HUMIDITY. A FRONTAL BOUNDARY/BAROCLINIC
ZONE WILL REMAIN AT OR CLOSE ENOUGH BY THROUGH THE PERIOD TO NOT
ALLOW FOR ONE WHOLE DAY WHERE ITS COMPLETELY STORM FREE. NOT
EVERYONE WILL SEE RAIN...BUT THE MODELS ARE FAVORING A LIKELIHOOD
FOR MORE ORGANIZED CONVECTION TO MOVE ACROSS SATURDAY...WITH DIURNAL
BASED MORE FRI-SUN-MON.

THE TEMPS WILL BE CLOSER TO NORMAL GIVEN THE VARIATION IN FRONTAL
BOUNDARY AND CLOUD COVER FROM UPSTREAM STORMS. LOW TEMPS HOWEVER
WILL GET BACK TO THE MUGGY 60S...LOWER 70S.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 150 AM EDT TUESDAY...

LOCAL RADAR INDICATED SCATTERED SHOWERS OVER THE MOUNTAINS EARLY
THIS MORNING. EXPECT THESE SHOWERS TO WEAKEN AND DISSIPATE AS
THEY MOVE EAST BUT HAVE STILL INCLUDED RAIN IN THE KBCB AND KBLF
TAFS. CLOUD COVER WILL LIMIT FOG FORMATION AT KLWB SO ONLY HAVE
MVFR FOG IN JUST BEFORE SUNRISE.

SHOWERS AND THUNDERSTORMS WILL REDEVELOP THIS AFTERNOON ALONG OLD
OUTFLOW BOUNDARIES AND IN THE LEE TROF EAST OF THE APPALACHIANS.
LOW CONFIDENCE ABOUT WHERE THE STORMS WILL DEVELOP SO HAVE KEPT
OUT OF THE TAFS EAST OF THE BLUE RIDGE FOR NOW.

STORMS WILL DIMINISH WITH THE LOSS OF HEATING AFTER SUNSET. HAVE
VFR CONDITIONS FORECAST FOR LATE TONIGHT.

EXTENDED AVIATION DISCUSSION...

THE REGION WILL BE IN A GENERAL NORTHWEST FLOW PATTERN THROUGH
SATURDAY. WHILE ISOLATED TO SCATTERED SHOWERS AND STORMS CANNOT BE
RULE OUT ANY OF THESE DAYS...THE BEST POTENTIAL WILL BE ON
THURSDAY...THEN AGAIN LATER FRIDAY...FOLLOWED BY A THIRD
POTENTIAL INCREASE IN COVERAGE ON SATURDAY AS SEPARATE SHORTWAVE
TROUGHS PROGRESS TROUGH THE NORTHWEST FLOW.

VFR CONDITIONS ARE EXPECTED FOR MOST OF THE AREA MUCH OF THE
TIME. THE EXCEPTIONS WILL COME AS TEMPORARY DECREASES WITHIN ANY
HEAVIER RAIN SHOWERS OR THUNDERSTORMS...AND THEN LATE AT NIGHT AND
EARLY MORNING DUE TO RIVER OR MOUNTAIN VALLEY FOG...ESPECIALLY IN
AREAS THAT RECEIVED PRECIPITATION THE DAY BEFORE.

&&

.EQUIPMENT...
AS OF 100 AM EDT TUESDAY...

THE OBSERVATIONS FROM THE BLACKSBURG AWOS (KBCB) WERE NOT
AVAILABLEDUE TO A COMMERCIAL POWER OUTAGE AT THE AIRPORT.

&&

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

&&

$$
SYNOPSIS...DS
NEAR TERM...DS/JH
SHORT TERM...WP
LONG TERM...WP
AVIATION...AMS/JH
EQUIPMENT...AMS


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