Area Forecast Discussion
Issued by NWS Blacksburg, VA

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FXUS61 KRNK 300853
AFDRNK

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

.SYNOPSIS...
TODAY THROUGH WEDNESDAY A COLD FRONT WILL APPROACH THE REGION.
THE FRONT WILL STALL ACROSS THE AREA BY WEDNESDAY NIGHT. A SERIES
OF LOWS WILL TRACK ALONG THE FRONT THURSDAY  THROUGH SATURDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 430 AM EDT TUESDAY...

ISOLATED SHOWERS AND THUNDERSTORMS CONTINUED OVER THE MOUNTAINS
TONIGHT. CLUSTER OF SHOWERS AND THUNDERSTORMS OVER NORTHEAST
TENNESSEE WILL MOVE INTO THE SOUTHWEST COUNTY WARNING AREA BEFORE
8AM BUT WILL DISSIPATE AS IT MOVES TOWARD THE BLUE RIDGE.

CHALLENGING TO FINE TUNE WHERE BEST CHANCE FOR SHOWERS AND
THUNDERSTORMS WILL BE THIS AFTERNOON AND EVENING. SHORT RANGE
MODELS...INCLUDED THE LOCAL WRF...SREF AND NSSL WRK SHOWED
DEVELOPMENT ALONG THE LEE TROF EAST OF THE APPALACHIANS LATE THIS
AFTERNOON. ALSO EXPECT THERE MAY BE REDEVELOPMENT FROM OUTFLOW
GENERATED BY THE SHOWERS AND THUNDERSTORMS IN TENNESSEE. ONCE
THESE STORMS DEVELOP...STORM MOTION MAY TAKE THEM INTO THE
SOUTHWEST COUNTY WARNING AREA. SHOWER AND THUNDERSTORMS WILL ALSO
FORM IN THE OHIO VALLEY THIS AFTERNOON AND MAY BE ORGANIZED INTO A
BROKEN LINE OF BY THE TIME THEY REACH WEST VIRGINIA OVERNIGHT.
HAVE INCREASED THE PROBABILITY OF PRECIPITATION IN THE EASTERN
COUNTY WARNING AREA LATE THIS AFTERNOON INTO THIS EVENING AND IN
THE FAR NORTHWEST COUNTY WARNING AREA TONIGHT BASED ON THESE MODEL
TRENDS.

CLOUD COVER OVER THE MOUNTAINS WILL LIMIT AMOUNT OF HEATING TODAY.
ENOUGH CONVECTIVE AVAILABLE POTENTIAL ENERGY AND STRONG ENOUGH MID
LEVEL WINDS FOR DECENT SHEAR THIS AFTERNOON THAT LEE-TROUGH STORMS
HAVE A SLIGHT RISK OF BEING SEVERE.

STAYED CLOSER TO COOLER MAV/ECMWF FOR MAXIMUM TEMPERATURES IN THE
WEST TODAY. LEANED TOWARD WARMER GUIDANCE IN ALL AREA FOR
OVERNIGHT LOWS.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 340 AM EDT TUESDAY...

BROAD TROUGH OVER THE EASTERN US WILL SLOWLY SLIDE EAST DURING THE
PERIOD. A SERIES OF SHORTWAVE WILL ROTATE SOUTHEAST THROUGH THE
UPPER TROUGH. ALLOWED FOR LIGHT POPS WEDNESDAY MORNING IN THE WEST
WITH WEAKENING STORMS ASSOCIATED WITH UPPER DISTURBANCE. ANOTHER
SHORTWAVE PIVOTS ACROSS WEDNESDAY AFTERNOON INTO WEDNESDAY EVENING.
THE DAY TWO CONVECTIVE OUTLOOK INDICATED A MARGINAL POTENTIAL FOR
SEVERE THUNDERSTORMS WEST OF I77 IN OUR SOUTHWEST MOUNTAINS. HIGH
TEMPERATURES WEDNESDAY WILL BE NEAR NORMAL WITH READINGS FROM THE
LOWER 70S IN THE NORTHWEST MOUNTAINS TO THE UPPER 80S IN THE
PIEDMONT. A DISTURBANCE WILL DROP SOUTHEAST WEDNESDAY NIGHT BRUSHING
OUR WEST. PLAYED THE HIGHEST POPS IN THE WEST TAPERING OFF AS ONE
HEADS EAST. LOW TEMPERATURES WEDNESDAY NIGHT WILL RANGE FROM THE
UPPER 50S IN THE MOUNTAINS TO THE UPPER 60S IN THE PIEDMONT.

SURFACE FRONT WILL SLIDE SOUTHWARD THURSDAY AS ANOTHER SHORTWAVE
ALOFT TRAVELS FROM THE MID MS VALLEY INTO OUR REGION. MODELS ARE
DIFFERENT ON THE PLACEMENT AND TIMING OF MOISTURE SURGE THURSDAY
AFTERNOON INTO THURSDAY NIGHT. IN ANY CASE...THERE IS A BETTER
CHANCE FOR SHOWERS AND THUNDERSTORMS SUPPORTED BY ECMWF AND GFS
WITH LIKELY CHANCES IN THE WEST. THE SWODY3 PLACED A MARGINAL
THREAT FOR SEVERE STORMS TO OUR SOUTHWEST. HOWEVER...THE RAIN MAY
BE HEAVY AT TIMES. ELECTED TO RAISED QPF FOR FORECAST AREA ON
THURSDAY. HIGH TEMPERATURES THURSDAY WILL VARY FROM AROUND 70
DEGREES IN THE WEST TO THE MID 80S IN THE EAST. DECREASED POPS
THURSDAY NIGHT AND TRANSITION TO SHOWERS. LOW TEMPERATURES
THURSDAY NIGHT WILL GENERALLY BE FROM AROUND 60 IN THE WEST TO THE
UPPER 60S IN THE EAST.

&&

.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 THAT IS 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 /09Z 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.

&&

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

&&

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



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