Area Forecast Discussion
Issued by NWS Blacksburg, VA

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FXUS61 KRNK 301623
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
1223 PM EDT TUE JUN 30 2015

.SYNOPSIS...
A COLD FRONT WILL APPROACH THE REGION THROUGH WEDNESDAY. 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 1213 PM EDT TUESDAY...

UPDATED FORECAST TO REFLECT LOWER THREAT OF SHRA/TSRA EARLY ON BUT
THE HIGH-RES MODELS ARE STILL FIRING UP CONVECTION THIS AFTERNOON
EAST OF THE BLUE RIDGE...WITH ANOTHER BATCH RIDING IN FROM ERN KY
TOWARD MID AFTERNOON. MESOANALYSIS SHOWED HIGHER THETA-E AND
DEWPOINTS APPROACHING THE PIEDMONT...WITH SECONDARY RIDGE OVER MID
TN/WESTERN KY. OUR FORECAST AREA SEEMS TO BE IN A LULL.
HOWEVER...CLEARING SKIES OVER THE WEST AND SUNNY CONDITIONS IN THE
SOUTHEAST WILL HAVE A POSITIVE AFFECT ON CAPES THIS AFTERNOON.
THERE ARE SUBTLE UPPER AIR DISTURBANCES IN PLACE FROM INDIANA TO
TN AND OVER SOUTHSIDE VA AS OF 16Z. THESE SHOULD HELP DEVELOP
STORMS THIS AFTERNOON. FORECAST HIGHS ON TRACK TO REACH UPPER 80S
OUT EAST TO UPPER 70S/LOWER 80S WEST.

PREVIOUS VALID DISCUSSION...

SHOWERS 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 THIS EVENING
AND IN THE FAR NORTHWEST COUNTY WARNING AREA TONIGHT.

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 /16Z TUESDAY THROUGH SATURDAY/...
AS OF 740 AM EDT TUESDAY...

LOCAL RADAR INDICATED SCATTERED SHOWERS OVER EASTERN TENNESSEE AND
EXTREME SOUTHWEST VIRGINIA THIS MORNING. EXPECT THESE SHOWERS TO
WEAKEN AND DISSIPATE AS THEY MOVE NORTHEAST WITH NO IMPACT ON AREA
AIRPORTS. MEDIUM CONFIDENCE THAT MVFR CEILINGS AT KLWB AND KBLF
WILL LIFT TO VFR BY NOON.

SHOWERS AND THUNDERSTORMS WILL DEVELOP THIS AFTERNOON ALONG OLD
OUTFLOW BOUNDARIES AND IN THE LEE TROF EAST OF THE APPALACHIANS.
LOW CONFIDENCE ABOUT WHERE AND WHEN THE STORMS WILL DEVELOP BUT
HIGH CONFIDENCE OF OCCURRENCE SO HAVE ADDED VCTS TO THE TAFS
AFTER 20Z/4PM.

MOST OF THE STORMS WILL DIMINISH WITH THE LOSS OF HEATING AFTER
SUNSET. THUNDERSTORMS THAT FORM EAST OF THE BLUE RIDGE ARE
EXPECTED TO BE EAST OF KLYH AND KDAN BY 03Z/11PM BASED ON NSSL
AND LOCAL WRF MODELS. MORE STORMS WILL DEVELOP OVER THE OHIO
VALLEY TODAY AND BY EARLY THURSDAY MORNING WILL BE APPROACH KLWB
AND KBLF. HAVE ADDED MVFR CEILINGS IN THOSE TAFS 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/WP
SHORT TERM...KK
LONG TERM...WP
AVIATION...AMS/JH


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