Area Forecast Discussion
Issued by NWS Blacksburg, VA

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FXUS61 KRNK 021125
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
725 AM EDT SUN AUG 2 2015

.SYNOPSIS...
HIGH PRESSURE WILL REMAIN IN PLACE THROUGH TONIGHT. A COLD FRONT
SINKS SOUTHEAST TOWARD THE CENTRAL APPALACHIANS BY MONDAY
AFTERNOON...REACHING THE NORTH CAROLINA/VIRGINIA BORDER BY
TUESDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 302 AM EDT SUNDAY...

FORECAST THIS PERIOD STILL CENTERS AROUND UPPER TROUGH ACROSS THE
EASTERN U.S. FOR OUR AREA WILL SEE DRY WEATHER AGAIN DAY AND
WARM...HIGHS RANGING FROM THE UPPER 70S TO LOWER 80S OVER THE HIGHER
TERRAIN...TO MID 80S VALLEYS...AND UPPER 80S TO LOWER 90S PIEDMONT
INTO THE ROANOKE/LEXINGTON VA CORRIDOR.

THERE IS A COUPLE OF PIECES OF SHORTWAVE ENERGY MOVING ALONG THE
TROUGH ALLOWING FOR CIRRUS. EXPECT TO SEE THIS STREAK OF CIRRUS
TODAY THOUGH MOSTLY SUNNY SKIES WILL BE THE RULE.

TONIGHT...STILL LOOKING AT A QUIET WX NIGHT WITH CALM/LIGHT WINDS.
THE FRONT THAT MOVED THROUGH A COUPLE DAYS OR SO AGO MAY SHIFT NWD
WITH A SFC WAVE MOVING ACROSS THE CAROLINAS. NOT SEEING ANY MOISTURE
THOUGH CANNOT RULE OUT SOME SCATTERING OF LOWER CLOUDS TOWARD
SOUTHSIDE VA AND NC PIEDMONT LATE TONIGHT BUT MAJORITY OF MODEL
SOLUTIONS KEEP THE CLOUDS EAST AND SOUTHEAST OF OUR AREA...SO WILL
MAINTAIN MOSTLY CLEAR SKIES. LOWS AGAIN GOING TO VARY FROM THE LOWER
50S DEEPER MOUNTAIN VALLEYS TO MID TO UPPER 50S REST OF THE
MOUNTAINS...EXCEPT LOWER 60S ACROSS THE HIGHER PEAKS OF SE WV AS
ENOUGH FLOW TO KEEP IT MIXED. THE PIEDMONT/FOOTHILLS AND ROANOKE
VALLEY WILL BE IN THE LOWER TO MID 60S. PATCHY RIVER VALLEY FOG
EXPECTED AGAIN LATE IN THE WEST.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 AM EDT SUNDAY...

UPPER LEVEL TROUGHING IS EXPECTED TO HOLD ACROSS THE NORTHEAST
PORTION OF THE COUNTY THROUGH THE PERIOD...ALTHOUGH THE TROUGH WILL
BECOME LESS PRONOUNCED DURING THE SECOND HALF OF THIS WEEK AS THE
CENTER PUSHES OVER THE NORTH ATLANTIC. REGARDLESS...THE PATTERN WILL
ALLOW US TO MAINTAIN A GENERAL WEST TO EAST UPPER LEVEL WINDFLOW FOR
THE CENTRAL APPALACHIANS.

MONDAY WILL START DRY...BUT EXPECT A FEW SHOWERS/STORMS TO PUSH
AGAINST THE WESTERN RIDGES DURING THE EVENING AND OVERNIGHT AS A
COLD FRONT SINKS SOUTH FROM THE GREAT LAKES. MODELS ARE NOT
OPTIMISTIC THAT MUCH...IF ANY...OF THE RAINFALL WILL SURVIVE EAST OF
THE CONTINENTAL DIVIDE AS THEY ENCOUNTER DRY AIR IN PLACE AND
DOWNSLOPE WINDFLOW. DOWNSLOPING AND COMPRESSIONAL HEATING AHEAD OF
THE FRONT WILL ALSO PUSH AFTERNOON HIGHS INTO THE MID 80S MOST SPOTS
ACROSS THE MOUNTAINS...AND AS HIGH AS THE MID 90S ACROSS THE
SOUTHSIDE.

THE COLD FRONT WILL PROGRESS SLOWLY SOUTHWARD MONDAY NIGHT...AND
SOME DISAGREEMENT REMAINS AS TO HOW FAR ACROSS OUR AREA THE FRONT
WILL SINK ON TUESDAY. THE CONSENSUS IS THAT THE FRONT WILL ADVANCE
TO NEAR THE VA/NC BORDER BY EVENING. AS SUCH...WILL MAINTAIN HIGHER
RAIN CHANCES FOR LOCATIONS SOUTH OF HIGHWAY 460 DURING THE AFTERNOON
AND EVENING. THAT STATED...DO NOT EXPECT ANY STRONG RETURN OF
MOISTURE AHEAD OF THE FRONT...AND THEREFORE EXPECT CONVECTION TO
REMAIN WIDELY SCATTERED AT BEST.

ATTENTION TURNS TO OUR WEST ON WEDNESDAY...ESPECIALLY WEDNESDAY
NIGHT...AS A SERIES OF UPPER LEVEL DISTURBANCES APPROACH FROM THE
CENTRAL PLAINS/MIDWEST. LATEST MODELS ARE FOCUSING ON ONE SUCH
DISTURBANCE...POTENTIALLY THE DECAYING REMNANTS OF A THUNDERSTORM
COMPLEX RIDING UP THE OHIO RIVER VALLEY LATE WEDNESDAY NIGHT. WILL
CONTINUE TO MONITOR THE DEVELOPMENT OF THIS FEATURE IN THE MODELS
OVER THE NEXT COUPLE DAYS FOR TRACK...TIMING AND INTENSITY.

&&

.LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 325 AM EDT SUNDAY...

EAST-WEST BAROCLINIC ZONE REMAINS ESTABLISHED OVER OR NEAR THE
FORECAST AREA THROUGH MUCH OF THE LONG-TERM PERIOD AS ADDITIONAL
UPSTREAM SHORT WAVES AND/OR MESOSCALE VORTICITY CENTERS FROM
DECAYING OLD MIDWEST CONVECTIVE COMPLEXES PROVIDE SUFFICIENT
ENERGY/SUPPORT TO MAINTAIN THREAT FOR DAILY SCATTERED CONVECTION.

STRENGTH AND MOVEMENT/POSITIONING OF EACH WAVE IN MAINLY ZONAL UPPER
FLOW WILL INFLUENCE DAILY POSITION OF DECAYING FRONTAL BOUNDARY...
EXTENT OF CLOUD COVER...AND EXTENT OF WARM OR COOL ADVECTION
DEPENDING ON POSITION RELATIVE TO FRONT.

HIGHEST THREAT FOR PRECIPITATION FOR THIS PERIOD APPEARS TO COME ON
FRIDAY...WHEN TWO OF THE MORE NOTABLE UPSTREAM WAVES ARRIVE...AND
THIS IS REFLECTED ACCORDINGLY IN GRIDS FOR THIS TIMEFRAME.
OTHERWISE...A LOWER AND MORE GENERALIZED THREAT FOR DAILY
PRECIPITATION WILL BE MAINTAINED INTO SATURDAY UNTIL REGIONAL/
MESOSCALE FEATURES BECOME BETTER RESOLVED.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
AS OF 720 AM EDT SUNDAY...

EXPECT VFR TODAY INTO THIS EVENING WITH PASSING HIGH CLOUDS. MAY
SEE A LITTLE FOG AT LWB LATER SUNDAY NIGHT TAKING VSBYS TO IFR
LEVELS.



EXTENDED AVIATION FORECAST...
AS OF 1230 PM EDT SATURDAY...

MOSTLY VFR OUTSIDE OF ANY CONVECTION THROUGH THE PERIOD. A FRONT
WILL SET UP IN THE MID ATLANTIC WHICH COULD BRING A FEW SHRA/TSRA
BY TUESDAY...WITH PERHAPS A BIT MORE COVERAGE LATER WEDNESDAY AT
THIS POINT. THUS THE THREAT OF SUB-VFR REMAINS LOW UNTIL AROUND
MIDWEEK...EXCEPT FOR THE TYPICAL FOG POTENTIAL AT KLWB/KBCB EACH
MORNING BETWEEN 09-13Z.

&&

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

&&

$$
SYNOPSIS...JH/WP
NEAR TERM...WP
SHORT TERM...NF
LONG TERM...NF/WERT
AVIATION...DS/JH/WP



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