Area Forecast Discussion
Issued by NWS Blacksburg, VA

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS61 KRNK 021358
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
958 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 955 AM EDT SUNDAY...

CURRENT FORECAST OF A VERY NICE SUNDAY IS ON TRACK WITH HIGH
PRESSURE OVER THE REGION. SATELLITE IMAGES AND SURFACE OBS SHOW
THAT MORNING FOG IN THE RIVER VALLEYS HAS JUST ABOUT COMPLETELY
DISSIPATED WHILE UPPER LEVEL SHORT WAVE ENERGY IS PUSHING CIRRUS
INTO THE AREA...WHICH GUIDANCE KEEPS AROUND MOST OF THE DAY. TEMPS
ARE STARTING OFF QUITE COOL AND COMBINED WITH THE LOSS OF GOOD
DOWNSLOPING FLOW EAST OF THE BLUE RIDGE THIS WILL LIKELY MAKE FOR
MAX TEMPS JUST A HAIR LOWER THAN READINGS YESTERDAY. GENERALLY
LOOKING FOR UPPER 80S/AROUND 90 EAST OF THE RIDGE AND UPPER
70S/LOWER 80S WEST.

PREVIOUS AFD...

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 /14Z 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...MBS/WP
SHORT TERM...NF
LONG TERM...NF/WERT
AVIATION...DS/JH/WP


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.