Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000
FXUS61 KRNK 301944
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
344 PM EDT SUN AUG 30 2015

.SYNOPSIS...
A SERIES OF WEAK UPPER LEVEL DISTURBANCES WILL LIFT NORTH ALONG
THE APPALACHIAN CHAIN THIS AFTERNOON INTO EARLY MONDAY...BRINGING
A GREATER CHANCE FOR SHOWERS TO THE REGION. UPPER LEVEL HIGH
PRESSURE WILL THEN STRENGTHEN AND KEEP US IN A RATHER STAGNANT
PATTERN...MAINTAINING A CHANCE FOR AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS THROUGH THE MIDDLE OF THE WEEK.

&&

.NEAR TERM /THROUGH MONDAY/...
AS OF 330 PM EDT SUNDAY...

SATELLITE IMAGES CONTINUE TO SHOW A SOLID MID/UPPER OVERCAST BUT
SURFACE OBS ARE NOT INDICATING MUCH IN THE WAY OF LOWER CLOUDS
UNDERNEATH. FOR MOST OF THE AFTERNOON THIS DRIER AIR IN THE LOW
LEVELS HAS RESULTED IN RETURNS ON AREA RADARS YIELDING LITTLE MORE
THAN SPOTTY SPRINKLES. HOWEVER BY LATE IN THE AFTERNOON SOME
ISOLATED DIURNAL CONVECTION HAD BEGUN TO DEVELOP ALONG THE FAR
WESTERN SLOPES OF THE APPALACHIANS. BELIEVE ISOLATED/SCATTERED
DIURNAL CONVECTION WILL CONTINUE TO FORM ALONG THE FAR WESTERN
SLOPES THROUGH EARLY THIS EVENING BEFORE WANING WITH THE LOSS OF
HEATING. THEN AN APPROACHING SHORT WAVE WILL BEGIN TO BRING SOME
LOW LEVEL MOISTURE INTO THE REGION FROM THE SOUTH AND HELP
GENERATE ANOTHER CHANCE OF PRECIPITATION OVERNIGHT MAINLY FOR THE
FOOTHILLS AND PIEDMONT OF NC AND INTO SOUTHSIDE VA. MONDAY WILL
SEE MOST OF THIS SHORT WAVE ENERGY PULLING OFF TO THE EAST...LEAVING
US IN A MOIST AND WEAKLY FORCED ENVIRONMENT THAT SHOULD HELP GENERATE
SOME SCATTERED SHOWERS/THUNDERSTORMS DURING THE AFTERNOON.

CLOUDS TONIGHT WILL KEEP TEMPERATURES IN THE MIDDLE 60S EAST OF
THE BLUE RIDGE WITH UPPER 50S/LOWER 60S TO THE WEST. HIGHS
TOMORROW LOOK TO BE IN THE MIDDLE 80S EAST TO UPPER 70S/AROUND 80
WEST.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
AS OF 330 PM EDT SUNDAY...

EXPECTING 500 MB RIDGE TO BUILD OVER THE EASTERN UNITED STATES BY
TUESDAY NIGHT. MODELS SUGGEST SOME POTENTIAL PIECES OF ENERGY BUT
THESE WILL BE WEAK AND DO NOT APPEAR ORGANIZED ENOUGH TO PROVIDE ANY
DECENT LIFT FOR THE REGION. BEST PROBABILITY OF PRECIPITATION WILL
BE ON WEDNESDAY WHEN A SHORT WAVE CROSSES THE MID ATLANTIC STATES.

WHILE THERE MAY BE WEAK SURFACE TROFS IN THE AREA THROUGH
WEDNESDAY...OVERALL HIGH PRESSURE REMAINS IN PLACE AND NO CHANGE OF
AIRMASS IS EXPECTED. COMBINATION OF MAV AND MOS GUIDANCE WAS
REASONABLE FOR HIGHS AND LOWS THIS TIME FRAME.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 330 PM EDT SUNDAY...

MODELS SHOW A HIGH AMPLITUDE RIDGE OVER THE EASTERN UNITED
STATES WITH 500 MB HEIGHTS AROUND 594 DM OVER THE OHIO VALLEY BY
SUNDAY. CHALLENGING TO TRACK ANY SUBTLE SHORT WAVES ON THE EAST SIDE
OF THE RIDGE THAT MAY IMPACT THE AREA. 850 MB TEMPERATURES GRADUALLY
WARM INTO THE +16 TO +20 RANGE BY SUNDAY. BY SATURDAY AND SUNDAY
MAXIMUM TEMPERATURES WILL BE 5 TO 10 DEGREES
ABOVE NORMAL.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 130 PM EDT SUNDAY...

WILL GO WITH A LIGHT WIND VFR FORECAST THROUGH THE PERIOD AT ALL
SITES...BUT WITH SOME CAVEATS. DIURNAL SHOWERS ARE DEVELOPING
AHEAD OF INCREASING MOISTURE AND A SHORT WAVE APPROACHING FROM THE
SOUTH. LOW LEVEL DRY AIR IS SLOW TO SATURATE DESPITE GOOD
TRANSPORT OF TROPICAL MOISTURE ALOFT FROM THE GULF OF MEXICO. THE
RESULT IS ABUNDANT MID/UPPER CLOUDS... SPOTTY SHOWERS/SPRINKLES...
AND NO SUB VFR CIGS. BELIEVE THIS WILL CONTINUE TO BE THE CASE
INTO EARLY THIS EVENING AS DIURNAL ACTIVITY STARTS TO WANE WITH
THE LOSS OF HEATING SO WILL GO WITH VFR CONDITIONS AND VCSH
THROUGH THE FIRST PART OF THE TAFS.

HOWEVER...THE APPROACHING WAVE LOOKS TO BRING ANOTHER CHANCE OF SHOWERS
IN FOR THE OVERNIGHT. MODELS ARE QUITE DIFFERENT IN HANDLING PRECIPITATION
POTENTIAL AND ADVECTION OF LOW LEVEL MOISTURE SO DO NOT HAVE A LOT OF
CONFIDENCE IN SPECIFIC LOCATION/TIMING OF ANY SHOWERS AND LOWER CIGS.
THUS...WILL INDICATE A GRADUAL THICKENING/LOWERING OF VFR CLOUDS AND
LEAVE OUT MENTION OF PRECIPITATION FOR NOW. WILL USE VCSH ONLY AT KDAN
SINCE THEY WILL BE CLOSEST TO ADVANCING MOISTURE AND INTRODUCE SOME
LOWER VFR CIGS FOR KBLF/KBCB/KDAN LATE TONIGHT. BELIEVE THICKENING/LOWERING
CLOUDS WILL PREVENT FOG FORMATION SO WILL HEDGE AGAINST MOST GUIDANCE
AND NOT INCLUDE ANY FOG AT KBCB OR KLWB. THERE WILL BE MORE DIURNAL
SHOWERS AND POSSIBLY SUB VFR CIGS ON MONDAY BUT MOST LIKELY BEYOND
THIS TAF PERIOD.

EXTENDED AVIATION DISCUSSION... THE FORECAST AREA WILL REMAIN IN A
WEAKLY FORCED SYNOPTIC ENVIRONMENT THROUGH MIDWEEK...WITH CHANCES FOR
DIURNAL CONVECTION MAINLY FROM THE BLUE RIDGE WEST...AND SOME MVFR/IFR
FOG/STRATUS DEVELOPMENT AT NIGHT...ESPECIALLY AT KBCB AND KLWB.

&&

.EQUIPMENT...
AS OF 700 AM EDT SUNDAY...

THE DEW POINT READING AT KJFZ...RICHLANDS VA AWOS...IS INCORRECT.
AT THIS TIME WE DO NOT KNOW WHEN THIS SENSOR WILL BE REPAIRED.

&&

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

&&

$$
SYNOPSIS...MBS
NEAR TERM...MBS
SHORT TERM...AMS
LONG TERM...AMS
AVIATION...MBS/NF
EQUIPMENT...PW



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