Area Forecast Discussion
Issued by NWS Blacksburg, VA

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FXUS61 KRNK 160516
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
116 AM EDT TUE SEP 16 2014

.SYNOPSIS...
A WEAK COLD FRONT WILL MOVE THROUGH LATER TONIGHT RESULTING IN
WIDELY SCATTERED SHOWERS FOLLOWED BY DRIER AND COOLER WEATHER
INTO MID WEEK. HIGH PRESSURE WILL BUILD NORTH OF THE AREA FOR THE
REST OF THE WEEK KEEPING RATHER COOL BUT OVERALL DRY WEATHER IN
PLACE.
&&

.NEAR TERM /THROUGH TODAY/...
AS OF 930 PM EDT MONDAY...

LIGHT RAIN IS BEING REPORTED AT BOONE AND JEFFERSON. ADJUSTED THE
ISOLATED POPS ACROSS NW NC FOR THE NEXT FEW HOURS. EVENING
SOUNDING SHOWS A SHALLOW MOIST LAYER IN THE LOWER LEVELS WITH
PLENTY OF DRIER AIR IN THE MID LEVELS...SO NOT EXPECTING MUCH MORE
THAN A TRACE OF PRECIP WHERE IT DOES RAIN.

AS OF 730 PM EDT MONDAY...

A FEW SHOWERS MOVING ACROSS THE MOUNTAIN EMPIRE OF SOUTHWEST
VIRGINIA EARLY THIS EVENING...ASSOCIATED WITH WEAK THETA-E
RIDGING AT THE SFC AND A SHORTWAVE ALOFT PUSHING ACROSS SOUTHEAST
KENTUCKY. MODELS OVERALL PAINT A PICTURE OF LIMITED SHOWERS IN THE
SOUTHERN FORECAST AREA THIS EVENING WITH PASSING OF ONE SHORTWAVE.
MEANWHILE...THE NEXT UPSTREAM SHORTWAVE OVER THE OHIO VALLEY WILL
SLIDE SE INTO THE CENTRAL APPALACHIANS LATE...SO KEPT A SLIGHT TO
LOW CHANCE IN THE SE WV MOUNTAINS. FORECAST OTHERWISE IS ON TRACK.
MADE SOME ADJUSTMENTS TO SKY COVER BUT OVERALL LOOKS LIKE A FAIRLY
CLOUDY EVENING WITH SOME CLEARING POSSIBLE OVERNIGHT BETWEEN
SHORTWAVES.

PREVIOUS VALID DISCUSSION...

BROAD UPPER TROUGH OVER THE EASTERN CONUS AND CANADA WILL AMPLIFY
OVER THE NEXT 12 TO 24 HOURS. CLOUDS WILL KEEP OVERNIGHT LOWS
LIKELY A FEW DEGREES WARMER THAN THIS MORNING AND CHANGE OF AIR
MASS WILL BE MODEST THROUGH THE DAY WITH 850 TEMPS FALLING JUST A
FEW DEGREES AND WESTERLY DOWNSLOPING OFFSETTING THE COLD AIR
ADVECTION EAST OF THE MOUNTAINS. HIGHS WILL BE WITHIN A FEW
DEGREES OF TODAY..UPPER 60S FAR NW TO LOW 80S OUT EAST WITH MORE
UPSLOPE CLOUDS IN THE WEST.

&&

.SHORT TERM /TONIGHT THROUGH THURSDAY/...
AS OF 330 PM EDT MONDAY...

UPPER PATTERN AMPLIFIES THIS TIME FRAME WITH A RIDGE IN THE WEST AND
TROUGHING IN THE EAST.

NEXT SHORT WAVE COMING ACROSS THE AREA WEDNESDAY NIGHT. MODELS
INCREASE THE MOISTURE ACROSS THE SOUTHERN COUNTY WARNING AREA WITH
THIS FEATURE. HIGHER PRECIPITABLE WATER VALUES..ABOVE ONE INCH ARE
CONFINED TO THE SOUTHEAST COUNTY WARNING AREA BEHIND THIS WAVE ON
WEDNESDAY.

THURSDAY THE FORECAST AREA WILL BE IN BETWEEN LARGE SURFACE HIGH
PRESSURE SYSTEM OVER THE NORTHEAST UNITED STATES AND A LOW OFF THE
SOUTHEAST COAST. NORTHEAST WINDS WILL FINALLY DRIVE SOME DRIER AIR
INTO THE COUNTY WARNING AREA.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 330 PM EDT MONDAY...

HIGH PRESSURE OVER SOUTHEAST CANADA AND NEW ENGLAND WILL WEDGED DOWN
THE EAST COAST THROUGH SATURDAY NIGHT. SUNDAY THE HIGH WILL BE FAR
ENOUGH OFF THE COAST THAT THE FORECAST AREA WILL BE IN WEST TO
SOUTHWEST FLOW. ECMWF/GFS BLEND IS FAVORED WHICH BRINGS THE NEXT
COLD FRONT THROUGH THE FORECAST AREA ON SUNDAY NIGHT OR MONDAY. THE
00Z ECMWF LOWERS 850 MB TEMPERATURES INTO THE +4 TO +8 RANGE BEHIND
THE FRONT BY TUESDAY MORNING.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 100 AM EDT TUESDAY...

BAND OF MOSTLY MID DECK AHEAD OF THE COLD FRONT NEAR THE OHIO
RIVER WILL CONTINUE TO SLIDE EAST OVERNIGHT WITH SPOTTY MAINLY
MOUNTAIN SPRINKLES OR -SHRA POSSIBLE. HOWEVER ANY PRECIP APPEARS
TOO ISOLATED TO MENTION IN THE TAFS SO KEEPING THINGS DRY FOR NOW.
HOWEVER LOW LEVEL UPSLOPE FLOW WILL KEEP IFR/LIFR CIGS AT KBLF
WITH MVFR CIGS DEVELOPING AROUND KLWB AND PERHAPS KBCB. ELSW
THINKING THAT CIGS SHOULD REMAIN VFR OVERNIGHT WITH PATCHY FOG
LIKELY DEVELOPING AROUND KDAN AND POSSIBLY AT KLYH. HOWEVER GIVEN
CLOUDS...SOME LINGERING SPREAD IN TEMPS/DEWPOINTS AND A LIGHT
BREEZE AHEAD OF THE FRONT...APPEARS FOG FORMATION MAY BE SLOWER
IN SPOTS SO DELAYED UNTIL ALMOST DAYBREAK IN SPOTS.

ANY FOG/STRATUS FADES TUESDAY BY 14Z/10AM...WITH BKN VFR CIGS
TAKING SHAPE. A FEW SHOWERS MAY SKIRT BY KBLF/KBCB DURING THE
MORNING AS THE ACTUAL SURFACE COLD FRONT CROSSES OTRW EXPECTING
LIMITED PRECIP AT THIS POINT.

WEDGE WILL START TO REDEVELOP BEHIND THE FRONT TUESDAY NIGHT WITH
LOW LEVEL MOISTURE LIKELY LEADING TO WIDESPREAD LOWER CIGS
INCLUDING STRATUS BY EARLY WEDNESDAY MORNING. ALSO ADDED SHOWERS
POSSIBLE ESPCLY DURING THE EVENING ACROSS SOUTHERN SECTIONS AS A
WAVE PASSES TO THE SOUTH. OTRW SHOULD INIT AS VFR TUESDAY NIGHT
DURING THE END OF THE CURRENT VALID TAF PERIOD.

EXTENDED AVIATION DISCUSSION...

BROAD UPPER TROUGH REMAINS IN PLACE ACROSS THE EASTERN STATES FOR
THE REMAINDER OF THE WEEK ALLOWING A LARGE AREA OF HIGH PRESSURE
TO BUILD SOUTH FROM THE GREAT LAKES FOR MID WEEK BEFORE WEDGING IN
FROM OFF THE MID ATLANTIC COAST BY THE WEEKEND.

THIS SHOULD PUSH THE PESKY DEEP MOISTURE FURTHER SOUTH AWAY FROM
THE REGION. HOWEVER BIGGER CONCERN WILL BE WITH TRAPPED RESIDUAL
LOW LEVEL MOISTURE THAT MAY KEEP SOUTHERN/WESTERN LOCATIONS STUCK
IN PERIODS OF MVFR CIGS ESPCLY WEDNESDAY INTO FRIDAY AS THE LOW
LEVEL EAST/SE FLOW TAKES SHAPE. HIGH PRESSURE MAY BE STRONG ENOUGH
TO PUSH THE LOW LEVEL MOISTURE TO THE SOUTHWEST SATURDAY AND WITH
HEATING/MIXING COULD SEE THINGS RETURN TO OVERALL VFR FOR EARLY
IN THE WEEKEND...BUT NOT UNTIL SATURDAY AFTERNOON AT THIS POINT.

&&

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

&&

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



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