Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000
FXUS61 KRNK 011741
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
141 PM EDT WED OCT 1 2014

.SYNOPSIS...
BACK DOOR FRONT SINKS SOUTH INTO THE CAROLINAS BY TONIGHT BEFORE
ERODING. HIGH PRESSURE TO THE NORTH WILL AGAIN WEDGE SOUTH ALONG
THE EASTERN SLOPES OF THE APPALACHIANS THURSDAY. A STRONG COLD
FRONT ARRIVES LATER FRIDAY FOLLOWED BY MUCH COOLER AIR FOR THE
WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1225 PM EDT WEDNESDAY...

VISIBLE SATELLITE LOOPS SHOWED WESTERN EDGE OF LOW CLOUDS FROM
ROCKBRIDGE COUNTY TO NEAR NEAR BEDFORD TO REIDSVILLE AT NOON. THE
GOES R NSSL SIMULATED WRF SKY COVER HAS MUCH OF THE LOW CLOUD
SCATTERED OUT BY 2PM. STILL JUST BEGINNING TO SEE STRATOCUMULUS
DEVELOP IN THE WEST WHERE THERE HAS BEEN MORE SUNSHINE SO FAR
TODAY. HAVE ADJUSTED MAXIMUM TEMPERATURE FORECAST BASED ON THESE
CLOUD TRENDS.

LOCAL WRF DATA...SREF AND LATEST HRRR HOLD CHANCE OF RAIN IN THE
FAR NORTHEAST AND EAST PART OF THE FORECAST AREA FOR THIS
AFTERNOON AND EVENING...MAINLY EAST OF A HOT SPRINGS TO LYNCHBURG
TO HALIFAX LINE. DO NOT EXPECT DEVELOPMENT OF SHOWERS UNTIL
19-20Z/3-4PM.

TONIGHT...THE FRONT DISSIPATES LEAVING BEHIND HIGH PRESSURE AND
SEMBLANCE OF ANOTHER WEDGE. NAM/CMC AGAIN FOCUSING MORE CLOUDS IN
THE ERN CWA OVERNIGHT. FORECAST SOUNDINGS ARE NOT AS AGGRESSIVE
WITH DZ BUT WILL KEEP SOME TOWARD MORNING IN THE EAST ALONG WITH
FOG.

LOWS TONIGHT WITH NOT MUCH CHANGE IN AIRMASS WILL RANGE FROM THE
UPPER 40S ACROSS THE VALLEYS IN THE WEST WITH LOWER TO MID 50S
ELSEWHERE.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 240 AM EDT WEDNESDAY...

SURFACE RIDGE WILL BE WEDGED SOUTH ALONG THE EASTERN SLOPES OF THE BLUE
RIDGE EARLY THURSDAY LIKELY RESULTING IN AREAS OF LOW CLOUDS ALONG WITH
SOME SPOTTY DRIZZLE AND FOG. HOWEVER GUIDANCE AGAIN LESS OPTIMISTIC
ABOUT DRIZZLE GIVEN VERY SHALLOW NATURE TO THE MOISTURE AND EARLY
MORNING TIMING OF BRINGING IN THE LOW DECK. THUS TRIMMED BACK
DRIZZLE/FOG COVERAGE TO MAINLY THE BLUE RIDGE IN VIRGINIA AND POINTS
EAST EARLY ON. INCREASING SHORTWAVE RIDGING ALOFT SHOULD ACT TO BUMP
THE SURFACE RIDGE FARTHER EAST DURING THURSDAY AFTERNOON ALLOWING
MIXING TO SCOUR OUT MOST OF THE WEDGE AS WARMING ALOFT KICKS IN. THIS
SHOULD ALSO PUSH HIGHS INTO THE 75-80 RANGE WEST AND LOW/MID 80S EAST
EXCEPT COOLER NE PENDING CLOUDS.

RIDGING BOTH SURFACE AND ALOFT WILL REMAIN IN PLACE THURSDAY NIGHT
AHEAD OF THE STRONG UPSTREAM 5H TROF AND ITS ASSOCIATED COLD FRONT THAT
SHOULD REMAIN WELL TO THE WEST THROUGH EARLY FRIDAY. COULD SEE SOME
ISOLATED PRE-FRONTAL -SHRA WORK INTO THE FAR SW LATE THURSDAY NIGHT
WITH POTENTIAL FOR THE LOW LEVEL WEDGE TO REDEVELOP OUT EAST WHERE SOME
SPOTTY DRIZZLE EVEN POSSIBLE LATE. OTRW ANY LIFT PER RIDGING LOOKS TOO
WEAK TO PRODUCE MUCH SO RUNNING BASICALLY DRY WITH LOWS 50S TO LOWER
60S.

STRONG COLD FRONT APPROACHES FROM THE WEST FRIDAY BUT LOOKS TO SLOW
UPON ENCOUNTERING THE EASTERN RIDGE WHILE THE BEST DYNAMICS PASS WELL
OFF TO THE NORTH. LATEST ECMWF REMAINS THE SLOWEST GIVEN A BIT MORE
NEGATIVE TILT AS MOST OTHER SOLUTIONS BRING THE BOUNDARY INTO THE WEST
LATE FRIDAY BUT DONT CLEAR THE PIEDMONT UNTIL LATE FRIDAY NIGHT. THIS
SUGGESTS A NEED TO SLOW ONSET OF HIGHER POPS DOWN A FEW HOURS WITH THE
HIGHER LIKELY/CAT POPS OVER THE MOUNTAINS DURING THE AFTERNOON...THEN
SLOWLY WORKING/DEVELOPING EAST UPON GETTING BOOTED ALONG BY THE
APPROACH OF THE MIDWEST 5H COLD POOL/SPEED MAX. HOWEVER APPEARS SHOWERS
MAY LINGER OUT EAST WELL INTO THE OVERNIGHT WITH POPS FINALLY TAPERING
OFF IN THE PIEDMONT TOWARD DAYBREAK WHILE REDEVELOPING WESTERN RIDGES
PER INCREASING POST FRONTAL UPSLOPE. OVERALL LOW TOPPED SEVERE THREAT
LOOKS MARGINAL ALTHOUGH A SLOWER SOLUTION COULD ACT TO ENHANCE WESTERN
INSTABILITY FRIDAY AFTERNOON PER BETTER NAM CAPE VALUES. HOWEVER WIND
FIELDS ALOFT AND LAPSES APPEAR WEAKER OVER THE WEST AND STRONGER EAST
WHERE LIKELY OFFSET VIA SOMEWHAT OF A RESIDUAL WEDGE UNTIL LATE.
THEREFORE KEPT SOME THUNDER MENTION MOST SPOTS AND MORE IN LINE WITH
THE STRONGER GFS SOLUTION. SLOWER TIMING SHOULD MEAN A BOUNCE IN HIGH
TEMPS ESPCLY EAST FRIDAY WHERE AROUND 80 POSSIBLE WITH MOST OTHER SPOTS
IN THE 70S GIVEN A FEW MORE HOURS OF INSOLATION FOR NOW.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 310 PM EDT TUESDAY...

A COLD FRONT WILL BE ALONG THE EAST COAST SATURDAY MORNING WITH
DRIER COOLER AIR MOVING IN ON WEST-NORTHWEST FLOW. HIGH PRESSURE
ALONG THE GULF AND LOW PRESSURE OVER NEW ENGLAND WILL PLACE A
PRESSURE GRADIENT OVER THE AREA SATURDAY. BREEZY AND GUSTY
CONDITIONS THROUGH SATURDAY EVENING...THEN HIGH PRESSURE BUILDS
NORTH INTO THE REGION. HIGH PRESSURE WILL CONTINUE TO TRACK EAST
ALONG THE GULF OVER THE WEEKEND...SHUTTING DOWN ANY MOISTURE
RETURNING INTO THE REGION. MODELS ARE MOVING A MID LEVEL DISTURBANCE
ACROSS THE OHIO VALLEY MONDAY NIGHT INTO TUESDAY. AS THIS
DISTURBANCE APPROACHES THE AREA...IT WILL BE HARD-PRESSED TO PRODUCE
WIDESPREAD SHOWERS DUE TO A LACK OF MOISTURE RECOVERY.

TEMPERATURES WILL RUN 5F-10F COOLER THAN NORMAL OVER THE WEEKEND.
TEMPERATURES BEGIN TO MODERATE TOWARDS NORMAL MONDAY AND TUESDAY.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 130 PM EDT WEDNESDAY...

VISIBLE SATELLITE LOOP SHOWED STRATUS EAST OF THE BLUE RIDGE
CONTINUING TO LIFT AND BECOME SCATTERED EARLY THIS AFTERNOON.
EXPECT VFR CONDITIONS AT KLYH AT THE BEGINNING OF THE 18Z TAF
FORECAST PERIOD. A WEAK SHORT WAVE CROSSING THROUGH THE MID
ATLANTIC REGION MAY TRIGGER ISOLATED TO SCATTERED SHOWERS LATE
THIS AFTERNOON INTO THIS EVENING. THE PROBABILITY WAS TOO LOW AT
THIS TIME TO INCLUDE IN THE TAFS. THE MOST LIKELY LOCATION FOR
SHOWERS WILL BE JUST NORTH AND EAST OF KLYH.

TONIGHT...WEDGE EXPECTED TO SET UP AND LOOKING AT MVFR/IFR
CIGS/VSBYS REFORMING AT LYH/DAN OVERNIGHT. NSSL WRF AND NAM BUFKIT
FORECAST BOTH SHOWED REDEVELOPMENT OF THE LOW CLOUDS AROUND
07Z/1AM TONIGHT. FOG AGAIN AT BCB/LWB IN THE IFR/LIFR RANGE LATE.
HIGH CONFIDENCE THAT IFR CONDITIONS WILL PERSIST UNTIL 13Z/9AM.

EXTENDED AVIATION DISCUSSION...

EXPECT VFR THU AFTERNOON INTO THU NIGHT. FRONTAL BOUNDARY AND
ASSOCIATED SHOWERS TO IMPACT THE MOUNTAINS BY LATE FRIDAY MORNING
AND THE PIEDMONT IN THE AFTERNOON. SUB VFR EXPECTED IN HEAVIER
SHOWERS OR ISOLATED TSRA.

SHOWERS EXITING THE MTNS BY LATE FRIDAY EVENING AND THE PIEDMONT
TOWARD DAWN SATURDAY. TIMING OF CLEARING IS STILL TRICKY.
SATURDAY SHOULD BE CLEARING OUT IN THE PIEDMONT TO
ROANOKE/BLACKSBURG BUT UPSLOPE MVFR CIGS AT BLF/LWB MAY OCCUR INTO
SAT AFTERNOON...WITH BREEZY NW WINDS.

WINDS DIMINISH SATURDAY NIGHT. THEN VFR SUNDAY.

&&

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

&&

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



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