Area Forecast Discussion
Issued by NWS Blacksburg, VA

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FXUS61 KRNK 302003
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
403 PM EDT TUE SEP 30 2014

.SYNOPSIS...
WEAK HIGH PRESSURE WILL BEGIN TO SHIFT OUT OF THE AREA THIS
EVENING. A BACK DOOR COLD FRONT WILL SLIDE SOUTH INTO THE AREA
WEDNESDAY. A STRONG COLD FRONT ARRIVES FRIDAY.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
AS OF 345 PM EDT TUESDAY...

MOST LOCATIONS ARE OBSERVING MOSTLY SUNNY TO PARTLY CLOUDY SKIES
THIS AFTERNOON...WITH THE EXCEPTION OF PORTIONS OF FAR EASTERN
CHARLOTTE THROUGH BUCKINGHAM COUNTIES...WHERE A STUBBORN STRATUS
DECK HAS BEEN SLOW TO ERODE ALL DAY. AT THE RATE THE STRATUS IS
DISSIPATING...FOLKS UNDER THESE CLOUDS SHOULD AT LEAST GET TO SEE
A NICE SUNSET. STRONGER HEATING FURTHER WEST IS SUPPORTING
VERTICAL CLOUD DEVELOPMENT ALONG THE BLUE RIDGE. ALTHOUGH RADAR
IS CLEAR AT THE MOMENT...CANNOT RULE OUT A SHOWER OR TWO
DEVELOPING THROUGH 8 PM.

OVERNIGHT...MOISTURE WILL CONTINUE TO POOL AHEAD OF AN APPROACHING
COLD FRONT. WITH MOSTLY CLEAR SKIES AND LIGHT WINDS EXPECTED...
PATCHY FOG WILL AGAIN BE AN ISSUE BEGINNING DURING THE EARLY HOURS
OF WEDNESDAY. FOG IS ESPECIALLY LIKELY IN THE MOUNTAIN RIVER
VALLEYS...AS WELL AS LOCATIONS EAST OF A DANVILLE TO LYNCHBURG
LINE...WHERE CLOUD COVER HELPED LIMIT DRYING OF MOISTURE FROM
RAINFALL ON MONDAY EVENING. OVERNIGHT LOWS ARE EXPECTED TO REMAIN
MILD...RANGING FROM THE LOW TO MID 50S ACROSS THE MOUNTAINS...TO
THE UPPER 50S ACROSS THE SOUTHSIDE.

AN AREA OF LOW PRESSURE SOUTH OF THE GREAT LAKES WILL DROP
SOUTHWARD INTO THE MID ATLANTIC WEDNESDAY MORNING...BRINGING A
COLD FRONT TO THE INTERSTATE 64 CORRIDOR BY SUNRISE...WITH THE
FRONT CONTINUING TO DRIFT SOUTH THROUGH THE DAY. BEST INSTABILITY...
WHICH OVERALL IS VERY MODEST...WILL BE LOCATED IN THE VICINITY OF
THE LOW...AND WILL SUPPORT SPOTTY SHOWER ACTIVITY FROM THE
ALLEGHANY HIGHLANDS INTO THE PIEDMONT. EVEN WITH THE FRONT SINKING
ACROSS THE AREA...TRULY COOLER AIR WILL REMAIN TO THE NORTH.
EXPECT AFTERNOON HIGHS TO RANGE FROM THE LOW TO MID 70S ALONG THE
INTERSTATE 64 CORRIDOR AND THE NORTH CAROLINA MOUNTAINS...TO THE
LOW 80S ACROSS THE NORTH CAROLINA PIEDMONT.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
AS OF 257 PM EDT TUESDAY...

A CLOSED LOW WILL MOVE OFF THE NORTHEAST COAST WEDNESDAY AFTERNOON.
NORTHERLY FLOW ON THE BACK SIDE OF THIS LOW WILL HELP PUSH A WEAK
COOL FRONTAL BOUNDARY SOUTH OF THE AREA WEDNESDAY NIGHT. THIS WEDGE
OF HIGH PRESSURE WILL HAVE LIGHT EASTERLY FLOW AND...COMBINED WITH
MOISTURE...LOW CLOUDS/FOG/DRIZZLE ARE LIKELY ALONG AND EAST OF THE
BLUE RIDGE INTO AT LEAST THURSDAY MORNING. THROUGH THE DAY
THURSDAY...AN UPPER LEVEL RIDGE AXIS WILL MOVE OVER THE EAST COAST
AND WITH THE HELP OF WESTERLY FLOW...FOG AND STRATUS DECK SHOULD
SCOUR BY THE AFTERNOON. ISENTROPIC LIFT MAY REMAIN OVER THE PIEDMONT
LONGER WITH LOW CLOUDS LINGERING WELL INTO THE AFTERNOON...POSSIBLY
THE EVENING. A COLD FRONT WILL APPROACH THE AREA THURSDAY NIGHT.
INCREASED MIXING OVER THE REGION WILL ERODE WHAT IS LEFT OF THE
WEDGE THROUGH THE NIGHT AND INTO FRIDAY MORNING.

THE COLD FRONT WILL MOVE QUICKLY ACROSS THE EASTERN HALF OF THE USA
FRIDAY AND FRIDAY NIGHT. AROUND SUNRISE FRIDAY...THE FRONT IS OVER
THE MISSISSIPPI VALLEY. AROUND SUNSET...THE FRONT IS OVER THE
OHIO/TENNESSEE VALLEYS MOVING INTO THE APPALACHIAN MOUNTAINS. THIS
FRONT WILL BE ALONG THE EASTERN SEA BOARD BY SUNRISE SATURDAY
MORNING. MODEL TIMING OF PREFRONTAL SHOWERS REMAINS CONSISTENT...
OVER THE MOUNTAINS IN THE MORNING...ENTIRE FORECAST AREA IN THE
AFTERNOON...EXITING THE PIEDMONT DURING THE EVENING. INSTABILITIES
ARE NOT TOO IMPRESSIVE WITH THIS STRONG FRONT...SOME MAYBE LUCKY TO
HEAR A FEW RUMBLES OF THUNDER. RAINFALL AMOUNTS WILL RANGE FROM A
QUARTER TO HALF OF AN INCH /0.25-0.50/. BEHIND THE FRONT...A TIGHT
PRESSURE GRADIENT WILL BRING BREEZY AND GUSTY CONDITIONS ALONG RIDGE
TOPS...WITH STRONGER WINDS MIXING TO THE LOWER LEVELS DURING THE DAY
SATURDAY. WEST-NORTHWEST FLOW MAY KEEP CLOUDS OVER THE MOUNTAINS
FRIDAY NIGHT WITH SOME PATCHY DRIZZLE ALONG WESTERN SLOPES.
DOWNSLOPE FLOW EAST OF THE BLUE RIDGE WILL ERODE CLOUDS AND BE CLEAR
BY SUNRISE.

WITH EASTERLY FLOW AND A WEAK WEDGE IN THE EAST...UNIFORM
TEMPERATURES IN THE 70S ARE EXPECTED THURSDAY. SINCE SHOWERS WILL
OVERSPREAD THE MOUNTAINS DURING THE MORNING...HIGH TEMPERATURES MAY
REACH 70F. LATER ARRIVAL OF SHOWERS AND CLOUDS ACROSS THE FOOTHILLS
AND PIEDMONT COULD HAVE TEMPERATURES PEAKING OUT IN THE UPPER
70S...POSSIBLY LOWER 80S TOWARDS SOUTHSIDE FRIDAY AFTERNOON.

&&

.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 /20Z TUESDAY THROUGH SUNDAY/...
AS OF 725 AM EDT TUESDAY...

VISIBILITIES HAVE BEEN VARIABLE EARLY THIS MORNING BUT MOST SITES
ARE SUB VFR...WITH THE VLIFR AT BCB/LWB. STILL EXPECTING THE FOG
TO LIFT/BURN OFF BY 15Z. COULD BE A PERIOD OF FOG AT BLF AS THE
MOISTURE LIFTS FROM THE VALLEYS THROUGH 14Z.

VFR CONDITIONS ARE EXPECTED THIS AFTERNOON. A SHORTWAVE MOVING
INTO THE MID ATLANTIC BY 12Z WED MAY BRING SOME SCT-BKN STRATO-AC
TO LYH WITH ANY SHOWERS STAYING NORTH. WITH NOT MUCH CLOUD COVER
ANTICIPATED TYPICAL AREAS LIKE LWB/BCB/LYH/DAN WILL HAVE MVFR
VSBYS WITH FOG...MORE DENSE IN THE LWB AREA.

EXTENDED AVIATION DISCUSSION...

VFR CIGS AND VSBYS CAN BE EXPECTED WEDNESDAY AND
THURSDAY...ALTHOUGH PERIOD OF SUB VFR LIKELY TO OCCUR FOR OUR
MOUNTAIN VALLEY AIRPORTS...KBCB...KLWB AGAIN THURSDAY MORNING. THE
NEXT THREAT FOR SUB VFR CIGS/VSBYS WILL COME WITH A FRONTAL
PASSAGE ON FRIDAY. THIS FRONT WILL LIKELY BE ASSOCIATED WITH A
LINE OF SHOWERS AND FEW THUNDERSTORMS...SWEEPING WEST TO EAST
ACROSS THE REGION.

NORTHWEST WINDS INCREASE BEHIND THIS FRONT FRIDAY NIGHT INTO
SATURDAY. SATURDAY SHOULD BE VFR ALTHOUGH SOME UPSLOPE MVFR CIGS
ARE POSSIBLE AT LWB/BLF.

&&

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

&&

$$
SYNOPSIS...NF/PM
NEAR TERM...NF/PM
SHORT TERM...RCS
LONG TERM...RCS
AVIATION...MBS/PM/WP



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