Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000
FXUS61 KRNK 021305
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
905 AM EDT THU OCT 2 2014

.SYNOPSIS...
HIGH PRESSURE WILL AGAIN WEDGE SOUTH ALONG THE EASTERN SLOPES OF
THE APPALACHIANS THROUGH TONIGHT. A STRONG COLD FRONT ARRIVES
LATER FRIDAY FOLLOWED BY MUCH COOLER AIR FOR THE WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 905 AM EDT THURSDAY...
MORNING LOW CLOUDS AND FOG SHOULD MIX OUT OR LIFT BY LATE MORNING
AS UPPER RIDGE BUILDS ACROSS OUR REGION THIS AFTERNOON.
MEANWHILE...AM SHORTWAVE SHOULD PUSH INTO EAST INTO THE ATLANTIC
OCEAN. MADE SOME MINOR ADJUSTMENTS IN TEMPERATURES AND CLOUD COVER
FOR THIS MORNING INTO THIS AFTERNOON. HIGHS THIS AFTERNOON WILL
RANGE FROM THE LOWER 70S IN THE MOUNTAINS TO THE LOWER 80S IN THE
PIEDMONT.

AS OF 720 AM EDT THURSDAY...

FORECAST ON TRACK THIS MORNING WITH FOG AND LOW CLOUDS OUT EAST.
EXPECT THIS LAYER TO SLOWLY ERODE AND SHIFT EAST THROUGH THE
MORNING. MOST LOCATIONS WILL BE SUNNY/MOSTLY SUNNY GOING INTO
LUNCHTIME.

PREVIOUS VALID DISCUSSION...

MODELS FAVOR DRIER SOLUTION WITH UPPER RIDGING MOVING IN THIS
AFTERNOON...WITH ANY SHOWER ACTIVITY WITH LAST VORT STAYING EAST
OF OUR AREA THIS MORNING.

WEAK WEDGE TO ERODE AS WELL BY LATE IN THE DAY AS FLOW TURNS MORE
SOUTHEAST AHEAD OF THE STORM SYSTEM MOVING INTO THE MISSISSIPPI
VALLEY. THE MODELS ARE TRACKING THIS FRONT INTO OHIO/WRN KY AND WRN
TN BY LATE TONIGHT WITH SHOWERS ARRIVING IN ISOLATED FASHION TOWARD
THE SW VA MTNS BY DAWN.

OVERALL LOOKING AT SKIES BEING SUNNY/MOSTLY SUNNY WEST
TODAY...BECOMING MOSTLY SUNNY IN THE AFTERNOON EAST...WITH HIGHS
RANGING FROM THE MID TO UPPER 70S MOUNTAINS...TO LOWER 80S SOUTHEAST.

TONIGHT...GOING TO SEE ADVANCEMENT OF LOWER CLOUDS AGAIN TOWARD THE
PIEDMONT AS SE-E FLOW CONTINUES. FORECAST SOUNDING SUGGEST PATCHY
DRIZZLE IN THE FOOTHILLS OF VA NORTH OF BEDFORD/LYNCHBURG LATE.

CLOUD COVER WILL INCREASE LATE IN THE WEST. LOWS WILL BE MILDER THAN
PAST COUPLE OF DAYS WITH MOST LOCATIONS IN THE MID TO UPPER 50S.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 310 AM EDT THURSDAY...

SHORTWAVE RIDGING SLOWLY BREAKS DOWN FRIDAY IN ADVANCE OF THE UPSTREAM
5H TROUGH AND ITS ASSOCIATED COLD FRONT THAT LOOKS TO PUSH THROUGH THE
REGION FROM THE WEST FRIDAY NIGHT. MODELS HAVE SETTLED A BIT MORE ON
THE SLOWER TIMING OF THE BOUNDARY WITH SORT OF AN INITIAL PUSH OF
SHOWERS ACROSS THE WEST AHEAD OF THE LEADING WIND SHIFT BOUNDARY FRIDAY
AFTERNOON...WITH THIS AXIS OF PRECIP POSSIBLY HEADING EAST OF THE BLUE
RIDGE LATE FRIDAY INTO FRIDAY NIGHT. HOWEVER THE LATEST 00Z ECMWF
BASICALLY SPLITS MUCH OF THE PRECIP ENTERING THE WEST FRIDAY AS BEST
UPPER SUPPORT/LIFT LAGS THE SURFACE BOUNDARY AS A SECONDARY SPEED MAX
ROTATES AROUND THE DEEP UPPER COLD POOL. OTHER SOLUTIONS SURGE THE
INITIAL BAND OF PRECIP INTO THE AREA A BIT FASTER BUT MOSTLY INTO WEAK
INSTABILITY/LAPSES OVER THE WEST AND THE LINGERING WEDGE OUT EAST. FOR
NOW PLAN TO KEEP TIMING SIMILAR WITH HIGHEST CAT/LIKELY POPS WEST OF
THE BLUE RIDGE THROUGH EARLY AFTERNOON...THEN OUT EAST LATE DAY INTO
THE EVENING.

SEVERE THREAT AGAIN LOOKS MARGINAL PER FORECAST CAPES OF BELOW 1K J/KG
AND A RATHER SATURATED ENVIRONMENT THAT LIKELY WILL KEEP STRONG
UNIDIRECTIONAL WINDS ALOFT UNLESS SOME SORT OF LOW TOPPED CONVECTIVE
BAND SURGES OUT FRIDAY AFTERNOON. MAY ALSO HAVE THE SCENARIO OF SEEING
MORE CONCENTRATED LOW TOPPED SHRA/TSRA TO THE NORTH CLOSER TO THE
DYNAMICS ALOFT...AND MORE SURFACE BASED CONVECTION SOUTH PER HIGHER
INSTABILITY. THIS WOULD LEAVE WEAKER SHOWERS IN BETWEEN ACROSS OUR
REGION MAINLY FRIDAY EVENING SO SOMETHING TO WATCH. OTRW HIGH TEMPS
REMAIN A BIT TRICKY AS GUSTY SOUTHERLY WINDS DEVELOP ALOFT WHILE WILL
HAVE CLOUDS INCREASING AND THE BEST WARM ADVECTION TO THE SOUTH. THINK
WITH SLOWER PRECIP ARRIVAL THAT THE EAST SHOULD RISE CLOSER TO THE
WARMER MAV MOS WITH COOLER 70S SIMILAR TO THE MET VALUES IN THE WEST.

SHOWERS/ISOLATED TSRA SHOULD PUSH EAST AND OUT OF THE AREA AFTER
MIDNIGHT FRIDAY NIGHT WITH A SURGE OF COLD ADVECTION SPILLING ACROSS
THE MOUNTAINS LATE. THIS WILL TURN ON A BRIEF PERIOD OF UPSLOPE -SHRA
BUT LIMITED BY MORE OF A WESTERLY TRAJECTORY AND EXODUS OF MOISTURE
WITH THE FRONT TO THE EAST...SO MAINLY CHANCE POPS THERE. OTRW HIGH
POPS EAST EARLY...AND CHANCE ELSW TAPERING TO MOSTLY THE FAR NW LATE AS
DOWNSLOPE DRYING KICKS IN. PART OF THE UPPER COLD POOL ROTATES ACROSS
SATURDAY AS STRONG SURFACE HIGH PRESSURE BUILDS IN FROM THE SW ON GUSTY
NW BREEZES. GRADUAL DRYING AND INCREASING SUBSIDENCE SHOULD CURTAIL
MOST UPSLOPE SHOWERS BY AFTERNOON BUT LIKELY STILL SOME CLOUDS UNDER
THE TROUGH OUT WEST FOR MUCH OF THE DAY. WILL FEEL LIKE OCTOBER WITH
85H TEMPS NEAR 0C NW AND COOL ADVECTION FOR MOST OF THE DAY KEEPING
HIGHS ONLY IN THE LOW/MID 50S MOUNTAINS. A BIT WARMER EAST WHERE SHOULD
BUMP INTO THE MID/UPPER 60S GIVEN DOWNSLOPE AND MORE INSOLATION SOONER.

COLDEST NIGHT OF THE SEASON SO FAR IN STORE SATURDAY NIGHT WITH HIGH
PRESSURE NOSING IN FROM THE SW AND MOUNTAIN CLOUDS FADING. MOST MOS
TEMPS SUPPORT A RATHER WIDESPREAD SWATH OF LOW/MID 30S WESTERN
MOUNTAINS WITH UPPER 30S/LOW 40S EAST. HOWEVER STILL UNCERTAINTY WITH
THE DEGREE OF DECOUPLING WITH THE PARENT HIGH SO FAR SOUTH AND A
WESTERLY COMPONENT IN PLACE. A BIT MORE CLOUDS NW COULD ALSO LIMIT TEMP
FALLS AS APPEARS LOCATIONS ACROSS THE SW MAY BE COLDER PER BETTER
RADIATIONAL COOLING UNDER THE RIDGE WHILE THE NORTH AND NW STAY
SLIGHTLY WARMER UNDER A LIGHT BREEZE. THIS MAY BRING SOME FROST ESPCLY
FROM THE NEW RIVER VALLEY AND POINTS SW INTO THE N CAROLINA MOUNTAINS
WITH EVEN BRIEF FREEZE CONDITIONS POSSIBLE IN THE VALLEYS IF WINDS CAN
DIMINISH SOONER.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 310 PM EDT WEDNESDAY...

FOLLOWING THE PASSING OF A COLD FRONT FRIDAY NIGHT...THE REGION
WILL REMAIN UNDER AN UPPER LEVEL TROUGH THROUGH EARLY NEXT WEEK.
COOLER THAN NORMAL AFTERNOON TEMPERATURES LIKELY THROUGH
MONDAY...THEN MODERATING TOWARDS NORMAL BY MID WEEK. OVERNIGHT
LOWS SATURDAY AND POSSIBLY SUNDAY NIGHT WILL BE COLD WITH
MOUNTAINS TEMPERATURES DROPPING INTO THE 30S...40S IN THE EAST.
FROST IS POSSIBLE ACROSS THE WEST IF WINDS COULD DECOUPLE EARLY
SUNDAY MORNING. GROUND TEMPERATURES WILL REMAIN WARM ENOUGH TO
LIMIT ANY FROST TO ISOLATED AREAS.

THE EASTERN HALF OF THE USA WILL REMAIN UNDER A BROAD BUT FLAT
TROUGH THROUGH TUESDAY. THERE COULD BE A MID LEVEL DISTURBANCE
MOVING ACROSS THE OHIO VALLEY MONDAY...BUT WITH LIMITED
MOISTURE...JUST SEEING AN INCREASE IN CLOUD COVER FOR THE AREA.
TUESDAY MAYBE THE NEXT CHANCE FOR RAIN...AS A FRONT IS SCHEDULED
TO MOVE OVER THE REGION.

&&

.AVIATION /13Z THURSDAY THROUGH MONDAY/...
AS OF 730 AM EDT THURSDAY...

LOW CIGS/VSBYS WILL HINDER TERMINALS EARLY BUT EXPECT TO SEE VFR
AT ALL SITES IN THE 13-15Z TIME FRAME.

WEAK HIGH PRESSURE IN PLACE WILL BRING VFR INTO THIS EVENING...BUT
EAST FLOW WILL ALSO BRING A THREAT OF LOWER CIGS AROUND
DAN/LYH/BCB/ROA OVERNIGHT WITH PATCHY FOG. FRONTAL BOUNDARY WILL
BE STAYING WEST OF US THIS PERIOD BUT EXPECT SOME INCREASING
CLOUDS LATE IN THE WEST OF THE VFR VARIETY.

WIND FIELDS REMAIN LIGHT THROUGH THE PERIOD.

EXTENDED AVIATION DISCUSSION...

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 INTO MONDAY. A FRONT
CLOSES IN MONDAY AFTERNOON WITH SOUTHWEST WINDS INCREASING. LOOKS
LIKE SHOWERS MAY IMPACT THE MOUNTAINS BY MONDAY EVENING...WITH
POSSIBLE SUB VFR.

&&

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

&&

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



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