Area Forecast Discussion
Issued by NWS Blacksburg, VA

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS61 KRNK 270814
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
314 AM EST THU NOV 27 2014

.SYNOPSIS...
A FAST MOVING AREA OF LOW PRESSURE WILL PASS JUST SOUTH OF THE
REGION THIS MORNING AND OFFSHORE LATER THIS AFTERNOON. COLD HIGH
PRESSURE BUILDS IN BEHIND THIS SYSTEM BRINGING COLDER AIR AND
GUSTY WINDS OVERNIGHT INTO FRIDAY. THE HIGH WILL SLIDE OFFSHORE
THIS WEEKEND RESULTING IN WARMER...AND DRIER WEATHER INTO SUNDAY
BEFORE ANOTHER COLD FRONT ARRIVES WITH THE NEXT CHANCE OF SHOWERS
BY EARLY NEXT WEEK.
&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 230 AM EST THURSDAY...

STRONG SHORTWAVE ROUNDING THE BASE OF THE 5H TROUGH WILL FINALLY SERVE
AS THE CABOOSE TO THE ONGOING WINTRY WEATHER TODAY AS IT PASSES ACROSS
THE NC RIDGES THIS MORNING AND TO THE SE OF THE REGION THIS AFTERNOON.
THIS FEATURE WILL AGAIN TEND TO ENHANCE MOISTURE CONVERGENCE OVER THE
CWA THIS MORNING...WITH THE MAIN LIFT BACK OVER THE WEST/SW PORTIONS IN
THE COLDER AIR ALOFT EARLY ON BEFORE BETTER SUPPORT SHIFTS OFF TO THE
SE WITH A WEAK INDUCED SURFACE WAVE. MODELS CONTINUE TO PAINT MOST OF
THE REGION IN A BROAD SWATH OF LIGHT PRECIP THIS MORNING BEFORE
TAPERING TO MAINLY THE EAST BY EARLY AFTERNOON BEFORE ENDING.
DEGREE OF ORGANIZATION LOOKS IFFY BUT SUSPECT WILL SEE A FEW MORE
BANDS OF SNOW WEST THIS MORNING WITH ENHANCEMENT ALONG THE WESTERN
SLOPES AS THE FLOW TURNS MORE UPSLOPISH BEHIND THE PASSING VORT
AXIS. THEREFORE WILL BE LEAVING THE GOING ADVISORY IN PLACE WITH
ANOTHER INCH OR TWO POSSIBLE MAINLY SW PORTIONS...AND ONLY SPOTTY
ADDED TOTALS HEADING OUT TOWARD THE BLUE RIDGE WHERE MAY INIT AS
RAIN BEFORE DAYBREAK. SHOULD ALSO SEE PATCHY/BANDS OF RAIN EAST
BUT PERHAPS MIXED WITH SNOW AT TIMES WHERE PRECIP COMES DOWN A BIT
HARDER. PRECIP MAY ALSO END AS A BRIEF PERIOD OF SNOW PIEDMONT
LATE MORNING AS THE COLD POCKET ALOFT PASSES. HOWEVER QPF LOOKING
RATHER LIGHT WITH A TENTH OR LESS MOST SPOTS TODAY EXCEPT UP TO A
QUARTER INCH OUT EAST AND ACROSS THE SW RIDGES. EXPECT A BREAK IN
POPS THIS AFTERNOON WITH SOME SUN POSSIBLE AS DOWNSLOPE KICKS IN
AND BEFORE BETTER UPSLOPE DEVELOPS WEST THIS EVENING. KEPT HIGH
TEMPS CLOSER TO THE COLDER MAV MOS ALTHOUGH MAY BE EVEN COLDER SE
PENDING DEGREE OF CLOUDS/PRECIP COVERAGE THIS MORNING.

COLD HIGH PRESSURE SLOWLY BUILDS IN BEHIND THE PASSING CLIPPER TYPE
WAVE TONIGHT WITH LEFTOVER MOISTURE LEADING TO ADDED UPSLOPE -SHSN
ESPCLY THROUGH MIDNIGHT. SOME ADDED ACCUMULATIONS POSSIBLE BUT
THINKING WONT NEED MORE HEADLINES WITH AN INCH OR SO ALONG THE
WESTERN SLOPES AND FLURRIES OUT TO THE BLUE RIDGE EARLY THIS
EVENING. OTRW GRADUAL CLEARING OUTSIDE THE UPSLOPE AREAS AS
MOISTURE BECOMES SHALLOW AND MIXES OUT IN BETTER DOWNSLOPING OUT
EAST. HOWEVER DECENT PRESSURE GRADIENT WITH THE OFFSHORE WAVE
DEEPENING AND STEADY 85H COLD ADVECTION...TO MAKE WINDS QUITE
GUSTY AND POSSIBLY JUST BELOW ADVISORY LEVELS ACROSS THE HIGHER
RIDGES IN NW NC. OTRW QUITE COLD AGAIN WITH LOWS IN THE MIDDLE OF
MOS GUIDANCE GIVEN MIXING OFFSET OF COLD ADVECTION...EXCEPT IN
SPOTS OVER THE WEST WHERE SOME SNOW COVER WILL RESIDE AND LIKELY
HELP PUSH LOWS INTO THE TEENS.
&&

.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM EST THURSDAY...

HIGH PRESSURE WILL BUILD ACROSS THE AREA ON FRIDAY...CAUSING
RESIDUAL UPSLOPE SNOW SHOWERS ACROSS THE WESTERN RIDGES TO COME TO
AN END BY LUNCHTIME. ALTHOUGH A COLD UPPER LEVEL TROUGH WILL HAVE
SHIFTED OVER THE ATLANTIC BY SUNRISE...HIGH CLOUDS MOVING IN DURING
THE AFTERNOON WILL LIMIT HEATING...AND EXPECT AFTERNOON HIGHS TO
RANGE FROM THE LOW/MID 30S ACROSS SOUTHEAST WEST VIRGINIA TO THE LOW
40S ACROSS THE SOUTHSIDE. HIGH PRESSURE WILL SHIFT TOWARD THE COAST
FRIDAY NIGHT...BRINGING A RETURN OF SOUTHERLY FLOW TO OUR AREA. LOWS
WILL BE ON CHILLY SIDE...GENERALLY FALLING INTO THE MID TO UPPER
20S...WITH A FEW UPPER TEENS IN THE DEEPER MOUNTAIN VALLEYS.

SOUTHWESTERLY FLOW WILL LEAD TO A WARM UP THROUGH THE WEEKEND...WITH
A WARM FRONT PASSING ACROSS OUR AREA SATURDAY NIGHT. MAY SEE A FEW
SHOWERS DEVELOP ACROSS SOUTHEAST WEST VIRGINIA AND THE MOUNTAIN
EMPIRE ON SUNDAY AS GULF MOISTURE FLOWS NORTHWARD AHEAD OF A COLD
FRONT MOVING EAST ACROSS THE PLAINS. EXPECT SATURDAY AFTERNOON HIGHS
TO BE IN THE UPPER 40S/LOW 50S...WITH SUNDAY AFTERNOON HIGHS SOME 10
DEGREES WARMER. THE COLD FRONT IS EXPECTED TO APPROACH THE
APPALACHIAN CHAIN LATE SUNDAY NIGHT...BRINGING RAIN SHOWERS TO THE
WESTERN RIDGES.
&&

.LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 330 PM EST WEDNESDAY...

MONDAY INTO MONDAY NIGHT...A BACK DOOR FRONT WILL TRY AND PUSH SOUTH
OF THE AREA. WITH A STRONG AND BROAD RIDGE ACROSS THE SOUTH...
EXPECTING LATER MODEL RUNS TO DELAY THE FRONTAL PASSAGE UNTIL
SOMETIME TUESDAY. SINCE THE ECM/GFS HAS THIS FRONT ENTERING THE AREA
MONDAY AND MONDAY NIGHT...WILL HAVE SLIGHT/CHANCE POPS FOR RAIN
SHOWERS OVER THE AREA. ALSO HAVE SLIGHT/CHANCE POPS TUESDAY FOR A
POSSIBLE FRONTAL PASSAGE OR FOR THE FRONT STALLING IN THE REGION.
EITHER WAY AND/OR EITHER DAY...TEMPERATURES AND THICKNESSES ARE WARM
TO KEEP ANY PRECIPITATION FALLING AS RAIN. SURFACE HIGH PRESSURE
WILL MOVE OVER NEW ENGLAND FOLLOWING THE FRONTAL PASSAGE AND REMAIN
IN THE AREA TROUGH THE REMAINDER OF THE WORKWEEK. EVEN THOUGH THIS
WEDGE IS STRONG (1035MB)...MODELS REMAINING WARM AND CLOSE TO
SEASONAL TEMPERATURES.
&&

.AVIATION /08Z THURSDAY THROUGH MONDAY/...
AS OF 100 AM EST THURSDAY...

SURFACE OBSERVATIONS INDICATE A LOW PRESSURE SYSTEM OVER FAR
WESTERN VIRGINIA THIS MORNING...TRAVELING EAST. THE LOW IS BRINGING
WITH IT BANDS A LIGHT SNOW THAT WILL SPREAD ACROSS THE MOUNTAINS
THROUGH THE NIGHT. CEILINGS ACROSS THE AREA ARE VARIABLE...
RANGING FROM IFR TO MOSTLY CLEAR. HOWEVER...PATCHY DENSE FOG IS
DEVELOPING WHERE CEILINGS SCATTER...MAKING MOST OF THE REGION LOW
MVFR/IFR AS A NET RESULT.

POOR FLIGHT CONDITIONS WILL PERSIST THROUGH MUCH OF THE NIGHT AS
SNOW BANDS PASS ACROSS THE MOUNTAINS...CHANGING OVER TO RAIN IN
THE WARMER AIR EAST OF THE BLUE RIDGE. ONCE THE LOW PASSES EAST
LATE THURSDAY MORNING...HIGH PRESSURE WILL BEGIN TO BUILD INTO THE
AREA...WITH WIND SPEEDS FROM THE WEST GUSTING 15KT TO 25KT...
TOPPING 30KT AT TIMES. CEILINGS WILL ALSO IMPROVE TO VFR FOR
ROA/LYH/DAN...HOWEVER THE TRANSITION TO VFR WILL BE MORE GRADUAL
FOR BLF/BCB/LWB...TAKING UNTIL LATE EVENING.

EXTENDED DISCUSSION...
HIGH PRESSURE WILL PASS ACROSS THE REGION FRIDAY...RESULTING IN
VFR CONDITIONS AREAWIDE. A COLD FRONT WILL PASS ACROSS THE REGION
ON MONDAY...BRINGING A RETURN OF SUB-VFR CONDITIONS.

&&

.HYDROLOGY...
STORM TOTAL PRECIPITATION AMOUNTS RANGED FROM ABOUT 0.50 TO 1.25
INCHES OF LIQUID EQUIVALENT WITH A FEW GAGES PICKING UP IN EXCESS
OF 1.50 INCHES MAINLY ACROSS PARTS OF THE NEW RIVER AND UPPER
ROANOKE AND DAN RIVER BASINS. THE LESSER AMOUNTS WERE GENERALLY
OBSERVED OVER THE WESTERN BASINS INCLUDING THE GREENBRIER AND
UPPER JAMES. RADAR PRECIPITATION ESTIMATES EXTREMELY CONTAMINATED
BY BRIGHT BAND EFFECTS. RUNOFF CAUSING SMALLER STREAMS TO SHOW
SOME NICE RISES BUT ALL WELL WITHIN BANKS.

&&

.EQUIPMENT...
AS OF 1030 AM EST WEDNESDAY...

VISIBILITY SENSOR AT KLYH...LYNCHBURG AIRPORT...WAS MALFUNCTIONING
AGAIN. PARTS HAVE BEEN ORDER BUT THE REPAIR MAY NOT BE UNTIL
MONDAY. THE VISIBILITY AT KLYH WILL BE AUGMENTED BY STAFF WHEN THE
CONTROL TOWER IS OPEN...OTHERWISE THE VISIBILITY WILL BE MISSING.

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR VAZ007-009-
     015.
NC...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR NCZ001-018.
WV...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR WVZ508.

&&

$$
SYNOPSIS...JH/MBS
NEAR TERM...JH
SHORT TERM...NF
LONG TERM...RCS
AVIATION...NF/PC
HYDROLOGY...PC
EQUIPMENT...AMS


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.