Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 272054 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 354 PM EST FRI FEB 27 2015 .SYNOPSIS...
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COLD HIGH PRESSURE WILL BUILD OVER THE REGION TONIGHT INTO SATURDAY. OUR NEXT WEATHER SYSTEM WILL BRING A LIGHT WINTRY MIX TO THE AREA SUNDAY INTO MONDAY. TEMPERATURES WILL MODERATE THROUGH THE MIDDLE OF THE WEEK...PRIOR TO THE PASSAGE OF A STRONG COLD FRONT WEDNESDAY INTO THURSDAY.
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&& .NEAR TERM /THROUGH SATURDAY/...
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AS OF 230 PM EST FRIDAY... HIGH PRESSURE WILL BUILD FROM THE GREAT LAKES REGION TO OVER PENNSYLVANIA OVERNIGHT. AS IT DOES...A RIDGE OF HIGH PRESSURE WILL PROGRESS SOUTH ALONG THE LEE OF THE APPALACHIANS. ONCE THIS IS ESTABLISHED...LOW LEVEL FLOW WILL SWITCH FROM LIGHT NORTHWESTERLY FLOW....TO LIGHT SOUTHEASTERLY FLOW. THIS WILL HAVE THE IMPACT OF BRINGING LOW LEVEL MOISTURE BACK INTO THE REGION AND THE FORMATION OF LOW LEVEL CLOUD COVER...ESPECIALLY IN AREAS ALONG AND EAST OF THE CREST OF THE BLUE RIDGE. MOISTURE LOOKS TO BE TOO SHALLOW...AND LIFT TOO LIMITED FOR PRECIPITATION. HOWEVER...THE TREND WILL BE FOR INCREASING CLOUD COVER THROUGH THE NIGHT...ESPECIALLY AFTER MIDNIGHT. FORECAST LOW TEMPERATURES RANGE FROM THE SINGLE DIGITS OVER THE MOUNTAINS TO THE TEENS ACROSS THE PIEDMONT. THESE TEMPERATURES WILL EASILY HELP REFREEZING AND WATER THE FORMED ON SURFACES TODAY FROM SNOW MELT. THE MOST LIKELY AREAS WILL BE EAST OF THE CREST OF THE BLUE RIDGE WHERE TEMPERATURES REACHED THE UPPER 30S TO LOWER 40S. MOST AREAS ACROSS THE MOUNTAINS MAINTAIN TEMPERATURES BELOW FREEZING TODAY...BUT HAD MORE SUN THAN CLOUDS WHICH COULD HAVE PROMPTED SOME MELTING BY WARMING THE GROUND SURFACE ABOVE FREEZING. ONLY THE AREA BETWEEN ROUGHLY RICHLANDS AND WESTERN GREENBRIER COUNTY PROBABLY DID NOT EXPERIENCE ANY MELTING WITH TEMPERATURES IN THE LOW TO MID 20S AND MOSTLY CLOUDY TO CLOUDY CONDITIONS MOST OF THE DAY. THE PLAN IS TO ISSUE A WINTER WEATHER ADVISORY FOR BLACK ICE FOR OUR NORTH CAROLINA COUNTIES EAST OF THE MOUNTAINS. FOR THE VIRGINIA PIEDMONT...A SPECIAL WEATHER STATEMENT WILL BE ISSUED THAT ADDRESSES AREAS OF BLACK ICE LIKELY OVERNIGHT. FOR THE MOUNTAINS...AN SPECIAL WEATHER STATEMENT FOR ISOLATED BLACK ICE WILL BE ISSUED FOR ALL BUT THE FAR WESTERN MOUNTAIN COUNTIES. ON SATURDAY...THE CLOUD COVER THAT DEVELOPS TONIGHT IS EXPECTED TO REMAIN IN PLACE THROUGH AT LEAST THE MORNING HOURS...AND SLOWLY GIVE WAY TO INCREASING SUN DURING THE AFTERNOON. THE INFLUENCE OF THE ARCTIC HIGH WILL LIMIT TEMPERATURES FROM GETTING ABOVE FREEZING AT MOST LOCATIONS. HIGHS IN THE MID TO UPPER 20S WILL BE COMMON ACROSS THE MOUNTAINS WITH UPPER 20S TO LOWER 30S ACROSS THE PIEDMONT. THE HIGHER END OF THIS RANGE WILL BE NEAR THE VA/NC BORDER.
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&& .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
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AS OF 330 PM EST FRIDAY... BROAD SOUTHWEST LOW LEVEL WINDS BETWEEN THE OFFSHORE HIGH AND AND APPROACHING COLD FRONT ON SATURDAY NIGHT THROUGH SUNDAY NIGHT. MODELS WERE DEPICTING FLOW DIRECTLY OFF THE GULF ON SUNDAY NIGHT. ECMWF BRINGS THE FRONT THROUGH EARLY MONDAY MORNING. HIGH PRESSURE BEGINS TO BUILD IN BEHIND THE FRONT LATER MONDAY. COASTAL TROFING ON SUNDAY AND SUNDAY NIGHT WILL HELP MAINTAIN THE WEDGE UNTIL THE FRONT COMES THROUGH LATE SUNDAY NIGHT INTO MONDAY MORNING. WINDS BECOME GUSTY BEHIND THE FRONT ON MONDAY. STRONG COLD AIR ADVECTION AND DECENT PRESSURE RISES WILL RESULT IN GUSTY WINDS. AT THIS TIME DO NOT EXPECT WIND GUSTS TO EXCEED 40 KNOTS. INCREASING CLOUD COVER AND WARM AIR ADVECTION WILL LIMIT DROP IN TEMPERATURES SATURDAY NIGHT. MAV GUIDANCE SHOWED RISING TEMPERATURES AT HIGHER ELEVATIONS OVERNIGHT. CLOUD COVER AND WEDGE WILL HOLD BACK MAXIMUM TEMPERATURE ON SUNDAY. WENT COOLER THAN GUIDANCE FOR BOTH SATURDAY NIGHT AND SUNDAY. ON SUNDAY NIGHT EXPECTING ENOUGH MIXING AND CLOUDS AS WELL AS HIGHER DEW POINTS TO HAVE ONLY A SMALL DROP IN TEMPERATURES. STAYED CLOSE TO MAV GUIDANCE FOR OVERNIGHT LOWS. COLD FRONT MAY BE JUST INTO FAR WESTERN COUNTY WARNING AREA ON MONDAY MORNING. FAR WESTERN COUNTIES MAY REACH LOW TEMPERATURE FOR THE NIGHT AROUND 12Z/7AM. HIGH TEMPERATURE ON MONDAY WILL DEPEND ON HOW FAST FRONT MOVES TO THE EAST. PIEDMONT COUNTIES HAVE THE POTENTIAL TO WARM UP INTO THE 50S BEFORE THE FRONT COMES THROUGH. IN CONTRAST...VERY LITTLE RISE IS LIKELY BEHIND THE FRONT IN THE WEST. BUFKIT SOUNDINGS SHOWED THE POTENTIAL FOR FREEZING RAIN AND SLEET UNTIL SUNDAY MORNING. HOT SPRINGS FORECAST SOUNDING WAS SLIGHTLY COLDER AND INDICATED SNOW THOUGH MUCH OF SUNDAY.
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&& .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
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AS OF 315 PM EST FRIDAY... WILL START MONDAY NIGHT OFF DRY AS HIGH PRESSURE PASSES FROM THE SOUTHERN GREAT LAKES TO NEW ENGLAND...AND THEN BUILDS SOUTHWARD ACROSS THE MID ATLANTIC...HUGGING THE EASTERN FACE OF THE APPALACHAINS. CHILLY NORTHEASTERLY WINDFLOW WILL KEEP OVERNIGHT LOWS RANGING FROM THE LOW 20S ALONG THE INTERSTATE 64 CORRIDOR TO AROUND THE FREEZING MARK IN NORTHERN NORTH CAROLINA. WARM MOIST AIR WILL ENTER FROM THE WEST OVERNIGHT AS A DEEP LOW PRESSURE SYSTEM EJECTS FROM THE CENTRAL ROCKIES...AND RAPIDLY PUSHES TOWARD THE GREAT LAKES. THE WARM MOIST AIR OVERRIDING SUB FREEZING AIR AT THE SURFACE WILL MAKE AN IDEAL SETUP FOR FREEZING RAIN FOR AREAS NORTH OF HIGHWAY 460...POSSIBLY AS FAR SOUTH AS THE NORTH CAROLINA STATE LINE FOR A FEW HOURS. TEMPERATURES WILL WARM ABOVE FREEZING AREAWIDE BY LATE TUESDAY MORNING AS THE WARMER SOUTHWESTERLY FLOW ALOFT MIXES DOWN TO THE SURFACE...CAUSING ANY FREEZING TO CHANGE OVER TO LIQUID. LATEST ROUND OF WEATHER FORECAST MODELS AGREE THAT THE HEAVIEST RAINFALL ASSOCIATED WITH A WARM FRONT LIFTING WEST OF THE APPALACHIANS WILL REMAIN OUTSIDE OUR AREA ON TUESDAY...ALTHOUGH SCATTERED SHOWERS WITH BRIEF PERIODS OF HEAVY RAIN WILL STILL BE POSSIBLE. TUESDAY AFTERNOON HIGHS WILL RANGE FROM THE MID 50S ACROSS THE MOUNTAIN EMPIRE...TO THE UPPER 30S NEAR INTERSTATE 64. TUESDAY NIGHT LOWS WILL FALL INTO THE UPPER 30S AND LOW 40S MOST LOCATIONS. BY WEDNESDAY MORNING...THE LOW PRESSURE SYSTEM WILL BE LOCATED OVER SOUTHERN CANADA...AND WILL DRAG A STRONG COLD FRONT TOWARD THE APPALACHIAN CHAIN. FORECAST MODELS VARY IN THE TIMING OF THE FRONT`S ARRIVAL INTO OUR AREA...WITH THE GENERAL CONSENSUS LEANING TOWARD THE FRONT REACHING OUR SOUTHEAST WEST VIRGINIA COUNTIES DURING THE EVENING. AS SUCH...EXPECT WEDNESDAY TEMPERATURES TO BE THE WARMEST WE HAVE SEEN IN WEEKS...WITH HIGHS RANGING FROM THE LOW/MID 50S FOR THE MOUNTAINS...AND THE UPPER 50S TO MID 60S FOR THE PIEDMONT. ATMOSPHERIC MOISTURE ACROSS OUR AREA AHEAD OF THE FRONT WILL BE SIGNIFICANTLY ABOVE NORMAL FOR EARLY MARCH...SO WILL BE KEEPING OUR EYE ON THE POTENTIAL FOR WIDESPREAD HEAVY RAIN FOR WEDNESDAY EVENING/WEDNESDAY NIGHT...ESPECIALLY IF THE COLD FRONT BECOMES STALLED ACROSS OUR AREA AS SOME MODELS SUGGEST. WHILE WE SHOULD SEE A SIGNIFICANT REDUCTION IN THE SNOWPACK ACROSS OUR AREA BEFORE THE HEAVY PRECIPITATION ARRIVES...EXPECT THERE WILL STILL BE AREAS OF FROZEN GROUND DUE TO THE PROLONGED COLD WEATHER OF RECENT WEEKS... WHICH WILL CAUSE MUCH OF THE RAIN TO TRANSLATE DIRECTLY INTO RUNOFF RATHER THAN SOAK INTO THE GROUND. WILL CONTINUE TO MONITOR THE EVOLUTION OF THIS SYSTEM THROUGH THE WEEKEND FOR THE POTENTIAL OF FLOODING WEDNESDAY NIGHT. THE COLD FRONT WILL REPRESENT THE LEADING EDGE OF YET ANOTHER ARCTIC AIRMASS...WHICH WILL ADVANCE FROM THE CENTRAL PLAINS UP THE OHIO RIVER VALLEY ON THURSDAY. DOWNSLOPE NORTHWESTERLY FLOW WILL LEAD TO DRYING CONDITIONS AND DIMINISHING CLOUD COVER ACROSS OUR AREA...WITH AFTERNOON HIGHS RANGING FROM THE 30S WEST TO THE 40S EAST.
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&& .AVIATION /21Z FRIDAY THROUGH WEDNESDAY/... AS OF 1230 PM EST FRIDAY... VFR CONDITIONS PREVAIL ACROSS THE VAST MAJORITY OF THE FORECAST REGION. THE EXCEPTION IS A NARROW BAND OF CLOUD COVER AND SCATTERED SHOW SHOWERS THAT EXTENDS ALONG A LINE FROM ROUGHLY KJFZ...KBLF...15NM W KLWB. AS THE AFTERNOON PROGRESSES...THIS NARROW STRIP IS EXPECTED TO SCATTER. SURFACE WINDS ACROSS THE MOUNTAINS ARE MAINLY FROM THE NW AROUND 10 KTS WITH SOME GUSTS CLOSE TO 20KTS. EAST OF THE MOUNTAINS...LIGHT AND VARIABLE WAS COMMON. OVERNIGHT...SURFACE HIGH PRESSURE WILL BUILD OVER PENNSYLVANIA...AN ASSOCIATED RIDGE AXIS WILL NOSE SOUTH ALONG THE LEE OF THE APPALACHIANS. FLOW AROUND THIS AXIS WILL TURN SOUTHEAST...AND LOW LEVEL MOISTURE WILL ADVECT INTO THE REGION AROUND DAYBREAK YIELD A IFR/MVFR CIG ACROSS MUCH OF THE AREA THAT WILL LAST THROUGH THE MORNING. FRIDAY AFTERNOON INTO SATURDAY...CIGS ARE EXPECTED TO IMPROVE TO VFR EAST OF THE BLUE RIDGE...WITH THE SUB-VFR CIGS CONTINUING AS SOUTHEAST FLOW CONTINUES ACROSS THE AREA. SUNDAY INTO MONDAY...OUR NEXT WEATHER SYSTEM WILL APPROACH AND THEN MOVE THROUGH THE AREA. CONFIDENCE IS LOW CONCERNING THE EXACT DETAILS ON TIMING AND PRECIP TYPE. HOWEVER...IT IS PROBABLE THAT THIS TIME PERIOD WILL BE ONE WITH SUB-VFR CONDITIONS FOR MANY PARTS OF THE AREA. A SHARP COLD FRONT WILL CROSS THE AREA MONDAY AFTERNOON WITH NORTHWEST WINDS INCREASING. ON THE HEELS OF THE SUNDAY/MONDAY SYSTEM WILL BE YET ANOTHER POTENTIALLY POTENT SYSTEM THAT MAY IMPACT ALL OR PARTS OF THE REGION TUESDAY INTO WEDNESDAY. && .RNK WATCHES/WARNINGS/ADVISORIES...
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VA...NONE. NC...WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO 4 PM EST SATURDAY FOR NCZ003>006-019-020. WV...NONE.
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&& $$ SYNOPSIS...DS NEAR TERM...DS SHORT TERM...AMS LONG TERM...NF AVIATION...DS

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