Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 191711 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 1211 PM EST WED NOV 19 2014 .SYNOPSIS... HIGH PRESSURE WILL SLIDE SOUTH OF THE AREA THIS AFTERNOON ALLOWING FOR CONTINUED DRY WEATHER UNDER A SLIGHTLY WARMER SOUTHWEST FLOW. ANOTHER FAST MOVING MAINLY DRY COLD FRONT WILL APPROACH FROM THE NORTHWEST TONIGHT BEFORE SLIDING ACROSS THE REGION EARLY THURSDAY. COLD HIGH PRESSURE SHOULD AGAIN FOLLOW THIS FRONT FOR WEEKS END BEFORE A COMPLEX LOW PRESSURE SYSTEM BRINGS INCREASING MOISTURE AND MILDER TEMPERATURES FOR LATER IN THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 925 AM EST WEDNESDAY... AFTER A VERY COLD START...WARM ADVECTION PATTERN TO ESTABLISH THIS AFTERNOON AS THE SURFACE HIGH SHIFTS FARTHER SOUTH AND WINDS TURN MORE SW. HOWEVER GIVEN SUCH COLD AIR ALOFT TO INIT AND BEST 85H WARMING LATE...WONT BE ABLE TO REALIZE ALL THE WARMING ABOVE AT THE SURFACE...BUT AT LEAST SOME IMPROVEMENT WITH THICKNESS GIVING 30S WEST AND UPPER 30S/LOW 40S EAST. HEATING OF DRY AIR AND BETTER MIXING LATE OUT EAST COULD CAUSE READINGS TO JUMP EVEN WARMER OVER THE FAR SE...OTRW JUST SOME MINOR TWEAKS TO GOING HIGHS. SHOULD BE MAINLY SUNNY INTO EARLY AFTERNOON BEFORE COMBO OF WARM ADVECTION AND SHEARED HIGH CLOUDS TO THE WEST CAUSE SOME INCREASE IN MID/HIGH LEVEL MOISTURE LATER ON AS SEEN VIA NEW 12Z NAM RH SECTIONS. HOWEVER EXPECT EXTENSIVE DRY AIR ALOFT TO LIMIT SO ONLY INCREASING CLOUDS A BIT WEST LATE IN THE DAY. AS THE LOW MOVES THROUGH THE GREAT LAKES...IT WILL SWING A WEAK FRONT THROUGH THE REGION TONIGHT. THERE IS LITTLE MOISTURE ASSOCIATED WITH THIS FEATURE AND WINDS DO NOT COME AROUND TO A VERY FAVORABLE DIRECTION FOR UPSLOPE WEST OF THE BLUE RIDGE...BUT THERE SHOULD BE ENOUGH TO WORK WITH TO GENERATE A FEW SNOW SHOWERS TONIGHT ACROSS THE FAR WESTERN SLOPES. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 355 AM EST WEDNESDAY... MAINLY DRY COLD FRONT COMES THROUGH THURSDAY MORNING WITH A REFRESHING SHOT OF COLD AIR...BUT NOT ARCTIC LIKE MONDAY/TUESDAY. 8H FLOW IS MORE SITUATED FROM THE WEST SO NOT AS FAVORABLE FOR UPSLOPE ENHANCEMENT. STILL A SHORTWAVE IN THE 5H FLOW WILL BE LIFTING NWD THU MORNING ACROSS THE SRN/CENTRAL APPALACHIANS AND WILL HELP SQUEEZE OUT SNOW SHOWERS ACROSS THE NC MTNS NEAR THE TN BORDER AS WELL AS THE MTNS OF TAZEWELL NORTH TO GREENBRIER. STILL ONLY LOOKING AT A DUSTING. WINDS BEHIND THIS SYSTEM NOT AS STRONG EITHER AND LOOKING AT GUSTS MORE IN THE 20 TO 30 MPH RANGE. HIGHS THURSDAY WILL RANGE FROM THE LOWER 30S HIGHER ELEVATIONS...TO AROUND 40 NEW RIVER VALLEY...THE MID TO UPPER 40S FROM ROA EAST TO LYH AND AROUND 50S SOUTHSIDE VA INTO NW NC PIEDMONT. THE 8H FLOW TURNS MORE NW THU NIGHT WITH ANOTHER WEAK UPPER WAVE MOVING ACROSS. MOISTURE IS SCANT ASIDE FROM CLOUDS ON THE LOWER DECK OVER THE MTNS. MAINLY WILL SEE FLURRIES IN THE WRN GREENBRIER AREA LATE THU NIGHT AS TEMPS DROP INTO THE TEENS UNDER COLD ADVECTION IN THE MTNS WITH MID 20S EAST. 1030 HIGH MOVES FROM THE OHIO VALLEY FRIDAY MORNING INTO THE CENTRAL APPALACHIANS/VA PIEDMONT BY FRIDAY EVENING. WILL BE ANOTHER COOLER DAY WITH LIGHTER WINDS WITH HIGHS RANGING FROM THE LOWER TO MID 30S IN THE HIGHER MOUNTAINS OF SE WV...TO UPPER 30S/LOWER 40S REST OF THE MOUNTAINS OF VA/NC TO LOWER TO MID 40S EAST OF THE BLUE RIDGE. FRIDAY NIGHT...THE HIGH SLIDES EAST TO THE PIEDMONT WITH RETURN FLOW FROM THE SOUTH SETTING UP INTO THE MTNS. LOOKS LIKE A NIGHT WHERE LOW TEMPS WILL BE EARLY IN THE HIGHER ELEVATIONS WITH STEADY TEMPS LATE AS SOUTH WINDS BRING WAA LATE. LOWS FURTHER EAST WERE LOWERED GIVEN BETTER RADIATIONAL COOLING...SO LOOKING AT MIN TEMPS FROM LOWER 20S OVER THE PIEDMONT INTO THE MTN VALLEYS OF THE WEST...WITH MID TO UPPER 20S OVER THE BLUE RIDGE AND WEST INTO THE HIGHER ELEVATIONS OF THE WEST. BY SATURDAY WAA ENSUES WITH SOME HIGH LVL MOISTURE ENTERING THE CWA. WILL STILL BE ABOUT TEN DEGREES BELOW NORMAL WITH LIGHT SE TO SOUTH FLOW WITH STRONG HIGH OVER THE VA/NC PIEDMONT. HIGHS SHOULD BE IN THE UPPER 40S TO LOWER 50S MOST LOCATIONS...THOUGH SOME OF THE MTNS IN FAR SW VA ARE IN LINE FOR BETTER MIXING/WAA AND COULD GET INTO THE MID TO UPPER 50S. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 355 AM EST WEDNESDAY... MODELS IN DECENT AGREEMENT THAT BULK OF PRECIP WITH THE NEG TILT TROUGH/LOW OVER THE ARKLATEX REGION SAT NIGHT TAKES A LITTLE LONGER TO REACH OUR AREA...BUT EXPECT WIDESPREAD RAIN TO OVERSPREAD THE REGION DURING THE DAY SUNDAY. PRIOR TO THIS IN SITU WEDGE WILL KEEP DRY AIRMASS IN PLACE SUCH THAT ONLY VERY LIGHT RAIN MAY ENTER THE NC MTNS/FOOTHILLS BY LATE SAT NIGHT...AND POSSIBLY UP THE BLUE RIDGE/FOOTHILLS OF VA. ISSUE BECOMES SUNDAY MORNING ESPECIALLY OVER THE HIGHLANDS OF GREENBRIER.BATH/ALLEGHANY COUNTY INTO ROCKBRIDGE. THINK WAA AND STRONG UVM WITH HEAVIER RAIN WILL BRING MAINLY LIQUID TO MOST AREAS...BUT FORECAST SOUNDINGS SUGGEST LOW LVL TEMPS COULD BE AT OR BELOW FREEZING AT THE ONSET WHICH COULD LEAD TO A SMALL WINDOW FOR FZRA OR SLEET. SO FOR NOW BASED OFF THE 00Z GFS FORECAST WILL JUST HAVE A FEW POCKETS OF FZRA SUNDAY MORNING FROM ERN GREENBRIER EAST INTO ROCKBRIDGE COUNTY. TEMPS WILL BE IN THE LOWER 30S IN THE NRN CWA SAT NIGHT TO MID TO UPPER 30S SOUTH...BUT WILL SEE POTENTIAL RISING TEMPS LATE OVER THE SOUTHERN CWA. SUNDAY WILL STAY COOL WITH RAIN AND INSITU WEDGE ERODING IN THE AFTERNOON EAST. MAKES FOR SOME TEMP FORECAST ISSUES. BASED ON ONSET OF RAIN LOWERED TEMPS IN THE EAST SOME WITH LOWER TO MID 50S LYH/DAN WITH UPPER 40S...LOWER 50S ACROSS THE NEW RIVER VALLEY INTO ROANOKE AND SOUTHEAST WV. STRONG LLJ LOOKS TO BRING WAA INTO THE FOOTHILLS AND MTNS OF NC WHERE TEMPS MAY REACH NEAR 60S IF THE RAIN MOVES OUT FASTER. THE MODELS SUGGEST A DRY SLOT WORKING INTO THE MTNS BY SUNDAY EVENING AND SHIFTING EAST OVERNIGHT. LOWERED POPS INTO SLIGHT CHANCE RANGE IN THE WEST BUT KEPT CHANCE IN THE EAST THROUGH THE NIGHT AHEAD OF THE FRONT WITH BETTER LIFT AND 50+ KNOT LOW LVL JET. MAIN FRONT TO ARRIVE MONDAY SO KEPT POPS IN THE CHANCE RANGE HERE...BUT COULD SEE IT BEING RAISED IF MODELS STAY THE COURSE. SVR POTENTIAL SUN/MONDAY WILL HAVE TO BE WATCHED GIVE SUCH A DYNAMIC SYSTEM AND WEDGE ACTING TO INCREASE LOW LEVEL TURNING ACROSS THE PIEDMONT/FOOTHILLS OF NC/SOUTHSIDE VA...HOWEVER CAPE LOOKS LIMITED...BUT DOES NOT TAKE MUCH TO GET A SPINUP. THIS WILL BEAR WATCHING. FRONT WILL SLOW DOWN/HANG UP AS UPPER FLOW STARTS TO PARALLEL IT...SO FORECAST FOR MON NIGHT INTO TUESDAY WILL KEEP CHANCE POPS IN...THOUGH BOTH 00Z GFS/EC DRY THINGS OUT BUT DIFFER ON STRENGTH OF TROUGH AND COLDER AIR MOVING IN BEHIND IT. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
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AS OF 1145 AM EST WEDNESDAY... EXPECT VFR CONDITIONS INTO THIS EVENING AS HIGH PRESSURE SHIFTS TO THE SOUTHEAST WHILE A DEVELOPING LOW PRESSURE SYSTEM APPROACHES THE GREAT LAKES FROM THE NORTHERN PLAINS. THE TRANSIT OF THESE SYSTEMS WILL CAUSE AN INCREASING SOUTHWEST TRAJECTORY THIS AFTERNOON WITH GUSTS INTO THE 15 KT TO 20 KT RANGE POSSIBLE AS THE PRESSURE GRADIENT BETWEEN THE TWO SYSTEMS TIGHTENS. MID AND HIGH CLOUDS WILL ALSO INCREASE ACROSS MUCH OF THE REGION THIS AFTERNOON AND EVENING. A COLD FRONT WILL TRACK INTO WESTERN AREAS AROUND DAYBREAK THURSDAY. MOISTURE AHEAD OF THE FRONT WILL BRING BKN/OVC VFR CIGS AT KBLF/KLWB AFTER MIDNIGHT...WITH BASES POSSIBLY LOWERING INTO MVFR ALONG AND JUST BEHIND THE BOUNDARY EARLY THURSDAY. SOME SNOW SHOWERS ALSO POSSIBLE AT TIMES BETWEEN DAWN AND MID MORNING THURSDAY BUT NOT ENOUGH TO INCLUDE MUCH MENTION OUTSIDE OF PERHAPS KBLF IN THE TAFS FOR NOW. SOME OF THESE VFR/OCNL MVFR CIGS COULD ALSO SPILL OUT TO THE BLUE RIDGE...AFFECTING KBCB/KROA EARLY THURSDAY MORNING AS WELL WITH MAINLY CLEAR SKIES TO THE EAST. OTRW MAIN CONCERN WITH POTENTIAL LLWS THIS EVENING/OVERNIGHT AS A STRONG JET MOVES ATOP A WEAK SURFACE INVERSION. THIS WOULD AFFECT ALL TAF LOCATIONS EXCLUDING KDAN AT THIS POINT AND WHERE BETTER MIXING SUCH AS AT KBLF LOOKS TO KEEP SURFACE WINDS RATHER GUSTY ALONG THE RIDGES. THUS INCLUDING A PERIOD OF LLWS AT THE OTHER FOUR TAF SITES STARTING THIS EVENING AND CONTINUING OVERNIGHT UNTIL THE JET PASSES AND MORE CLOUDS ARRIVE LATE. MVFR/VFR CIGS LIKELY TO LINGER THURSDAY MORNING IN THE WEST BEFORE DRYING ALLOWS ALL LOCATIONS TO RETURN TO VFR IN THE AFTERNOON. WILL AGAIN BE GUSTY BEHIND THE PASSING FRONT WITH WESTERLY WINDS LIKELY TO GUST TO 20-25 KTS FROM MID MORNING THURSDAY THROUGH MUCH OF THE AFTERNOON. EXTENDED DISCUSSION... THURSDAY NIGHT THROUGH SATURDAY WILL AGAIN BE VFR...WITH HIGH PRESSURE IN THE REGION. A MORE SIGNIFICANT SYSTEM WILL APPROACH THE AREA WITH RAIN AND SUB-VFR CONDITIONS SUNDAY INTO SUNDAY NIGHT. MAY SEE A BRIEF RETURN TO VFR DURING MONDAY OUTSIDE OF THE MOUNTAINS AS A DRY SLOT DEVELOPS BETWEEN THE EXITING FRONT FROM SUNDAY AND THE NEXT UPSTREAM COLD FRONT.
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&& .EQUIPMENT... AS OF 355 AM EST WEDNESDAY... THE VISIBILITY SENSOR AT KLYH...LYNCHBURG AIRPORT...WILL BE OUT OF SERVICE UNTIL PARTS ARRIVE TO REPLACE THE SENSOR. UNTIL THEN THE VISIBILITY WILL ONLY BE REPORTED WHEN THE CONTROL TOWER IS STAFFED. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...JH/MBS NEAR TERM...JH/MBS SHORT TERM...WP LONG TERM...WP AVIATION...JH/PC/WP EQUIPMENT...

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