Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 291138 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 738 AM EDT MON SEP 29 2014 .SYNOPSIS... LOW PRESSURE ACROSS THE GULF COAST WILL TRACK TO OFF THE SOUTHEAST COAST BY THIS EVENING...THEN OUT TO SEA WITH WEAK HIGH PRESSURE ACROSS OUR AREA. A WEAK TROUGH MOVES ACROSS TUESDAY FOLLOWED BY HIGH PRESSURE FOR WEDNESDAY AND THURSDAY. A STRONGER COLD FRONT ARRIVES AT THE END OF THE WEEK. && .NEAR TERM /THROUGH TONIGHT/...
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AS OF 720 AM EDT MONDAY... TWO AREAS OF RAINFALL THIS MORNING...ONE FROM THE NC TRIAD...NE INTO THE PIEDMONT OF VA...AND ANOTHER FROM TRI CITIES NORTHEAST INTO SE WV. LATEST HRRR HAS DECENT HANDLE ON THIS AND WEAKENS THE WRN LINE LATER THIS MORNING...WHILE MAINTAINING AN INFLUX OF MOISTURE EAST OF THE BLUE RIDGE. STILL LOW QPF AMOUNTS THOUGH HAVE UPPED POPS GIVEN THAT SOME AREAS WILL AT LEAST SEE A FEW HUNDREDTHS TO AS MUCH AS QUARTER INCH. OTHERWISE...THINK THE FORECAST IS IN LINE BUT THINK DRYING MAY TAKE PLACE SOONER AS UPPER SHORTWAVE IS NOW OVER NE KY AND SHOULD SLIDE ACROSS THE MTNS BY 18Z TODAY...ALTHOUGH FORECAST SOUNDINGS ALLOW FOR SOME LINGERING LOW LVL MOISTURE. PREVIOUS VALID DISCUSSION... AS THE UPPER TROUGH MOVES SOUTHEAST INTO THE TN VALLEY AND CENTRAL APPALACHIANS THIS AFTERNOON...EXPECT THE MAIN NOSE OF DEEPER MOISTURE TO GET SHOVED EAST. APPEARS THE SOUTHEAST CWA WILL BE MORE IN LINE TO GET A QUARTER INCH OF RAIN OR SO COMPARED TO THE NW CWA...ONCE THIS SHORTWAVE MOVES INTO THE MTNS EARLY THIS AFTERNOON. THE 0Z NAM/CMC SHOWING DRIER AIR ERODING CLOUD COVER IN THE WEST THIS AFTERNOON BUT GIVEN WEAK LOW IN THE LOW LVLS THE MOISTURE MAY BE HARDER TO SCOUR OUT...WITH LINGERING STRATOCU HANGING IN. NONETHELESS THE MAIN SHORTWAVE EXITS THIS EVENING LEAVING BEHIND RESIDUAL CLOUD COVER WITH PATCHY LIGHT RAIN IN THE MTNS. SOME CLEAR TO TAKE PLACE OVERNIGHT LEADING TO FOG FORMATION AS NO APPRECIABLE WINDS TO KEEP THINGS MIXED. AS FOR TEMPS...TRICKY TODAY GIVEN EXTENT OF CLOUDS AND LIGHT RAIN. INSITU WEDGE WILL REMAIN IN PLACE ALTHOUGH IN A VERY WEAKENED STATE. STILL TEMPS WILL STRUGGLE TO REACH 70 ALONG THE BLUE RIDGE AND SLIGHTLY EAST. COUNTING ON SOME LIMITED INSOLATION AND A MILD START TO BOOST TEMPS INTO THE LOWER 70S IN THE PIEDMONT...WITH SOME BREAKS IN THE WEST TO ALLOW FOR LOWER 70S AS WELL ACROSS SE WV...PORTIONS OF SW VA. LOWS TONIGHT TO STAY ABOVE SEASONAL NORMS AS NO APPRECIABLE CHANGE IN AIRMASS. LOOKING AT MOST PLACES GETTING INTO THE LOWER TO MID 50S.
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&& .SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/... AS OF 310 AM EDT MONDAY... UPPER TROF CURVES OUT CLOSED LOW OVER THE GREAT LAKES TUESDAY WHICH TRACKS EASTWARD TO OFF THE ENGLAND COAST BY WEDNESDAY NIGHT. THIS NORTHERN STREAM CLOSED LOW WILL PHASE WITH THE SOUTHERN STREAM GULF DISTURBANCE WEDNESDAY NIGHT...WELL OFF THE EAST COAST. WITH SOME DRYING OF THE COLUMN AND WARMING OF THICKNESS EXPECTED TUESDAY...THUS WENT WITH HIGH TEMPERATURES TUESDAY FROM THE LOWER 70S IN THE MOUNTAINS TO AROUND 80 DEGREES IN THE PIEDMONT. LEANED LOW TEMPERATURES TUESDAY NIGHT CLOSE TO THE ADJMETBC WITH READINGS FROM THE MID 40S IN THE NORTHWEST TO THE UPPER 50S IN THE SOUTHEAST. AS SHORTWAVE TO OUR NORTH ROTATES EAST WEDNESDAY...ALLOWED FOR SOME LIGHT POPS ACROSS THE NORTH. HIGH WEDNESDAY WILL RANGE FROM AROUND 70 DEGREES TO THE UPPER 70S. THE BULK OF THE RICHEST MOISTURE WILL REMAIN CLOSE TO THE CENTER. HOWEVER...LOW LEVEL MOISTURE MAY REMAIN ABUNDANT WITH A THETA-E RIDGE OVER THE REGION. LOW CLOUDS LIKELY TO LOCATED OVER THE AREA AND AS WINDS TURN TO THE EAST AS ANOTHER WEDGE OF HIGH PRESSURE BUILDS SOUTH...LIGHT RAIN/DRIZZLE IS POSSIBLE ALONG AND EAST OF THE BLUE RIDGE WEDNESDAY NIGHT INTO THURSDAY. PLAYED LOW TEMPERATURES WEDNESDAY NIGHT GENERALLY IN THE 50S. SURFACE HIGH PRESSURE AND EASTERLY FLOW WILL REMAIN OVER THE REGION THURSDAY INTO THURSDAY NIGHT. AN AXIS OF HIGH PRESSURE ALOFT MAY HELP SCOUR CLOUDS THURSDAY AFTERNOON AND EVENING...BEFORE THEY SPREAD BACK IN THURSDAY NIGHT. SHAPED HIGHS ON THURSDAY CLOSE TO SUPERBLEND MOS FROM AROUND 70 IN THE WEST TO THE UPPER 70S IN THE EAST. AS FRONTAL BOUNDARY APPROACHES FROM THE WEST THURSDAY NIGHT ALLOWED FOR SOME LIGHT POPS IN THE WESTERN MOUNTAINS. MAINTAINED CONTINUITY LOW TEMPERATURES THURSDAY NIGHT FROM THE MID 50S IN THE MOUNTAINS TO AROUND 60 DEGREES IN THE PIEDMONT. && .LONG TERM /FRIDAY THROUGH SUNDAY/... AS OF 310 AM EDT MONDAY... THE WEDGE WILL ERODE AND BREAK THROUGH THE DAY FRIDAY AS A COLD FRONT APPROACHES THE AREA LATE FRIDAY. PREFRONTAL SHOWERS WILL ENTER THE MOUNTAINS FRIDAY AFTERNOON THEN MOVE EAST OF THE BLUE RIDGE FRIDAY EVENING. MAJORITY OF THE RAIN /0.25/ WILL FALL OVER THE MOUNTAINS WITH LIGHTER AMOUNTS /0.10/ EAST OF THE BLUE RIDGE. WE DO EXPECTED SHOWERS TO ADVANCE EAST OF THE BLUE RIDGE AS WINDS BACK TO THE SOUTH AHEAD OF THE FRONT. INSTABILITIES ARE NOT LOOKING STRONG...THEREFORE MOSTLY SHOWERS WITH A FEW RUMBLES OF THUNDER FROM ELEVATED CONVECTION WITH THE FRONTAL PASSAGE. MODELS ARE ALSO MOVING THIS FRONT FASTER ACROSS THE REGION...CLEARING THE PIEDMONT BY EARLY SATURDAY MORNING. A STRAY MOUNTAIN SHOWERS IS POSSIBLE SATURDAY AFTERNOON AS AN UPPER LEVEL TROUGH/SHORT WAVE PIVOT ACROSS THE SOUTHERN OHIO VALLEY. WITH LITTLE TO NO GREAT LAKES TRAJECTORY...WE WILL JUST CALL SATURDAY A RAIN FREE DAY. HIGH PRESSURE BUILDS IN FROM THE SOUTHWEST SUNDAY. A WEAK PRESSURE GRADIENT WILL BRING BREEZY AND GUSTY CONDITIONS TO THE AREA OVER THE WEEKEND. TEMPERATURES WILL WARM ABOVE NORMAL ON FRIDAY...AHEAD OF THE COLD FRONT. ONCE THE FRONT PASSES EAST...SATURDAY AND SUNDAY HIGHS WILL RUN 5F-10F COOLER THAN NORMAL. && .AVIATION /12Z MONDAY THROUGH FRIDAY/...
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AS OF 728 AM EDT MONDAY... MOST IF NOT ALL TAF SITES TO SEE AT LEAST LIGHT RAIN THIS MORNING...ONGOING AT LYH/DAN/BLF/LWB AND PUSHING INTO BCB/ROA BY 14Z. OVERALL THINK BCB/ROA WILL NOT SEE VSBY ISSUES BUT EARLY ON LWB/DAN COULD SEE A PERIOD OF MVFR/IFR VSBYS. CIGS STILL STAYING VFR...AND THIS SHOULD CONTINUE THROUGH THE DAY. MAJORITY OF ANY RAINFALL SHIFTS EAST OF THE BLUE RIDGE BY 18Z ENDING AT LYH/DAN AROUND THAT TIME FRAME. THE ISSUE HEADING INTO TONIGHT IS MAINLY FOG AND HOW LOW VSBYS COULD GO. PATTERN WITH LACK OF MIXING COMBINED WITH GROUND MOISTURE SHOULD LEAD TO FAVORABLE FOG FORMATION AND THE GFSLAMP AND NAM FORECAST SOUNDINGS BOTH SHOW FOG AT ALL TAF SITES EXCEPT POSSIBLY ROANOKE...BUT NOT OUT OF THE QUESTION. WILL TAKE LYH/DAN/BLF TO IFR VSBYS BY 07-9Z TUESDAY WHILE LWB/BCB GET INTO VLIFR IN THE SAME TIME FRAME. FOG WILL BE OCCURRING INTO THE END OF THE TAF PERIOD...BEFORE DISSIPATING IN THE 12-15Z TUESDAY TIME FRAME. EXTENDED AVIATION DISCUSSION... VFR CIGS AND VSBYS CAN BE EXPECTED MOST OF TUESDAY- WEDNESDAY...THOUGH SOME LIGHT EASTERLY FLOW COULD LEAD TO SUB VFR CIGS/VSBYS ALONG/EAST OF THE BLUE RIDGE MIDWEEK. A COLD FRONT IS EXPECTED TO REACH US BY THE END OF NEXT WEEK WITH A THREAT OF SHOWERS AND POTENTIAL SUB VFR CONDITIONS.
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&& .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...WP NEAR TERM...WP SHORT TERM...KK LONG TERM...KK/RCS AVIATION...WP

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