Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 291508 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 1108 AM EDT FRI APR 29 2016 .SYNOPSIS...
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A WEAK LOW PRESSURE AREA WILL RESIDE OVER THE MOUNTAINS THIS AFTERNOON WITH HIGH PRESSURE WEDGING SOUTHWEST FROM THE MID ATLANTIC INTO THE PIEDMONT OF VIRGINIA. A FRONTAL BOUNDARY WILL SAY STRETCHED FROM THE RED RIVER VALLEY OF TEXAS/OKLAHOMA EAST TO SOUTHERN NORTH CAROLINA DURING THIS TIME. SATURDAY AND SUNDAY A LARGE LOW PRESSURE SYSTEM WILL TRACK OUT OF THE CENTRAL PLAINS...AND WILL REACH THE MID ATLANTIC REGION BY MONDAY MORNING. WIDESPREAD SHOWERS AND THUNDERSTORMS ARE EXPECTED THROUGH THE WEEKEND.
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&& .NEAR TERM /THROUGH TONIGHT/...
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AS OF 1100 AM EDT FRIDAY... OUR FORECAST AREA WILL BE IMPACTED BY A WEAK LOW PRESSURE TROUGH OVER THE MOUNTAINS THIS AFTERNOON...BUT MOISTURE IN THE LOW LEVELS IS SHALLOW ENOUGH WITH ANY LACK OF UPPER SUPPORT TO KEEP US DRY. THE HIGH PRESSURE WILL BE WEAKENING IN THE EAST WITH ITS WEDGE ERODING TO AT LEAST THE LYNCHBURG AREA. WILL STILL MAINTAIN SOME CLOUDINESS ACROSS OUR VIRGINIA PIEDMONT THIS AFTERNOON...BUT STILL SHOULD BE SOME SEMBLANCE OF SUNSHINE POKING THROUGH FROM TIME TO TIME. FORECAST HIGHS STILL LOOK GOOD FROM PREVIOUS FORECAST...RUNNING FROM THE MID TO UPPER 70S WEST OF THE BLUE RIDGE...TO UPPER 70S TO LOWER 80S EAST...EXCEPT MID 60S TO LOWER 70S FROM AMHERST TO LYNCHBURG EAST AND NORTHEAST TO BUCKINGHAM. WITH A DRIER LOOK IN THE NEAR TERM...DECIDED TO TAKE OUT ISOLATED SHOWERS OVER OUR NORTHEAST FORECAST AREA. PREVIOUS VALID DISCUSSION... THE LOW WEAKENS TONIGHT AND DEEPER EASTERLY WINDS RETURN TO THE LEE OF THE APPALACHIANS...BRINGING LOW LEVEL MOISTURE BACK INTO THE AREA. HAVE LEFT A LOW PROBABILITY OF PRECIPITATION IN THE EASTERN UPSLOPE AREAS FOR LIGHT RAIN TONIGHT. IN ADDITION TO THE LOW CLOUDS FILLING BACK IN OVER EASTERN COUNTIES...MID AND HIGH CLOUDS WILL BE SPREADING INTO THE REGION FROM THE WEST OVERNIGHT. THE CLOUD COVER WILL HOLD LOW TEMPERATURES MAINLY IN THE 50S.
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&& .SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/... AS OF 400 AM EDT FRIDAY... THE UPPER PATTERN WILL BE TRANSITIONING DURING THE PERIOD TO A WESTERN RIDGE/EASTERN TROF REGIME. THIS WILL BRING GOOD MOISTURE TRANSPORT UP AND OVER A WEDGE OF HIGH PRESSURE AT THE SURFACE AS LOW PRESSURE MOVES OUT OF THE MISSISSIPPI VALLEY AND SLIDES INTO THE MID ATLANTIC REGION. THIS WILL BRING PERIODS OF SHOWERS AND THUNDERSTORMS TO THE REGION FROM LATE SATURDAY THROUGH SUNDAY NIGHT. AS THE LOW MOVED BY TO OUR NORTH THERE ARE INDICATIONS THAT BY SUNDAY AFTERNOON THE WEDGE WILL BE LOSING ITS GRIP ON THE AREA AND WE WILL ENTER THE UNSTABLE WARM SECTOR AHEAD OF THE COLD FRONT TRAILING THE LOW. DYNAMIC SUPPORT MAY BE ADEQUATE TO CREATE SOME ORGANIZED CONVECTION SO THIS WILL BE WATCHED CLOSELY... ALONG WITH THE POTENTIAL FOR HYDRO ISSUES AS PWATS WILL BE RUNNING WELL OVER ONE INCH AND LOCALLY HEAVY RAIN WILL BE ADDED TO OUR RECENT WET SPELL. THE FRONT WILL BE THROUGH THE REGION ON MONDAY WITH GENERALLY IMPROVING CONDITIONS EAST OF THE BLUE RIDGE BUT SOME LINGERING MOISTURE IN NWLY UPSLOPE FLOW WILL KEEP A SLIGHT CHANCE OF SHOWERS TO THE WEST. TEMPERATURES LOOK TO GENERALLY REMAIN ABOVE NORMAL THROUGH THE PERIOD WITH THE EXCEPTION OF SATURDAY WHEN WEDGE EFFECTS WILL LIKELY KEEP TEMPERATURES ON THE COOL SIDE. && .LONG TERM /TUESDAY THROUGH THURSDAY/... AS OF 324 PM EDT THURSDAY... A WAVY FRONTAL BOUNDARY WILL STALL TO OUR SOUTH ON TUESDAY INTO TUESDAY NIGHT. HIGH TEMPERATURES WILL VARY FROM THE UPPER 50S IN THE MOUNTAINS TO THE LOWER 70S IN THE PIEDMONT. LEANED TOWARDS GFS WITH HIGH PRESSURE BUILDING IN FROM THE NORTH TUESDAY NIGHT...AND DRIER AIR OVER THE WET ECMWF. LOW TEMPERATURES TUESDAY NIGHT WILL DROP INTO THE MID 40S IN THE WEST TO THE LOWER 50S IN THE EAST. HARD TO JUDGE HOW FAR NORTH MOISTURE ADVECTED WITH A DISTURBANCE THAT MOVES ACROSS THE SOUTHEASTERN STATES MIDWEEK INTO THURSDAY. FOLLOWED THE SUPERBLEND WITH COOLING TREND AND ISOLATED TO SCATTERED SHOWERS WEDNESDAY INTO THURSDAY. && .AVIATION /15Z FRIDAY THROUGH TUESDAY/... AS OF 725 AM EDT FRIDAY... EXPECT IFR CLOUDS TO ERODE FROM SOUTHWEST TO NORTHEAST IN THE MORNING...HOWEVER...KLYH MAY NOT IMPROVE TO VFR UNTIL AROUND 18Z/2PM...IF AT ALL. MEDIUM CONFIDENCE ON IMPROVING TO VFR AT KLYH. MID AND HIGH LEVEL CLOUDS SPREAD ACROSS THE AREA TONIGHT FROM THE WEST. SURFACE A A LOW LEVEL WINDS COME BACK AROUND TO THE EAST AND NORTHEAST LATE TONIGHT...BRINGING IFR CLOUDS AND MVFR FOG BACK INTO THE FOOTHILLS AND PIEDMONT. MEDIUM CONFIDENCE ON THE TIMING OF THE RETURN OF THE CONDITIONS. NCAR ENSEMBLE FORECAST SHOWED IFR CEILINGS RETURNING TO KDAN AND KROA AFTER 07Z/1AM. EXTENDED AVIATION DISCUSSION... WIDESPREAD SHOWERS WITH MVFR INCLUDING LOCALLY IFR CONDITIONS RETURN BY SATURDAY AFTERNOON AND PERSIST INTO SUNDAY NIGHT AS LOW PRESSURE TRACKS UP THE RESIDUAL STALLED FRONT RESULTING IN WIDESPREAD RAINFALL...AND SUB VFR CONDITIONS. A WEAK COLD FRONT SHOULD CROSS THE REGION MONDAY BRINGING IMPROVING FLYING CONDITIONS BY AFTERNOON AND VFR CONDITIONS MONDAY NIGHT INTO TUESDAY. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...AMS/WP NEAR TERM...AMS/WP SHORT TERM...MBS LONG TERM...KK AVIATION...AMS/JH

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