Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 151800 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 200 PM EDT TUE APR 15 2014 .SYNOPSIS... FRONT NOW LOCATED JUST EAST OF THE BLUE RIDGE WILL SLIDE OUT OF THE AREA BY LATE AFTERNOON. COLDER AIR BUILDS IN BEHIND THE FRONT. HIGH PRESSURE WILL BUILD ACROSS THE AREA WEDNESDAY AND REMAIN IN CONTROL OF THE AREAS WEATHER THROUGH FRIDAY WITH MODERATING TEMPERATURES. A WEAK DISTURBANCE MOVING TOWARD THE REGION FROM THE NORTHWEST MAY BRING THE NEXT CHANCE OF SHOWERS TO THE REGION FOR THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1145 AM EDT TUESDAY... NARROW BAND OF MODERATE TO HEAVY SHOWERS FORMING ALONG THE FRONT STRETCHED FROM AMHERST AND ROCKBRIDGE SOUTH TOWARD THE NC/VA LINE JUST ALONG AND EAST OF THE BLUE RIDGE. THE LATEST RAP/RUC SHOWS THIS AREA SHIFT EAST THRU THE AFTERNOON. INSTABILITY REMAINS LIMITED BUT ENOUGH TO ADD TO ISOLATED THUNDER EAST OF A LYH/DAN LINE EARLY THIS AFTERNOON. FRONT SHOULD CLEAR THE EASTERN CWA BY 19-20Z. COLDER AIR WORKING IN BEHIND IT TO BRING SNOW SHOWERS TO THE HIGHER ELEVATIONS THIS AFTERNOON. BROAD AREA OF PRECIP FROM ERN TN INTO WRN WV SHOULD START TO EDGE INTO THE MOUNTAINS OF WRN NC/SW VA/NW NC...BUT MODELS WEAKEN IT THRU THIS TIME WHERE AMOUNTS OF ANY SNOW WILL BE LIGHT AROUND 1-2 INCHES AT MOST BY THIS EVENING OVER THE HIGHEST RIDGES...DUE TO WARM GROUND. TEMPS SHOULD BE IN THE 30S ACROSS THE WEST BY DUSK AND INTO THE 40S AROUND ROANOKE/FOOTHILLS AND LOWER 50S EAST. STILL LOOKS LIKE CLEARING TO THE EAST OF THE MOUNTAINS WILL BE AFTER 5 PM...AND THAT SHOULD BE THE TIME THE HIGHER WIND GUSTS START TO ROLL IN. PREVIOUS VALID DISCUSSION... VERY TIGHT PRESSURE GRADIENT WILL DEVELOP QUICKLY ALONG WITH STRONG CAA. STRONGEST WINDS WILL BE ALONG THE BLUE RIDGE AS TYPICAL FOR THIS TYPE OF PATTERN. HOWEVER...WINDS DO NOT MEET HIGH WIND WARNING CRITERIA...SO HAVE ISSUED A WIND ADVISORY FROM WATAUGA NORTHEASTWARD TO ROANOKE FROM 2 PM TO MIDNIGHT. THE TIME FRAME OF THE VERY STRONG WINDS WILL BE A NARROW WINDOW...AND MOSTLY FOCUSED WITHIN A FEW HOURS OF FRONTAL PASSAGE. STRONG CAA WILL QUICKLY NET WINTERLIKE TEMPERATURES JUST A FEW HOURS AFTER FRONTAL PASSAGE. LOW-LEVEL THICKNESS VALUES QUICKLY DROP TO CRITICAL SNOW LEVELS WITHIN A FEW HOURS ACROSS THE MOUNTAINS AS 850MB TEMPS PLUNGE TOWARD -12C IN EASTERN WV BY 06Z WED. HAVE CONTINUED MENTION OF -SHSN THROUGH THE MOUNTAINS OF EASTERN WV...SOUTHWEST VA...NORTHWEST NC AS TEMPERATURES DROP. ACCUMULATIONS UP TO AN INCH APPEAR POSSIBLE...MAINLY AFTER 00Z WHEN SFC TEMPS FALL BELOW FREEZING IN THOSE AREAS. WILL START THE EVENING OFF WITH NORTHWEST WINDS HOLDING STRONG ACROSS THE MOUNTAINS...WITH 45 TO 55 MPH GUSTS AT SPOTS ALONG THE BLUE RIDGE SOUTH OF ROANOKE. TEMPERATURES BY SUNSET WILL BE COLD ENOUGH THAT RAIN SHOWERS WILL HAVE ALREADY CHANGED TO SNOW ALONG OUR WESTERN RIDGELINES...WITH AN ADDITIONAL HALF INCH OF SNOW POSSIBLE THROUGH MIDNIGHT ACROSS WESTERN GREENBRIER COUNTY. WIND SPEEDS AND SNOW SHOWERS WILL GRADUALLY DIMINISH THROUGH THE NIGHT AS COLD HIGH PRESSURE MOVES UP THE OHIO RIVER VALLEY. ALL MODELS ARE IN GOOD AGREEMENT THAT TEMPERATURES WILL FALL BELOW FREEZING AREAWIDE BY SUNRISE WEDNESDAY...WITH WIND SPEEDS DIMINISHING ENOUGH ACROSS THE PIEDMONT FOR A FEW PATCHES OF FROST TO POSSIBLY DEVELOP. A FREEZE WARNING WILL BE IN EFFECT FOR COUNTIES EAST OF THE BLUE RIDGE FOR TUESDAY NIGHT...MEANING THAT ANY VEGETATION SENSITIVE TO FREEZING TEMPERATURES MAY BE KILLED IF NOT PROTECTED. ALTHOUGH WE DO NOT BEGIN ISSUING FREEZE WARNINGS FOR THE MOUNTAINS UNTIL BEGINNING APRIL 30TH...WE SHOULD BE MINDFUL THAT THE RECENT WARM WEATHER MAY HAVE CAUSED SENSITIVE VEGETATION TO BEGIN GROWING THERE AS WELL...WHICH WOULD ALSO BE AFFECTED BY THE COLD. && .SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/... AS OF 400 AM EDT TUESDAY... AT ANY RATE...HIGH PRESSURE WILL BUILD SOUTHWARD TO HUG THE EASTERN FACE OF THE APPALACHIANS ON WEDNESDAY...ALLOWING WINDS TO SHIFT INCREASINGLY NORTHEASTERLY. CAN EXPECT ANOTHER ROUND OF FREEZING OVERNIGHT LOWS FOR WEDNESDAY NIGHT AREAWIDE...THIS TIME WITH A MUCH BETTER CHANCE FOR AREAS OF FROST TO DEVELOP DUE TO THE LIGHT WIND SPEEDS AND CLEAR SKIES. AS SUCH...EXPECT WE WILL NEED ANOTHER FREEZE WARNING FOR WEDNESDAY NIGHT EAST OF THE BLUE RIDGE. LOOK FOR A SLIGHT WARMING TREND AS WE HEAD INTO THE FINAL DAYS OF THE WORKWEEK AS WINDS ALOFT SHIFT SOUTHWESTERLY AHEAD OF ANOTHER APPROACHING TROUGH. AT THE SURFACE...BELIEVE MODELS ARE TRYING TO ERODE THE COLD HIGH PRESSURE WEDGED AGAINST THE APPALACHIANS TOO QUICKLY...AND THEREFORE HAVE UNDERCUT MODEL GUIDANCE BY A FEW DEGREES FOR THURSDAY AND FRIDAY TEMPERATURES. THAT STATED...BELIEVE THURSDAY NIGHT LOWS WILL BE A FEW DEGREES WARMER...WITH THE POTENTIAL FOR FREEZING TEMPERATURES LIMITED TO THE SHENANDOAH VALLEY AND THE MOUNTAINS. THE HIGH PRESSURE WEDGE WILL FINALLY BEGIN TO BREAK FRIDAY EVENING AS ANOTHER LOW PRESSURE SYSTEM MOVES ACROSS THE GREAT LAKES... DRAGGING A COLD FRONT TOWARD OUR AREA. EXPECT A FEW SHOWERS ACROSS THE MOUNTAINS AS THE FRONT PASSES...BUT WITH NO RETURN FLOW OF MOISTURE FROM THE GULF OR ATLANTIC AHEAD OF THE BOUNDARY... PRECIPITATION IS EXPECTED TO BE LIGHT. && .LONG TERM /SATURDAY THROUGH MONDAY/... AS OF 355 PM EDT MONDAY... WEAK TROUGH THROUGH THE MIDWEST EVENTUALLY PUSHES EAST...AND WEDGING HIGH PRESSURE EVENTUALLY DEPARTS THIS WEEKEND. WITH A RATHER DRY ANTECEDENT AIRMASS...QUESTIONABLE IF THIS MIDWEST TROUGH PRODUCES ANY PRECIP ONCE IT ARRIVES ACROSS THE OHIO VALLEY AND MIDDLE ATLANTIC THIS WEEKEND. OP GFS IS FAR MORE WET THAN THE ECMWF. THUS...POPS WERE KEPT RATHER LOW. A ZONAL UPPER FLOW TAKES SHAPE BY LATE WEEKEND INTO EARLY NEXT WEEK...WITH UNEVENTFUL AND DRY WEATHER CONTINUING ACROSS THE REGION. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/...
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AS OF 145 PM EDT TUESDAY... DEALING WITH RAIN SHOWERS AND VARIABLE CIGS/VSBYS. COLDER AIR WILL TRANSITION RAIN TO SNOW IN THE BLF/LWB SOON. SHOULD SEE CIGS LIFT TO MVFR/VFR THROUGH THE AFTERNOON WITH DOWNSLOPE WINDS CLEARING THINGS OUT THIS EVENING EAST OF THE MTNS. WINDS WILL BE GUSTY IN THE 19-04Z TIME FRAME LEADING TO SVR TURBULENCE PER MOUNTAIN WAVE ACTION. ANY CIGS WILL BE GONE AT BLF/LWB AROUND 06Z TONIGHT. HIGH PRESSURE ENTERS THE AREA WEDNESDAY WITH VFR THROUGH FRIDAY. THE NEXT COLD FRONT APPROACHES FROM THE WEST FRIDAY BUT APPEARS SLOW AND WEAK ENOUGH TO MAINTAIN VFR DURING THE DAY FOR NOW. THIS SYSTEM MAY BRING MVFR CIGS TO THE MOUNTAINS SATURDAY ALONG WITH A FEW SHOWERS OTRW VFR ELSW TO START THE WEEKEND.
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&& .RNK WATCHES/WARNINGS/ADVISORIES... VA...FREEZE WARNING FROM 3 AM TO 9 AM EDT WEDNESDAY FOR VAZ022>024- 032>035-043>047-058-059. WIND ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR VAZ014>017-022. NC...FREEZE WARNING FROM 3 AM TO 9 AM EDT WEDNESDAY FOR NCZ003>006- 019-020. WIND ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR NCZ001-002-018. WV...NONE. && $$ SYNOPSIS...RAB/WP NEAR TERM...RAB/WP SHORT TERM...NF LONG TERM...KM AVIATION...JH/RAB/WP

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