Area Forecast Discussion
Issued by NWS Blacksburg, VA

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273 FXUS61 KRNK 211759 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 159 PM EDT Fri Oct 21 2016 .SYNOPSIS... A strong cold front will move across the Mid-Atlantic Region today. Behind the front there will be a noticeable change with blustery northwest winds ushering in much cooler temperatures for the weekend. && .NEAR TERM /THROUGH TONIGHT/... As of 1055 AM EDT Friday... at 10AM a strong cold front extended from the Maryland panhandle into the foothills of Virginia and North Carolina. The front was moving quickly east and will east of Buckingham and Danville by 18Z/2PM. Showers will accompany the front, although not much qpf. Rainfall amounts will range from a quarter to a half an inch in the mountains, but the shower activity is expected to dry-up as the front moves east. The development of strong downward motion lee of the mountains resulting in a fraction of the qpf across the piedmont, with rain totals of a tenth of an inch or less. Main weather focus for the afternoon and evening will be the development of moderately strong northwest wind and falling temperatures. Wind gusts will range from 25 to 40 mph. Models suggest the pressure gradient may be strong enough to support some 40 to 50 mph gusts for elevations above 4000 feet by late this afternoon. Accompanying the increasing wind speeds will be falling temperatures. Cold air advection behind the front will result in a noticeable change with both temperature and dewpoints taking a tumble. By sunset, readings will be in the 40s west of the Blue Ridge and 50s across the Piedmont, a 30 degree change compared to yesterday. Dewpoints will be lower yet with readings in the 30s. Folks heading out for Friday high school football will certainly need an extra layer or two, wind chills in the 30s. Temperatures will continue to tumble through the overnight tonight with lows in the 30s across the mountains by daybreak Saturday, and 40s across the piedmont. Clouds will linger across the mountains with the potential for some sprinkles of flurries for the higher elevations, elevations above 4000 feet having the best chance for seeing snowflakes as temperatures dip to near freezing. Anyone camping in the mountains tonight will can expect wind chills by daybreak Saturday in the 20s, and wind chills as low as the teens for elevations above 4000 feet. && .SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/... As of 400 AM EDT Friday... Saturday morning, the area will still be under the influence of a sharp pressure gradient between the upper low situated over eastern Pennsylvania and an upper ridge building across the central United States. Magnitudes differ from model to model, but a consensus would be somewhere in the neighborhood of an 850mb 30 to 40 kt wind across the area in the morning, that loses little momentum throughout the day. This flow will yield upslope cloud cover across southeast West Virginia, south into the Northern Mountains of North Carolina. Rain showers, and some isolated snow showers at higher elevations, are expected during the morning across primarily southeast West Virginia. By the afternoon, coverage will have decreased and temperatures will have warm enough for an end to the localized areas of snow showers. Little or no snow accumulation is expected on the ground given how mild the area has been this past week. Any dusting of snow will be confined to elevated surfaces. Wind gusts at the surface will average 25 to 35 mph across the mountains with some isolated gusts approaching 40 mph at highest elevations. Across the Piedmont, gusts of 15 to 25 mph will be more common. Freezing temperatures will continue for a few hours after sunrise, mainly at elevations at or greater than 4000 feet MSL. High temperatures on Saturday will average the mid 40s to around 50 across the mountains, with the highest elevations around 40 degrees. Across the Piedmont, highs of the mid 50s to around 60 are expected. By Saturday night, the precipitation is expected to have ended, but a comparable 850 mb wind is anticipated. While areas east of the crest of the Blue Ridge are expected to decouple with limited gusts reaching the surface, ridge tops and channeled mountain valleys will continue to experience gusty through the night, but likely trend weaker as the night progresses. Low will range from the mid 30s to around 40 across the mountains, with the highest elevations around freezing. Across the Piedmont, expect lows in the upper 30s to lower 40s. Sunday into Monday, winds will trend weaker as the upper low slowly heads east into the Canadian Maritimes and the axis of the upper ridge makes gradual progress eastward as well. Anticipate the synoptic pattern across the area to become zonal with primarily a dry forecast. A shortwave trough moving through this pattern across the Great Lakes region will bring a relatively dry cold front through the area Monday. Isolated showers are forecast for western Greenbrier county only at this time. Temperatures will rebound by Monday to high temperatures ranging from the upper 50s to lower 60s across the mountains with upper 60s to lower 70s across the Piedmont. Low temperatures Monday night will be five to ten degrees cooler to those of Sunday night thanks to the aforementioned passage of the cold front. Across the mountains mid to upper 30s are forecast with readings around 40 to the lower 40s across the Piedmont. && .LONG TERM /TUESDAY THROUGH THURSDAY/... As of 500 AM EDT Friday... Zonal flow will across the lower 48 will promote a rather dry week with few temperature extremes. Not until late Thursday does another front organize over the midwest and begin advancing eastward. This front looks to arrive early Friday with timing not too dissimilar to tonights frontal passage and again with best dynamics and deeper moisture to our north. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
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As of 150 PM EDT Friday... Conditions were changing quickly across southwest Virgina and northwest North Carolina this afternoon. A cold front trailed from central Maryland to south central North Carolina and was moving east. Behind the front temperatures were dropping into the upper 40s to mid 50s and wind wind was gusting out of the west. Elevations above 3500 feet were already reporting gusts of 30 to 35 knots. Downslope winds will improve ceilings east of the Blue Ridge to VFR before 00Z/8PM. Models have some mid level clouds with the upper trof over central Virginia. Have some BKN ceilings, but still VFR, in at KLYH overnight. IFR to MVFR clouds will be widespread in the mountains tonight. Cold air aloft and upslope winds will produce isolated to scattered showers around KLWB and KBCB. Lower confidence that these upslope showers will make it as far east as KBCB and KROA. The lower clouds will lift and dissipate Saturday morning. Medium confidence that KLWB and KBLF will be VFR by the 18Z end of the TAF forecast period. Extended aviation discussion... Saturday night through Monday...Widespread VFR. No flight restrictions. High pressure building in over the Tennessee Valley then southeast United States will result in lighter wind speeds. Tuesday and Wednesday...Potential for river valley fog in the mountain valleys with local vsby restrictions between 08-14Z each morning, otherwise widespread VFR.
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&& .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...PM NEAR TERM...AMS/PM SHORT TERM...DS LONG TERM...DS/PC AVIATION...AMS/PM is the U.S. government's official web portal to all federal, state and local government web resources and services.