Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 152003 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 303 PM EST Mon Jan 15 2018 .SYNOPSIS...
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High pressure will cover the Mid Atlantic region tonight. A low pressure system will track across Wisconsin into Ontario through Tuesday, which will bring a cold front into western Virginia and North Carolina on Tuesday. Low pressure developing along the front will move offshore as high pressure builds into the region on Wednesday.
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&& .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
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As of 303 PM EST Monday... Posted a Winter Weather Advisory for 10 AM Tuesday morning until 10 AM Wednesday morning from Greenbrier county southward to Smyth county. Refer to WSW for more details. Low pressure over the Great Lakes with a trailing cold front will travel east tonight into Tuesday. Moisture will increase this evening into tonight as a cold front approaches from the west. With a positive tilted upper trof, the movement of the front will be relatively slow. Clouds will increase tonight from west to east. Some light snow or snow flurries will develop in the far west by dawn Tuesday morning. Low temperatures tonight will range from the mid teens in the coldest mountain valleys to the lower 20s in the piedmont. A cold front with areas of snow along it will move east Tuesday into Tuesday night. The heaviest snow will occur in the west during daylight hours where up to 2 to 3 inches is possible in western Tazewell and western Greenbrier counties. Many areas in the east will stay dry. High temperatures Tuesday will vary from the mid 20s in northwest Greenbrier county in southeast west Virginia to the lower 40s in the Piedmont.
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&& .SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY NIGHT/...
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As of 303 PM EST Monday... A positive tilted trough draped from the Great Lakes back into the southern plains, will slowly push a cold front over the region Tuesday night into Wednesday morning. This front will also be slowed by a series of reflections developing along the front, tracking to the northeast. The trough moves over the OH-TN Valleys Wednesday pushing the front east of the piedmont by Wednesday afternoon. Associated with this front will be snow, wind, and cold temperatures/wind chills. Initially, the best dynamics with this system are to the north over OH-PA in the evening. After midnight, dynamics intensifies over GA- SC-NC and more so in the coastal piedmont. This will further limit snowfall amounts over the area. However, the series of reflections tracking along the front will provide enough lift and even though return flow is limited, there may be enough moisture to deposit 1-4 inches of dry snow across the forecast area. Additional snowfall accumulations Tuesday night into Wednesday, to include upslope on the backside of the system, may range from 1-2 inches (storm total 3- 5 inches). Along the Blue Ridge and into the foothills, lesser amounts (up to an inch) are likely with dynamics shifting to the coastal piedmont. If the series of reflection tracks further westward, the piedmont may see 2-3 inches. Snow will end by noon Wednesday. In coordination with surrounding offices, we will have a winter weather advisory for snow Tuesday morning into Wednesday morning. However, at this time, we will only issue for our far western counties with snow starting earlier Tuesday morning/afternoon. Additional advisories are likely to be posted tonight into tomorrow for the Tuesday night Wednesday time frame. Temperatures Wednesday morning will drop down into the 10F-15F range across the mountains with wind chills in the single digits. East of the Blue Ridge will have lows in the 20s and wind chills in the teens. Temperatures will not warm much Wednesday, but the winds will increase with pressure rises behind the front. Cold temperatures and breezy/gusty conditions remain Wednesday night to send wind chill values to near zero across the mountains, single digits out east. If the forecast holds, wind chill advisories will be issued once the advisory for snow ends on Wednesday. Less wind expected Thursday as high pressure builds over the region. Afternoon high temperatures rebound into the 30s. Under good radiational cooling, temperatures will fall into the teens Thursday night to lower 20s east. If snow pack remains on the ground, temperatures will be colder, but with little wind, wind chill values will stay above zero.
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&& .LONG TERM /FRIDAY THROUGH SUNDAY/...
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As of 225 PM EST Monday... Despite a lee surface trough taking residence over the piedmont Friday and Saturday, high pressure will keep the region dry into Sunday night. Temperature will warm to normal levels on Friday then above normal for the weekend. With the above normal temperatures, the front Sunday night into Monday will be all rain with a brief period of upslope snow showers on the back side Monday night.
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&& .AVIATION /20Z MONDAY THROUGH SATURDAY/... As of 1242 PM EST Monday... SCT to BKN MVFR clouds in the west especially KBLF and KLWB will linger this afternoon into tonight. Otherwise, VFR conditions will continue at taf sites this afternoon into tonight. High pressure will slide east this afternoon into tonight. Some mid and high clouds will spread east across the region into tonight. Ceilings will lower on Tuesday across the region from west to east. Low pressure over the Great Lakes will push a cold front through the region on Tuesday. This should lead to MVFR conditions with some light snow Tuesday in the mountains. Medium confidence in Ceilings,visibilities and winds during the taf period. Extended Discussion... Some light snow is possible Tuesday afternoon through Wednesday morning especially east of the Blue Ridge. Light snow accumulations are likely at KDAN and KLYH. After frontal passage, a reinforcing blast of arctic air will move into the region. Dry air will restore sky conditions to VFR, however wind will become a factor for some aviation interests Wednesday night into Thursday morning. VFR conditions should persist into the weekend with warming temperatures. Moisture will return to west Sunday night into Monday. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...AMS/KK NEAR TERM...KK SHORT TERM...RCS LONG TERM...RCS AVIATION...AMS/KK

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