Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 111430 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 930 AM EST Mon Dec 11 2017 .SYNOPSIS... High pressure will bring a brief period of fair weather to the Appalachians and central mid Atlantic region to start the work week. However, low pressure moving through the Great Lakes region will push another surge of very cold air into the region on Tuesday with blustery conditions and snow showers in the mountains. && .NEAR TERM /THROUGH TONIGHT/...
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As of 929 AM EST Monday...No significant alterations needed to the going forecast; only minor change made was to increase warm advection cloudiness into the mid-late afternoon hours in the Greenbrier Valley and into the southern Shenandoah ahead of Alberta Clipper system. Eastern extent of these clouds extends into eastern Ohio and will continue to advance eastward as the day progresses. Did increase high temperatures by a degree or two as well. Many areas today should see sunny to mostly sunny skies, and will help to erode the light snowpack seen in visible imagery from the weekend`s snowstorm. Previous discussion issued at 245 AM follows... Not too much change from previous forecast for this period with upslope cloudiness expected to erode by dawn or shortly thereafter. Today will likely be the warmest day this week with temperatures rising into the 40s, maybe close to 50 in the southeast CWA. Clouds increase tonight ahead of shortwave/clipper front seen on water vapor this morning over the northern Plains. Most model solutions show light precip arriving by dawn in the far west along the front, with main sfc low and better lift staying north over the Ohio Valley. With clouds tonight will see low temperatures close to normal with upper 20s to lower 30s.
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&& .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... As of 255 AM EST Monday... Looking at strong cold air advection behind front Tuesday with temperatures starting out steady or slightly warming in the west in the lower to mid 30s, with mid 40s east, then temperatures should crash into the 20s by late afternoon. There will be a burst of winds behind this front with gusts to advisory levels likely in the higher terrain of the Blue Ridge and Alleghanys, but coverage at the moment is borderline in terms of issuing headlines. Since its 3rd period will let next shift re-evaluate it. Will mention in the HWO. Will see snow shower machine kick in shortly thereafter in the mountains with best upslope and upper support occurring late Tue afternoon into late Tue night. Could see 4-6 inches on the western slopes of Greenbrier by Wed morning with 1-3 inches to southern WV near Bluefield, and possibly the NC/TN border mountains into Mt Rogers, with a dusting as far east as the Alleghanys to New River Valley. As this trough deepens should another period of stronger wind Tuesday night and Wednesday. In addition, temperatures falling into the lower teens in the mountains, combined with wind speeds should send wind chills below zero in the mountains, and single digits to around zero in the foothills/piedmont Wednesday morning. Will see axis of trough accelerate east Wednesday with snow showers ending early. Still cold with highs in the 20s west to lower to mid 30s east. By Wed night, next clipper enters the TN valley with increasing clouds with maybe a few snow showers reaching the mountains by dawn. With flow turning more west and some warm advection ahead of clipper lows should will be in the mid teens to around 20 west, to lower 20s east, with potential for some rise in temperature late. && .LONG TERM /THURSDAY THROUGH SUNDAY/... As of 340 PM EST Sunday... Upper air pattern is forecast to remain amplified with a cold upper level trough over eastern North America through Friday. Embedded short waves passing through the general flow pattern will result in clouds and potential for mountain snow showers and flurries. Temperatures will favor the colder side of normal until Friday...trending back closer to normal for the weekend as the upper flow becomes more zonal. && .AVIATION /15Z MONDAY THROUGH FRIDAY/... As of 615 AM EST Monday... Lower clouds eroding west of LWB at 11z, and expect VFR conditions at all sites for the rest of the day. Some mid level warm advection and moisture will bring mid and high clouds to the Mid Atlantic region in the afternoon. Winds will also diminish during the afternoon. Late in the TAF period...ceilings will begin to lower as a stronger short wave approaches out of the Ohio Valley. Expect ceilings at KLWB and KBLF to remain VFR until after 06Z with medium confidence, with some high end MVFR reaching BLF by the end of this TAF period. Extended Discussion... The more prominent clipper moves in Tuesday with the passage of a cold front and gusty winds behind it. MVFR to IFR snow showers are expected west of the Blue Ridge Tuesday and Tuesday night. Weak high pressure builds in Wednesday followed by another weaker clipper Thursday. Overall mainly VFR during the Wed-Fri time frame. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...MBS/WP NEAR TERM...AL/WP SHORT TERM...WP LONG TERM...PM AVIATION...AMS/WP is the U.S. government's official web portal to all federal, state and local government web resources and services.