Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 030536 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 1236 AM EST Sat Dec 3 2016 .SYNOPSIS... High pressure will continue to build in from the southwest through Saturday with seasonably cool temperatures. Weather pattern then turns more active Sunday as a weak disturbance moves northeastward from the Gulf Coast. A wetter storm system then moves in for Monday night and Tuesday. A strong cold front trailing the second system will usher in below normal temperatures through mid late next week. && .NEAR TERM /THROUGH TODAY/... As of 336 PM EST Friday...A relatively cool afternoon with a variable degree of cloud cover across the area. Conditions range from clear skies across the southside of Virginia and the NC piedmont/northwest NC mountains to persistent overcast stratocumulus across the Alleghany Highlands, southeastern West Virginia into northern Tazewell County VA. On the large scale, we remain in confluent mid- level flow between an upper trough extending from Quebec into IL/IN and building heights across the Deep South...with northwesterly gradient flow across a large part of the central Appalachians. For tonight...925-700 mb cold advection in the northwesterly flow stands to continue through tonight as the mid-level trough brushes our southern Shenandoah Valley, with 850 mb temps falling to values running from -2 to -6C by 12z Saturday. BUFKIT RH cross sections from the 12z NAM and GFS suggest that the stratocu will remain difficult to scour out in this regime, and probably will build southward as the evening progresses. While northwesterly winds should begin to diminish especially after midnight tonight, the overall message is for a dry but rather chilly evening. Lows ranging from the mid/upper 20s west of the Blue Ridge and around or a few degrees above freezing east. With the northwest wind around for at least the first part of the evening, definitely want to bring a coat for any plans outdoors. For Saturday...Ridging continues to build both surface and aloft into the area which should again maintain a dry forecast. Lingering morning stratocu in western areas should erode through mid-morning Saturday, giving way to increasing high clouds as mid to high- level moisture advects in from the southwest. 850 mb temps are generally a couple degrees either side of 0C. Highs upper 30s to near 40 into western Virginia and southeast West Virginia, the mid 40s for the NRV/Grayson Highlands and northwest North Carolina mountains, and the upper 40s to low 50s from the Roanoke Valley, southside Virginia and the Virginia/North Carolina piedmont. && .SHORT TERM /TONIGHT THROUGH MONDAY/... As of 336 PM EST Friday...A chilly high pressure system will become centered over the Mid Atlantic region Saturday night and Sunday. Meanwhile, a closed low over Mexico will send Gulf moisture towards the area. This Gulf moisture will begin to overrun the surface high sometime Saturday night. The air column will slowly saturated, but precipitation is not expected into SW VA until after midnight. If clouds invade the region by Saturday evening, temperatures will remain warm to keep precipitation type as mostly rain. However, the environment will be dry and the initial precipitation could fall as snow or sleet. Any frozen precipitation falling will be brief, maybe 5-10 minutes, with no accumulations. Light rain will spread north through the day Sunday while any measurable rainfall will primarily be along and south of the VA/NC border. Isentropic lift and warm air advection continue Sunday night to keep rain chances across the south while fog and drizzle will be more common to the north. Rain chances continue to decrease on Monday as a surface reflection across the Carolinas develops. Even though the chance for measurable rain will be low, thick low clouds and gray conditions will prevail through the day Monday. Temperatures will be the coldest for the period Saturday night then gradually warm through Monday. Sunday will be chilly with afternoon temperatures in the 40s. Temperatures Sunday night will not fall much but could make a rebound Monday into the low to mid 50s. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... As of 336 PM EST Friday...A closed low will move out of Mexico and into the Midwest Monday night. A surface wave will accompany this low and track from the Tennessee Valley to the Ohio Valley Monday night into Tuesday. Another surface reflection will track from the Carolinas to off the Virginia outer banks. In between these two systems will be a cool wedge and a very good chance for rain. All these systems track north Tuesday as a cold front slides across the region. Behind this front will be windy and very cold conditions. High temperatures going into next weekend will be in the 20s across the mountains and 30s east of the Blue Ridge. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... As of 1230 AM EST Saturday... Generally VFR for most of the TAFs except with MVFR stratocu ceilings at BLF/LWB/BCB. Should see some scattering out in BCB by 12z with BLF/LWB having broken cigs through midday but lifting to VFR then scattering out by late afternoon. Will see mid and high clouds arrive Saturday evening. Winds will stay up overnight but slacken through the day as high pressure builds overhead. Extended aviation discussion... VFR conditions to prevail through Saturday night, though will start to see moisture stream northeast from a low pressure system moving across the Gulf Coast states Sunday into Monday with increasing threat of mainly rain. Will likely see a period of sub- VFR cigs and possibly vsbys at most sites Monday but confidence still is low as to how far north MVFR or lower conditions will advance. A strong cold front will likely bring more in the way of widespread sub-VFR in rain and low cigs on Tuesday. Expect a bit of improvement after Tuesday as front moves offshore with another front entering from the west, with mainly VFR expected then though some MVFR cigs into BLF/LWB possible. && .CLIMATE... Record event report sent earlier today /WBCRERRNK/ for the warmest fall season on record at Roanoke and Blacksburg. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...AL NEAR TERM...AL SHORT TERM...RCS LONG TERM...RCS AVIATION...AL/WP CLIMATE...PC

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