Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 241147 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 747 AM EDT Sat Sep 24 2016 .SYNOPSIS... Cold front arrives from the north today, moving south into the Carolinas Sunday, before stalling. Another cold front will shift in from the west Tuesday. && .NEAR TERM /THROUGH TONIGHT/... As of 342 AM EDT Saturday... Clear skies across our area this morning with weak high pressure centered over the Alleghany Highlands. Some fog will be around in the river valleys around dawn then clear out by 9am. Looking at a cold front stretched from northern Ohio into Pennsylvania this morning to move south into the Shenandoah Valley by midday then to the NC border by dark. Mainly dry weather with this front given limited low level moisture. A few showers still possible from the mid deck accompanying the front mainly from the Alleghany Highlands to the piedmont late today. Looking at sunshine this morning giving way to cloudier skies this afternoon over the north. Still overall a warmer than normal day, with warmest temperatures in the NC piedmont and foothills, where some may approach 90. Elsewhere mainly 80s. Tonight behind the front models agree on increasing the low level moisture from the Greenbrier Valley east across the Virginia piedmont. Threat of light rain and drizzle exists along and east of the Blue Ridge north of the NC border overnight, with some light rain as far west as the Alleghanys. Fog will also be around in the higher terrain of the Blue Ridge and late in the Mountain Empire of SW Virginia into NW NC where skies should stay clear to partly cloudy, while the rest of the region stays cloudy. Lows will be affected by the cloud cover and be held up in the lower to mid 60s, with mid to upper 50s across portions of the mountains. && .SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/... As of 330 AM EDT Saturday... A high amplitude upper ridge will allow a cool and moist high pressure wedge to remain in place along the east slopes of the Appalachians for Sunday and into Monday. Isentropic lift coupled with low level moisture will be sufficient to generate some precipitation, mainly of the drizzle/sprinkle variety, with the best chances along the Blue Ridge. As the upper ridge axis pushes to our east Monday, a vigorous closed low will drive an area of low pressure across southern Canada and swing the trailing cold front to our western doorstep by evening. Expect the wedge to hold tough through Monday with some erosion along the western and southern flanks, until the cold front passes through and scours it out Monday night. This scenario will yield increasing precipitation chances with the focus shifting westward with time. Some late day thunder is also possible well west of the Blue Ridge as unstable air encroaches on the eroding flanks of the wedge. The best chance of showers will be Monday night with the frontal passage, with some precipitation lingering into Tuesday in the east as the low level flow is slow to come around to the northwest to usher the front along. Temperatures in the wedge on Sunday and Monday will be running a few degrees below normal generally in the 70 to 75 degree range, with some warmer readings on the fringes of the wedge far west and south. Out of the wedge and behind the front on Tuesday, temperatures will be in the mid/upper 70s east to upper 60s/lower 70s west. && .LONG TERM /WEDNESDAY THROUGH FRIDAY/... As of 330 AM EDT Saturday... Conditions will be improving by Wednesday as the upper trof axis swings through the region and the surface front continue to push away from the area. Used a Superblend/ensemble solution for timing of features. High pressure will then bring us fair and seasonable weather as it builds over the eastern part of the country for the end of the week. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
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As of 740 AM EDT Saturday... Any fog will be gone by 13z with VFR expected through this evening. Backdoor front will bring some scattered to broken altocu today. As we head into the evening and flow turns more northeast behind the front lower cigs will become more common along and east of the Blue Ridge. Will see patchy drizzle and fog at ROA and LYH and possibly DAN/BCB after midnight. Cigs will drop to IFR or lower across most of the area, with MVFR at BLF. Extended aviation discussion... Sub VFR expected into Sunday, and possibly Monday with wedge in place. Fog and drizzle or light rain will be possible Sunday along/east of the Blue Ridge with showers scattered into Monday ahead of a west to east moving front. A strong, but slow moving, cold front will be approaching the area from the west on early Tuesday. Models have significant differences on the timing and location of this front, but rain chances during the first half of next week will be on the increase. Until the front pushes across, Tuesday, we should stay in a period of sub-VFR at times, especially northeast of a line from LWB-BCB-DAN.
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&& .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...WP NEAR TERM...WP SHORT TERM...MBS LONG TERM...KK/MBS AVIATION...RAB/RCS/WP is the U.S. government's official web portal to all federal, state and local government web resources and services.