Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 190714 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 314 AM EDT Wed Apr 19 2017 .SYNOPSIS...
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High pressure weakens into Wednesday night. A cold front will then approach from the west later in the week, stall and bring a chance for showers and thunderstorms Thursday into Saturday.
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&& .NEAR TERM /THROUGH TONIGHT/...
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As of 300 AM EDT Wednesday... Nose of high pressure stays wedged east of the Appalachians today, with increasing moisture/lift over the 300K Theta Surface as we head through the morning. The overall scheme favors mainly light to at times moderate rain. Will not see it raining all day but most folks will have rain at some point, with most receiving around a tenth of an inch with locally higher to one half inch possible toward the mountains of Southwest VA if thunderstorms occur. SPC has general thunder as far east as Greenbrier to Mt Rogers. Limited instability due to cloud cover will keep thunder chances isolated at best. The surface high and subsequent wedge weaken by this evening but expect cloudiness and light rain to linger in spotty fashion into this evening, then some drying to the east of the mountains after midnight, as flow starts to turn more southwest to west in the low/mid levels. Fog may become an issue late tonight if we get any clearing but overall models showing cloudiness around through the period with some breaks at times, so fog will be patchy. Highs today factored toward cooler mos in the wedge with mid to upper 50s from Greenbrier to the New River Valley east to the piedmont north of Danville/South Boston. Warmer air will stay southwest of a BKW-MKJ line with mid to upper 60s expected. Tonight the airmass remains moist so lows should stay elevated in the upper 40s to mid 50s.
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&& .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... As of 345 PM EDT Tuesday... Increasing southwest wind flow ahead of an approaching front from the Ohio Valley will bring warming temperatures and partial clearing for Thursday. Can`t rule out a stray pop-up shower or thundershower Thursday, but think day as a whole will be dry with primary focus for showers residing along the front which will be over the Ohio Valley. Better threat for showers will accompany the front as it enters the CWA late Thursday night, crossing the forecast area Friday. Forward progress of the front is expected to slow as main area of upper support passes from the Great Lakes into Ontario then exits to the northeast across New England. This will leave us in a situation where the front will either stall over or just south of the VA/NC border Friday night. With front stalled across the Mid-Atlantic, this will set the stage for a wet weekend, models indicating a strong area of low pressure developing over the central Plains and moving east along the front. && .LONG TERM /SATURDAY THROUGH TUESDAY/... As of 415 PM EDT Tuesday... An area of low pressure is forecast to move east along a stalled front which will be aligned east west from the Mid-Atlantic Coast to the central plains. The low will cross the Mid-MS valley Saturday, then directly across the Mid-Atlantic Region Sunday. Primary focus for wetting rain will be along the stalled front with increasing southwest wind flow aloft over-running the front. Dynamic lift will also increase, especially Sunday as the area of low pressure passes overhead, yielding 2 day rain amounts (Saturday-Sunday) of 1-2 inches, with isolated higher amounts possible pending thunderstorm development. High pressure will build into the area Monday into Tuesday, dry weather returning for the middle of next week. Maximum temperatures will average near to slightly below normal this weekend thanks to abundant cloud cover, and the forecast area residing on the cool side of the front. A transition to warmer than normal temperatures will return by the middle of next week after a couple of near normal days Monday and Tuesday. && .AVIATION /07Z WEDNESDAY THROUGH SUNDAY/... As of 123 AM EDT Wednesday... Expect mainly MVFR cigs this period but at times, will see VFR early before low levels moisten up more. High pressure pushing southwest to the piedmont this morning and increasing rain will continue to bring cloud bases lower, and should see some IFR to possible LIFR at times along/east of a LWB-HLX line. Rain will be mainly light keeping vsbys above 5sm, though some periods of moderate rain and patchy fog could drop it to MVFR. Question later today will be the erosion of wedge and how high cigs get. Appears models keep the damming in place at all but BLF but also insist on high end MVFR to low end VFR taking shape, then going more VFR Wednesday evening. Confidence is low in this but will trend toward VFR after 00z Thu. Extended Aviation Discussion... By Thursday, the front will return north as a warm front just as a new front approaches from the northwest. Showers and thunderstorms will be on the increase Thu-Fri as this front also drifts into the area and then stalls Friday just south of the CWA, most likely near the NC/SC border. This front will return to the north as a warm front Saturday as a much stronger weather system moves into the southeast U.S. While there may be some periods of VFR cigs Thursday as the area comes into the warm sector, expect MVFR or worse ceilings to return at times Fri- Sat, with widespread sub-VFR ceilings Sunday with widespread heavy rainfall and some storms in the KDAN area during the afternoon Sunday. Winds may be a factor late in the weekend as well. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...WP NEAR TERM...WP SHORT TERM...PM LONG TERM...PM AVIATION...AL/WP

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