Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 201850 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 250 PM EDT Thu Oct 20 2016 .SYNOPSIS... A front extended from New England through the Ohio Valley to a low over the Southern Plains. This low will track across the Tennessee and Ohio Valleys by Friday morning and will push a strong cold front across much of the eastern United States Thursday night and Friday. High pressure build in behind the low on Sunday and Monday. && .NEAR TERM /THROUGH TONIGHT/... As of 930 AM EDT Thursday... Current forecast is in good shape. Morning satellite imagery shows some fog/stratus mainly from the NRV, across southeast WV, and into the Alleghany Highlands of VA with some scattered high clouds over the top. Expect diurnal heating to mix the fog/stratus out in short order this morning with a good amount of sun before clouds start increasing this afternoon ahead of the cold front approaching from the west. Morning RNK sounding supports current forecast of highs today in the mid 80s east to upper 70s/lower 80s west. Some showers may creep into the far western portion of the area late in the day and current slight chance POPs cover the situation well. Previous AFD... A strong upper level trough mid-conus will move east across the MS Valley today. At the surface, low pressure will move northeast through the Ohio Valley and into the eastern Great Lakes by tonight. A strong cold front will trail the surface low and will move east, crossing the Appalachian mountains tonight, then east across the foothills and piedmont Friday. An extensive area of showers with embedded thunderstorms will move east with the front, this activity overspreading our CWA from west to east beginning this evening (5-10PM time frame) west of Interstate 77, then spreading across the New River, Greenbrier, and Shenandoah Valleys between 10PM-2AM...before spilling east of the Blue Ridge late. Per late arrival of any thunderstorm activity, do not anticipate anything severe. The storm prediction center does highlight areas mainly west of our CWA for fast-moving storm cells and line segments capable of marginally severe wind or hail...this threat focused on the eastern Oh/TN Valleys. Today will be the last day of near record warmth with temperature readings 10-20 degrees above normal. The unseasonable warmth will come to an end with tonights frontal passage, temperatures taking a noticeable tumble Friday. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... As of 350 AM EDT Thursday... An upper trough will deepen and move into the East over the next couple of days. A wave of low pressure will lift northward into New England and push a strong cold front east across our region. The cold front will push off the coast by Friday evening and move further out into the Atlantic ocean on Saturday. Scattered showers and a few thunderstorms will develop ahead and along the front. The Day 2 convective outlook places general thunderstorms over eastern portions of our Forecast area. However, Surface instability looks quite limited given the morning timing of the fropa. Generally it seems like a band of showers with front. Used an non-diurnal temperature curve for Friday with falling temperatures expected west of the Ridge throughout Friday, and falling across the Piedmont by the afternoon. High temperatures Friday will range from the lower 50s in the mountains to the mid 60s in the Piedmont. As a large area of high pressure over the Mississippi valley ushers in significantly colder air behind the front, the low level flow will become energized and make for blustery conditions for Friday afternoon into Saturday. Expect about 40 kt of 850 mb flow during the peak of the cold advection Friday afternoon to Saturday morning. However, winds are expected to remain below wind advisory levels. It is time for you to find your cold weather gear Friday night with temperature readings dropping to lows from the mid 30s in the west to the mid 40s in the east. There will also be the prospect for the first snowflakes of the season Friday night into Saturday morning at the higher elevations (above 3500 feet msl) west of the Blue Ridge but no significant snow accumulations expected with warm ground. But, low temperatures at or below freezing may well end the growing season for some higher elevations west of the Blue Ridge Friday night. Light upslope showers will continue Saturday with cold advection combined with lingering low level moisture in the Northwest flow. High temperatures on Saturday will vary from the lower 40s in the northwest mountains to the lower 60s in the Piedmont, with the blustery wind making it feel even colder. Clear to partly cloudy conditions will prevail Saturday night into Sunday morning. Low temperatures will drop into the mid 30s in the mountains to the lower 40s in the Piedmont. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... As of 320 PM EDT Wednesday... The upper pattern will be trending toward reestablishment of an upper ridge over the eastern US through the middle of next week. This will generally keep our weather quiet and dry through the period. Return flow around high pressure to our south will push some warmer temperatures into the region for Sunday and Monday. A fast moving short wave will zip through the Great Lakes region and drive a low through New England. This will swing a weak cold front through the region later on Monday afternoon with any precipitation expected to remain off to our north. Cooler high pressure will then build in on Tuesday and take up a wedge position east of the Appalachians by Wednesday. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/...
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As of 245 PM EDT Thursday... VFR conditions will persist for a few more hours ahead of the cold front approaching from the west. Some shower activity may develop ahead of the main body of precipitation associated with the front, but confidence in this is low so will not include in TAFs west of the Blue Ridge and focus on the front. Expect several hours of persistent rain with some embedded thunder possible mainly after Midnight for sites west of the Ridge. As best dynamic forcing shears off to our north and west expect precipitation to be sluggish and lessen a bit as it continues eastward, reaching KLYH and KDAN close to daybreak. The precipitation will be accompanied by IFR conditions due to cigs and vsbys. Behind the front, conditions will improve east of the Ridge but as winds veer to NW upslope conditions will only allow for marginal improvement at KBLF and KLWB. Also, as winds veer around to NW the energetic low level flow will mix down and create gusty conditions toward the end of the TAF period with some gusts AOA 30KTS possible. Extended aviation discussion... A return to VFR conditions is expected for most areas Friday night into Saturday. The exception will be western parts of the region where a healthy northwest upslope flow, and lingering low level moisture, will prolong an IFR/MVFR ceiling during this time period. Even the mountain areas will become VFR again for Sunday and Monday.
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&& .CLIMATE... As of 515 AM EDT Thursday... Record maximum temperatures... New record max temperatures were set at Blacksburg and Danville Wednesday with 83 and 86 degrees, respectively. Record temperatures are possible again today. Oct 20 Location Record Max Bluefield.....79 in 1993 Danville......88 in 1984 Lynchburg.....85 in 1993 Roanoke.......84 in 2005 Blacksburg....82 in 1985 && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...AMS NEAR TERM...PM SHORT TERM...KK LONG TERM...MBS AVIATION...MBS/PM CLIMATE...AMS is the U.S. government's official web portal to all federal, state and local government web resources and services.