Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 142006 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 306 PM EST Wed Feb 14 2018 .SYNOPSIS...
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High pressure will drift southeast tonight into Thursday into the Atlantic ocean. A cold front will approach the area from the northwest late Thursday, but take until Saturday to move through the region. Unseasonably warm temperatures and widespread rainfall is expected Thursday through Saturday until the front moves south of the area.
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&& .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
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As of 305 PM EST Wednesday... High pressure centered along the South Carolina coastline this afternoon will move southeast tonight into Thursday. A couple of weak upper disturbances will rotate eastward across our region. This will result in periods of rain and drizzle. The best chance of rain will occur in the western mountains. The ECMWF and GFS looked overdone with rainfall tonight. Leaned towards the NAM and HRRR for pops this afternoon into tonight. Added patchy fog to isc grids. With a 590+dm ridge aloft off the southeast U.S. coast, overnight low temperatures will be unseasonable mild with readings from the upper 40s in the mountains to the mid 50s along the western ridges. Refer Climate section to see Records. The warm front will continue to lift north on Thursday as the high center migrates east. Scattered showers are expected especially west of the Blue Ridge mountains. Rainfall will be less than a quarter inch. Widespread flooding is not currently anticipated during daylight hours on Thursday. The axis of the heavier rain will be northwest of our region generally along the Ohio River. The west to southwest flow will transport mild air into the region. High temperatures on Thursday will be challenging record highs with readings from the upper 50s in the northwest to the lower 70s in the piedmont.
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&& .SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY NIGHT/...
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As of 305 PM EST Wednesday... A cold front will slowly move across the Ohio Valley Thursday night, then stalls just west of the central and southern Appalachian Mountains Friday. A series of mid level waves will track along the front bring moderate to heavy rain to central and northern West Virginia Thursday night into Friday. By the time this front stalls to the west of the Appalachians, waves become weaker and moisture transport will decrease, resulting in light to moderate rain for southeastern West Virginia and southwestern Virginia. Forecasted rainfall amounts may range from a half an inch to an inch /0.50- 1.00/ along western slopes Thursday night into Friday. Creeks, streams and river levels will already have receded from this past weekend`s event. The ground remains wet but with no snowpack, the flood threat is low for Friday. The front will move across the area Thursday afternoon and evening. Winds become westerly quickly, keeping rainfall amounts along and east of the Blue Ridge to a quarter of an inch or less. Despite strong pressure rises and a 40 kt low level jet behind the front, subsidence inversion and lack of strong cold air advection will keep the stronger winds aloft Friday afternoon/night. High pressure will move from the Ohio Valley to the mid Atlantic states Friday night, then wedges south into the Carolinas Saturday. A disturbance moving over the Tennessee Valley will push overrunning moisture over the southern end of the wedge during the day Saturday. Isentropic lift, moist easterly flow and soggy soils could possibly bring flood concerns to the mountains. This flood threat also hinges on the amount and duration of rain the area gets Friday. Rainfall amounts (quarter to half an inch) may trend lower if convection across the Tennessee Valley develops and tracks southward. Also complicating the issue is the chance for a wintry mix Saturday morning, possibly lingering into the afternoon. A secondary wave develops off the NC/VA coast Saturday evening and quickly pulls the front across the area. Record warm low temperatures possible Thursday night with readings in the 50s. These temperatures are around 30 degrees warmer than normal for overnight lows and 10 degrees warmer than average daytime highs this time of year. The warm trend continues Tuesday with temperatures peaking into the 60s to lower 70s. Areas that have rain early Friday morning may only have highs in the 50s, still not bad for February. Temperatures cool down into the 30s following the front Friday night. Not much warming expected Saturday with a cold wedge in play.
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&& .LONG TERM /SUNDAY THROUGH WEDNESDAY/...
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As of 250 PM EST Wednesday... High pressure builds in behind Saturday night`s front and wedges south into the Carolinas on Sunday. A warm front will track over the wedge bringing another round of precipitation to the region Monday. Temperatures may be warm enough for an all rain event, but there is a small window for a wintry mix Monday morning. The warm front will remove the shallow wedge by Tuesday. The area will stay in the warm sector Tuesday and Wednesday with well above normal temperatures with readings in the 60s.
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&& .AVIATION /20Z WEDNESDAY THROUGH MONDAY/... As of 1237 PM EST Wednesday... Surface high pressure off the Mid-Atlantic coast will drift southeast tonight into Thursday. A warm front will lift northward through the area combined with a weak disturbance resulting in period of rain. SCT to BKN MVFR clouds expected this afternoon into tonight. Visibilities will be VFR, except MVFR to locally IFR in areas of lower clouds at higher elevations (e.g., KBLF) and light rainfall or drizzle. Ceilings will likely trend down overnight into Thursday morning, IFR west to MVFR east in low clouds, drizzle, and areas of fog. Low-level southwest jet 35-40 kts will overspread the airspace tonight into Thursday and with light east to calm winds. Low- level wind shear mentioned in taf, especially from KBCB west. Surface winds become south to southwest 5-10 kts Thursday with gusts around 20-25 kts. Medium confidence on ceilings, visibilities and wind through the TAF valid period. Extended Aviation Discussion... Rather poor aviation conditions expected through the period as a series of weather systems continues to track across the country. Southwest flow aloft will prevail across the eastern U.S. as a high amplitude right of high pressure aloft remains strong. Numerous periods of widespread sub-VFR conditions expected through the period. Winds will be quite strong and gusty through much of this period as well. && .CLIMATE...
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As of 300 PM EST Wednesday... Thursday 02/15/2018 Site MaxT Year HiMin Year KBLF 72 1990 54 1990 KDAN 76 1990 57 1949 KLYH 77 1989 55 1949 KROA 79 1989 55 2001 KRNK 66 1990 46 1990
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&& .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...KK NEAR TERM...KK SHORT TERM...RCS LONG TERM...RCS AVIATION...KK/RAB CLIMATE...KK

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