Area Forecast Discussion
Issued by NWS Blacksburg, VA

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648 FXUS61 KRNK 260429 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 1129 PM EST Sat Feb 25 2017 .SYNOPSIS... High pressure will build in from the west overnight into Sunday before passing off the southeast coast on Monday. A warm front will lift northeast toward the region early next week resulting in an increasing chance of showers by Tuesday into Wednesday. && .NEAR TERM /THROUGH SUNDAY/... As of 815 PM EST Saturday... Surface cold front has now pushed well east of the region with steady cold advection ongoing under gusty west/northwest winds that will persist overnight. However latest evening RNK sounding shows the inversion level quite a bit higher than earlier model forecasts with the much stronger winds above 6K feet. This despite deepening cold advection should keep most advisory level winds confined to the highest ridges even as the inversion lowers some late when the jet aloft is expected to weaken. Otherwise much drier air within a well mixed environment will keep things mostly clear overnight, with the northwest slopes possibly seeing some upslope aided low clouds as the cold pool aloft rotates through later. However snow showers of any consequence appear quite iffy given shallow moisture under even better drying late per progged dewpoints. Thus cut back on snow shower chances northwest given little precip off any short term guidance, while leaving in a token dusting of snow over the higher elevations of northwest Greenbrier where perhaps could see a band or two overnight. Lows to be much colder than seen in quite some time with most western locations falling into the 20s, while expecting 30-35 out east where may see periods of decoupling late. Previous discussion as of 320 PM EST Saturday... The cold front/line of convection will move east of the piedmont and away from the forecast area by 4PM, therefore we will cancel the severe thunderstorm watch #39. As the cold front tracks to the coast this evening, modest pressure rises and a 45kt cross barrier jet will bring breezy conditions to the region. Winds will begin to subside over the piedmont after midnight but remain breezy across the mountains, especially along the Blue Ridge where subsidence will be the greatest. Gusts up to 45 mph are possible this evening. High pressure builds in by noon Sunday allowing the winds to subside. An upper level trough will pivot over the Ohio Valley to the Mid Atlantic region overnight. A short wave axis and lingering low level moisture may produce light snow across Western Greenbrier this evening. Flow becomes zonal after midnight and trajectories are lost from the Great Lakes to end snow showers shortly after midnight. Dry high pressure will keep the area dry with clear skies Sunday. Lows tonight will drop into the low to mid 20s across the mountains and lower 30s east of the Blue Ridge. Believe it or not, these temperatures are normal for this time of year. Couple the cold temperatures and wind, Sunday morning temperatures will feel like they are in the teens across the mountains and low 20s in the east. Once the wind relaxes, abundant sunshine will help warm temperatures into the mid 40s west to mid 50s east. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/... As of 230 PM EST Saturday... High pressure heads off the coast Sunday night. A warm front lifts north across us Monday into Tuesday bringing a threat of rain, albeit low chance as main low and energy stay over the midwest. Temperatures warm back to above seasonal levels Tuesday as we get into the warm sector. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... As of 130 PM EST Saturday... Not much change from previous forecast. Will see upper trough move east to the Mid-Atlantic by Thursday. A strong cold front moves across the region Wednesday night into Thursday. Temperature slide back to normal or below normal as we dry out Friday into Saturday. && .AVIATION /04Z SUNDAY THROUGH THURSDAY/...
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As of 1115 PM EST Saturday... Upper cold pool will cross parts of the region overnight as surface high pressure gradually builds east into the area later tonight through Sunday. Upslope aided low clouds under the passing shortwave energy aloft likely to result in periods of VFR/MVFR cigs at KLWB/KBLF overnight, with some of these cigs possibly spilling out to KBCB and KROA during the early morning hours of Sunday. However quite uncertain to the eastward/southern extent of the cloud cover and any snow showers given ongoing mixing and dry air. For now will include mainly VFR cigs far western locations, and TEMPO in some ocnl MVFR canopy espcly around KBLF through daybreak Sunday. This while also leaving out any snow shower mention attm. Strong subsidence along with deepening cold advection should also keep winds gusty across the mountains overnight into Sunday morning, while speeds subside east of the ridges later tonight. Otherwise high pressure to build in overnight and Sunday before sliding offshore by Monday. This looks to keep VFR under overall light winds in place from Sunday into early next week with perhaps some increase in mid/high clouds by Monday. Extended Aviation Discussion... A warm front is expected to lift northeast toward the region Monday night into Tuesday before passing to the north on Wednesday. This will keep a threat of showers in place including periods of sub-VFR Tuesday into Wednesday. A cold front pushes east into the area late Wednesday into Wednesday night with potential for more widespread MVFR/IFR in showers until the boundary exits the area early Thursday. Strong northwest winds along with mountain sub-VFR in upslope low clouds and light precip will likely follow the front for much of Thursday. Expect downslope drying to return VFR to eastern locations by Thursday afternoon.
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&& .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...JH/RCS NEAR TERM...JH/RCS SHORT TERM...WP LONG TERM...WP AVIATION...JH/RCS

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