Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 011939 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 339 PM EDT Sat Oct 1 2016 .SYNOPSIS... Low pressure was over the Ohio Valley and a front was along the Mid Atlantic and Southeast coast. By Monday high pressure will build in over much of the eastern United States and remain over the area through Wednesday. Toward the end of the week a cold front will approach the region from the west while Hurricane Matthew tracks off the southeast coast. && .NEAR TERM /THROUGH SUNDAY/... As of 325 PM EDT Saturday... Tonight the upper low begins to move northeast then feature will be over the eastern Great Lakes on Sunday. A low level trof crosses into the central Appalachians on Sunday turning the surface winds to the west. Models were showing some moisture below 700 mb over the mountains on Sunday. Will keep more cloud cover over the mountains and less east of the Blue Ridge Sunday. Lows cloud and fog had cleared out as of noon. Good mixing with the drier air mass above the surface had dew points in the lower 40s to lower 50s. Enough clearing and winds decouple tonight for a surface based inversion. Expecting fog in the river valleys. Will stay cooler than guidance for the overnight lows, especially in the sheltered valleys. Locations that get more sun on Sunday will have maximum temperatures about 5 degrees above normal. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/... As of 245 PM EDT Saturday... During this portion of the forecast, the upper low that has been parked over the Ohio Valley the past several days, will progress northeast in advance of a building upper ridge across the Mississippi Valley. This upper ridge will progress eastward so that by Tuesday into Tuesday night, it is expected to be overhead. At the surface, high pressure will build over NY/PA and nose south along the lee of the Appalachians, forming a wedge that will be in place across central and eastern parts of the area by late Tuesday night. Our forecast will reflect a precipitation free forecast through Tuesday, along with limited cloud cover. Conditions will change as we progress into Tuesday night. The strengthening wedge and an increasing onshore flow will yield an increase in cloud cover, along with the potential for some light rain and patchy drizzle along and near the crest of the Blue Ridge from roughly Floyd, VA to points northeast. Temperatures during this portion of the forecast will experience little change from day to day with readings averaging around five degrees above normal for this time of year. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... As of 315 PM EDT Saturday... This portion of the forecast will have a number of challenges to it, especially in the latter half. The lee side wedge is expected to hold fast through at least Wednesday, if not Thursday. Small chances of precipitation will continue through this time period. The activity may transition to be a bit more showery in nature towards Thursday, depending on just how much or little we experience in erosion. Friday into Saturday, the forecast will ride on just where Hurricane Matthew tracks and how quickly. Flow on the northern side of the system could help greatly enhance the wedge through at least Friday if it has a track near or across eastern North Carolina. This track would also allow for associated precipitation and strong winds to impact the eastern parts of the forecast area on Saturday, via the left track leaning operational GFS. The 12Z/8AM ECMWF solution is trending farther west than its 00Z/8PM counterpart, but its solution is farther east and slower compared to the 12Z/8AM GFS. The track of the storm also will affect how quickly or involved an approaching cold front will impact our region at the start of the weekend. Our forecast will reflect a solution that keeps some remnant of the wedge across the area still on Friday along with light precipitation mainly the east, but also allows for precipitation associated with the approaching cold front to reach western parts of the area late Saturday. Temperatures during the period will trend slightly milder through Friday, with a small decrease on Saturday. Readings will continue to average around five degrees above average. && .AVIATION /20Z SATURDAY THROUGH THURSDAY/... As of 135 PM EDT Saturday... IFR fog and stratus over southwest Virginia and southeast West Virginia had dissipated as of noon today. Satellite pictures showed scattered stratocumulus clouds over the region at 1PM. Winds will decouple tonight and a shallow surface based inversion will form. High confidence of MVFR to LIFR fog formations in the river valleys. Lower confidence how much fog will develop east of the Blue Ridge. Fog and any low clouds will dissipate quickly after sunrise on Sunday. High confidence of VFR conditions by 14Z/10AM. Extended aviation discussion... The deep upper level low will finally shift farther to the north and away from the region on Sunday. The weather will trend back into a dry pattern with mainly VFR conditions next week. However some sub-VFR low clouds may occur along the eastern slopes of the Appalachians later Monday night into Tuesday night as the next low level wedge develops. Also appears some river valley fog could occur in the mountains, resulting in brief period of late night early morning LIFR conditions at some of the mountain valley airports through Wednesday, especially KBCB and KLWB. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...AMS NEAR TERM...AMS SHORT TERM...DS LONG TERM...DS AVIATION...AMS/JH is the U.S. government's official web portal to all federal, state and local government web resources and services.