Area Forecast Discussion
Issued by NWS Blacksburg, VA

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160 FXUS61 KRNK 280508 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 108 AM EDT Fri Oct 28 2016 .SYNOPSIS... A weak cold front will drift southeast through the region overnight followed by high pressure for Friday into Saturday. Another weak cold front will move through the area Sunday. This will be followed by high pressure until the end of next week along with unseasonably warm temperatures. && .NEAR TERM /THROUGH TODAY/... As of 900 pm EDT Thursday... A weak cold front continues to move through the region. Evening soundings indicate uniform westerly winds aloft, which is prohibitive of showers per downslope drying. Actual surface wind will come around to the northwest with the passage of the front, which will take place across the mountains between now and midnight...then east of the mountains after midnight. Can`t rule out a brief sprinkle with the passage of the front, but synoptic lift and any lingering thermodynamic lift is all but gone. Until the front passes, there may be some patchy fog across southside va and piedmont of NC. Temperatures vicinity of Danville and Reidsville and Mount airy have dropped close to the dewpoint values. This may allow for fog formation, but think this will be temporary. Once the front moves through during the late night, mixing should commence and disperse any fog/haze. Behind the front, upslope clouds and a few sprinkles may persist across the western areas, with clearing across the east. There may be a period of low end gusty winds west of the Blue Ridge with the passage of the front, but the stronger 850mb winds are lifting north of the area overnight. Given that the post-frontal air mass is mainly continental Pacific, 850mb temps actually begin to rise, not fall behind the front Friday. Clouds overnight and turbulent mixing along with little to no cold advection should yield temperatures well above freezing. Clouds will decrease in the western mountains by mid-morning Friday leaving most of the CWA clear by early afternoon if not sooner. With greater insolation and slightly warming temperatures at 850mb Friday, expect afternoon maximum temperatures to be on par with readings experienced today, likely warmer across the Piedmont. Bottom line is that temperatures will continue to remain well above normal for the foreseeable future. && .SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/... As of 230 PM EDT Thursday... Surface high pressure will track south across the region Friday night and Saturday. This high pressure system along with heights increasing aloft will keep the region dry Saturday with high temperatures warming 10F-15F above normal. Flow aloft becomes zonal Sunday resulting in similar high temperatures as Saturday. Normal high temperatures for late October range from the lower 60s across the mountains to mid to upper 60s across the foothills and piedmont. && .LONG TERM /MONDAY THROUGH THURSDAY/... As of 300 PM EDT Thursday... An upper level ridge centered over Texas will track east along the Gulf states through most of next week. This ridge will keep the region dry with any northern stream disturbances tracking east from the Great Lakes to New England. Boundaries from a few northern stream systems may dip far enough south to increase clouds and have a slight chance for rain for area north of I64 Sunday afternoon and evening and again next Thursday afternoon and night. Cool air will wedge south across the region Monday with temperatures warming to near normal. This wedge will begin to erode Tuesday with temperatures moderating 10F to 15F warmer && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... As of 1255 AM EDT Friday... A weak cold front nearing the Blue Ridge will continue to push slowly southeast and should pass to the south of the region around daybreak. Only an isolated shower or two is expected with the front as it crosses KLYH/KDAN overnight so leaving out mention. Conditions will remain primarily VFR with the exception of the western slopes vcnty of KBLF and KLWB where cigs will continue to lower through MVFR to possible IFR or even worse around KBLF where LIFR could occur. Some of this cloudiness may also spill east to KBCB/KROA overnight given decent northwest flow aloft so including a period of MVFR cigs at KBCB and VFR above 4k feet at KROA until early Friday morning. Spotty light MVFR fog is also possible across the piedmont of VA/NC overnight before the front passes and light mixing develops early Friday. Some guidance suggests that visibility at KLWB could become IFR late tonight (due to fog formation along the river), however, enough uncertainty exists to just entertain tempo group for now. Post frontal winds and cloud cover should prohibit fog formation in spite of the model forecast. For Friday, widespread VFR is anticipated. Any lingering cloudiness along the western slopes of the Appalachians is expected to erode by mid to late morning, leaving widespread VFR conditions for the afternoon into the overnight. Extended aviation discussion... Saturday...VFR with no flight restrictions. Only exception would be river valley fog in some of the mountain valleys early Saturday morning which could temporarily impact KBCB and KLWB. Sunday...VFR. Weak front passing to the north could generate some MVFR cigs Sunday night. Impact would be mainly to the WV mountains and western slopes of the VA highlands. Monday and Tuesday...Mainly VFR. Only exception would be formation of river valley fog in some of the mountain valleys which would occur during the 08z/4am to 13z/9am time frame resulting in a brief period of IFR due to surface based obscurations at KLWB, KBCB. Some light early morning ground fog may also occur at KLYH and KDAN but conditions temporary. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...JH/RAB NEAR TERM...PM/RAB SHORT TERM...RCS LONG TERM...RCS AVIATION...JH/PM is the U.S. government's official web portal to all federal, state and local government web resources and services.