Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 211954 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 354 PM EDT Fri Oct 21 2016 .SYNOPSIS... Low pressure over Pennsylvania with a cold front trailing into northeast Florida was moving east this evening. High pressure over the central United States will move southeast Saturday and Sunday. A weak cold front will cross through the Mid Atlantic region on Monday. && .NEAR TERM /THROUGH SATURDAY/... As of 345 PM EDT Wednesday... Upper low will close off over Pennsylvania tonight then move northeast on Sunday. Cold pool at 500 MB crosses the Mid Atlantic region tonight and Saturday. Area of relative instability and showers associated with this colder air aloft. Significant change is air mas has started with strong cold air advection continuing across the region through tonight. By 12Z Saturday 850MB temperatures will range from +2 over the North Carolina and Virginia piedmont to -4 in southeast West Virginia. Moisture above 700MB with the upper trof moves across the northern part of the forecast area, mainly north of Lewisburg and Lynchburg tonight. Lower level moisture east of the Blue ridge dries up quickly this afternoon, but remains over the mountains tonight. Western upslope areas will be gradually clearing out Saturday morning. Stayed closed to the cooler MAV/LAV guidance for lows tonight. Some elevations above 5000 feet already down to 40 degrees at 2PM. These highest ridges and other elevated valleys like Mountain Lake and Burkes Garden will have lows around freezing tonight. The rest of the mountains will be in the mid to upper 30s but way too much wind and cloud cover for any frost. Will take through mid morning to clear out the clouds in southeast West Virginia on Saturday which will limit heating. Again, MAV numbers looked reasonable. Magnitude of pressure rises and cold air advection behind the front is enough to support wind gusts of 25 to 40 mph through Saturday. The strongest winds will be at the highest elevations. However, 850MB jet and height of the inversion as seen on the NAM/GFS Bufkit forecast is not as supportive for strong winds. Wind Advisory has been issued in coordination with neighboring National Weather Service Offices. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/... As of 330 PM EDT Friday... The low amplitude upper pattern is not very progressive as the closed low over New England slides up into eastern Canada and keeps a broad trof over the northeast as a ridge develops over the Rockies. Aside from some lingering clouds west of the Blue Ridge Saturday night, this pattern will keep fair weather with breezy conditions in the tight pressure gradient between high pressure over the southeast and low pressure under the closed low through Sunday. A surge of short wave energy will spill over the ridge and push a weak low from the Great Lakes region late Sunday to off the mid Atlantic coast by Monday morning. This will initiate another round of strong gusty winds Sunday night and send a plume of low level moisture into the region from the northwest. This will result in a good amount of clouds west of the Blue Ridge and maybe some upslope rain showers for the western slopes late Sunday night into Monday. With surface high pressure over the southeast giving us west to southwest winds, warmer temperatures will start making their way into the region and highs on Sunday will be seasonably in the 60s, a bit cooler on Monday west of the Blue Ridge as cooler air starts filtering in. && .LONG TERM /TUESDAY THROUGH FRIDAY/... As of 330 PM EDT Friday... High pressure will move in from the upper midwest and bring fair weather with slightly below normal temperatures to the region for Tuesday and Wednesday. The high will then take up a wedge position east of the Appalachians as a vigorous short wave amplifies and drops out of the upper midwest. This looks to bring a chance of precipitation back to our forecast for Thursday with some additional upslope precipitation west of the Blue Ridge lingering into Friday. Temperatures will generally be near seasonal norms through the period. && .AVIATION /20Z FRIDAY THROUGH WEDNESDAY/... As of 150 PM EDT Friday... Conditions were changing quickly across southwest Virgina and northwest North Carolina this afternoon. A cold front trailed from central Maryland to south central North Carolina and was moving east. Behind the front temperatures were dropping into the upper 40s to mid 50s and wind wind was gusting out of the west. Elevations above 3500 feet were already reporting gusts of 30 to 35 knots. Downslope winds will improve ceilings east of the Blue Ridge to VFR before 00Z/8PM. Models have some mid level clouds with the upper trof over central Virginia. Have some BKN ceilings, but still VFR, in at KLYH overnight. IFR to MVFR clouds will be widespread in the mountains tonight. Cold air aloft and upslope winds will produce isolated to scattered showers around KLWB and KBCB. Lower confidence that these upslope showers will make it as far east as KBCB and KROA. The lower clouds will lift and dissipate Saturday morning. Medium confidence that KLWB and KBLF will be VFR by the 18Z end of the TAF forecast period. Extended aviation discussion... Saturday night through Monday...Widespread VFR. No flight restrictions. High pressure building in over the Tennessee Valley then southeast United States will result in lighter wind speeds. Tuesday and Wednesday...Potential for river valley fog in the mountain valleys with local vsby restrictions between 08-14Z each morning, otherwise widespread VFR. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...Wind Advisory until noon EDT Saturday for VAZ009-012>020- 022>024. NC...Wind Advisory until noon EDT Saturday for NCZ001-002-018. WV...None. && $$ SYNOPSIS...AMS NEAR TERM...AMS SHORT TERM...MBS LONG TERM...MBS AVIATION...AMS/PM is the U.S. government's official web portal to all federal, state and local government web resources and services.