Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 221736 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 136 PM EDT Sat Oct 22 2016 .SYNOPSIS... Low Pressure over New England will move north into eastern Canada today, while dry high pressure works its way across the southeastern United States and into the Mid Atlantic region. A fast moving clipper sort of front will move east through the upper Midwest on Sunday, passing through our region late Sunday night or early Monday as a dry cold front. High pressure will then build southeast from the upper midwest and across the Ohio Valley and Mid-Atlantic states from Monday through Wednesday. Little or no precipitation is expected today and No precipitation is expected from Sunday through Wednesday. && .NEAR TERM /THROUGH TONIGHT/... As of 1225 PM EDT Saturday... Wind Advisory over the southern Blue Ridge has expired. 12Z soundings from RNK and GSO this morning showed winds through the lowest 8000 feet up to 35KTS. Strongest gusts once mixing started this morning were in the 30 to 40 mph range. Do not expect anything higher than this for the rest of the day. Models maintain some low level cloudiness across the mountains impacting areas primarily west of the Blue Ridge. Have increased coverage and duration of cloud cover over the mountains. Short term models hold clouds in well into the evening. With the little if any heating, lowered maximum temperatures, mainly west of the Blue Ridge. Favorable conditions for potential frost will occur tonight for areas west of the Appalachian divide. High pressure will move from the mid MS valley and become centered over the Tennessee Valley tonight. This will result in near calm winds for the Tennessee Valley which includes Smyth and Tazewell counties and areas to the southwest toward Bristol. A near calm wind and clear sky will allow temperatures to dip into the lower to mid 30s for these areas supporting frost. East of the Appalachian divide, temperatures will also fall into the 30s to lower 40s, but turbulent mixing from the wind will be unfavorable for widespread frost. Certainly can`t rule out some patchy frost in the sheltered valleys, but not enough coverage forecast at-time to warrant an advisory. If future forecast models indicate less wind, then we may need to extend the advisories farther to the north and east. && .SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/... As of 230 AM EDT Saturday... During this portion of the forecast, an upper low will continue to make slow progression eastward through southeast Canada. A surface high pressure will build over the southeast U.S., while an upper ridge strengthens across the central U.S. The resultant synoptic pattern across our region will be one of zonal to northwest flow. Within this flow, and shortwave trough is expected to cross over, or just north of the region, Sunday night into Monday. For the vast majority of the region, and for the vast majority of this portion of the forecast, no precipitation is expected. There may be some isolated showers across parts of southeast West Virginia late Sunday night into early Monday morning in association with the shortwave trough. Temperatures will trend milder through Monday, then decline again Monday night into Tuesday in the wake of the shortwave trough and its associated weak cold front. High pressure will again build into the region by Monday night into Tuesday. Temperatures will likely dip into the mid 30s across a generous potion of southeast West Virginia and neighboring counties of southwest Virginia. Patchy frost is probable given the expected light winds and limited cloud cover. While winds are expected to be weaker on Sunday as compared to those of yesterday and today, speeds and gusts ramp up once again with the passage of the shortwave trough Sunday night into Monday. Another case of gusts approaching wind advisory criteria is likely at the highest elevations. && .LONG TERM /WEDNESDAY 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 /18Z SATURDAY THROUGH THURSDAY/... As of 135 PM EDT Saturday... MVFR ceilings will continue in the mountains for the rest of the day with ceilings gradually lifting and then becoming scattered. Isolated light showers may occasionally bring ceilings down to 2500 feet at KLWB this afternoon. Based on short term models, medium confidence that clouds will clear out of KBLF and KLWB by 03Z/11PM. VFR conditions are expected east of the Blue Ridge. Pressure gradient will continue to result in gusty northwest winds today with surface gusts of 15-30 kts. Winds will subside tonight. Extended aviation discussion... Sunday 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...Frost Advisory from 2 AM to 9 AM EDT Sunday for VAZ007-009. NC...None. WV...None. && $$ SYNOPSIS...PM NEAR TERM...AMS/PM SHORT TERM...DS 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.