Area Forecast Discussion
Issued by NWS Blacksburg, VA

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629 FXUS61 KRNK 181537 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 1037 AM EST Thu Jan 18 2018 .SYNOPSIS... High pressure over the Lower Mississippi Valley will move east across the Gulf Coast states today through Friday. Low pressure will develop in the Central Plains on Sunday then track into the Great Lakes by Tuesday. This system will push a cold front through the area on Monday and Tuesday. && .NEAR TERM /THROUGH TONIGHT/...
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As of 1025 AM EST Thursday... Wind chill advisory expired at 10am for the mountains and adjacent foothills. Will still see gusty winds and wind chills near zero to a few degrees below zero for another hour before it "warms" up. Wind has been an issue in isolated spots along the Blue Ridge this morning, with Virginia DOT sensors showing gusts over 50 mph along Fancy Gap on I-77, which resulted in tractor- trailer accidents. Special Weather Statement issued to cover this but overall should see a diminishing trend in the winds through the afternoon under plenty of sunshine. Warm air advection at 8h will work against the snow cover and cold low levels this afternoon, and will see which one wins out, but historically warm advection does so kept highs close to the previous forecast with upper 20s to mid 30s west, to mid 30s to near 40 east. A public information statement of final snow totals will be sent around 11am. Previous discussion from early morning... Closed upper low was over eastern North Carolina this morning. This low will move offshore and begin to fill today. At the surface high pressure was over the Lower Mississippi Valley with a lee trof along the central and southern Appalachians. The trof was tightening the pressure gradient leading to increased wind speeds this morning. The 850MB jet will pick up to around 50 knots this afternoon which will prolong the gusty winds at higher elevations, especially in southeast West Virginia and along the Blue Ridge north of Roanoke. Satellite pictures showed the clouds had cleared out of the foothills and piedmont of Virginia and North Carolina. Snow will hold temperatures below guidance today and tonight despite the warm air advection at 850MB. Dry air mass does favor a large diurnal temperature spread but expect solar insolation that goes toward snow melt to counteract that. Low clouds along the western slopes of the Appalachians this morning with a few flurries. Boone, NC was reporting a reduced visibility and light snow with a clear sky. Based on the wind of 15G25MPH the observation instruments are likely sensing some blowing snow. Models have a bulk of this cloud cover dissipating around 10AM.
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&& .SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/... As of 330 AM EST Thursday... The upper pattern will be transitioning to more of an eastern ridge/western trof, which will bring breezy and much warmer conditions to the region this weekend. By late Saturday developing low pressure over the Rockies will start to push a warm front in our direction. However the better moisture and isentropic lift will only brush the Appalachains and central mid Atlantic region, bringing just a slight chance for a shower far west Saturday evening through Sunday morning. Temperatures will warm to well above normal levels with readings by Sunday rising well into the 50s, though lingering snow cover mainly east of the Blue Ridge will temper the warm up. && .LONG TERM /MONDAY THROUGH WEDNESDAY/... As of 235 PM EST Wednesday... We stay warmer than normal ahead of a deep trough/closed low moving across the central U.S. Monday which then sends a front across us Tuesday with a threat of showers. Colder air behind it may bring a few snow showers to the mountains of WV, but temps behind this system are not as cold as the pattern we are in now. && .AVIATION /16Z THURSDAY THROUGH MONDAY/... As of 635 AM EST Thursday... High pressure will move from the Lower Mississippi Valley to the Gulf Coast region today and tonight. Satellite pictures showed a narrow strip of IFR clouds on the western slopes of the Appalachians between KMGW and KJFZ. Conditions were VFR across the rest of the region. The lower clouds were already beginning to erode. High confidence this cloud cover will dissipate by 16Z/11AM. Winds will also be gusty today from the northwest, up to 30 knots in the mountains and 15 to 20 knots elsewhere. Winds will diminish tonight. LLWS is in the TAFs tonight for KROA,KLYH and KBCB. Extended Discussion... Dry air will and high pressure will cover the region Friday through Sunday. VFR conditions are expected as well as warming temperatures. Moisture will return to west Sunday night into Monday with sub-VFR conditions possible ahead of another cold front. VFR conditions should return late Tuesday. && .EQUIPMENT... As of 245 PM EST Wednesday... NOAA Weather Radio, WXL60 (Roanoke Transmitter) which broadcasts at 162.475 MHz remains off the air. Telephone company will be working on this and hope to have it back up by Thursday afternoon. && .RNK WATCHES/WARNINGS/ADVISORIES...
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VA...None. NC...Winter Weather Advisory until 1 PM EST this afternoon for NCZ001>003-018>020. Winter Weather Advisory until noon EST today for NCZ004>006. WV...None.
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&& $$ SYNOPSIS...AMS NEAR TERM...AMS/WP SHORT TERM...MBS LONG TERM...WP AVIATION...AMS/JH EQUIPMENT...PM

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