Area Forecast Discussion
Issued by NWS Blacksburg, VA

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551 FXUS61 KRNK 271954 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 354 PM EDT Tue Sep 27 2016 .SYNOPSIS... A stationary front with weak areas of low pressure extended from the Mid Atlantic states to Louisiana. Another cold front will track through the Ohio and Tennessee Valleys on Wednesday and Wednesday night. This low pressure system over the Mid Atlantic will move slowly northeast into New England this weekend. && .NEAR TERM /THROUGH WEDNESDAY/... As of 335 PM EDT Tuesday... Front was hung up along the Blue Ridge this afternoon. Lowered clouds had just cleared out of the piedmont after 2PM. MSAS analysis showed east of the front that the lifted index values were as high as -5 where there has been breaks in the clouds today. Highest probability for precipitation remains east of a Lynchburg to Wilkesboro line. Expect a sharp gradient on the western side of the clouds and precipitation tonight and Wednesday. Mean flow from 850-500mb will be from the southwest tonight and Wednesday which will result in little movement of the surface front. Axis of deepest moisture and lift will remain over the piedmont of Virginia and North Carolina on Wednesday. Models fill low clouds and some fog back in overnight, especially east of the Blue Ridge. Amount of clearing on Wednesday will be the biggest influence on afternoon high temperatures. Fog is also expected to form overnight in the western river valleys. Have lowered minimum temperatures in southeast West Virginia based on the lack of cloud cover and the surface dew points that have lowered in the mid 30s to lower 40s. Otherwise stayed close to bias corrected MAV guidance for lows tonight and highs on Wednesday. && .SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/... As of 300 PM EDT Tuesday... Closed upper low center in the Ohio Valley Wednesday evening will move eastward and reach Eastern Kentucky by Thursday night. Scattered showers and thunderstorms associated with the shortwave riding northward along the frontal boundary will continue Wednesday evening into Wednesday night as the low digs south. The SWODY2 has highlighted a marginal risk for severe weather east of the Blue Ridge mountains. Low temperatures Wednesday night will range from the mid 40s in the northwest mountains to the lower 60s in the Piedmont. Coop guidance suggest that a few lower 40s may be possible. A cold front will drop southeast out of the Ohio valley and move east into the Appalachians on Thursday. Scattered showers and thunderstorms will develop ahead and along the frontal boundary. Some the thunderstorms could be strong with hail, gusty winds and heavy downpours. An impressive low to mid level lapse rates combined with very low freezing heights across the area could help the hail potential. High temperatures on Thursday will vary from around 60 degrees in the west to the lower 70s in the East. Cloudy conditions with scattered showers will continue Thursday night. The best chance for rain will be across the north. Low temperatures Thursday night will vary from lower 40s in the mountains to the mid 50s in the Piedmont. && .LONG TERM /FRIDAY THROUGH TUESDAY/... As of 300 PM EDT Tuesday... Closed upper low over Kentucky Friday morning lifts northward in the Ohio Valley this weekend. The low center continue to push into the Great lakes by Sunday evening and New England by Monday. The low will move into the Atlantic ocean on Tuesday. Meanwhile, the potential for tropical low development across the Caribbean may lead to a threat for the southeast early next week. This is being monitored by the NHC and WPC. Temperatures will start cooler for Friday with clouds along with unsettled weather and improve Saturday, then moderate Sunday into Tuesday. && .AVIATION /20Z TUESDAY THROUGH SUNDAY/... As of 120 PM EDT Tuesday... A front extended from central Virginia to western North Carolina this afternoon. There will be little movement of the front tonight and Wednesday. Showers and thunderstorms will develop this afternoon east of the front, with the best probability of precipitation at KLYH and KDAN. Medium to high confidence that the showers and thunderstorms will form around 21Z/5PM. Gusty winds are possible with any of the stronger storms but the chance is too low at any individual TAF site to include in the forecast at this time. Models, especially the NAM, showed IFR to LIFR ceilings east of the front overnight. High confidence that KLYH will have LIFR ceilings after midnight. LIFR ceilings are possible at KDAN too but confidence was too low to include in the forecast. Over the mountains with little cloud cover, fog will form in the river valleys. Expect LIFR fog and stratus at KLWB after 2AM. Low confidence about how long it will take the low clouds in the foothills and piedmont of Virginia and North Carolina to lift after sunrise. Extended aviation discussion... A deep upper low will remain over the Ohio and Tennessee Valley through Friday. This will keep variable clouds, MVFR cigs, and periods of -SHRA across the region through much of the period. Saturday is the most likely day to be drier and have VFR conditions. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...AMS NEAR TERM...AMS SHORT TERM...KK LONG TERM...KK AVIATION...AMS/PM is the U.S. government's official web portal to all federal, state and local government web resources and services.