Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 191912 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 312 PM EDT Wed Apr 19 2017 .SYNOPSIS...
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High pressure weakens into Wednesday night. A cold front will then approach from the west Thursday, stall and bring a chance for showers and thunderstorms Friday into Saturday. More showers and thunderstorms will cross the region Sunday with the passing of a strong cold front.
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&& .NEAR TERM /THROUGH THURSDAY/...
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As of 330 PM EDT Wednesday... A wedge of high pressure extends from New England south into the Carolinas. Meanwhile, an upper level ridge centered over the Gulf stretches north over the south-central Appalachian Mountains. Short waves on the outer rings of this ridge have been tracking over the surface wedge today. It is this interaction between the waves and wedge that has kept conditions gray and damp. The last short wave is tracking over the mountains this afternoon and will exit the piedmont late this evening. Until this short wave exits, light rain and drizzle will remain over the area. Rain chances decrease overnight while thick clouds and patchy valley fog develop. Areas along the Blue Ridge that maintain a southeasterly flow will continue to see drizzle or dense fog through Thursday morning. Widespread dense is possible if clouds develops breaks tonight. However, models are hanging on to the wedge into mid Thursday morning, therefore thick clouds will also remain. The wedge will likely be gone by the afternoon. A weak prefrontal trough with abundant low level moisture to work with, may produce a few showers and thunderstorms in the afternoon. Any showers that develop will fade with lose of heating in the evening. The wedge is firm entrenched over the entire area this afternoon. Temperatures on the outer edge of the wedge have warmed into the upper 50s. Those deep in the wedge kept temperatures in the low 50s. These afternoon temperatures will likely be our overnight lows tonight. The wedge will erode over the mountains through the night as a warm front moves north of the area. Areas that see the wedge erode will also see temperatures warming a few degrees. Areas remaining in the wedge will maintain temperatures in the lower 50s. Once the wedge break and the sun makes a return tomorrow, temperatures will warm into the mid to upper 70s along and west of the Blue Ridge to the lower 80s east.
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&& .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
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As of 235 PM EDT Wednesday... Thursday evening, anticipate waning coverage of the earlier diurnal showers from Thursday afternoon. By midnight, we expect the bulk, if not all, of this activity to have ended. Later Thursday night, showers associated with an approaching cold front will start to enter the far western sections of the forecast area. The cold front will move into and across the area on Friday. While mainly showers are expected during the morning hours, during the peak heating of the afternoon, anticipate a greater potential for isolated thunderstorms across the southeastern sections of the area. Friday night, the front is expected to stall near the NC/SC border, and then start to buckle north again as a warm front in repsonse to a shortwave trough/low heading east through the Missouri Valley. Shower chances will remain greatest across the southern third of the forecast area through the night. Northern sections may see precipitation end, or at least greatly diminish, through the evening hours, only to increase again late Friday night. On Saturday, the low to our west will move into the Lower Ohio Valley, all while a frontal boundary remains positioned from eastern Kentucky, northeast into western Maryland. The result will a be a potentially very wet Saturday into Saturday night across central and western sections of the region. Lighter rainfall would impact eastern sections. Temperatures through Friday will average about ten to fifteen degrees above normal. By Saturday, average temperatures will be around normal to about five degrees above normal.
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&& .LONG TERM /SUNDAY THROUGH WEDNESDAY/...
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As of 250 PM EDT Wednesday... Low pressure will continue to approach our region from the west with the associated stalled frontal boundary shifting east across our region as well. Not until Sunday night into early Monday morning does the axis of this upper trough/low move east of our area and allow for drier high pressure to enter our forecast picture. We will need to monitor the trends of the Saturday night into Sunday night precipitation. Given the expected rounds of precipitation the remainder of this week, if a prolonged area of rainfall establishes itself over western portions of the area, we may need to start to become concerned for a least some minor flooding. A dry forecast is predicted for Tuesday and Wednesday, along with a warming trend. Temperatures Sunday and Monday will be around normal to slightly below normal, with readings Tuesday and Wednesday around normal to slightly above normal.
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&& .AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
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As of 352 PM EDT Wednesday... Moisture overrunning wedge front will keep cigs at least MVFR into this evening. Most sites overnight will drop into IFR range. If for some reason clouds develop breaks overnight, dense fog is possible. At this time, thick low clouds will remain with mountain ridges obscured. Conditions will improve Thursday morning with VFR at all sites expected in the afternoon. Extended Aviation Discussion... By Thursday, the front will return north as a warm front just as a new front approaches from the northwest. Showers and thunderstorms will be on the increase Thu-Fri as this front also drifts into the area and then stalls Friday just south of the CWA, most likely near the NC/SC border. This front will return to the north as a warm front Saturday as a much stronger weather system moves into the southeast U.S. While there may be some periods of VFR cigs Thursday as the area comes into the warm sector, expect MVFR or worse ceilings to return at times Fri- Sat, with widespread sub-VFR ceilings Sunday with widespread heavy rainfall and some storms in the KDAN area during the afternoon Sunday. Winds may be a factor late in the weekend as well.
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&& .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...RCS NEAR TERM...RCS SHORT TERM...DS LONG TERM...DS AVIATION...RCS

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