Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 192320 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 720 PM EDT Mon Jun 19 2017 .SYNOPSIS...
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A cold front will then move more slowly eastward into eastern Virginia and northern and central North Carolina tonight. Noticeably drier air and mostly sunny conditions expected for Tuesday into Wednesday. The next chance for more unsettled weather is not until late in the week.
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&& .NEAR TERM /THROUGH TUESDAY/...
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As of 719 PM EDT Monday...Update to cancel Severe Thunderstorm Watch 356 for the rest of the affected counties. While thunderstorms - a few still on the strong side at times - are still ongoing in the Southside of VA and into the NC Piedmont, focus for greater severe potential is east of the forecast area into eastern VA. Heavy rainfall and short-lived sub-severe wind gusts still are possible in the stronger storms in this area through about 9 pm. However, from an instability standpoint, atmosphere is becoming well worked over at this point and additional severe storms are not anticipated. Removed earlier enhanced wording and adjusted PoPs downward faster as the cold front has cleared most areas except for the Southside/NC Piedmont. May still see some showers, perhaps a rumble or two of thunder in this area through midnight. Clearing and drying should take place elsewhere with ridging building in. Still think fog is a good bet beginning around midnight this evening. Best chance is in the favored river valleys, will need to evaluate greater fog potential elsewhere in later updates. Lows range from the mid 50s to mid/upper 60s. Previous discussion... Cold front continues to progress eastward, with strong to severe thunderstorms lying out ahead of the front. Regional radar shows more cellular activity in the Piedmont currently, although starting to see storms organize into a line that runs essentially parallel to I-81. Instability values still remain high - in the 2000-2500 J/kg range in terms of SBCAPE - in the area ahead of the line and really have not been effectively worked over from earlier pre-frontal cells. Effective shear values are still somewhat marginal but are the increase, supporting at least loosely organized storms. Primary spatial area of greatest threat is in the Watch area as storms approaching the Blue Ridge interact with the aforementioned unstable air mass. Damaging winds posing the greatest potential convective hazard. Localized heavy downpours are possible in any thunderstorm. Recent short- term guidance moves the cold front and associated frontal storms into the VA/NC Piedmont region toward 8 pm. While the severe convective threat should have shifted east and ended after sunset, will need to monitor for localized hydro issues as the front slows and stalls near the Southside and into the NC Piedmont. Will hold on any flash flood watches due to lower confidence at this point. Behind the front, much drier air should filter in associated with post- frontal surface ridging. This may lead to development of patchy fog as winds slacken after midnight, given recent rainfall and in favored river valleys. Lows will tend warmest in eastern counties in the mid/upper 60s, but running some 8 to 10 degrees cooler from the Blue Ridge west. Cooler and continued drier air filters into the region behind the front for Tuesday. Dewpoints may be some 10 degrees lower than today, so we should experience a little more refreshing air than the past several days. Front does hang up along the southern Chesapeake Bay west-southwest into central NC/SC, and some guidance suggests slight to lower end Chance-range PoPs for showers overrunning the boundary along/south of Route 58. Highs look to top out from the mid 70s to middle 80s, warmest in the VA Piedmont due to added warming effect from northwest downslope off the Blue Ridge.
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&& .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... As of 320 PM EDT Monday... Tuesday night into Wednesday, the cold front will remain positioned just to the southeast of the region. It will be in close enough proximity for precipitation associated with weak waves moving along it to spread showers into southern and southeastern section of the forecast area. Gradually, coverage will diminish by Wednesday evening as the front inches its way far enough from the region. The break in the precipitation will be short lived. The moisture fetch back into the region will start to increase on the east side of a remnant low that is progged to be positioned somewhere near LA/TX by mid-day Thursday. Look for showers to increase across the area from south to north during the course of the day, but probably be no more organized than isolated to scattered coverage. Temperatures during this portion of the forecast will be within a couple of degrees within normal. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... As of 320 PM EDT Monday... Thursday night through Saturday continues to look to be on the wet side. Guidance is trending with more consistency regarding tropical moisture/remnant tropical system moving northeast into or near our region coincident to the arrival of a cold front. While exact timing still is in question, the general trend of this scenario is looking more promising. The result could be a period with some localized flash flooding in the near term, followed closely behind with some longer term river flooding. Again, it is too early for any specifics, but if timing of both the front and tropical moisture are just right, not an unreasonable scenario. For Sunday, the region is expected to be on the backside of the departing surface cold front. At the same time, the upper trough axis associated with the cold front`s parent low is expect to cross the area. While the GFS is less robust with this feature, its European counterpart hints at both more activity from this trough, plus less progression southeast of the surface cold front, thus keeping it in closer proximity to the southeastern sections of the region. The GFS provides a dry forecast by Monday, but not so much so by its counterpart with showers lingering across the southeast still on Monday. During this portion of the forecast, high temperatures will be plus or minus a degree or two of normal, with low temperatures a few degrees above normal on average. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/...
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As of 719 PM EDT Monday... With exception for Danville, cold front has largely cleared the TAFs. While short-term MVFR conditions in TSRA can be expected at Danville, expect a return to VFR conditions through 06z. Thereafter, will be watching for IFR to LIFR patchy fog development as winds go light and variable overnight. As each of the TAFs saw some rain, potential does exist everywhere, but in particular at Blacksburg and Lewisburg where skies will be clearer the longest. Expecting any fog that develops to burn off by morning to VFR conditions. A few high clouds at many terminals, but potentially lower VFR ceilings at Danville. West winds 4-8 kts Tuesday. Extended Aviation Discussion... Will see more widespread VFR conditions behind the front with only brief periods of fog resulting in brief sub-VFR during the late night/early morning hours for Tuesday through Thursday. More widespread precipitation and the possibility of sub-VFR conditions, returns on Friday.
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&& .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...AL NEAR TERM...AL SHORT TERM...DS LONG TERM...DS AVIATION...AL/AMS

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