Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 190549 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 149 AM EDT Mon Jun 19 2017 .SYNOPSIS... High pressure offshore will maintain a warm and humid airmass across the region, continuing our chances for scattered showers and thunderstorms through tonight. A weak cold front will approach the area from the northwest by Monday with a better chance for strong thunderstorms and heavy rainfall. Behind the front, a bit drier weather is expected through the middle of next week, along with a warming trend to above normal temperatures. && .NEAR TERM /THROUGH TODAY/... As of 645 PM EDT Sunday... Latest radar trends indicate only isolated showers and showers and thunderstorms this evening, focused across the mountains. Regardless, instability continues to diminish as daytime heating is coming to an end, and believe we will see remaining showers and storms fade after sunset. Given low coverage of rainfall, have lowered rain chances with the early evening forecast update. Expect a relatively quiet night before things ramp up again as the front draws near tomorrow morning. Guidance varies a bit with timing but expect showers/storms to slowly spread across the region from the west and spill east of the Blue Ridge by the afternoon. Heavy rain is definitely a concern as precipitable water values approach 2.0 inches, but rather than issue a blanket flash flood watch for the entire region, believe it better to hold off and wait to see if later model runs zero in on a particular area of concern. While the best dynamics with the front will be pulling off to the northeast as the front moves through, there looks to be ample shear with the boundary coupled with pooling instability to maintain some vigorous updrafts and a severe threat. Expect storm clusters in the west to possibly form a broken line as the front moves east of the Ridge and reaches the best instability tomorrow afternoon, also bearing in mind that extent and magnitude of any convection upstream can influence how the situation unfolds tomorrow. Warm and muggy conditions will continue tonight and tomorrow before some cooler and slightly drier air moves in on Tuesday. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY/... As of 325 PM EDT Sunday... Monday night into Tuesday, the cold front will progress through the area and stall just to our southeast. Coincident to the passage of the front, anticipate heavy rain producing showers and storms across the eastern sections of the area during the evening. Lingering isolated to scattered showers are anticipated behind the front across central and western sections through the evening. By daybreak Tuesday, the last of the showers will still be across the far southeastern sections. As Tuesday progresses, look for a redevelopment of isolated to scattered showers across the far southern and southeastern parts of the area given the close proximity of the front, with late afternoon isolated thunderstorms near and south of the VA/NC state line. Western and northern parts of the region will experience mostly sunny skies. Tuesday night the stalled front is expected to buckle a bit eastward and northward. This progression will allow for isolated showers to work their way at little farther north into parts of Southside Virginia. Temperatures during this part of the forecast will average around or slightly cooler than normal for this time of year. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... As of 325 PM EDT Sunday... What is interesting is there is less uncertainty in the details of the forecast Wednesday night through roughly Friday, as compared to better certainty next weekend. The fly in the ointment is the progression of what likely will be remnants of a tropical system. Model guidance offers a huge variety of solutions, some of which offer a relatively dry solution for our area, others offer solutions with a more wet scenario. For now, until there greater clarity, will opt to follow the output of the superblend of models which averages the solutions into a ramping up of precipitation chances Wednesday night into Friday. Even without the potential for tropical remnants, this trend makes sense as moisture pools and instability increases in advance of what will be an approaching cold front for the weekend. That is why the weekend has higher clarity than the days immediately prior. Models are in decent agreement of bringing a cold front through the area Saturday into Sunday. Temperatures during this portion of the forecast will average a few degrees above normal through Saturday, but then be a few degrees below normal on Sunday. && .AVIATION /06Z MONDAY THROUGH FRIDAY/...
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As of 145 AM EDT Monday... Cluster of showers and thunderstorms over northern North Carolina and southern Virginia will continue to move northeast early this morning. Expect a majority of the thunderstorms to stay east and south of KDAN. A cold front will cross the region from west to east today. High confidence of showers and thunderstorms with MVFR ceilings and visibilities along the front by this afternoon. Amount of cloud cover over the mountains will impact instability ahead of the front. Highest probability for strong thunderstorms will be in KLYH and KDAN after noon. Gusty winds and locally heavy downpours which will limit visibilities to less than one quarter mile at times. Patchy MVFR fog is expected this morning. Once the showers and thunderstorms move out of KDAN, MVFR is possible at KDAN before sunrise. Confidence on timing and occurrence is low. Extended Aviation Discussion... Appears 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. However given uncertainty in just how far south the deeper moisture may or may not make it, the threat for isolated showers could still linger Tuesday through Thursday at this point.
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&& .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...JH NEAR TERM...MBS/NF SHORT TERM...DS LONG TERM...DS AVIATION...AMS/NF

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