Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 112357 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA Issued by National Weather Service Raleigh NC 657 PM EST Thu Jan 11 2018 .SYNOPSIS... A strong cold front along with an associated area of low pressure will approach the region from the west later tonight before crossing the area late Friday into Friday night. Cold high pressure follows this system for early next week, with a chance of upslope snow showers. && .NEAR TERM /THROUGH TONIGHT/... As of 430 PM EST Thursday... Appears best shot at more widespread moderate to even heavy rain will occur overnight as deep moisture per PWATS of around 1.5 inches stream inland from off the Atlantic associated with residual energy with the low off Florida. Guidance shows this combined with a lobe of strong 85h theta-e advection and within a good veering profile with height including a 40-50 kt jet out east. This should result in a swath of steadier rain during the evening across the region with perhaps some enhancement out east late where can`t totally rule out isolated thunder given forecast lift and strong warm advection/shear as the wedge quickly erodes. This supports likely to categorical pops most areas early, then mainly eastern half overnight, with added QPF totals of perhaps an inch or more. Otherwise once the weak wedge exits during the evening should see temps steady, then rise overnight with some spots possibly in the upper 50s to 60s by daybreak. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... As of 430 PM EST Thursday... Deep southwesterly flow will continue to pump in warm moist air into the region Friday. With the cold front over the Ohio Valley Friday morning, only isolated to scattered showers are possible. Waves of low pressure will form along the front as it moves over the Tennessee Valley. Each wave will track northeast along the boundary allowing the front to advance eastward. Widespread showers, possibly embedded rumble of thunder, will move over the mountains by mid afternoon, then across the entire area by the evening. PWATS are 2-3 standard deviations above normal. Upward of an inch of rain is possible for the area mainly falling Friday afternoon and evening. Current antecedent conditions have creeks, streams, and river levels running low. Therefore there are no hydro concerns. However, the ground is still frozen, with the exception of the first couple of inches, and high rainfall rates could lead to localize flooding, especially in poor/clogged drainage areas. One bit of good news is that temperatures will run above normal with widespread 60s across the area to possibly 70F in the piedmont. The final wave along the front will move north of the area by midnight with the surface front tracking into North Carolina early Saturday morning. Downsloping flow will bring an end to the rain east of the Blue Ridge, while the deformation zone with the upper level trough keeping showers across the mountains through Friday night. By sunrise, typical upslope snow showers are expected along western slopes and flurries across the rest of the mountains. Cold air will be slow to move in, therefore the transition from rain to snow over the mountains may not occur until early Saturday morning. Cold air will slowly bleed into the area Saturday with mountain high temperatures peaking by noon then becoming steady or falling during the afternoon. High temperatures in the west will range from the upper 20s to mid 30s. East of the Blue Ridge, temperatures should peak in the 40s in the early afternoon. A stronger surge of cold air will come in Saturday night, sending temperatures into the teens west to the 20s east. Snow showers will continue Saturday night with most accumulations remain on western slopes of SE WV. Total snow accumulations Saturday into Saturday night will range from 2 inches in western Greenbrier to round an inch at Bluefield. A dusting of snow may occur across the rest of the mountains. && .LONG TERM /SUNDAY THROUGH THURSDAY/... As of 425 PM EST Thursday... Upslope snow showers begin to dissipate Saturday night, with a reinforcing shot of even colder air for the rest of the weekend. That will be the main story for the weekend into early next week - that being the return to below normal temperatures as cyclonic flow aloft and troughing becomes established and reinforced. It looks to overall be a dry period, though some indication in the global models of a clipper type system in the late Monday through Tuesday timeframe that could introduce light snows, lingering into Wednesday in upslope areas. Fortunately it does not appear that temperatures will get as cold as the case last month. Temperatures should begin to moderate and trend closer to normal into the midweek timeframe. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/...
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As of 655 PM EST Thursday... 24 Hour TAF Period: Poor flying conditions in low cigs including areas of rain/fog can be expected tonight and Friday. Shallow inversion with northeast winds at the surface was less than 2000 feet deep with warmer air and winds above the strong inversion from the south at up to 50 knots. LLWS remains in the KBLF, KLWB, KDAN, KROA, and KLYH TAFs through Friday morning. Little to no improvement in conditions overnight. Ceilings will remain IFR to LIFR across southwest Virginia, northwest North Carolina and southeast West Virginia. Ridges will be obscured in the low stratus. Several rounds of light to moderate rain is expected tonight into Friday. High confidence of occurrence of this precipitation along with areas of drizzle and fog along the Blue Ridge and the eastern foothills that will result in sub-VFR visibilities. Outlook: A prolonged period of sub-VFR conditions continue Friday night into early Saturday. Rain showers will change to accumulating wet snow in the western mountains late Friday night into early Saturday. Colder northwest flow then brings a period of VFR with upslope MVFR ceilings and lingering mtn snow showers Saturday into Saturday night. East of the Blue Ridge will return to VFR Saturday with VFR across the region Sunday. Moderate confidence on gusty northwest wind gusts in the weekend as well. MVFR snow showers are possible late Monday ad Tuesday.
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&& .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...JH NEAR TERM...AMS/JH SHORT TERM...RCS LONG TERM...AL/GIH AVIATION...BSD/AMS/JH/WP is the U.S. government's official web portal to all federal, state and local government web resources and services.