Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 070500 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 1200 AM EST Sat Dec 7 2019 .SYNOPSIS... A weak cold front will depart offshore tonight. High pressure should arrive to provide dry weather for the weekend. Another cold front will provide a wet start to early next week. && .NEAR TERM /THROUGH SATURDAY/... As of 1150 PM EST Friday... No significant changes needed. Clouds are hanging in across all but the far northeast and eastern sections of the CWA. Models hang on to the clouds across most areas west of I-81 overnight. The main impact this has had is on the temperatures, with northern areas running warmer than earlier anticipated. Raised temperatures a few degrees, especially in the western part of the I-64 corridor. Otherwise no significant changes made at this time. Remaining light rain across WV continues to dissipate, so trend toward < 15% pops looks good overnight. As of 140 PM EST Friday... A weak cold front will cross overhead this afternoon. Skies should remain cloudy through the evening as light rain showers linger west of the Blue Ridge. However, the echoes on radar crossing the Blue Ridge into the Piedmont appear to be mostly virga. Any shower activity outside of southeast West Virginia will likely dissipate after sunset. Despite the cloud cover, the warm air advection from a light southwest breeze is allowing high temperatures to reach close to model guidance. After the frontal passage, winds should shift around to the northwest tonight. A little bit of upslope moisture should provide a quarter of an inch of snow showers for western Greenbrier County during the overnight hours. The snow showers will subside after midnight as drier air arrives. Elsewhere, skies will partially clear before sunrise as high pressure begins to build from the northwest. Low temperatures were kept slightly elevated compared to model guidance due to the clouds holding for a good chunk of the night. Saturday should be dry with near seasonable temperatures as high pressure takes control. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/... As of 315 PM EST Friday... A large area of surface high pressure will slide from New England to off the East Coast. In concert with the approaching trough to the west, these features will turn our large scale flow such that it is southerly. This will bring increasing amounts of Gulf moisture into our area on Sunday, building cloud cover throughout the day. Showers will begin late Sunday night or early Monday morning and continue with varying strength until Tuesday night, when a strong cold front passes over the area. Most of the precipitation associated with this event will be liquid. Sunday will be slightly cooler than what is normal for this time of year, but Monday and Tuesday will see a warm up into the 50s in the west and even low 60s for parts of the southside. && .LONG TERM /TUESDAY THROUGH FRIDAY/... As of 315 PM EST Friday... Rain will continue throughout the day Tuesday, and as the cold air behind the front approaches on Tuesday night, those west of the Blue Ridge may see some snow. Overnight into Wednesday morning some gusty winds will accompany the frontal passage, especially affecting the higher ridges. Once the front has moved on, the moist environment of the early week will be supplanted by drier air and a new surface high heading our way from the northern plains. The cold air mass behind the front will drop our temps well below normal for December, so the end of the week will be chilly. The next opportunity for active weather will be late Friday or early Saturday as a low pressure system comes to us from the south. Guidance has been wavering from run to run on the track and timing, but there is a good consensus that a surface low will bring precipitation around next weekend. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... As of 1150 PM EST Friday... A weak front will continue to sink southward through the region overnight. Remaining light rain in WV is dissipating as there is very limited upper-level support and downslope west winds east of the Alleghany front. The WV precipitation is mainly due to light upslope, which will dissipate overnight as the winds veer to the northeast. Low-level moisture will linger west of the Blue Ridge with MVFR ceilings likely to continue for many of the TAF sites overnight, with the exception of KLYH and KDAN, which should see some periods of VFR. KBLF will be up in the clouds and expect IFR conditions with some fog and drizzle to become established later tonight. A gradual trend back toward VFR will begin after daybreak with all sites VFR toward the end of the valid period. However, models hang onto the clouds pretty tough on Saturday, so have advertised more pessimistic TAFs into the afternoon than previously indicated. Ceilings may remain MVFR throughout much of the day west of the Blue Ridge, but especially along and west of the I-77/New River Valley area. No precipitation is expected Saturday and fog is not expected either, so any restrictions to visibility would be entirely the result of a location obscured by clouds due to elevation. Winds will veer to the northeast overnight and early Saturday at all sites, but first across the Piedmont. Speeds will gradually increase from 5kts overnight to 6-10kts during the day Saturday with low end gusts possible across the Piedmont by afternoon. /Confidence in Forecast Parameters/ Ceilings - Moderate to High, Visibility - High, Winds - Moderate to High. .Extended Aviation Discussion... High pressure should dominate the area Saturday with mostly VFR conditions. Confidence continues to increase in poor flying weather for Monday and Tuesday as a complex low pressure system develops to provide low ceilings and rain. The cold front from this low pressure system should cross overhead by Tuesday night to bring gusty northwest winds for Wednesday. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...PW NEAR TERM...PW SHORT TERM...VFJ LONG TERM...VFJ AVIATION...MBS/PW/RAB is the U.S. government's official web portal to all federal, state and local government web resources and services.