Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 12/07/19

Area Forecast Discussion
National Weather Service Blacksburg VA
652 PM EST Fri Dec 6 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 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 /00Z SATURDAY THROUGH WEDNESDAY/... As of 645 PM EST Friday... A weak front will gradually sink into the region overnight. Do not expect a lot in the way of weather to accompany the front and expect locations east of the Blue Ridge to remain VFR through the period. However, low level moisture will linger west of the Ridge with a period of MVFR cigs expected at KBCB and especially at KLWB. 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. Winds will surge east of the Blue Ridge as the front moves through with northeast flow becoming a big gusty at KLYH and KDAN toward daybreak. Otherwise, winds will generally be light with little impact to aircraft operations. .Extended Aviation Discussion... High pressure will keep VFR conditions in place for Saturday night and Sunday. 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
Area Forecast Discussion
National Weather Service San Diego CA
205 PM PST Fri Dec 6 2019 .SYNOPSIS... A moist, southwest flow aloft will bring increasing clouds, with light rain likely by evening. The clouds will persist through the weekend, along with a chance for periods of light rain showers as a weak storm system drops south across the State. It will move east on Monday, with clearing skies and a warming trend for next week. Further warming is on tap for next weekend as dry weather persists. At the beaches, a large west swell bring high surf this weekend. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... ...Update... Quick update to increase POPS through this evening. Doppler radar shows a shield of rain entering Orange County extending south off the San Diego County coast. This area is moving northeast at about 35 mph. The radar bark is worse than the bite. Aircraft sounding data shows a dry layer in the lower levels, so some of the rain falling is evaporating. Upstream gauges over San Clemente Island show max rain over the past hour of 0.07". So this will be a light rain but most coast and valley locales do look to get wet late this afternoon through this evening. As such, increased POPS substantially to account for this expectation. Rainfall of trace-0.10 inches is expected through this evening west of the mountains and along the coastal mountain slopes. ...Previous Discussion (Issued at 1223 PM PST Fri Dec 6 2019)... Satellite imagery at midday showed a thicker blanket of high clouds spreading NE across the area. In addition, the radar indicated some precipitation moving NE over the coastal waters. Some of this could make it into Orange and San Bernardino Diego Counties by late afternoon. The sfc pressure gradients from the deserts were still weak to moderate offshore, supporting NE winds below the passes with local gusts 25-35 MPH. Still, the sea breeze was evident into the western valley areas. A storm system centered 500 miles west of Cape Mendocino today, will drift east through Saturday, and then drop south through Monday as a strong ridge builds off the Coast. Weak disturbances off the Pacific ahead of it will gather up some Pacific moisture, sparking some occasional light precip that will favor the coastal slopes. Upslope is generally weak though, so no heavy amounts are likely with no good atmospheric lift to squeeze it out. Snow levels will be quite high initially, above 8K FT through Saturday, then fall to around 7K FT by late Sunday. The final trough axis passes through SoCal on Monday morning, so some light, scattered showers may continue into early Monday for San Diego County especially. Overall precip amounts of 1/4-1/2 inch are expected west of the mts, and 0.5 to 1.5 inches on the coastal slopes and higher terrain. For the deserts, less than one-quarter inch total. Several inches of snow are possible in the San Bernardino Mts by Mon morning above 7500 FT. A highly amplified ridge develops early next week along the West Coast and keeps SoCal protected from activity in the westerlies through next week. Even though the ridge flattens, it strengthens further next weekend along 30N latitude. This will likley bring well above average temps to SoCal by next weekend, along with continued fair and dry weather. && .AVIATION... 062020Z...Coasts/Valleys...SCT-BKN high clouds AOA 20000 ft MSL and unrestricted vis this afternoon. Cigs 2000-2500 ft MSL and vis 2-4 SM in areas of RA after 01Z Sat. Mountains...SCT-BKN high clouds AOA 20000 feet MSL with unrestricted vis through this afternoon. Low clouds will obscure terrain above 3000 ft MSL, with vis 1-3 SM at times after 01Z Sat with -RA/-SN. Deserts...Mostly clear skies through Fri. Chance of -RA Sat. Cigs around 5000 ft MSL and vis 3-5SM possible in RA. && .MARINE... Scattered rain showers this afternoon through Sunday. Combined seas of 6 to 8 ft are expected Saturday afternoon through Sunday evening. && .BEACHES... A High Surf Advisory has been issued as long-period northwest swells of 14 to 18 seconds arrive at the coasts of Southern California. The swells will start to build on Saturday, peaking Sunday morning, and subsiding by Monday morning. Surf of 6-8 ft is expected in San Diego County and 4-7 ft surf is expected on beaches prone to WNW swells in Orange County. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...High Surf Advisory from 4 AM Saturday to 4 AM PST Monday for Orange County Coastal Areas-San Diego County Coastal Areas. PZ...NONE. && $$ PUBLIC...Gregoria (Update)/10 (Prev Discussion) AVIATION/MARINE...PG