Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 06/18/19

Area Forecast Discussion
National Weather Service Denver/Boulder CO
811 PM MDT Mon Jun 17 2019 .UPDATE... Issued at 800 PM MDT Mon Jun 17 2019 Areas of rain and a few storms continue over the plains early this evening. Meanwhile a weak upper level trough will move across the area overnight. Thus expect scattered showers and and a few tstms to continue past midnight over much of the area, however, intensity will be lighter as compared to what occurred this aftn. && .SHORT TERM...(This evening through Tuesday) Issued at 230 PM MDT Mon Jun 17 2019 Afternoon convection is underway across the mountains and foothills with heavy rain and small hail the main threats. So far, storms have been producing about a half inch per hour or less rainfall rates. PW values ranging from 3/4 to an inch over the plains. Initially the Front Range urban corridor and adjacent areas are a bit more stable with ACARS soundings over Denver still showing weak stable layer near 700mb due to more cloud cover from this morning. With time, storms expected to push east over the plains and still looking at strong to severe storms further east of the urban corridor with better surface heating. CAPE values still expected to push 2000 J/kg but mid level flow only 15-25kt. With several weak impulses aloft expect another round of storms through the evening so will carry chance pops through at least midnight. For Tuesday, expect another cool and showery day with another round of showers and thunderstorms in the afternoon. Precipitable water values will remain high on Tuesday, generally around one inch so main threat will be heavy rain. Instability is a bit weaker on Tuesday, generally under 1000 J/kg along with weak shear profile, so severe weather threat will be lower. Temperatures will remain in the upper 60s and lower 70s across lower elevations. Will keep the likely PoPs going through Tuesday given the high moisture levels. .LONG TERM...(Tuesday night through Monday) Issued at 230 PM MDT Mon Jun 17 2019 A shortwave trough axis will push across the area Tuesday night to usher in drier air in northwesterly flow aloft. This will bring gusty downslope winds to the foothills and nearby urban corridor, keeping temperatures moderated. A shortwave upper ridge will bring warmer and drier weather to the area ahead of the next system dropping into the Pacific Northwest. PWATs will be about one to two tenths drier compared to the last two days, with values in the 0.5 inch range over the mountains, 0.75 inch over the urban corridor and up around an inch over the far northeastern corner of the state. Showers and weak storms will be isolated to scattered in coverage, with gusty winds and small hail the main impacts. Minimum temperatures will be relatively warm overnight with a continued surface trough to the lee of the mountains. An upper low will travel east along the US/Canadian border extending a trough into the Great Basin Thursday and Friday. Flow aloft will turn flow more westerly Thursday before more southwesterly Thursday night into Friday as a jet pushes down across the northern Rockies. After the warm night, Thursdays temperatures will likely be the warmest, with readings in the low 80s over the plains, and in the upper 50s to lower 70s over the high country. Lift from the jet and low level moisture moving north from the southern Great Plains into the surface lee low will bring a higher chance for thunderstorms, especially near the northern border. High values of shear will allow some of these storms to have the chance to become severe each afternoon and evening. Friday night, a cold front will drop south across the area. The upper trough will slowly transition across the forecast area this weekend with cooler temperatures and daily showers and thunderstorms, keeping our area green well into the month of June. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 800 PM MDT Mon Jun 17 2019 Showers and a few weak tstms have redeveloped over western portions of Weld county and are slowing moving southeast. For now will just mention vcsh in the taf as this activity should stay northeast of DIA. Otherwise will see stratus develop overnight around 09z. Winds have gone to a light northerly northeast and should become southerly by 06z. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...RPK SHORT TERM...Entrekin LONG TERM...Kriederman AVIATION...RPK
Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
841 PM PDT Mon Jun 17 2019 .SYNOPSIS...17/809 PM. Onshore winds will bring low clouds and fog across the coast and valleys throughout the week, mainly for the morning and overnight hours. Maximum temperatures will be slightly below normal across the coasts and valleys and slightly above normal across the interior. && .SHORT TERM (MON-THU)...17/840 PM. Weak upper level trough of low pressure combined with strong onshore flow continued to bring a deep marine layer pattern to Southwest California today, with low clouds lingering across some immediate coastal areas through the afternoon hours. For this evening, satellite imagery showing a chaotic low cloud pattern, but expecting low clouds to fill in across most coastal and valley areas overnight into Tuesday morning. Latest ACARS data showing marine layer depth around 3000 feet across the LA basin this evening. Over the next 24 hours, expecting the marine layer depth to decrease a bit due to rising heights and a slightly weaker onshore gradient. In fact, latest 00Z NAM model showing a weak low level northeast flow pattern across interior sections on Tuesday morning. This should allow the low clouds to burn off better on Tuesday. There were some afternoon cloud build-ups over the the mountains this afternoon. Latest 00Z NAM model showing slightly better moisture/instability for Tuesday afternoon, so will continue with slight chance of convective showers for the Ventura county mountains. Cannot totally rule out an isolated thunderstorm, but at this point would say the probability is around 10 percent for the Ventura county mountains. If any storms were to develop, model soundings suggest they would be high-based, with gusty downdraft winds being the biggest threat (due to inverted-v type sounding structure). *** From previous discussion *** Heights increase on Wednesday as the trof axis moves further south and the Pacific high nudges back in from the west. Subsequent warming aloft will strengthen the capping inversion. Onshore flow will increase back to Monday`s levels. Both of these things will slow clearing in the valleys and allow only partial clearing across the coastal areas. Afternoon high temperatures will run about 5 degrees below normal along the coasts and valleys due to the marine layer and strong onshore flow but will rise to slightly above normal across in the interior on Wednesday and Thursday due to the higher heights. Gradients of over 10mb suggest the already strong onshore flow will increase on Thursday. Expect slow marine layer clearing in the valleys and very limited clearing along the coasts. It will be windy across the Antelope Valley. Temperatures will cool a few degrees. .LONG TERM (FRI-MON)...17/205 PM. The gradient remains exceptionally strong into Friday with conditions similar to those on Thursday. Gradients relax somewhat over the weekend as the upper-level low moves to the northeast. The night through morning low cloud pattern will persist but there will be somewhat better afternoon clearing although beach clearing will be questionable. The pattern looks very zonal for our area by Monday as a large upper-level low centers itself about 250 miles west of Seattle, and we are at the southern extend of the feature with westerly flow aloft. Temperatures should warm a bit. && .AVIATION...18/0028Z. At 0015Z at KLAX...The marine layer was 3000 feet deep. The top of the inversion was around 4500 feet with a temperature of 18 C. High confidence in TAFs. Strong onshore flow pattern and deep marine layer resulted in delayed burnoff of low clouds this afternoon, with some coastal areas continuing to see cigs as of 00z. Low clouds and fog expected to spread into most coastal/valley areas overnight, however marine layer depth not expected to be quite as deep as this morning. With weak low level offshore wind influence across the interior, look for better clearing on Tuesday afternoon, especially valleys. KLAX...High confidence in TAF. MVFR cigs expected to prevail across most of the forecast period. There is a 30 percent chance of clouds burning off on Tuesday afternoon. KBUR...High confidence in TAF. With deep marine layer pattern in place, expecting low clouds to quickly redevelop later this evening. Higher probability of clouds burning off by late morning or early afternoon on Tuesday. && .MARINE...17/821 PM. Winds and seas will likely remain below Small Craft Advisory (SCA) levels through at least Thursday. There is a 30% chance for a low end (SCA) for Friday afternoon across the outer waters. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...NONE. PZ...NONE. && .HAZARD POTENTIAL OUTLOOK (THU-MON). No significant hazards expected. && $$ PUBLIC...Gomberg/jld AVIATION...Gomberg MARINE...Sweet SYNOPSIS...Phillips/B