Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 05/24/22

Area Forecast Discussion
National Weather Service Los Angeles/Oxnard CA
830 PM PDT Mon May 23 2022 .SYNOPSIS...23/820 PM. Warmer conditions away from the coast expected through at least the middle of the week under developing high pressure. The marine layer will continue to impact coastal areas and nearby valley areas, most expansive after Tuesday. Gusty winds will affect the mountains and interior valleys each afternoon and evening after Tuesday. && .SHORT TERM (MON-THU)...23/820 PM. ***UPDATE*** The marine layer is a touch deeper than 24 hours ago, but should shrink back down a little as onshore flow weakens later tonight. Low clouds and marginal fog will impact all coastal areas over southern Santa Barbara, Ventura, and Los Angeles Counties tonight into Tuesday, along with some of the coastal valleys. Some dense fog is possible but not certain from Lompoc to Santa Ynez, otherwise the Central Coast will be clear. There will be a bit of a battle between the marine layer, and a quick burst of offshore flow (20-30 mph) Tuesday morning. With a temperature inversion on the order of 10 degree Celsius however, this generally weak wind burst will be far too impotent to scale back the marine layer much if at all. If anything, it should help bring quicker clearing over the valleys on Tuesday. That extra sunlight should bring a few degrees of warming as a result. Coastal areas however should see little to no warming with the marine layer holding fast. The mountains and interior valleys on the other hand, being outside of the marine layers reach, will see about 5 degrees of warming with highs in the 90s. This includes the Santa Clarita Valley which, going from marine layer to no marine layer, should see the largest jump (10+ degrees) of temperatures on Tuesday. A few temperature records (Lancaster and Paso Robles) could break on Tuesday, but those records are abnormally low compared to records on the days surrounding May 24th. Along with morning lows fairly cool (providing much heat relief), Heat advisories are NOT being considered at this point, but folks should be mindful and smart with the heat. Seek air conditioning, drink lots of water, and avoid prolonged sun exposure. ***From Previous Discussion*** Stronger onshore flow develops Wednesday afternoon with an onshore LAX-DAG gradient of around 7-8 mb will support west winds of 25 to 35 mph, with gusts to 45 mph over the Antelope Valley. Minor edits were made to account for lingering marine layer clouds this afternoon and increase cloud coverage this evening into Tuesday morning. Otherwise, the forecast looked on track. Overall, 00Z models in good synoptic agreement through the short term period. At upper levels, ridge will build over the eastern Pacific today/Tuesday then will be pushed eastward as a trough approaches the West Coast. Near the surface, moderate onshore flow will persist. Forecast-wise, main challenge will be the marine layer stratus. Currently, AMDAR soundings indicate marine inversion around 1300 feet deep. With onshore gradients and eddy over the Bight, stratus and fog should become widespread across the coastal plain south of Point Conception, but could struggle getting into the coastal valleys (based on latest satellite trends). North of Point Conception, stratus/fog will remain confined to the west coast of SBA county (mainly Lompoc and Vandenberg area) this morning. Stratus should dissipate by late morning all areas. For tonight/Tuesday, rising H5 heights will help squash the inversion a bit, but areal coverage will be very similar to this morning (with a little more penetration into the lower coastal valleys). For Tuesday night/Wednesday, high resolution models indicate a "southerly surge" which will combine with slightly lower H5 heights to allow for more widespread stratus coverage across the coastal plain, reaching up to the SLO county coast (with a bit more coverage across the lower coastal valleys). Other than the stratus/fog, skies should remain mostly clear through Wednesday. Secondary issue will be the temperatures. Given the overall pattern, will expect a general warming trend for the area through Wednesday. In fact by Wednesday, coastal areas will generally be 4-8 degrees above normal with inland areas 6-12 degrees above normal. However, there is a chance that the coastal plain could be a little bit cooler on Wednesday due to the southerly surge increasing the marine influence. As for winds, moderate onshore gradients will continue to generate some gusty southwesterly winds each afternoon/evening across interior sections. However, any advisory-level gusts will be very localized in the usual `wind tunnels" such as Lake Palmdale. .LONG TERM (FRI-MON)...23/224 PM. For the extended, models continue to exhibit decent synoptic agreement through the period. At upper levels, ridging gradually slips eastward Thursday as a trough passes Friday. Near the surface, onshore flow will prevail to the east with an increase in northerly offshore flow over the weekend. Forecast-wise, Thursday and Friday look similar with the continuation of strong onshore flow. The LAX-DAG onshore gradient is forecast to peak Thursday near 8-9 mb. The combo of continued onshore flow and cyclonic flow aloft will allow for a bit more widespread stratus/fog, reaching into the coastal valleys, with mostly clear/partly cloudy skies elsewhere (due to high clouds drifting overhead). Temperatures through Friday will exhibit a cooling trend. From Friday night through Sunday, things get a little more interesting, mainly due to increasing northerly winds. Models indicate northerly gradients will gradually increase through the weekend, peaking Saturday night/Sunday morning. Looking at the NBM probabilities, there is generally a 75-85% chance of northerly gusts 45-50 MPH Saturday night and Sunday night across the Santa Ynez Range and the Interstate 5 Corridor. With this increased northerly flow, areal coverage of marine layer stratus will noticeably diminish through the weekend. Additionally, the lesser marine influence and northerly offshore winds will allow for a warming trend for the area (with the best warming west of the mountains). && .AVIATION...24/0020Z. At 23Z at KLAX, the marine layer was 1600 feet deep. The inversion top as at 3800 feet and 23 degrees Celsius. The next 24 hours should see a similar marine layer stratus evolution expected as last 24 hours. 30 percent chance of LIFE conditions at KSMX. OVC006-012 chances at at KSBA (80%) KOXR (100%) KCMA (90%) KSMO (100%) KLAX (100%) KLGB (90%) KBUR (50%) KVNY (30%). Moderate confidence in timing by +/- 3 hours. High confidence in VFR at KPRB KSBP KWJF KPMD. High confidence in gusty onshore winds typical for this time of the year. KLAX...High confidence in low clouds for majority of tonight. Random breaks are possible 01-08Z but less likely than last night. Moderate confidence in CIGS staying above OVC010, with a chance of dipping just below 06-12Z. High confidence in and east winds staying well under 8 knots. KBUR...High confidence in VFR through at least 06Z. 50 percent chance of OVC006-010 09-17Z. && .MARINE...23/759 PM. High confidence in Gale Force winds affecting the outer waters north of Santa Cruz island through late tonight, especially well offshore, with Small Craft Advisory conds eastern portions and and S of Santa Cruz Island. SCA conds will continue Tue into Tue evening N of Santa Cruz Island. The rest of the area should have fairly benign and seasonal conditions through Tue night. For Wednesday through Thursday afternoon, southerly winds will push up to Monterey County and shove the seasonal coastal jet well offshore. Local south to southeast winds of 10-15 knots are likely near all coasts in the morning hours, especially Wednesday. More significantly, seas will fall to nearly lake-like conditions by Thursday, with only 2-4 feet total waves everywhere including the Central Coast. The coastal jet should reform quickly Thursday Night into Friday, with Gale Force (focused outer waters to Central Coast) and widespread choppy seas returning for the weekend. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...NONE. PZ...Gale Warning in effect until 3 AM PDT Tuesday for zones 670-673. (See LAXMWWLOX). Small Craft Advisory in effect until 3 AM PDT Tuesday for zone 676. (See LAXMWWLOX). && $$ PUBLIC...Phillips/Kittell AVIATION...Kittell MARINE...Munroe/Kittell/Sirard SYNOPSIS...Kittell Experimental Graphical Hazardous Weather Outlook at: