05/608 PM.
Temperatures will remain near to slightly below normal through at least early next week as a series of low pressure systems move over the region. Low clouds and fog will cover most of the coast and valley locations through at least mid morning, clearing to near the beaches each afternoon. A warming trend is expected later next week.
(Fri-Mon), 05/842 PM.
***UPDATE***
June Gloom low clouds and fog will continue each day for the coasts and valleys. The region will remain under the influence of multiple low pressure systems centered over the Pacific Northwest with the associated trough extending all the way down the US west coast. 500 mb heights look to bottom out on Sunday and surface pressure gradients will remain strongly onshore over the next few days. Tomorrow, high clouds passing over the area will keep skies at least partly cloudy even after the marine layer low clouds and fog clear out in the afternoon. Additionally, cold air will spill into from the interior, resulting in dramatic cooling across the inland areas and deserts. Highs will be in the mid 60s to mid 70s across the beaches and inland coastal plains, and in the 80s for the warmer valleys and the deserts. Minor temperatures chances are then forecast for Sunday and Monday.
Gusty southwest winds will continue each afternoon and evening for the Antelope Valley due to the onshore pressure gradients. Additionally Sundowners Winds are favored across southwestern Santa Barbara County Saturday and Sunday nights (and possibly the I5 corridor) as northwest flow sets up across the coastal waters.
***From Previous Discussion***
Forecast soundings are finally starting to show a deepening marine layer through the weekend, rising from 2000 feet today south of Pt Conception to around 3000 feet tomorrow morning and 3500 feet Sunday. A little less deep north of Pt Conception. This combined with increasing onshore flow and weak eddy circulation will bring inland temperatures down at least 4-8 degrees and coastal areas down 1-3 degrees. Low clouds and fog will push into the valleys each night, including the Santa Clarita Valley with later clearing inland and minimal clearing at the beach, if any. Central coast areas will likely clear earlier than areas to the south but temperatures will be cooling there as well, especially inland.
(Tue-Fri), 05/155 PM.
Medium range models continue to favor a warming at least through next week as high pressure builds in from the west. Sundowners will be a daily occurrence each afternoon and evening most of the week and temperatures will warm at least 1-3 degrees each day. Still expecting valley highs to remain no higher than the 80s through Wednesday and the Antelope Valley mostly in the lower 90s.
Confidence in the forecast beyond that remains rather low. While more than half of the ensemble solutions do continue to show a very slow climb of temperatures into next weekend, there are still at least 40% that maintain a weak trough over the southwest with a steady dose of onshore flow each day. While the latter would be the climatologically favored solution, certainly cannot discount a warmer pattern at this point. There are even around 20% of solutions showing a light to moderate offshore gradient, which would be very anomalous for this time of year. Based on the latest NBM there is roughly a 5-10% chance of warmer valleys reaching 100 next weekend and Downtown reaching the 90.
06/0106z.
At 0029Z at KLAX, the marine layer was 1600 feet deep. The top of the inversion was at 4000 feet with a temperature of 22 degrees Celsius.
For the 00Z TAF package, high confidence in KPMD and KWJF. For all other sites, moderate confidence in current forecast due to uncertainties in behavior of marine layer. Low confidence in KPRB due to uncertainty in low cloud coverage and timing. Otherwise, the timing of flight category changes could be +/- 3 hours of current forecasts.
KLAX, Moderate confidence in the 00Z TAF. Timing of flight category changes could be +/- 3 hours of current forecasts. 30-40% chance that no IFR conds occur. No significant easterly wind component expected.
KBUR, Moderate confidence in the 00Z TAF. Timing of flight category changes could be +/- 3 hours of current forecasts. 30% chance of IFR conds between 06Z and 18Z.
05/845 PM.
For the Outer Waters, moderate to high confidence in current forecast. Through Wednesday, high confidence in a combination of Small Craft Advisory (SCA) level winds and seas. Additionally, there is a 60-80% chance of GALE force winds across PZZ670/673 Saturday and Saturday night. A GALE WARNING is in effect for these areas. Starting Sunday, there will be SCA winds and steep seas every day through at least Wednesday night. There will be a 30% chance of Gales during the late afternoon and evening each day Monday through Wednesday.
For the Inner Waters north of Point Sal, high confidence in current forecast. Through Saturday morning, winds and seas will remain below SCA levels. From Saturday afternoon through Wednesday, SCA level winds are expected during the afternoon and evening hours, along with seas approaching SCA levels.
For the Inner Waters south of Point Conception, moderate confidence in current forecast. For a majority of the southern Inner Waters, high confidence in winds and seas remaining below SCA levels through Wednesday. The only exception will be the western half of the Santa Barbara Channel, where there is a 40-60% chance of SCA level winds Monday through Wednesday, mainly in the late afternoon and evening hours.
Ca, NONE. PZ, Small Craft Advisory in effect from 3 PM Saturday to 3 AM PDT Sunday for zone 645. (See LAXMWWLOX). Small Craft Advisory in effect until 3 AM PDT Saturday for zone 670. (See LAXMWWLOX). Gale Warning in effect from 3 AM Saturday to 3 AM PDT Sunday for zone 670. (See LAXMWWLOX). Small Craft Advisory in effect until 3 PM PDT Saturday for zone 673. (See LAXMWWLOX). Gale Warning in effect from 3 PM Saturday to 3 AM PDT Sunday for zone 673. (See LAXMWWLOX). Small Craft Advisory in effect until 3 AM PDT Sunday for zone 676. (See LAXMWWLOX).
