09/115 PM.
Temperatures away from the coast will warm into the 80s and 90s through Monday. 100 degree readings may occur locally in the warmest valleys and Antelope Valley Sunday and Monday. Coastal low clouds will develop each night through the weekend. Cooling will begin on Tuesday.
(tdy-Tue), 09/116 PM.
High pressure continues to build over the region, however a persistent marine layer is so far keeping temperatures on the mild side. A slight offshore trend the next couple days will result in warming in most areas, peaking Monday, though the gradient trends will likely not be strong enough to wipe out the marine layer and coastal areas should remain on the cooler side. The tricky part of the forecast will be the intermediate areas between the coast and the valleys. This includes the Downtown LA area as well most areas between 5 and 15 miles of the coast. The most likely scenario for these areas is highs mostly in the 70s to lower 80s, but if some of the bolder ensembles verify then the warmer air could push closer to the coast. For the valleys there is still high confidence with highs in the 90s, but the latest heat risk calculations indicate that they will be below heat advisory levels. Will re-evaluate Sunday, but unless gradients shift significantly offshore, high temperatures will not be hot enough to qualify.
On Tuesday high pressure will weaken and shift east as an upper low moves into the Pac NW. This will induce a strong onshore trend with all coast and coastal valley areas cooling off 5-10 degrees. Desert areas will cool slightly but remain hot and dry, and with the big increase in onshore flow there is an elevated fire weather risk there.
(Wed-Sat), 09/113 PM.
A cooler weather pattern with a return of morning low clouds and fog is favored to continue through at least next Thursday when the next upper low is expected to move through California and into the Great Basin. Following the low passage Thursday and Friday gusty north winds are expected to develop over the mountains and portions of southwest Santa Barbara county. Early indications suggest winds gusty to around 50 mph in those areas. Another warming trend will begin later next week into next weekend, mainly for valleys and other inland areas, with lower 90s returning to the valleys.
09/2212z.
At 2130Z at KLAX, the marine layer was 1300 feet deep. The top of the inversion was at 3700 feet with a temperature of 20 degrees Celsius.
For 00Z TAF package, high confidence in CAVU conditions for KWJF and KPMD.
For all other sites, moderate confidence in 00Z TAFs. Timing of flight category changes could be +/- 3 hours of current forecasts. Additionally, there is a 40% chance of VLIFR conditions at KPRB in the 11Z-17Z time frame.
KLAX, Moderate confidence in 00Z TAF. Timing of flight category changes could be +/- 3 hours of current forecasts. No significant easterly wind component is expected.
KBUR, Moderate confidence in 00Z TAF. Timing of flight category changes could be +/- 3 hours of current forecasts.
09/147 PM.
GALE Warnings go in effect this afternoon across the Outer Waters to the west and north of Point Conception. These conditions should last through the evening hours - may linger past midnight across PZZ670. Short period seas peaking 10 to 12 feet are expected through tonight. In addition, Strong Small Craft Advisory (SCA) winds are expected nearshore along the Central coast during this timeframe.
Winds and seas should diminish throughout the day on Sunday. By Monday, conditions should be much calmer and are expected to remain below advisory levels through Tuesday. From Wednesday through Friday, chances for SCA level winds will increase each day especially across the outer waters.
Ca, NONE. PZ, Small Craft Advisory in effect until 3 AM PDT Sunday for zones 645-676. (See LAXMWWLOX). Gale Warning in effect until 11 PM PDT this evening for zone 670. (See LAXMWWLOX). Gale Warning in effect until 9 PM PDT this evening for zone 673. (See LAXMWWLOX).
