27/331 AM.
Night and morning low clouds will be common through at least Thursday, with temperatures well below normal. Modest warming likely to follow. A few spits of drizzle is possible, especially on Monday. Gusty winds will continue over the interior mountains and deserts, as well as southwest Santa Barbara County through at least the weekend.
(tdy-Mon), 27/327 AM.
The main weather concern continues to be extensive marine layer clouds during the overnight to morning/early afternoon hours, gusty winds and cooler than normal temperatures. Last night low clouds advanced well inland over the coasts and coastal valleys, and into interior San Luis Obispo County, the Santa Clarita Valley and up the lower coastal slopes. This is expected to recur tonight into Saturday. Today LA County cleared more slowly than the Ventura coast and valleys, and the HREF low cloud cover forecast indicates that this is likely again on Wednesday. Over portions of Ventura County, clearing may be delayed or limited tomorrow. This deep marine layer with extensive low cloud cover and slow/limited clearing is likely to persist through early next week.
As for winds, the Wind Advisories for SW Santa Barbara County (NW winds) and the Antelope Valley and Foothills (SW winds) are increasing slowly, with a chance of falling short of Advisory levels (45 mph). Saturday afternoon and night appear more likely to reach Advisory levels in SW SBA County, with stronger surface pressure gradients between KSBA and KSMX.
A persistent upper trough over the West Coast along with continued strong onshore flow and an extensive marine layer will result in a cooling trend for the area through Sunday. Highs along the coast will change little, but away from the coast cooling of 2 to 6 degrees is expected on Saturday, especially over the far interior. Weaker cooling of 2 to 3 degrees is expected going into Sunday and Monday.
(Tue-Fri), 27/338 AM.
Broad upper level troughing and seasonably healthy onshore flow will keep temperatures well below normal through at least Thursday. Expecting an expansive marine layer in depth and areal extent. This is especially the case starting Tuesday as the Sundowner winds weaken, which should allow the low clouds to expand over all coastal areas. Most computer projections and ensemble solutions favor upper level ridging to form starting Friday or Saturday of next week, which should bring some warming and decrease in the marine layer. There is a rather large envelope in the ensemble suites however as to the magnitude of that change. So look for a warming trend as we head into the 250th July 4th weekend, but stay tuned as to how much warming to plan for.
27/1026z.
At 10Z at KLAX, the marine layer was 2500 ft deep. The top of the inversion was at 5000 feet with a temperature of 18 Celsius.
High confidence in VFR TAFs for KPMD KWJF with abnormally strong and persistent onshore winds. Possible UDDF near mountains.
High confidence in ceilings at all other airports. Moderate confidence in timing (+/- 3 hours) and flight categories (+/- 1 category.
KLAX, High confidence in ceilings and flight categories. Moderate confidence in timing (+/- 3 hours). High confidence in any east wind component staying under 8 knots.
KBUR, High confidence in ceilings and flight categories. Moderate confidence in timing (+/- 3 hours).
27/326 AM.
High confidence in Small Craft Advisory (SCA) level winds for the outer waters from the Central Coast through San Nicolas Island through Sunday or Monday, with some improvement after. The nearshore waters will likely see SCA winds each afternoon and evening.
High confidence in SCA winds over the western Santa Barbara Channel late this afternoon and evening, with lowering chances to follow. The rest of the waters will likely stay under SCA, except for localized winds approaching 25 knots in the afternoon and evening hours today.
All waters will see short-period choppy seas into early next week, with today likely being the worst.
Ca, Wind Advisory now in effect until 6 AM PDT early this morning for zones 349-351. (See LAXNPWLOX). Wind Advisory now in effect from 5 PM this afternoon to 6 AM PDT Sunday for zones 349-351. (See LAXNPWLOX). Wind Advisory remains in effect until 5 AM PDT Sunday for zones 381-383. (See LAXNPWLOX). PZ, Small Craft Advisory in effect until 3 AM PDT Sunday for zone 645. (See LAXMWWLOX). Small Craft Advisory in effect from 11 AM this morning to 3 AM PDT Sunday for zone 650. (See LAXMWWLOX). Small Craft Advisory in effect until 9 AM PDT Monday for zones 670-673-676. (See LAXMWWLOX).
