25/653 PM.
Marine layer clouds with patchy fog will reoccur each night from the coasts to the coastal valleys, expanding into the valleys over the weekend. Temperatures will trend cooler, with below normal temperatures through Sunday. A slow warming trend will begin on Monday.
(Thu-Sun), 25/826 PM.
***UPDATE***
Short term forecast concerns include a deep marine layer that is expected to cover the coasts and coastal valleys tonight, with a chance of being somewhat deeper, moving farther inland than last night. This would push low clouds across interior San Luis Obispo County, into the Santa Clarita Valley, and up the lower coastal slopes. The combination of a +8 mb LAX to Daggett surface pressure gradient and a developing coastal eddy will help to deepen the marine layer and push the low clouds well inland.
Another side effect of the strong onshore flow is gusty winds through the passes and canyons of LA County into the Antelope Valley. Lake Palmdale has been seeing gusts of 45 to 52 mph since around 300 PM this afternoon. Gusts elsewhere in the area are limited to 25 to 35 mph so will not issue a Wind Advisory for the isolated strong gusts. The winds are expected to diminish later this evening and overnight. Strong onshore gradients will continue through Saturday, finally weakening some on Sunday. Expect to see persistent gusty winds, with isolated strong gusts, in the afternoon to evening hours through Saturday and possibly into Sunday. As usual, the strongest winds will be over the interior, especially the Antelope Valley.
As for temperatures, a cooling trend is expected through the weekend, as heights aloft lower under the influence of a low pressure system in the Pacific Northwest. Some high clouds will move over the area at times, helping to keep the high temperatures down somewhat. Expect daytime temperatures to cool by several degrees each day through Sunday before a gradual warming trend begins on Monday.
(Mon-Thu), 25/1133 AM.
PacNW low pressure system will continue rotating northward into Canada with another closed low forming over Washington early next week. Ensemble solutions begin to differ in the details heading into middle of next week but all feature general troughing for the upper-level pattern over CA through late next week. This will keep onshore flow in place with low stratus/fog along coastal areas and valleys each evening and morning. Winds will run lighter next work week. Temperatures will remain fairly consistent into mid- to late next week, with daytime highs right around climatological norms to slightly above.
26/0319z.
At 0300Z at KLAX, the marine layer was 500 ft deep. The top of the inversion was at 3900 feet with a temperature of 19 C.
High confidence in VFR TAFs for desert airfields (KPMD & KWJF).
Moderate confidence in the remainder of the TAFs. Timing of flight cat changes could be off +/- 2 hours and CIG heights +/- 300 ft.
KLAX, Moderate confidence in TAF. Expecting MVFR/IFR CIGs through the overnight hours. Timing of flight cat changes could be off +/- 2 hours. No wind issue expected.
KBUR, Moderate confidence in TAF. Arrival of IFR CIGs should be accurate within +/- 2 hours of current forecast. No wind issues expected.
25/826 PM.
Small Craft Advisory (SCA) level wind gusts expected to increase overnight across the northern outer waters and will expand south through Friday and into the weekend. SCA winds will be strongest on Saturday, and will reach into the nearshore waters along the Central Coast and Santa Barbara Channel at times (more often than not). Local gusts may approach 35 kt near Pt. Conception Saturday evening into the overnight hours. Seas will near 10 ft Saturday evening through at least Monday morning. Beyond, conditions look to quiet down a bit through mid next week.
CA, NONE.
PZ, Small Craft Advisory in effect until 9 AM PDT Monday for zones 670-673. (See LAXMWWLOX).
Small Craft Advisory in effect from 3 AM Friday to 9 AM PDT Monday for zone 676. (See LAXMWWLOX).
