05/1251 AM.
Temperatures will be slightly above normal inland and near normal along the coast through Friday, then dropping below normal over the weekend and into next week as a large low pressure system develops over the West coast. Skies will be mostly clear except for night and morning low clouds and fog across the coast and valley areas.
(tdy-Sun), 05/453 AM.
A large upper level low currently situated off the British Columbia coast is expected to dive south towards PAC NW and deepen some through this weekend. This will result in the current weak ridging over our area to break down and by Sunday slightly below normal 500mb heights are expected.
Moderate onshore flow is expected to persist through the weekend both to the north and east. This in combination with decreasing heights will likely result in a 2500-3000 ft marine layer. Low clouds will have difficulty clearing near the coasts each afternoon. Marine layer stratus is most likely to cover the Santa Clarita Valley on Saturday due to LAX-BFL gradients peaking night through morning period.
A cooling trend is expected through the weekend. Most noticeable change is expected on Saturday, and along the Central Coast. By Sunday, most areas will be slightly below to below normal except across the Antelope valley where temps will cool to near normal.
There is a decent signal for low-end advisory level Sundowners Sunday evening. ECWMF and NAM indicate a 3-4mb gradient from the north.
(Mon-Thu), 05/258 AM.
The EURO and GFS ensemble suites are in agreement with another upper low diving southward but keeping the energy well to the north. Weak upper troughing will remain over the area through mid-week with slowly warming temperatures, but still either near to slightly below normal. Onshore flow to the east will persist but gradually weaken some Wednesday and beyond. While LAX-BFL projections indicate by Tuesday neutral to even weak offshore flow from the north is likely.
Potential for Advisory level Sundowners will continue at least through Wednesday evening. Most likely strongest on Tuesday. With the potential for offshore flow from the north, there is a small signal for low-end advisory winds across the I-5 corridor midweek.
05/1130z.
At 0524Z at KLAX, the marine layer was 1700 feet deep. The top of the inversion was at 3500 feet with a temperature of 23 C.
High confidence in VFR TAFs for desert airfields (KPMD & KWJF).
Moderate confidence in remaining TAFs. Timing of CIG/VSBY restrictions may be off +/- 3 hours and flight minimums by one category. Cigs may fail to clear in the afternoon/evening hours near the coasts.
KLAX, Moderate confidence in TAF. Arrival and clearing times of CIGs may be off +/- 2 hours of current forecast. Low MVFR CIGs 010-015 expected. There could be intermittent periods of IFR CIGs 008. No significant east wind component is expected.
KBUR, Moderate confidence in TAF. Arrival and clearing times of CIGs may be off +/- 2 hours. No wind issues expected.
04/836 PM.
For the Outer Waters, moderate to high confidence in current forecast. Through Tuesday, high confidence in a combination of Small Craft Advisory (SCA) level winds and seas. Additionally, there is a 30-40% chance of GALE force winds across PZZ670 and PZZ673 on Saturday and Saturday night, especially for zone PZZ670
For the Inner Waters north of Point Sal, moderate to high confidence in current forecast. High confidence in SCA level seas through late tonight. On Friday, high confidence in winds and seas remaining below SCA levels. For Saturday through Tuesday, there is a 60-80% chance of SCA level winds, mainly in the afternoon and evening hours. Additionally in the Saturday through Tuesday time frame, seas will be near or above 10 feet (SCA level).
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 Tuesday. The only exception will be the western half of the Santa Barbara Channel, where there is a 40-50% chance of SCA level winds Sunday through Tuesday, mainly in the late afternoon and evening hours.
Ca, NONE. PZ, NONE.
