Marine Weather and Tide Forecast for Lomita, CA

.SHORT TERM (THU-SUN)...15/819 PM.

***UPDATE***

Onshore gradients combined with a coastal eddy and a weak trough aloft should help to create a deeper and more widespread marine layer tonight. Low clouds are expected to develop for most coastal areas, most widespread across the Santa Barbara portion of the Central Coast and the LA Basin, extending inland to the adjacent coastal valleys. Low cloud coverage for the Ventura Coast and especially the Santa Barbara South Coast is less certain, but believe that the western portion of the Oxnard Plain and the Eastern SBA South Coast will see low clouds later tonight into early Friday. Gusty west to northwest winds continue this evening over portions of the area, but weaker than on previous days and well below Advisory level. The windiest areas continue to be SW Santa Barbara County and the interior sections, including the Antelope Valley and interior San Luis Obispo County.

High temperatures on Friday are expected to lower a few degrees, anywhere from 2 to 6 degrees cooler for the valleys with little change for the coast and deserts. Coastal low clouds and fog should clear by late morning, with clear to partly cloudy skies in the afternoon.

***From Previous Discussion***

Gradients are starting to trend onshore today as the last in a series of mostly weak troughs moves through the West Coast, peaking locally on Saturday. Temperatures today ended up being quite a bit warmer across the interior, but little changed near the coast.

As that trough advances southeast through northern and central California Friday and Saturday, onshore flow will continue to increase and peak Saturday afternoon at around 9mb with cooling temperatures each day. At the same time, cooling aloft will deepen the marine layer considerably. Latest forecast sounding across the LA Basin indicate the marine inversion depth rising to around 2000 feet Friday, then up to 4000 feet Saturday morning with a solid 5mb gradient. This combination of factors often, though not always, results in some drizzle across the coast and valleys. The one drawback in this case is the upper low is actually taking a more inside path through California with northwest flow aloft.
Most of the models do favor a rapidly deepening marine layer but given the interior trajectory and winds aloft the best chances for any drizzle would likely be the San Gabriel Valley in eastern LA County. Further west it will be a battle between the northwest flow aloft and the marine layer expanding from the southeast. By Saturday temperatures will again be 5-15 degrees below normal.
Gusty onshore winds will develop in the afternoon, especially across the Antelope Valley.

With models now in agreement that the first trough will take a more inland track and the next upper low also moving farther inland through Utah, there is increasing confidence that a slow warming trend will begin Sunday with earlier clearing of the marine layer, especially inland. Model forecast gradients are in line with that as well indicating a 2-3mb offshore trend.

.LONG TERM (MON-THU)...15/208 PM.

Confidence remains high in much warmer temperatures next week, especially Tuesday and beyond as high pressure builds and onshore flow weakens. Highs in the 90s are expected in the valleys and possibly some isolated lower 100s across the western San Fernando Valley. Inland coastal areas will at least reach the mid 80s and possibly lower 90s in downtown LA. Warmest day are expected to be Tue-Thu, but well above normal temperatures will continue at least through next Friday. There still may be a shallow marine layer at the coast creating some areas of dense fog.

AVIATION
15/2333Z.

At 2253Z at KLAX, the marine inversion was around 900 feet deep.
The top of the inversion was 2200 feet with a temperature of 18 degrees Celsius.

High confidence in TAFs for KPRB, KPMD, and KWJF.

Moderate confidence in remaining TAFs. Timing of cig/vsby restrictions may be off +/- 2 hours, with flight cats off by one.
There is a 40% chance of VLIFR vsbys & LIFR cigs at KSMX/KSBP from 06Z to 16Z Fri. There is a 20% chance of LIFR conds at kvny from 09Z to 16Z Fri.

KLAX...Moderate confidence in 00Z TAF. There is a 25% chance of IFR cigs 008-009 at some point between 06Z to 16Z Fri. No significant east wind component expected.

KBUR...Moderate confidence in 00Z TAF. There is a 30-40% chance of IFR Conds and a 10% chance of LIFR cigs w/ vsbys <1SM from 06Z to 16Z Fri.

MARINE
15/746 PM.

For the Outer Waters, high confidence in a combination of Small Craft Advisory (SCA) level winds and seas (at times), will lull in winds possible in the morning hours through the weekend. There is a 40% chance of GALE force NW wind gusts for northern portions of PZZ670 late Fri afternoon into the evening hours. Better chances for GALES for the waters around Point Conception, Northern Channel Islands, and down to San Nicolas Saturday evening through late Sunday. Seas will peak around 13 feet towards the end of the weekend. There is potential for SCA winds and seas to persist through next week.

For the Inner Waters north of Point Sal, there is a 80% chance of SCA level NW winds during the afternoon/eve hours on Fri - with a 30% chance of GALE force wind gusts across the waters > 5 NM offshore San Simeon. For the remainder of the weekend, high confidence in combination of SCA level winds and seas with a 30-50% chance of GALE force winds during the late afternoon/eve hours on Saturday and Sunday. Seas will build to around 12 feet during this time. Seas may fall below SCA levels sometime late Mon into Mid-week, while there is a moderate chance for SCA level winds during the afternoon/eve hours each day.

For the Inner Waters south of Point Conception, there is a 60% chance of SCA level W winds across western portions of the Santa Barbara Channel Fri afternoon/eve. For the remainder of the weekend, high confidence in SCA level winds. There is also a 40-50% chance of GALE force winds across the western half of the SBA channel during the late afternoon/eve hours on Saturday and Sunday. Steep and choppy seas around 8 feet are expected during this timeframe. Other than low chances across western SBA channel, winds and seas will likely remain below SCA criteria through mid- week.

LOX WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...Small Craft Advisory in effect until 9 PM PDT this evening for zone 645. (See LAXMWWLOX).
Small Craft Advisory in effect until 3 AM PDT Friday for zone 650. (See LAXMWWLOX).
Small Craft Advisory in effect until 3 AM PDT Saturday for zones 670-673-676. (See LAXMWWLOX).