Marine Weather and Tide Forecast for Vandenberg AFB, CA

.SHORT TERM (FRI-MON)...16/832 PM.

An unseasonably strong upper level trough will push through Southwest California this weekend. Lowering heights and stronger onshore flow brought some cooling to many areas today, with this cooling trend expected to continue into Saturday. Current satellite imagery showing some upper level clouds loving through Ventura and LA counties this evening, with some low clouds returning across portions of the coastal plain. Current ACARS sounding date showing the marine layer depth across the LA Basin ranging between 1500 and 2000 feet this evening.

The approaching upper level trough combined with the strengthening onshore flow and an eddy circulation is expected to bring a rapidly deepening marine layer overnight into Saturday, eventually increasing to 4000 to 5000 feet deep, highest in LA county. This rapidly deepening marine layer combined with light southerly flow through the boundary layer will make conditions favorable for areas of light and drizzle, especially LA county.
There will be a 10-20 percent chance of measurable rainfall, with highest pops favoring the lower coastal slopes and foothills.
Clearing will be slow to none for many areas on Saturday due to the deepening marine layer and stronger onshore flow. Temperatures will likely stay in the 60s in most areas, which would be 5-15 degrees below normal.

Onshore winds starting to increase this afternoon and evening across the interior, especially in the Antelope Valley. With the deepening upper level trough bringing increased upper level wind support and strengthening onshore gradients, looking for strengthening onshore winds across the interior, especially in the Antelope Valley and adjacent foothills, where a wind advisory is in effect on Saturday for wind gusts of 45 to 55 mph.
Similar strong winds are expected on Sunday for the Antelope Valley and adjacent foothills. The increased onshore winds across the interior will bring an increased risk for large grass fires, especially in the Antelope Valley, where there will also be the potential for reduced visibilities in blowing dust and sand. Gusty northwest to north winds will also impact southern Santa Barbara county and the I-5 corridor, where wind advisories will likely be posted at some point this weekend.

*** From previous discussion ***

The warming trend will continue Monday with some additional offshore trends leading to some morning northeast winds across the hills and mountains and possibly some of the valleys as well.
Expecting widespread warming trends of 5-10 degrees over Sunday and some valley areas as much as 15 degrees warmer, getting close to 90 degrees, including interior SLO County and the western San Fernando Valley.

.LONG TERM (TUE-FRI)...16/225 PM.

Next week is going to be a hot one and lasting at least two days longer than the previous heat wave. Highs are expecting to be fairly similar to the last heat wave, topping out in the low 100s in the warmer valleys Tuesday through, low 90s in Downtown LA, and 80s across most other areas except the beaches. There may still be a lingering shallow marine layer Monday morning across coastal LA County resulting in some dense fog but that should clear fairly quickly. If the forecast remains on track, and right now confidence is high, another round of heat advisories will be needed for the coastal valleys and possibly even parts of the interior coastal plain.

Onshore flow will start to return Thursday that will begin a slow cooling trend into next weekend.

AVIATION
17/0046Z.

At 00Z at KLAX, the marine inversion was around 15 feet deep. The top of the inversion was 2300 feet with a temperature of 17 degrees Celsius.

High confidence in TAFs for KWJF and KPMD.

Moderate confidence in TAFs for remaining sites where flight category changes may be off by 2 hours and 1 category. There is a 30-50 percent chance of only brief to no return to VFR at coastal sites from SBA and south including KLAX.

KLAX...Moderate confidence in TAF. There is a 20-30% chance for an east wind component of 8 kts between 10Z and 18Z. Best chances between 13Z and 17Z.

KBUR...Moderate confidence in TAF. Return of cigs may be off +/- 2 hours, and there is a 20% chance for cigs 007-009.

MARINE
16/720 PM.

For the Outer Waters through Tuesday, high confidence in combination of Small Craft Advisory (SCA) level winds and seas.
For Saturday afternoon through Sunday night, there is a 60-80% chance of Gale force winds. Gales look to be strongest and most widespread Sunday afternoon through late Sunday night. There may be a lull in the winds Sunday morning. Seas will reach 12-14 feet.
Rough, short period seas will exist into at least Monday.

For the Inner Waters (North of Pt. Sal) through Sunday night, high confidence in SCA level winds leading up to the GALE Warning, especially in the afternoon and evening hours. There is a 80% chance of Gale force winds Saturday afternoon/eve into the late hours. There will be a lull in the winds Sun morning. Another Gale Warning is likely (60% chance) for Sunday afternoon and evening.
For Monday through Tuesday, there is a 60-70% chance of SCA level winds continuing. Seas will reach 10-12 feet. Rough, short period seas will exist into Monday.

For the Inner Waters (south of Point Conception) through Saturday morning, high confidence in winds and seas remaining below SCA levels. However, there is a 30% chance of SCA level wind gusts for far western portions of SBA Channel into the late night hours tonight. For Saturday afternoon through Sunday night, high confidence in SCA level winds focused mostly through the Santa Barbara and western sections of the southern Inner Waters.
Additionally, there is a 50-60% chance of Gale force winds across the Santa Barbara Channel Saturday evening through Saturday night.
There will be a relative lull in the winds overnight, then another Gale Warning is likely (50-60% chance) for the Santa Barbara Channel Sunday afternoon into late night. Seas may approach 8 feet with short periods due to the wind. For Monday through Tuesday, moderate confidence in winds and seas remaining below SCA levels.

LOX WATCHES/WARNINGS/ADVISORIES
CA...Wind Advisory now in effect from 10 AM Saturday to 3 AM PDT Sunday for zones 381-383. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 3 PM PDT Saturday for zones 645-670-673-676. (See LAXMWWLOX).
Gale Warning in effect from 3 PM Saturday to 3 AM PDT Sunday for zone 645. (See LAXMWWLOX).
Small Craft Advisory in effect from noon to 6 PM PDT Saturday for zone 650. (See LAXMWWLOX).
Gale Warning in effect from 6 PM Saturday to 3 AM PDT Sunday for zone 650. (See LAXMWWLOX).
Small Craft Advisory in effect from 6 PM Saturday to 3 AM PDT Sunday for zone 655. (See LAXMWWLOX).
Gale Warning in effect from 3 PM Saturday to 3 AM PDT Monday for zones 670-673-676. (See LAXMWWLOX).