Marine Weather and Tide Forecast for Avalon, CA

.SHORT TERM (TDY-MON)...17/445 AM.

A deep marine layer depth is well-entrenched across the region this morning with clouds extending into the Cuyama Valley and the coastal slopes of the mountains. The latest AMDAR soundings from KLAX around 10Z indicate the marine layer depth to be around 2600 feet deep, but it is likely slightly deeper than that based upon the areal extent through the Soledad Canyon and Highway 14 Corridor. If NAM BUFR time height sections play out as advertised, the marine layer depth should deepen to near 4000 feet deep later this morning.

Strong onshore flow, driving the marine layer depth, remains across the area ahead of an upper-level trough moving over far northern California. KLAX-KDAG pressure gradients peaked at 7.2 mb a few hours ago, while KSMX-KBFL surface pressure gradients peaking near 7.1 mb last evening. These values will likely strengthen a bit more this afternoon or evening.

While the trough is strengthening the onshore push, the dynamics with the trough scraping the area today and tonight could bring either night through morning drizzle or light showers to the region. As the marine layer deepens, it could interact with the upper-level dynamics to lift the marine layer cloud deck and squeeze out some drizzle or light rain. The latest high-resolution multi-model ensemble members lean wetter. As a result, PoPs in the forecast PoPs were trended slightly higher for today and tonight. Slight chance to chance PoPs are being mentioned for now.
Precipitation could fall as a heavy drizzle or light showers, but amounts will be on the order a few hundredths or less.

With the deep marine layer depth and strong onshore flow in place, a cooler weather pattern will remain in place through the weekend. Today will very likely be the coolest day of the period with temperatures ranging 8 to 15 degrees below normal for this time of year. Temperatures in the 60s to lower 70s will be common across most of coastal and valley areas. Some warming will take place on Sunday as onshore flow starts to weaken, but strong onshore flow will still keep most areas 5 to 10 degrees below normal.

Gusty onshore to west to northwest winds will develop over the next couple of days. Strong onshore pressure gradients will bring advisory level winds to the Antelope Valley and adjacent foothills this afternoon and evening, but the pressure gradient will get some thermal support this afternoon as a weakening and dying frontal boundary slides down the coast. The dying boundary combined with some wind support aloft will give a extra kick to the winds. Wind advisories were added for the Central Coast and the Santa Ynez Valley, the southern Salinas Valley, and across southern Santa Barbara County as enough support will be in place to bring advisory level winds. As we get into this evening, colder thermal support and developing northerly gradient will add into the mix to support gusty winds through the Interstate 5 Corridor and across broader portions of southern Santa Barbara County.
While advisories were drawn for the highest confidence areas, there is a chance that a wind advisory could also be needed for the Ventura County beaches and across the Carrizo Plain this afternoon and evening. Much will depend how much thermal and wind support makes it far enough south with the boundary that is falling apart.

A tight northerly pressure gradient will remain in place into Sunday and Monday keeping wind advisories in effect across Southern Santa Barbara County, through the Interstate 5 Corridor, and down into the Antelope Valley. There is a small chance that a high wind watch could be needed for Sunday night and into Monday for eastern Santa Ynez Range at 850 mb winds are marginally strong enough.

The flow pattern will turn northeasterly between Monday and Tuesday and an atypical but not unusual weak offshore flow pattern for May could develop for Monday. Winds look to wanes and only breezy to locally windy conditions look on tap. The forecast has warming temperatures, breaking away from NBM values for the period. No adjustments were made temperatures for Monday as the warming looked agreeable.

.LONG TERM (TUE-FRI)...17/439 AM.

A warming trend will continue through at least Wednesday, and possibly into Thursday as high pressure aloft build over the region and weak flow settles into region. EPS ensemble members advertise a warming trend in place through Thursday across most locations, but there is a bit more uncertainty for Thursday.
Cluster analysis of the ensembles would agree that the air mass should warm into Thursday as a majority of the clusters lean toward the ridge axis being overhead on Thursday. The forecast breaks away from NBM values and maintains a warmer stance, but the wrinkle will likely need to be addressed for Thursday as it could end up being the warmest day of the stretch. Summer-like temperatures should be expected, especially away from the coast, for Tuesday through Friday. Heat advisory headlines may be needed for the stretch of hot temperatures, especially Wednesday and Thursday.

AVIATION
17/1050Z.

At 1000Z at KLAX, the marine inversion was based around 2800 feet.
The top of the inversion was 6000 feet with a temperature of 12 degrees Celsius.

Overall, moderate confidence in 12Z TAF package. Timing of flight category changes could be +/- 2 hours of current forecasts. There is a chance of drizzle or very light showers 12Z-18Z.

KLAX...Moderate confidence in 12Z TAF. Timing of flight category changes could be +/- 2 hours of current forecasts. There is a 30% chance that conditions will remain VFR this evening and overnight.
Southeasterly wind component around 6 knots will continue through 18Z. For 12Z-16Z, there is a 30% chance of easterly winds around 7 knots.

KBUR...Moderate confidence in 12Z TAF. Timing of flight category changes could be +/- 2 hours of current forecasts. There is a 20% chance that VFR conditions will prevail this evening and overnight.

MARINE
17/350 AM.

For the Outer Waters, high confidence in current forecast. Small Craft Advisory (SCA) level winds this morning will increase to Gale force this afternoon. The GALE FORCE winds will continue through Sunday night although there may be a bit of a lull Sunday morning. Along with the GALE FORCE winds, seas will hover around 10 feet through Sunday night. For Monday through Wednesday, winds will diminish to SCA levels while seas drop below 10 feet.

For the Inner Waters north of Point Sal, moderate to high confidence in current forecast. For today, high confidence in SCA winds developing this morning then increasing to GALE FORCE this afternoon through tonight. For Sunday and Sunday night, high confidence in SCA level winds with a 30-40% chance of GALE FORCE winds developing. Through Sunday night, seas will hover near 10 feet. For Monday through Wednesday, there will be a 30-40% chance of SCA level winds in the afternoon and evening hours each day.

For the Inner Waters south of Point Conception, moderate to high confidence in current forecast. Today through tonight, high confidence in the development of SCA level winds with a 60-70% chance of GALE FORCE winds across the western half of the Santa Barbara Channel. For Sunday and Sunday night, there is a 60-80% chance of SCA level winds across the western half of the Santa Barbara Channel and a 20-30% chance of SCA level winds elsewhere south of Point Conception. For Monday through Wednesday, high confidence in winds and seas remaining below SCA levels.

LOX WATCHES/WARNINGS/ADVISORIES
CA...Wind Advisory in effect from 10 AM this morning to 9 PM PDT this evening for zones 340-341-343-346>348. (See LAXNPWLOX).
Wind Advisory in effect from noon today to 3 AM PDT Sunday for zones 349>352. (See LAXNPWLOX).
Wind Advisory in effect from 10 PM this evening to 10 AM PDT Monday for zone 378. (See LAXNPWLOX).
Wind Advisory now in effect from 10 AM this morning to 3 AM PDT Monday for zones 381-383. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 3 PM PDT this afternoon for zones 645-670-673-676. (See LAXMWWLOX).
Gale Warning in effect from 3 PM this afternoon to 3 AM PDT Sunday for zone 645. (See LAXMWWLOX).
Small Craft Advisory in effect from noon today to 6 PM PDT this evening for zone 650. (See LAXMWWLOX).
Gale Warning in effect from 6 PM this evening to 3 AM PDT Sunday for zone 650. (See LAXMWWLOX).
Small Craft Advisory in effect from 6 PM this evening to 3 AM PDT Sunday for zone 655. (See LAXMWWLOX).
Gale Warning in effect from 3 PM this afternoon to 3 AM PDT Monday for zones 670-673-676. (See LAXMWWLOX).