Swell Matrix

Area Forecast Discussion

National Weather Service Los Angeles/Oxnard Ca

903 am PST Fri Jan 18 2019

Synopsis

18/749 AM.

A ridge of high pressure will build over the region through Saturday bringing dry conditions, sunshine, and warmer temperatures to the region. Low pressure will skirt the area from the north later Sunday into Monday with some clouds and cooler temperatures. Prolonged offshore winds should affect the area through much of next week with no rain expected.

Short Term

(tdy-Sun), 18/859 AM.

Some lingering low level moisture still generating a few clouds and some dense fog this morning but that will all be clearing out this afternoon as we transition to a Santa Ana tonight and Saturday. Main concerns next few days are the winds. Probably below advisory levels Saturday with the Santa Ana winds but the north/northwest flow that sets up Sunday night into early Monday following the passage of the next inside slider looks pretty strong and gradients would support at least advisory level winds in srn SB County and the I5 corridor.

***From previous discussion***

An upper level ridge will build in from the south and persist through Saturday before the ridge breaks down Sunday. a weak to locally moderate Santa Ana will develop by Saturday morning. The combination of the upper ridge overhead and offshore flow will allow for significant warming across the coast and valleys. Highs are expected to reach the mid 70s up 8 to 12 degrees from today. Highs will be in the lower 60s across the Antelope Valley and interior SLO Valleys.

Another upper trough will start to move into Nrn California causing an increase of high clouds by Sunday morning and bringing some cooling as offshore flow turns onshore by late Sunday morning. High temps will lower a decent amount across the coast and valleys while interior areas warm up, due to the onshore flow.

Long Term

(Mon-Thu), 18/308 AM.

The trough coming through late Sunday into Monday will begin to dive into NV/AZ, as is typical of an inside slider track. Northerly winds will increase across the mountains and SBA South Coast, while clouds develop across the nrn slopes of the mountains. Strong NW winds across the outer waters will cause a Catalina Eddy to develop in the SoCal Bight Sunday evening which should allow low clouds to develop across the L.A. Basin and possibly the San Gabriel and San Fernando Valleys by early Monday morning. Cold air will settle into Nevada and Great Basin by Monday night and Tuesday, which will set up a relatively cool Santa Ana. An amplified Eastern Pac ridge will set up off the west coast driving any storm systems well north into the PAC NW or Western Canada leaving Southern California dry through at least next week. Prolonged offshore flow should persist through the week as models are all in good agreement with similar solutions.

Aviation

18/1218z.

At 11Z at KLAX, there was no marine inversion present, but there was a moist layer up to 4000 feet.

Areas of clouds across the region this morning. Where there were cigs, conds were mostly VFR to high MVFR, except IFR to VLIFR on the Central Coast, in the Santa Ynez Valley and in the foothills. Skies should become partly cloudy to mostly clear this afternoon. Mostly VFR conds are expected tonight/Sat morning, except there could be some LIFR/VLIFR cigs and vsbys on the Central Coast and in the Santa Ynez Valley.

KLAX, Low to moderate confidence in the 12Z TAF. Expect mostly VFR conds, but there is a 30-40% chance of MVFR cigs thru 19Z today and there is a 20% chance of MVFR cigs between 09Z and 17Z Sat.

KBUR. Low to moderate confidence in the 12Z TAF. Expect mostly VFR conds, but there is a 30-40% chance of MVFR cigs thru 19Z today and there is a 20% chance of MVFR cigs between 09Z and 17Z Sat.

Marine

18/402 AM.

For the outer waters and northern inner waters, moderate to high confidence in the forecast. Very large seas will slowly subside thru tonight, but will likely remain above SCA levels thru mid morning Sat. There is a 20-30% chance of SCA level wind gusts across the southern outer waters (PZZ673/PZZ676) thru this eve, but these should be localized. There is a 20-30% chance of SCA level winds Sun afternoon. SCA level winds are likely Sun night thru Tue, except Mon thru Tue across the northern inner waters.

For the inner waters S of Pt. Conception, moderate to high confidence in the forecast. Very large seas will slowly subside thru tonight, but will likely remain at or above SCA levels thru late tonight. There is a 20-30% chance of SCA level wind gusts across western areas this morning, but these should be localized.

Across the SBA Channel, there is a 20% chance of SCA level winds across western areas Sun afternoon, then SCA level winds are likely much of the time Sun night thru Tue. Across the southern inner waters, there is a 40% chance of SCA level winds Sun night thru Tue.

Beaches

18/409 AM.

Very high surf will slowly subside later today and tonight. High Surf Warnings remain in effect for damaging surf across west facing beaches. Surf will average 18-22 ft with local sets to 25 ft on Central Coast beaches this morning. On west facing beaches of LA/Ventura counties expected surf of 10-15 feet, with local sets up to 17 feet near Ventura Harbor. Surf will likely remain at warning levels through this evening, then may remain at advisory levels thru Sat.

With this very large surf and moderately high astronomical tides, there is a good chance of moderate coastal flooding and beach erosion, especially around the high tide this morning. A Coastal Flood Advisory is in effect as well. High astronomical tides will continue thru the weekend, but surf will begin to subside tonight.

In addition to coastal flooding and beach erosion issues, there is a high potential for large breaking waves across the Morro Bay and Ventura Harbor entrances today.

Hazards associated with the very large and potentially damaging surf include strong and dangerous rip currents, minor to moderate coastal flooding and significant beach erosion, as well as waves washing over rock jetties. Conditions will be potentially dangerous for even the most experienced swimmer.

Watches, Warnings, Advisories

Ca, High Surf Warning in effect until 9 PM PST this evening for zones 34-35-40-41-87. (See LAXCFWLOX). Coastal Flood Advisory in effect until 9 PM PST this evening for zones 34-35-40-41-87. (See LAXCFWLOX). High Surf Advisory in effect until 9 PM PST this evening for zone 39. (See LAXCFWLOX). PZ, Small Craft Advisory for hazardous seas in effect until 9 AM PST Saturday for zones 645-670-673-676. (See LAXMWWLOX). Small Craft Advisory for hazardous seas in effect until 3 AM PST Saturday for zones 650-655. (See LAXMWWLOX).

Visit this site often? Consider supporting us with a $10 contribution.
Learn more

Share this forecast!