Marine Weather and Tide Forecast for Seal Beach, CA

.SHORT TERM (TUE-FRI)...03/148 PM.

Complex weather pattern this week. The main takeaway is it's going to be very windy in some areas, especially later Wednesday into Thursday morning, and again over the weekend. The first wind event will be a northerly wind resulting from the passage of the first of two inside slider troughs. Hi res models are consistent with the deterministic runs showing strong northerly flow aloft aligning favorably with north flow at lower levels. Not surprisingly ensemble pressure gradients are showing a 6-8mb north gradient setting up as well. And the EC is also showing strong northerly flow. Areas most affected will be the mountains, but winds will filter down into the valleys and some coastal areas, including the Malibu coast and southwestern Santa Barbara County.
But strong winds also expected in many of the LA/Ventura County valleys and possibly even through the west side of the LA Basin from Santa Monica to Palos Verdes. A slew of wind advisories and watches have been issued and taking effect late Wednesday afternoon or early Thursday.

Significant cooling is expected in the mountains Thursday as the first upper low moves through. There is some moisture with it though not much as the trajectory is from the northeast. So some light showers with lowering snow levels are possible near the north facing slopes, especially from Sandberg west through the Santa Barbara County mountains. Snow levels may get down to around 4000 feet so there is at least 10-20 percent chance of very light snow over the Grapevine on I5 early Thursday morning.

At lower elevations, especially south of Pt Conception, the downsloping flow off the Transverse range will compensate for the cold air advection, keeping temperatures near to slightly above normal through the week.

On Friday and early Saturday a second backdoor upper low will move through southern California. There is still a lot of uncertainty with this upper low so expect at least some adjustments moving forward. For now, this low will be colder as models bring the low directly overhead and then out over the ocean rather than the traditional path through interior California.
Because of this winds aloft will be veering to the east while lower level winds are also simultaneously veering to the east in response to a strong offshore gradient trends. Ensemble solutions indicate offshore gradients will peak out around -6 to -8mb Saturday. In a bit of good news models have, at least for now, shifted the upper level jet with 140kt winds farther to the north over the Central Coast so that the winds aloft are not aligned with the lower level winds as they were on yesterday's models.
Still, the potential for strong Santa Ana winds is there for the usual Santa Ana wind prone areas of LA/Ventura Counties, starting Friday but peaking Saturday. There is plenty of time for the mostly cutoff low to take a different path so will keep a close on the track and refine the forecast as needed. But for now there is a potential for strong Santa Anas Friday through Sunday.

.LONG TERM (SAT-TUE)...03/145 PM.

Adding more uncertainty to the forecast for early next week, based on the latest projections the upper low will reverse course late Sunday and move back onshore Monday and Tuesday. A small percentage of the ensemble solutions indicate that the upper low will pick up some moisture off the Pacific Ocean and drop some light wrap around showers as far north as southern LA County. This will most likely not happen but it's not a zero chance either. In any case, with the low moving inland and pressure gradients rapidly trending onshore temperatures are expected to cool slightly into early next week.

AVIATION
04/0051Z.

At 00Z over KLAX, the marine layer depth was 900 feet deep at KLAX. The top of the inversion was near 2200 feet with a temperature around 19 degrees Celsius.

Moderate confidence in KLAX, KLGB, KSMO, KCMA, KOXR, KPRB with a 60-80 percent chance of MVFR/IFR or lower cigs/vsbys focused between 10-20Z.

Low confidence in KBUR and KVNY with a 30-50 percent chance of IFR or lower cigs/vsbys focused between 12-18Z.

High confidence elsewhere with 80 percent or greater chance of VFR conds.

KLAX...Moderate confidence in TAF with a 20 percent chance that VFR conds prevail. Any east wind component should remain less than 6 kt.

KBUR...Low confidence in TAF between 10-18Z.

MARINE
03/902 AM.

Moderate to high confidence in the current forecast; seas could be up to 1-3 feet higher than forecast, especially between Wednesday and Friday.

Widespread SCA level winds are expected to rapidly increase again this afternoon. SCA level winds will affect the outer waters and the nearshore waters along the Central Coast through this afternoon. Then, widespread strong SCA and GALE conditions (winds and seas) will develop tonight through Friday.

An offshore flow pattern will set up Friday through Sunday, with a moderate (30 to 50 percent) chance of SCA levels winds inside the southern California bight and the nearshore waters along the Central Coast, with winds likely peaking on Saturday.

LOX WATCHES/WARNINGS/ADVISORIES
CA...Wind Advisory in effect from midnight Wednesday night to 9 AM PST Thursday for zones 87-366-367. (See LAXNPWLOX).
Wind Advisory in effect from 6 PM Wednesday to 9 AM PST Thursday for zones 88-371>375. (See LAXNPWLOX).
Wind Advisory in effect from 4 PM Wednesday to 9 AM PST Thursday for zones 349-351-352-381>383. (See LAXNPWLOX).
High Wind Watch in effect from Wednesday afternoon through Friday morning for zones 353-376>378. (See LAXNPWLOX).
High Wind Watch in effect from late Wednesday night through Thursday morning for zones 362-369-370. (See LAXNPWLOX).
High Wind Watch in effect from Wednesday evening through Thursday morning for zones 379-380. (See LAXNPWLOX).
PZ...Small Craft Advisory in effect until 3 PM PST Wednesday for zones 645-650. (See LAXMWWLOX).
Gale Warning in effect from 3 PM Wednesday to 9 AM PST Thursday for zones 645-650. (See LAXMWWLOX).
Small Craft Advisory in effect until 3 AM PST Wednesday for zones 670-673-676. (See LAXMWWLOX).
Gale Warning in effect from 3 PM Wednesday to 3 AM PST Friday for zone 670. (See LAXMWWLOX).
Gale Warning in effect from 3 AM Wednesday to 3 AM PST Friday for zones 673-676. (See LAXMWWLOX).