Santa Cruz Island to San Clemente Island to 60 NM offshore including San Nicolas and Santa Barbara Islands Marine Forecast
|Today...W Winds 15 To 20 Kt With Gusts To 25 Kt. Strongest Nw Of San Nicolas Island. Combined Seas 6 To 8 Ft Dominant Period 10 Seconds. Patchy Fog In The Morning.|
|Tonight...Nw Winds 15 To 20 Kt With Gusts To 25 Kt. Strongest Nw Of San Nicolas Island. Combined Seas 4 To 6 Ft Dominant Period 10 Seconds. Patchy Fog. Patchy Drizzle. A Slight Chance Of Rain After Midnight.|
|Sat...W Winds 10 To 20 Kt. Wind Waves 2 To 3 Ft. Nw Swell 4 To 6 Ft At 9 Seconds. A Chance Of Rain.|
|Sat Night...Nw Winds 15 To 20 Kt With Gusts To 25 Kt. Combined Seas 6 To 8 Ft Dominant Period 8 Seconds. A Slight Chance Of Rain.|
|Sun...Nw Winds 10 To 15 Kt, Becoming W 10 Kt In The Afternoon. Wind Waves 2 Ft Or Less. Nw Swell 5 To 7 Ft At 9 Seconds. A Slight Chance Of Rain.|
|Sun Night...Nw Winds 5 To 10 Kt. Wind Waves 2 Ft Or Less. Nw Swell 5 To 7 Ft At 10 Seconds, Subsiding To 3 To 5 Ft At 10 Seconds After Midnight. Patchy Fog After Midnight.|
|Mon...Nw Winds 10 To 15 Kt. Wind Waves 2 Ft Or Less. Nw Swell 3 To 5 Ft. Patchy Fog.|
|Tue...Nw Winds 10 To 15 Kt. Wind Waves 2 Ft Or Less. Nw Swell 3 To 5 Ft. Patchy Fog.|
| Area Forecast Discussion|
...UPDATED National Weather Service Los Angeles/Oxnard CA
1044pm PDT Thu September 28 2023
Much cooler weather is expected through the weekend with a chance of light rain Saturday into Sunday as an unseasonably cold upper low moves through the area. Night and morning low clouds and fog will push well into the valleys tonight and into the mountains Saturday with late or no clearing in the afternoon. A warming trend will begin Monday with high temperatures rising to above normal levels by the middle of next week.
Short Term - Thursday through Sunday
Temperatures remain below normal for this time of year, with highs ranging from the 60s to 70s for the coasts, mid 70s to 80s for the valleys, and near 90 degrees for the Antelope Valley. Tonight, low clouds should be more expansive than last night, and already blanket the southern waters and southern coasts. Clouds are rapidly expanding into the LA and Ventura valleys. As we head into Friday, the approaching low will lead to a deepening marine layer through the day and increased onshore flow, so clouds will struggle to clear.
The chance of showers still looks on track for Friday night into Sunday, peaking Saturday as the main front moves through. Did end up moving things up a little bit as some drizzle will be possible Friday night. Wouldn't be surprised if rainfall totals are a little higher for upsloped areas, especially over LA and Ventura Counties. Will hold off on making changes the to the precipitation amounts for now. PWAT (Precipitable Water) values are around 1 inch Friday, and will peak Saturday around 1.15 inches. With how cold aloft the airmass is (-17 to -19 degrees C), there is still a 5-10% chance for thunderstorms from early Saturday morning through the day.
***From Previous Discussion***
Overall the forecast has changed very little. There is increasing confidence in a relatively rare late September light rain event this weekend, most likely on Saturday when the upper low is closest to southern California. Forecast soundings continue to indicate a rapidly deepening marine layer the next couple days, peaking Saturday at around 5000-6000 feet. And there's enough energy and cold air aloft to provide an environment favorable for at least some rain reaching the surface in most areas. Most of the EPS and NAEFS ensemble solutions still favor a light rain event, mostly under a quarter inch. However, historically with deep moist layer patterns like this upslope areas, especially in the eastern San Gabriels, get twice as much or locally more. With this in mind, rain chances have increased by 10-20 percent area-wide. probability of precipitation should probably be higher, but lingering uncertainty on timing and the potential for some locations not to get measurable amounts are keeping probability of precipitation possibly lower than they should be. The air mass isn't quite cold enough for snow except possibly a dusting on the very highest peaks 9000 feet and higher.
Gusty west to northwest winds expected to develop later Saturday following this first impulse. While most of the typical guidance is showing standard daytime winds, the EPS ensembles are much stronger and are typically a better indicator after frontal passages. Advisory level winds are possible with gusts to 35 mph or greater.
The trough is still parked over Central California Sunday with a secondary low pressure area dropping into it Sunday afternoon. Once again NBM probability of precipitation are very low but moisture content remains high so another round of light showers are certainly possible. However, with the inversion weakening it's also possible clouds will struggle to form resulting in more sunshine and a decreasing chance of showers. So there is much lower confidence in the Sunday forecast in terms of rain potential. Temperatures will still be 10-20 degrees below normal for inland areas and 5-10 degrees below normal for coastal areas.
Long Term - Monday through Thursday
The trough will exit the area later Sunday with high pressure expected to push in from the west Monday. This will start a warming trend that will last through the week but peak either Wednesday or Thursday. Highs expected to be back into the 90s in the valleys by then and 80s for inland coastal areas. NAEFS gradients trend towards neutral and even very slightly offshore by mid week which will assist with the warm up. So far still not seeing in strong signals for Santa Ana's at least through next week but there is high confidence that temperatures will at least remain above normal going into next weekend.
Small Craft Advisory (SCA) level winds and seas will occur in the outer waters through Friday night, with the possibilty for a lull in winds in the early morning. SCA (Small Craft Advisory) winds and seas will affect nearshore Central Coast waters through at least this evening.
For the Santa Barbara Channel, there is a 30 percent chance of SCA (Small Craft Advisory) level wind gusts this afternoon and evening confined to the extreme western portion of the channel, although steep and choppy seas are expected.
Moderate confidence in Northwest swell heigheights from Santa Barbara to Orange County lowering on Friday.
Moderate confidence in improved conditions on Friday, but a low pressure system will form over the southwest United States on Saturday causing gusty west winds nearly everywhere. Saturday SCA (Small Craft Advisory) level winds are possible throughout the entire Santa Barbara Channel, with a 30 percent chance of Gale Force Winds.
The current high surf advisory is starting to subside, but the advisory will not be changed at this time as several buoys show significant waves still over 10 feet. The current advisory is set to expire at 9 pm this evening. Strong and potentially deadly rip currents are likely during this time frame. Nuisance coastal flooding and minor beach erosion may also occur during high tides.
NOAA Los Angeles/Oxnard CA Office: Watches - Warnings - Advisories
CA...NONE. PZ...Small Craft Advisory in effect from 3pm Friday to 3am PDT Saturday for zone 645.
Small Craft Advisory in effect until 3am PDT Saturday for zones 670-673-676.