13/1049 AM.
Multiple periods of light to moderate rain is expected well into next week, with the next period is all set for this afternoon and tonight. There will be a break this weekend, with the next round set for around Monday, then the next around Thursday. The risk of significant impacts and flooding with any of these storms is low, with generally light to moderate rain. Temperatures will remain at or below normal. Very large surf will bring coastal impacts well into next week, largest on Saturday.
(tdy-Sun), 13/1050 AM.
***UPDATE***
Playing catch up after a busy morning. Quite the shower and thunderstorm show occurred last night into early this morning as an unstable pre-frontal airmass moved through the region. We had 60 total cloud-to-surface lightning strikes over the ocean and LA County. Most of the rain rates were under 0.25 inch per hour, but there were a handful of spots from Santa Barbara to LA County that had rates of 0.5 to 1.0 inches per hour thanks to the convective element. While some showers are lingering over LA County, all the showers will taper down over the next few hours before main rain band and cold front moves through southwest California. This band is currently pushing through Monterey County, and will quickly push into the Central Coast this afternoon, then all the way through southern California tonight. Expect 3 to 6 hours of steady light to moderate rain over all areas. The thunderstorm threat is very low, and not expecting many impacts with this rain. By mid- Saturday morning, the rain should be largely done.
***From Previous Discussion***
Overall, latest models in good synoptic agreement through the short term period. Essentially, there will be several "pulses" of rainfall across the area today through Sunday.
The second "impulse," a more classic cold front, will begin to move into San Luis Obispo county later this afternoon and will sweep southeast across the area tonight/Saturday morning. This front will bring a 3-5 hour period of light to moderate rainfall. Fortunately, the instability looks much less, so any thunderstorm threat is very minimal. Rainfall rates will likely continue to be around 0.25 inches/hour or less with isolated rates around 0.50 inches/hour. By Saturday afternoon, the front will be east of the area and the rainfall threat with it will end.
Overall, rainfall totals through Saturday morning are expected to range between 0.25 and 0.75 inches for most areas. However, there may be isolated totals around 1.00, associated with areas that experience heavier showers or a thunderstorm.
From Saturday afternoon through Sunday evening, dry conditions are expected. However, beginning Sunday night, yet another system will begin to impact the area.
(Mon-Thu), 13/216 AM.
For the extended, the wet and unsettled weather is forecast to continue across the area. The first system will move across the area Monday and Monday night. Behind this system, there will be a chance of showers during the day on Tuesday. However for Wednesday and Thursday, another system will impact the area, bringing additional rainfall. At this time, these two systems look to bring additional beneficial rain to the area. For the first system, totals are currently estimated to be around 0.25 inches or less. The second system may bring a bit more rain with current estimates in the 0.25 to 1.00 inch range. Based on forecast snow levels, there could be some light snow accumulations above 6000-6500 feet with both systems.
13/1751z.
At 1750Z at KLAX, there was no marine layer and no marine inversion.
Moderate confidene in TAFs. Off and on showers will continue today with periods of MVFR cigs and vsbys due to rain. Steadier rain is expected to move from north to south from this afternoon through late tonight with IFR/MVFR cigs/vsbys likely in rain. Expecting some gusty south to west winds at times this afternoon and with the frontal passage. Onset of steadier rain may be off by +/- 90 minutes. KLAX, Moderate confidence in TAF. Off and on -SHRA and MVFR cigs/vsbys until steadier -RA to RA tonight. Rain may arrive as early as 04Z. Any east wind componenet is expected be remain below 8 knots. KBUR, Moderate confidence in TAF. Off and on -SHRA and MVFR cigs/vsbys until steadier -RA to RA tonight. Rain may arrive as early as 03Z.
13/832 AM.
For the Outer Waters, high confidence in current forecast. Today through Tuesday, a combination of Small Craft Advisory (SCA) level winds and seas is expected. Winds look to peak today and Saturday, then again on Monday. Dangerously large seas are expected to peak on Saturday (18-22 feet) with a secondary peak expected on Monday (12-18 feet).
For the Inner Waters north of Point Sal, high confidence in current forecast. Tonight through Tuesday, a combination of SCA level winds and seas are expected. Winds look to peak today and again on Monday. Dangerously large seas are expected to peak on Saturday (14-20 feet) with a secondary peak on Monday (11-15 feet).
For the Inner Waters south of Point Conception, moderate to high confidence in current forecast. Today through Saturday, low-end SCA winds associated with the frontal passage are likely. Also, SCA seas are likely on Saturday across western portion of the Santa Barbara Channel. On Sunday, high confidence in winds and seas remaining below SCA levels. On Monday and Monday, there is a 60-80% chance of SCA level winds and a 30-40% chance of Gale force winds.
With the expected large west-northwesterly swell this weekend, there is the threat of dangerous breaking waves at Ventura and especially Morro Bay harbor entrances.
Periodic rain can be expected tonight through at least Monday. There is a slight chance of thunderstorms through this morning for the waters south of Point Conception.
13/834 AM.
A series of very large, long period west-northwesterly swells will impact the coastline of southwest California through at least Tuesday of next week, creating large surf and dangerous conditions at all coasts. Largest surf will be focused along west to northwest facing shores and surf is expected to peak on Saturday, with a potential secondary increase Monday. Moderate to significant beach erosion and shallow flooding of sea water over low-lying beach walkways, parking lots, and roads is likely, especially in the morning hours near high tide. Large surf will create dangerous rip currents, along with strong long shore currents, potential sneaker waves, and large shore pound. Impacts will be less for south-facing shores.
The highest risk will be for the Central Coast with potential for localized damage to the most vulnerable areas - such as to piers, roads, and structures. High Surf and Coastal Flood WARNINGS are in effect for the Central Coast with impacts such as breaking waves at Morro Bay Harbor entrance and Pismo and Cayucos Piers, as well as widespread sandy beach flooding - including Oceano Dunes State Park and other vulnerable low lying areas (especially during high tide). Surf heights are expected to reach 18-25 feet, highest at west-northwest facing beaches.
For west-facing beaches in LA/Ventura counties, high surf advisories are in effect with high surf expected to continue through at least Tuesday. There may be a relative "lull" in the surf Sunday before the second swell arrives, but surf and rip currents will still be hazardous. Surf is expected to peak Saturday and there is a low chance for WARNING level surf at Ventura County beaches. Breaking waves may impact the Ventura Harbor entrance. Additionally, moderate coastal flooding is likely Saturday around high tide in the late morning, thus Coastal Flood Advisories will be considered for these areas.
Ca, Beach Hazards Statement in effect through Tuesday afternoon for zones 87-349-350. (See LAXCFWLOX). High Surf Advisory in effect until 9 PM PST this evening for zones 340-346. (See LAXCFWLOX). High Surf Warning in effect from 9 PM this evening to 3 AM PST Sunday for zones 340-346. (See LAXCFWLOX). Coastal Flood Warning in effect from 3 AM to 6 PM PST Saturday for zones 340-346. (See LAXCFWLOX). High Surf Advisory in effect until 3 PM PST Tuesday for zone 354. (See LAXCFWLOX). Beach Hazards Statement in effect until 2 PM PST this afternoon for zones 362-366. (See LAXCFWLOX). High Surf Advisory in effect from 2 PM this afternoon to 3 PM PST Tuesday for zones 362-366. (See LAXCFWLOX). PZ, Small Craft Advisory in effect until 3 AM PST Wednesday for zones 645-670-673-676. (See LAXMWWLOX). Small Craft Advisory in effect from 6 PM this evening to 3 AM PST Sunday for zone 650. (See LAXMWWLOX). Small Craft Advisory in effect from 6 PM this evening to 9 AM PST Saturday for zone 655. (See LAXMWWLOX).
