05/330 PM.
Tropical Cyclone Marie, which will remain well offshore of SoCal, will bring impacts to the region through at least early next week. Rain is favored early Sunday morning into the evening, focused over Los Angeles County. Rain will mostly be light to moderate, but there is a 15 percent chance of thunderstorms for Los Angeles County on Sunday. Increasing southerly swell will create hazardous surf conditions at the coasts.
(tdy-Tue), 05/224 PM.
Hurricane Marie is currently 815 NM south-southwest of Los Angeles, and is forecasted to travel in the northwest to north direction over the next several days, while weakening. Marie will remain well offshore of the California Coast, but will still be able to send weather impacts to SoCal this holiday weekend and possibly beyond. Some of the most significant hazards from Marie will be seen across the beaches where very hazardous ocean swimming conditions are expected for the Labor Day holiday weekend. Potentially deadly rip currents and high surf is expected for south-facing beaches. Please consider swimming near a lifeguard and follow their guidance. Additionally, moderate coastal flooding and coastal erosion is expected for vulnerable south-facing beaches. See the beaches section below for details on the coastal hazards.
Mid and high level clouds sent by Hurricane Marie will spread into the area later today and tonight. Marie will travel far north enough for some of her mositure to becoming entrained within the cyclonic circulation along the bottom of a large trough currently centered over Oregon. As for rain impacts, high resolutions models are generally in agreement that rain will start early Sunday morning and last into Sunday the evening. Rain is expected to be focused over Los Angeles County, mostly likely the central and eastern portions. Rain totals are favored to be 0.25 inches or less for most areas in LA county, except higher amounts in the foothills of the San Gabriel Valley (0.5 inches likely) and the eastern San Gabriel Mountains (locally to around 1.0 inch). Rain totals will generally be 0.10 inch or less for Ventura County northward. Rain rates will be light to moderate, topping out around 0.20 in/hr for most locations. Local heavier showers and thunderstorms with rain rates briefly 0.20-0.50 in/hr will be possible, especially for the eastern San Gabriel Mountains. There is overall only around 5 percent chance of rain rates high enough to cause minor/urban flooding in LA County. Even with mild rates or totals, with any wetting rain roads will become quite slick due to the build up of oils over the last many months.
There is a 15 percent chance of thunderstorms on Sunday across Los Angeles County and the southern coastal waters. At this point, thunderstorms appear the most likely in the afternoon over the Antelope Valley and the San Gabriel Mountains and foothills, as clouds may clear out enough to get some surface heating. Lapse rates are not overly impressive due to the warm air aloft with the tropical influence, but the PWATs (as high as 2 inches) and low level moisture are significant enough to support thunderstorm chances with some initiation such a daytime heating, vorticity, or jet dynamics.
Temperatures will feel warmer over the weekend with the additional humidity, but still remain within a few degrees of normal. Overnight lows could be quite warm and only into the 70s for our southern coasts and coastal valleys where the topical mositure will be the greatest. Monday and Tuesday will see slight warming each day, with continued humid conditions that will produce moderate Heat Risk, especially near the coast. On Monday, we can't rule out a stray shower or isolated thunderstorm, but for the most part expect dry weather. Tuesday, there is around a 50 percent chance of showers (and thunderstorms), this time focused over Santa Barbara County and San Luis Obispo County.
(Wed-Sat), 05/236 PM.
There is lower than normal forecast confidence for the overall pattern and rain chances in the long term. Remnants of Marie are likely to remain in the general region for much of next week and forecast models have struggled to resolve the impacts. Scattered showers and thunderstorms will be possible Wednesday, focused for Ventura County and the Central Coast. There is a moderate chance that a ridge will build over SoCal by late this week, thus temperatures are favored to warm with areas of at least moderate HeatRisk for Wednesday and Thursday. Please stay tuned if heat and/or rain may impact your plans next week, as forecast details may change.
06/0155z.
At 0013Z at KLAX, the marine layer was 700 feet deep. The top of a weak inversion was 1800 feet with a temperature of 25 deg C.
High confidence in CAVU conditions for all sites through this evening. Overnight, moderate confidence in current forecasts as tropical moisture moves in, bringing the threat of light showers and could wreak havoc with stratus formation.
KLAX, Moderate confidence in TAF. CAVU conditions are expected through this evening. Overnight and through Sunday, there is a 30-40% chance of BKN015-025 CIGs. Light showers are expected to develop Sunday morning. No significant easterly wind component is expected.
KBUR, Moderate confidence in TAF. CAVU conditions are expected through this evening. Overnight and Sunday morning, there is a 20-30% chance of BKN015-025 CIGs. Light showers are expected to develop Sunday morning.
05/1140 AM.
For the Outer Waters, moderate to high confidence in current forecast. Through Sunday morning, high confidence in winds and seas remaining below Small Craft Advisory (SCA) levels. For Sunday afternoon through Monday, there is a 60-80% chance of SCA level winds. For Tuesday and Wednesday, high confidence in winds and seas remaining below SCA levels. On Thursday, there is a 30-50% chance of SCA level winds.
For the Inner Waters north of Point Sal, high confidence in current forecast. Through Thursday, winds and seas are expected to remain below SCA levels.
For the Inner Waters south of Point Conception, moderate to high confidence in current forecast. Tonight through Wednesday, high confidence in winds and seas remaining below SCA levels. On Thursday, there is a 30-50% chance of SCA level winds across western sections.
Tropical moisture will stream over the area Sunday through Tuesday, bringing the threat of showers to the coastal waters. There is a 15% chance of thunderstorms Sunday afternoon for the waters south of the Channel Islands. A large southeast to south swell will also impact the area, causing increased currents and surges in the vulnerable harbors.
05/1140 AM.
Significant coastal impacts are expected across Southern California beaches this Labor Day weekend. A large southeast to south swell from Hurricane Marie will move into the coastal waters this weekend with swell heights of 5-7 feet and a period around 13 seconds.
High surf conditions are expected on south-facing beaches of Ventura and Los Angeles counties, peaking at 5-8 feet with local sets to 10 feet on Sunday and Monday. The Santa Barbara South Coast will be largely protected from this swell, but there are some small windows of southeasterly and southwesterly energy that could cause boosts in the waves. HIGH SURF ADVISORIES remain in place for Los Angeles and Ventura Counties, with BEACH HAZARDS STATEMENTS (a step below high surf advisories) in effect for Santa Barbara and San Luis Obispo Counties.
High tides will also be increasing through early next week. Due to a variety of reasons, the actual observed tides have been running 6 inches above predictions for sometime now. The south swell will likely boost that enhancement. As a result, high tides should exceed 7 feet by Monday. Adding large tides with the south swell will result in a moderate risk for coastal flooding over the vulnerable south-facing shores. Areas of most concern include Avalon, Long Beach (Alamitos Peninsula), and Oxnard to Malibu (including Point Mugu). COASTAL FLOOD ADVISORIES remain in effect for Los Angeles and Ventura Counties where the best combination of tides and waves will occur, but Santa Barbara and San Luis Obispo Counties could also see some isolated issues.
Ca, Coastal Flood Advisory in effect until 11 PM PDT Tuesday for zones 87-354-362-366. (See LAXCFWLOX). High Surf Advisory in effect until 11 PM PDT Tuesday for zones 87-354-362-366. (See LAXCFWLOX). Beach Hazards Statement in effect through Tuesday evening for zones 340-346-349-350. (See LAXCFWLOX). PZ, Small Craft Advisory in effect from 3 PM Sunday to 9 AM PDT Monday for zones 670-673-676. (See LAXMWWLOX).
