06/510 PM.
Rain due to distant tropical cyclone Marie will continue into this evening, focused mainly over Los Angeles County but also affecting portions of Ventura and Santa Barbara Counties. A significant southerly swell will cause hazardous surf conditions at the beaches through at least Tuesday. Heat will build across the region through the next several days, with moderate to major heat impacts for the coasts and valleys Tuesday through Thursday.
(Sun-Wed), 06/758 PM.
***UPDATE***
A deep layer of tropical moisture moved over the area today, with satellite analyzed PWAT values up to around 2 inches over the southern coastal waters and near-coastal areas of LA and SE Ventura Counties. An lengthy period of light to moderate rainfall affected both counties, with brief pockets of heavy rainfall at times throughout the day. The heavier rain was associated with a few thunderstorms that moved northeast over the area during the afternoon hours. Peak rainfall totals ranged from an inch to around 1.5 inches, highest in a line extending from the eastern Santa Monicas across Burbank to Beverly Hills and into the eastern San Gabriels. The Ventura Coast and valleys saw around 0.25 inch to 0.80 inch, otherwise the remainder of the area had light rain under 0.10 inch.
Light to locally moderate showers continue over eastern LA County this evening, on a diminishing trend as the band of showers moves off to the northeast. A few light showers could persist over the higher eastern San Gabriels after midnight, otherwise a clearing and drying trend is expected into Monday after later tonight.
Marie is now a tropical storm, and is centered 700 miles SSW of Point Conception, forecast to slowly move WNW over the next few days while weakening. This track will maintain her position well away from southern California, although the associated tropical moisture and southerly swells will continue to affect the area. The south swells have created an ongoing, significant hazard at area beaches, especially the exposed south facing beaches, with strong and potentially deadly rip currents.
***From Previous Discussion***
Starting Monday, a significant warming trend is expected. By Tuesday expect lots of areas of moderate to major HeatRisk for the coasts and coastal valleys, in particularly the LA Basin. Temperatures are expected to peak on Wednesday, with widespread major HeatRisk and highs largely 90 to 105 degrees. There is the potential that Heat Advisories will be needed (even near the coast) as early as Tuesday, becoming likely for Wednesday for most all coasts and valleys. Along the Central Coast, Tuesday is favored to remain cooler with a very dramatic warming trend for Wednesday, when temperatures could be in excess of 100 degrees. The warming trend for the region is due to a combination of a high pressure ridge that is likely to center over SoCal this week, along with periods of weak offshore flow. Very warm overnight lows (even at the coasts) and elevated humidity will contribute to the heat impacts.
A weak impulse acting on lingering low level moisture may A boundary lifting back north later Monday and especially into Tuesday may support another round of light to moderate showers, and cannot rule out an isolated thunderstorm focused across interior mountains.
(Thu-Sun), 06/200 PM.
Upper level ridge of high pressure expected to remain strong over the area on Thursday, then weaken some on Friday. During this time, pressure gradients will likely be weakly offshore to the north and weakly onshore to the east, resulting in a continuation of hot temperatures with associated heat impacts across much of the region on Thursday, with a slight cool-down possible by Friday. There is also the potential for some weak to moderate sundowner wind activity across southern Santa Barbara county each evening on Thursday and Friday.
The position of the ridge by Thursday may be favorable for some monsoon moisture or injection of tropical moisture from the south. So it will likely be quite humid with weak morning offshore flow potentially delaying the sea breeze. This type of pattern could support isolated showers focused across the interior.
Below normal confidence Friday into next weekend as the ridge may break down pretty quickly or be somewhat stubborn. Either way it does look somewhat likely that troughing off the coast may reestablish at times, keeping the door open for additional subtropical moisture to shuttle into southwest California.
07/0010z.
At 2308Z at KLAX, the marine layer was 600 ft deep. The inversion top was near 1200 ft with a temperature of 24 C.
Showers are expected to affect the Ventura and LA County TAF sites through 02Z-04Z this evening, with a 30% chance of -shra affecting KSMX and KSBA during this time. CIG heights will be VFR with VSBYs lowering to MVFR/IFR at times in heavier showers. There is also a 5-15% chance of thunderstorms for Ventura and Los Angeles TAF sites, until around 02Z Mon.
KLAX, Moderate confidence in the 00Z TAF. VSBY may lower to 4SM occasionally with heavier rain through around 02Z Mon. East wind component exceeding 8 kts is possible (40% chance) through 02Z, with winds then expected to shift to westerly between 02Z-04Z.
KBUR, Moderate confidence in the 00Z TAF. VSBY may lower to 4SM during moderate to heavy showers through around 02Z Mon but may linger through 04Z, followed by improving conds.
06/131 PM.
For the Outer Waters, through Monday morning SCA level winds and seas are expected, with a lull on Monday and Tuesday. Wednesday afternoon into at least late next week SCA winds are likely much of the time.
For the Inner Waters north of Point Sal, there is a 30% chance of SCA level winds on Wednesday evening and a 60% chance for Thursday. Otherwise conditions are expected to be below SCA levels.
For the Inner Waters south of Point Conception, there is a 50% chance of brief SCA level winds Tuesday afternoon and evening, and a 30-50% chance of SCA winds across western sections on Thursday. Otherwise conditions are expected to be below SCA levels.
Tropical moisture will stream over the area today and last into Tuesday, bringing showers to the coastal waters. There is a 15% chance of thunderstorms this afternoon for the waters south of the Channel Islands. A large southeast to south swell is impacting the area, causing increased currents and surges in the vulnerable harbors. Breaking waves may impact south harbor entrances, particularly for Ventura and Los Angeles Counties (observed at Ventura Harbor).
06/246 PM.
Significant coastal impacts are expected across Southern California beaches through at least Tuesday. A large southeast to south swell from Hurricane Marie has moved into 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 12 feet through Monday. Potentially life threatening rip currents will continue as well. The highest surf is near Zuma and Malibu Beach as well as Long Beach. 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.
Moderate coastal flooding has occurred and will continue around high tides for south facing shores. The actual observed tides have been running about 6 inches above predictions for sometime now. The south swell will likely boost that enhancement. As a result, high tides are expected to reach around 6.7 feet by 6 pm today, then exceed 7 feet by Monday evening high tide. Expect significant beach erosion, flooded sandy beach areas, bike paths, and parking lots, as well as low-lying roads. Of particular concern will be the Alamitos Peninsula area in Long Beach where coastal flooding will potentially cause local damage to structures near time of high tide later today, Other areas of concern the next couple of days include Catalina Island, 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 until 9 AM PDT Monday for zones 670-673-676. (See LAXMWWLOX).
