textproduct: Los Angeles

SYNOPSIS

11/235 AM.

Moderate to damaging coastal flooding will likely continue through at least Tuesday. Periods of light to moderate rain and a low chance of thunderstorms will persist through Monday with below normal temperatures. Beginning Tuesday and continuing through the end of the week, weak to moderate offshore flow will bring warm and dry conditions to the area.

LONG TERM (WED-SAT)

11/235 AM.

For the extended, 00Z models continue to exhibit good synoptic agreement through the period. At upper levels, ridge will build over the West Coast. At the surface, high pressure will settle over the Great Basin.

Forecast-wise, the above scenario will bring warm and dry conditions to the area. The combination of the upper level ridge and offshore surface gradients will bring a noticeable warming trend for all areas through Saturday. In fact by Friday and Saturday, moderate to locally major Heat Risk will be possible across the coastal plain and coastal valleys.

As for winds, all models indicate increasing offshore surface pressure gradients through the period. At the same time, models indicate some decent upper level wind support (925/850 mb) developing. So, there is increasing confidence in weak to moderate Santa Ana winds developing. At this time, the peak gradients and upper level wind support look to occur on Friday. Looking at the ensemble mean gusts, gusts around 40 MPH are indicated Friday morning at Camarillo and Newhall. So, there is a decent chance of moderate Santa Ana winds developing across Ventura/LA counties by Friday and Saturday. So, would not be surprised to see wind advisories issued for the Santa Ana wind corridor.

AVIATION

11/1834Z.

At 1753Z at KLAX, there was neither a marine layer nor a marine inversion.

Overall, moderate confidence in TAFs. For this afternoon through tonight, there will be a threat of showers at all sites. Through the TAF period, there will be 30-40% chance of MVFR CIGs at all sites. Additionally, there is a 5-10% chance of thunderstorms through the period.

KLAX...Moderate confidence in TAF. Periods of showers are possible late this afternoon through overnight. There is a 40% chance of MVFR CIGs anytime during the TAF period. No significant easterly winds are expected

KBUR...Moderate confidence in TAF. Periods of showers are possible late this afternoon through overnight. There is a 40% chance of MVFR CIGs anytime during the TAF period.

MARINE

11/857 AM.

For the Outer Waters, moderate to high confidence in current forecast. Through Monday, high confidence in a combination of Small Craft Advisory (SCA) level winds and seas. Additionally, there is a 20-30% chance of Gale force wind gusts this morning. On Tuesday, there is a 40-60% chance of SCA level winds, especially around Point Conception. For Wednesday through Thursday, high confidence in winds and seas remaining below SCA levels. Seas of 10+ feet will peak this morning and slowly diminish through Monday evening.

For the Inner Waters north of Point Sal, moderate to high confidence in current forecast. Through this evening, high confidence in a combination of SCA level winds and seas then dropping below advisory levels overnight. For Monday, high confidence in winds and seas remaining below SCA levels. For Tuesday through Thursday, there is a 30-50% chance of SCA level winds in the afternoon and evening hours.

For the Inner Waters south of Point Conception, moderate to high confidence in current forecast. Through this evening, high confidence in SCA level winds and choppy seas, then diminishing below advisory levels overnight. For Monday through Wednesday, high confidence in winds and seas remaining below SCA levels for most area, but the only exception is the western half of the Santa Barbara Channel where there is a 50% chance of SCA level winds Tuesday afternoon and evening. On Thursday, there is a 30-40% chance of SCA level northeast winds from Ventura south to Santa Monica.

Periods of light to moderate showers are likely through Monday with periods of no showers at times. There is a 10% chance of thunderstorms during the same time frame. While showers or thunderstorms are possible anywhere, the highest chances exist south of Point Conception.

Long period swell from the west and the south are affecting the coastal waters, and can create a confused sea state. This can make boating more challenging and dangerous, especially for small vessels.

BEACHES

11/858 AM.

A Coastal Flood Warning is in effect for the beaches of Los Angeles County (including Long Beach, the Malibu Coast and Catalina Island) through 3 PM today. DAMAGING sea-water coastal flooding is likely today, especially near the morning high tide where anticipated tide levels are expected to be around 8 feet. The most likely areas for DAMAGING coastal flooding this morning will be vulnerable south-facing beaches due to the expected combination of very high tides around 8 feet (including additive effect of low barometric pressure and onshore winds gusting to 15 to 25 mph), high surf of 5 to 8 feet, and periods of light to moderate rainfall. THERE IS GROWING CONFIDENCE THAT THE EXPECTED COASTAL FLOODING IMPACTS THIS MORNING FOR VULNERABLE SOUTH FACING BEACHES OF LA COUNTY COULD BE THE MOST SIGNIFICANT WE HAVE SEEN SO FAR THIS SEASON, INCLUDING THOSE SEEN WITH Marie.

For all other beaches and harbors of LA county, minor to moderate sea-water flooding will likely impact beaches and walkways, especially with the morning high tide which could cause local damage to the most vulnerable locations such as Venice and Long Beach. For all beach areas, significant erosion is expected. There is an increased risk of ocean drowning. Dangerous and life- threatening rip currents can pull swimmers and surfers out to sea. Large breaking waves can cause injury, wash people off beaches and rocks, and capsize small boats near shore. The projected high tides of around 8 feet for this morning would approach or exceed recent record tide levels for LA county. Large secondary high tides are also expected each evening.

For beaches from Ventura County northward, minor to moderate coastal flooding will be likely near times of high tide as well as periods of elevated to high surf and strong rip currents. In addition to the Coastal Flood Advisory for Ventura County, Coastal Flood Advisories have been added for the Central Coast and southern Santa Barbara coast. For Ventura county, there is the possibility of localized damage across low-lying areas during the morning high tide, along with the threat of significant sea spray and and water on sections of PCH between Point Mugu and Sycamore Cove.

A very complex series of swells from the south, west, and northwest will impact our coastlines into at least early next week. Energy from Tropical Storm Rachel, southern hemisphere swells, northwest swells, and local wind swells will add up with each other to produce the aforementioned coastal impacts. Please continue to monitor the forecast.

LOX WATCHES/WARNINGS/ADVISORIES

CA...Coastal Flood Warning in effect until 3 PM PDT this afternoon for zones 87-362-366. (See LAXCFWLOX). Coastal Flood Advisory in effect from 3 PM this afternoon to 2 PM PDT Tuesday for zones 87-362-366. (See LAXCFWLOX). Coastal Flood Advisory in effect until 10 PM PDT Monday for zones 340-346-349-350. (See LAXCFWLOX). High Surf Advisory in effect until 10 PM PDT Monday for zones 340-346. (See LAXCFWLOX). Beach Hazards Statement in effect through Tuesday afternoon for zones 349-350. (See LAXCFWLOX). Coastal Flood Advisory in effect until 2 PM PDT Tuesday for zone 354. (See LAXCFWLOX). High Surf Advisory in effect until 10 PM PDT this evening for zones 354-362-366. (See LAXCFWLOX). Wind Advisory in effect until 5 AM PDT Monday for zones 378>383. (See LAXNPWLOX). PZ...Small Craft Advisory in effect until 9 PM PDT this evening for zones 645-650-655-676. (See LAXMWWLOX). Small Craft Advisory in effect until 5 PM PDT Monday for zones 670-673. (See LAXMWWLOX).