textproduct: Los Angeles

SYNOPSIS

09/200 PM.

Temperatures will cool region wide through the weekend and into early next week. Tropical Storm Rachel is expected to track well south of Los Angeles County, but periods of light to moderate rain showers with a low chance of thunderstorms is forecast from Saturday evening into early next week. Another warm up with the potential for offshore flow is likely Wednesday into the weekend.

LONG TERM (TUE-FRI)

09/200 PM.

Rain shower chances continue into Tuesday with only light rain expected. Then there is solid model agreement that the upper low will move to the east fairly rapidly. We will then dry out and likely see some increasing northerly flow. Wednesday will more or less be a transition period as we enter a pretty rapid warming trend which will becoming more apparent Thursday and Friday as a ridge (near 590 dam) builds in and offshore flow is forecast to develop. While there is a wide range of outcomes regarding the offshore flow, the most likely outcome is a weak to moderate Santa Ana Wind event.

AVIATION

10/0000Z.

At 1722Z at KLAX, the marine layer was 900 feet deep. The top of the inversion was 2000 feet with a temperature of 23 degrees C.

High confidence in KWJF and KPMD. For all other sites, moderate confidence in TAFs as timing of flight category changes through the period could be +/- 3 hours of current forecasts, and there is a 20-40% chance that cigs may not develop at all where they are forecast.

KLAX...Moderate confidence in TAF. Timing of flight category changes could be +/- 3 hours of current forecasts, and there is a 20% of only a few hours if any of cigs developing tonight. No significant easterly wind component is expected.

KBUR...Moderate confidence in TAF. There is a 10% chance of BKN002-10 cigs forming between 12Z-15Z Sat.

MARINE

09/840 AM.

For the Outer Waters, moderate to high confidence in current forecast. Today through Saturday morning, high confidence in winds and seas remaining below Small Craft Advisory (SCA) levels. From Saturday afternoon through Monday morning, high confidence in a combination of SCA level winds and seas. On Tuesday, there is a 50% chance of SCA level winds around Point Conception with winds remaining below SCA levels elsewhere.

For the Inner Waters north of Point Sal, high confidence in current forecast. Today through Saturday morning, winds and seas are expected to remain below SCA levels. From Saturday afternoon through Tuesday, SCA level winds are expected (mainly in the afternoon and evening hours) with seas approaching SCA levels on Sunday and Monday.

For the Inner Waters south of Point Conception, moderate to high confidence in current forecast. Today through Saturday, high confidence in winds and seas remaining below SCA levels. For Sunday, there is a 60-80% chance of SCA level winds. For Monday through Tuesday, high confidence in winds and seas remaining below SCA levels except for a 50% chance of SCA level winds on Tuesday across the western half of the Santa Barbara Channel.

Periods of light to moderate showers is likely Saturday evening through Tuesday, with highest confidence for Sunday-Monday. There is a 10% chance of thunderstorms during the same time frame. While showers or thunderstorms are possible anywhere, highest chances exist south of Point Conception.

BEACHES

09/846 PM.

A Coastal Flood Warning is in effect for the beaches of Los Angeles County (including the Malibu Coast and Catalina Island), in effect through 3 PM Sunday. Highest impacts are likely for vulnerable south-facing beaches, especially Long Beach and Malibu, and damaging sea-water flooding of structures and beach roadways is likely near times of high tide, which are expected to range between 7.3 and 7.5 feet this weekend. There is the potential for additive factors to the water levels on Sunday as some computer model projections are showing lower atmospheric pressure values (somewhere between 995 and 1005 mb) due to Rachel passing to our south and east, as well as the possibility of enhanced southwest to west onshore winds over the coastal waters near the time of Sunday morning high tide. There is still some uncertainty in these additive factors due to the timing of Rachel's track in relation to the high tides on Sunday morning. But we can expect water levels to be at least 7.3 to 7.5 feet across LA county during the Sunday morning high tide, with the potential for water levels to reach 8 feet if the low pressure/onshore wind components materialize near time of high tide. As a result, Sunday has the highest risk for damaging coastal flooding (especially Long Beach and Malibu areas). The Coastal Flood Warning may be extended past Sunday, or converted to a Coastal FLood Advisory through Tuesday. High surf of 4 to 7 feet is also expected with locally higher sets possible Sunday, along with strong/dangerous rip currents.

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. Depending on the track of Rachel, there is a small chance (20 percent) that Ventura County will need to be upgraded to a Coastal Flood Warning. Please see CFWLOX for additional details.

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 Sunday for zones 87-362-366. (See LAXCFWLOX). Beach Hazards Statement in effect from 8 AM PDT Saturday through late Saturday night for zones 340-346. (See LAXCFWLOX). High Surf Advisory in effect from 6 AM Sunday to 10 PM PDT Monday for zones 340-346. (See LAXCFWLOX). Beach Hazards Statement in effect from 8 AM PDT Saturday 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 from 6 AM to 10 PM PDT Sunday for zones 354-362-366. (See LAXCFWLOX). PZ...Small Craft Advisory in effect from 3 PM Saturday to 3 AM PDT Sunday for zone 645. (See LAXMWWLOX). Small Craft Advisory in effect from 6 PM Saturday to 9 PM PDT Sunday for zones 650-655-676. (See LAXMWWLOX). Small Craft Advisory in effect from 6 AM Saturday to 9 PM PDT Monday for zones 670-673. (See LAXMWWLOX).