textproduct: Los Angeles

SYNOPSIS

08/242 AM.

Today will be the last day of the long lasting heat wave. Although afternoon high temperatures will be a few degrees cooler than yesterday they will still be dangerously high. Temperatures will trend cooler Friday into Sunday and there will be an increasing chance of showers and thunderstorms due to moisture from Hurricane Rachel.

LONG TERM (SUN-WED)

08/1213 PM.

On Monday the upper low will move into the vcnty of SBA county with 557 dam hgts. The low will bring clouds and chc of rain to the entire 4 county forecast area from midnight to midnight. Since most of the moisture will be to the east of the area rainfall totals will not be that great most areas can expect to recieve a tenth to a quarter inch of rainfall. Max temps will fall further to the mid 60s to lower 70s.

There is some disagreement on how fast the upper low will move out of the area. Enough solutions keep the upper low around long enough to keep a 20 to 30 percent chc of rain in the forecast. Even if it does rain there will not be much additional rainfall.

Aside from a small chc of a mtn shower Wednesday should be dry as drier NW flow moves into and over the state. Sunnier skies and rising temps will bring 3 to 6 degrees of warming. Even with the warming max temps will end up about 6 degrees blo normal.

AVIATION

08/2323Z.

At 2247Z at KLAX, the marine layer was 900 feet deep. The top of the inversion was 1600 feet with a temperature of 28 C.

High confidence in VFR TAFs for KPMD, KWJF, KBUR, KVNY, & KPRB. 10% chance of brief V/LIFR conditions between 09/10-17Z at KPRB.

Moderate confidence in remaining 00Z TAFs. Timing of CIG/VSBY restrictions may be off +/- 2 hours, and CIG height accuracy +/- 300 ft of current forecast.

KLAX...Moderate confidence in TAF. Arrival and clearing times of CIGs 008 (+/- 300 ft) may be off +/- 2 hours. No significant easterly wind component is expected.

KBUR...High confidence in VFR TAF. No wind issues expected. Fairly low chance (10%) of brief LIFR conds 13Z-17Z.

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MARINE

08/140 PM.

Relatively quiet conditions are expected across the coastal waters through much of Saturday. Localized Small Craft Advisory (SCA) gusts may occur each afternoon and evening between Point Conception and San Nicolas Island. Night through morning dense fog may affect portions of the coastal waters adjacent to the Central Coast and south to San Nicolas Island once again tonight through tomorrow morning.

Northwest to southwest winds will increase to 20-30 knots by Saturday afternoon/evening, becoming much more expansive all of Sunday and into early Monday morning. There is a 30-40% chance of Gale Force winds on Sunday, primarily focused across the nearshore waters adjacent to Los Angeles and Orange Counties. Large, steep, and choppy seas will develop Saturday, continuing through at least Monday. This fairly rapid and significant increase in winds is due to a very complex situation as an unseasonably cold trough drops down the California Coast, interacting with remnants of Tropical Storm Rachel, which will soon turn northeast and move towards the California/Mexico Border coastline over the next couple of days. It is worth noting that the projected track of Tropical Storm Rachel has shifted further south, most likely making landfall in northern Baja California.

In addition the the increasing gusty winds, widespread light to moderate rainfall is likely Saturday evening through Tuesday, with highest confidence for Sunday-Monday. There is a 10% chance of thunderstorms during the same timeframe. While rain or thunderstorms are possible anywhere, highest chances exist south of Point Conception.

As this is a complex and evolving situation, please continue to monitor the forecast.

BEACHES

08/201 PM.

A Coastal Flood Advisory is in effect through Tuesday afternoon for Los Angeles and Ventura Counties, while a Beach Hazards Statement (BHS) is in effect for the Santa Barbara South Coast and the Central Coast.

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 elevated surf and dangerous rip currents at times. Extremely high tides will be common each morning, peaking between 6.8 to 7.6 feet MLLW, highest further south. Additionally secondary high tides will peak each evening, likely most impactful through the weekend with tides reaching 5.5 to 6.5 feet MLLW.

While each day under the Coastal Flood Advisories or BHS should see fairly similar impacts, Sunday will likely see elevated impacts. Rapidly increasing wind speeds will likely add to the coastal flooding potential, creating a wind swell as well as elevating tides slightly. Additionally if one of the incoming low pressure systems arrives to our waters Sunday, water levels will also increase. If all these ingredients overlap on Sunday, a more significant coastal flooding event will be likely. This is a very narrow window, but there is a low chance for a targeted Coastal Flood Warning to be issued in southern Los Angeles County if all factors line up.

As this is a complex and evolving situation, please continue to monitor the forecast.

LOX WATCHES/WARNINGS/ADVISORIES

CA...Extreme Heat Warning in effect until 8 PM PDT this evening for zones 38-87-88-349>358-362-366>375-548-550. (See LAXNPWLOX). Coastal Flood Advisory in effect until 2 PM PDT Tuesday for zones 87-354-362-366. (See LAXCFWLOX). Heat Advisory in effect until 8 PM PDT this evening for zones 340>348. (See LAXNPWLOX). Beach Hazards Statement in effect from Saturday morning through Monday afternoon for zones 340-346-349-350. (See LAXCFWLOX). PZ...NONE.