textproduct: Los Angeles

SYNOPSIS

04/225 PM.

Tropical Cyclone Marie, which will remain well offshore of SoCal, will bring impacts to the region over the weekend into early next week. Rain is favored late Saturday and Sunday focused over Los Angeles and Ventura Counties. Increasing southerly swell will create hazardous surf conditions at the coasts.

LONG TERM (TUE-FRI)

05/301 AM.

Extremely low forecast confidence for Tuesday and beyond as what will likely be the remnants of Marie plays tricks with our model guidance.

Exactly when and how Marie or its moisture merges with an unseasonably far south jet stream will determine what version of weather and associated impacts we receive.

Two main scenarios seem to be emerging: 1) The remnants of Marie remain well offshore (80 percent chance). Even if this occurs continued moist south to southeast flow main bring light showers or isolated thunderstorms focused across interior mountains to deserts at times. This scenario has the greatest chance (50-60 percent chance) of a mid-week heatwave, potentially warranting heat products.

2) The remnants of Marie make a somewhat closer pass (20 percent chance), and bring widespread at least light to moderate rain in the Tuesdayish timeframe, especially Santa Barbara and San Louis Obispo Counties.

Please stay tuned if heat and/or rain may impact your plans next week as things will change.

AVIATION

05/1133Z.

At 07Z at KLAX, the marine layer was 1900 feet deep. The top of a weak inversion was 2700 feet with a temperature of 21 deg Celsius.

High confidence in desert TAFs, KPRB, and KSBA.

Moderate to high confidence remainder of TAFs through 00Z where there is a low cigs/vsbys may be patchy or not form at all where forecast and vice versa, although trends favoring VFR for most terminals KSBA and south including KLAX and KBUR. Low MVFR cigs/vsbys are favored where low cigs do form except IFR or lower for KSMX and possibly KSBP.

Lowering confidence after 06Z due to unusual influx of tropical moisture with a 30 percent chance of -shra as early as 08Z and 50 percent chance or greater after 15Z for LA County and Ventura County terminals.

KLAX...Moderate confidence in TAF. There is a 80% chance that VFR conds prevail through at least 03Z. -SHRA and low VFR to high MVFR cigs/vsbys possible as early as 08Z and more likely after 15Z.

KBUR...High confidence in TAF with a 10 percent chance of brief MVFR cigs through 16Z. -SHRA and low VFR to high MVFR cigs/vsbys possible as early as 08Z and more likely after 15Z.

MARINE

05/103 AM.

For the Outer Waters, moderate confidence in current forecast. There is a 20-30% chance of Small Craft Advisory (SCA) level winds through tonight. For Sunday, there is a 60-80% chance of SCA level winds. For Monday through Wednesday, there is a 30-40% chance of SCA level winds.

For the Inner Waters north of Point Sal, moderate to high confidence in current forecast. High confidence in winds and seas remaining below SCA levels through tonight. On Sunday and Monday, there is a 30-40% chance of SCA level winds in the afternoon and evening hours. For Tuesday and Wednesday, high confidence in winds and seas remaining below SCA levels.

For the Inner Waters south of Point Conception, moderate to high confidence in current forecast. For a majority of the southern Inner Waters, high confidence in winds and seas remaining below SCA levels through Wednesday. The only exception will be the western half of the Santa Barbara Channel where there will be 50-60% chance of SCA level winds late Sunday afternoon and evening.

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.

BEACHES

04/740 PM.

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 5-8 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.

LOX WATCHES/WARNINGS/ADVISORIES

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...NONE.