textproduct: Los Angeles

SYNOPSIS

09/259 AM.

Above-normal temperatures will persist today, before a weak storm system crosses the region later Tuesday through Wednesday. Light to moderate rain is expected, mainly Tuesday evening through early Wednesday, with gusty southerly winds over the higher terrain, especially Tuesday night. Temperatures will cool during the middle of this week, followed by a gradual warming trend for late week into the weekend. For the following week, multiple rounds of precipitation and much cooler conditions are increasingly likely.

LONG TERM (THU-SUN)

09/259 AM.

On Thursday the storm evolves into a long wave pos tilt trof with an axis from srn ID to SLO county. It is fairly dry and should produce any rainfall. Skies will be partly cloudy. The extra sunshine will bring a few more degrees of warming but max temps will remain a couple of degrees blo normal.

Friday will be the nicest day of the next 7 as a decent ridge moves into the area and hgts rise to about 570 dam. Skies will be mostly sunny and max temps will rise 3 to 5 degrees and end up in the upper 60s to lower 70s across the csts and vlys.

The ridge quickly collapses as a new storm system approaches from the west. The cloud shield assoc with the storm will move over the state and skies will turn mostly cloudy. Aside from a slight chc of rain across the Central Coast it should be dry through the afternoon. Hgts will fall to about 564 dam and this along with the cloudy skies will reduce max temps by 3 or 4 degrees.

A major pattern change develops Saturday evening and the weather will turn wetter and colder for Sunday and the rest of the week of the 15th to 20th.

On Saturday night a long wave trof will move into the west coast. Rain will overspread the area overnight and continue through most of Sunday. Snow levels will fall to 5000 ft and significant snowfall accumulations will be possible above 5500 ft. Since this system is still 7 days away there is uncertainly in the exact timing and intensity. The AI mdls favor the ensembles exhibiting the higher amounts and a half inch to an inch with hier amounts in the mtns/foothills is a best first guess, but higher amounts are very possible. There is uncertainty with the timing too and the system may not really arrive until later Sunday. This is cold system and max temps Sunday will fall 4 or 5 degrees and end up in the upper 50s and lower 60s or 5 to 6 degrees blo normal.

After this storm medium range ensemble mdls and AI-mdls show a following system arriving around Wednesday and another around Friday. Wednesday's system currently looks like the strongest and coldest of these three and may bring many rain and snow issues to the area.

These systems are still many days away and some changes to the forecast is an almost certain. Srn Californians are encouraged to continue reading this product for the latest developments with this evolving stormy pattern. As the system draws closer people should monitor all latest storm information published here at the National Weather Service in Los Angeles/Oxnard.

AVIATION

09/1021Z.

Around 0915Z, there was no marine layer depth at KLAX. There was a surface-based inversion up to around 1250 feet with a temperature near 22 degrees Celsius.

Moderate confidence in the current forecast. There is a high chance of VLIFR to LIFR conditions at terminals north of Point Conception through 16Z. There is a moderate to high chance of LIFR to IFR conditions developing at coastal terminals after 03Z Tuesday.

KLAX...VFR conditions are expected through at least 08Z Tuesday. There is a 40 percent chance of LIFR to IFR conditions after 08Z Tuesday. Any easterly winds will be less than 7 knots.

KBUR...VFR conditions are expected through the period. No wind impacts are expected through the period.

MARINE

09/228 AM.

Moderate to high confidence in the current forecast. Less confidence exists in the swell forecast. Higher confidence exists in the wind forecast.

For the waters southwest through northwest of the Channel Islands and the nearshore waters along the Central Coast, SCA conditions are likely (60-80 percent) chance through much of the week. There are a few periods where the swell and wind may drop off, but winds and seas will likely remain near hazardous levels to small craft through the forecast period. Local GALE force gusts are possible this morning. There is a high to likely (50-70 percent) chance of Gale Force southwesterly winds between mid-morning Tuesday through Tuesday night, especially for the waters west through north of Point Conception.

Inside the southern California bight, there is a moderate (30-40 percent) chance of SCA level winds through Tuesday morning, increasing to a high to likely (50-70 percent) chance by Tuesday evening. Winds will likely fall below SCA levels between Wednesday and the end of the week, but there is a high to likely (40-60 percent) chance of SCA conditions developing each evening across the western portions.

There is a high chance that marine conditions will be poor for the upcoming weekend with rain, widespread hazardous seas, and gusty winds spreading over the area between Friday and Tuesday. There is a moderate to high (30-50 percent) chance of widespread GALES early next week.

BEACHES

09/221 AM.

A high surf advisory remains in effect for the Ventura County beaches through Wednesday, but there is a 40 percent chance that the surf could subside this afternoon and evening then rise again for Tuesday. While the swell will primarily be out of the west, the swell will become more southwesterly late Tuesday through Wednesday. During this time period, typically more sheltered south to southwest-facing beaches and harbors will see elevated-to- high surf conditions, and there is a chance that a high surf advisory may be needed for Santa Barbara South Coast as swell direction are a little more favorable.

Surf and swell will build Friday and likely remain near high surf criteria through next weekend, then there is a moderate to high chance of more widespread and higher surf developing early next week. There is a 20-30 percent chance of damaging sets developing between next Monday and Tuesday.

LOX WATCHES/WARNINGS/ADVISORIES

CA...High Surf Advisory in effect until 9 PM PST Wednesday for zone 354. (See LAXCFWLOX). PZ...Small Craft Advisory in effect until 9 PM PST this evening for zones 645-670-673-676. (See LAXMWWLOX). Gale Watch in effect from Tuesday morning through late Tuesday night for zones 645-670-673. (See LAXMWWLOX).