textproduct: Los Angeles

SYNOPSIS

14/313 AM.

Dry conditions and seasonable temperatures are expected this weekend. Then, a strong storm system will affect the region late Sunday through Wednesday, bringing heavy rainfall, along with flooding and low elevation mountain snow, thunderstorms, strong winds, as well as marine and beach hazards.

LONG TERM (TUE-FRI)

14/313 AM.

Moist flow and multiple impulses will keep the shower activity going on Tuesday, but there will be some dry period as well. A better organized system will approach the Central Coast later in the afternoon and the rainfall will increase and intensify there. Rainfall totals for the day will range from a third to a half inch with local 1 inch amounts in some mtn areas. Significant snowfall will be possible above 5000 ft.

A new colder system will arrive Tuesday night and Wednesday. PWATs will be half as much a Monday's storm. It will be more unstable and the rainfall will be more showery. This system could bring an additional 1 inch of rain to the csts/vlys and up to 2 inches in the mtns. Snow may be the biggest talking point with this system Snow level may drop to 3500 ft and even lower under convective bursts. Snow at these levels would definitely affect all the major passes. Max temps will struggle to even reach 60 degrees.

Weak cyclonic flow will continue over the state on Thursday and Friday. This will keep a 20 to 30 percent chc of showers in the forecast for both days, but at this time no storms of consequence are forecast.

Looking further ahead the EC-AI does show another storm system moving through the area sometime in Tue-Thu Feb 24-26 time period.

AVIATION

14/1051Z.

At 1030Z at KLAX, the marine layer was 1600 ft deep. The top of the inversion was around 2800 feet with a temperature of 13 degrees Celsius.

For 12Z TAF package, high confidence in desert TAFs, but only moderate confidence in coastal/valley TAFs. Timing of dissipation of CIG/VSBY restrictions this morning could be +/- 2 hours of current forecasts. For tonight, high confidence in return of MVFR CIGs, but low confidence in timing (could be +/- 3 hours of current forecasts).

KLAX...Moderate confidence in 12Z TAF. Timing of dissipation of MVFR CIGs this morning could be +/- 2 hours of current 16Z forecast. Timing of return of MVFR CIGs tonight could be +/- 3 hours of current 04Z forecast. An easterly wind component of 6-7 knots will continue through around 18Z.

KBUR...Moderate confidence in 12Z TAF. There is a 20% chance of MVFR CIGs 13Z-17Z this morning. For tonight, timing of return of MVFR CIGs could be +/- 3 hours of current 08Z forecast.

MARINE

14/251 AM.

For the Outer Waters, moderate to high confidence in current forecast. Small Craft Advisory (SCA) level winds and seas will continue this morning, before diminishing below SCA levels this afternoon and evening. Tonight and Sunday, southeast winds will increase to SCA levels as well as the seas. For Sunday night through Wednesday, high confidence in SCA level winds and seas. Additionally, there is a 40-60% chance of GALE force winds Monday night and Tuesday, especially across PZZ670. SCA level this afternoon.

For the Inner Waters north of Point Sal, moderate to high confidence in current forecast. Through tonight, high confidence in winds and seas remaining below SCA levels. For Sunday through Wednesday, high confidence in combination of SCA level winds and seas developing. Additionally, there is a 50-60% chance of GALE force winds Sunday night through Tuesday.

For the Inner Waters south of Point Conception, moderate to high confidence in current forecast. Today through Sunday, high confidence in winds and seas remaining below SCA levels. For Sunday night through Wednesday, high confidence in SCA level winds with a 50% chance of SCA level on Wednesday. Additionally, there is a 40-50% chance of GALE force winds Monday through Tuesday.

(Late Sunday night - Monday night) *Timing will be refined later*

A squall line will likely develop in association with the cold front which will result in hazardous marine conditions. These include: GALE force winds, dangerous Lightning, heavy rainfall with reduced visibility, and waterspouts.

BEACHES

13/739 PM.

A High Surf Advisory is in effect for the Central Coast, and is expected to peak overnight with large breaking waves of 9 to 13 feet.

A period of very large waves continues to be advertised by the latest swell model guidance early next week. High confidence in widespread high surf between Monday and Thursday as a combination of SW and W-NW swells affect the SW California waters. Sets above 10 feet will be possible across all beaches, but there is a higher chances for W-NW facing shores. There is a moderate chance of damaging sets (near 20 ft) developing between Tuesday night and Wednesday night, especially along the Central Coast.

Elevated high tides as the new moon cycle approaches will coincide with the arrival of the higher surf and swell. This will bring an elevated chance of coastal flooding, or at the very least, minor tidal overflows especially during the time of the high tides. A coastal flood advisory may be needed should swell guidance remain consistent along with wind-driven factors.

LOX WATCHES/WARNINGS/ADVISORIES

CA...High Surf Advisory in effect until 9 AM PST this morning for zones 340-346. (See LAXCFWLOX). PZ...Small Craft Advisory in effect until 9 AM PST this morning for zones 670-673-676. (See LAXMWWLOX).