textproduct: Los Angeles

SYNOPSIS

06/338 AM.

A cool down is expected for today as an upper-level trough of low pressure brushes the area. Limited instability may produce a few showers over the mountains through this evening. Offshore flow will reestablish on the back side of the trough and bring warmer temperatures over the weekend. Better cooling is expected for next week as onshore flow returns. A storm system could affect the region with a chance of light rain between Tuesday and Wednesday.

LONG TERM (MON-THU)

06/342 AM.

The pattern should shift back to onshore on Monday as a storm system approach the region. The latest forecast ensembles indicate a majority of the solutions with rain across the region between Tuesday and Wednesday. Amounts look to be light to moderate at best. Ensemble means range between 0.25 and 0.50 inch, but there is about a 20 percent chance that amounts could be higher or lower than those values. There are still some solutions with no rain at all. If one factors in the deterministic solutions of the GFS and pattern recognition, the forecast ensemble precipitation means seem reasonable. 850 mb mixing ratios are on the drier side between 4 and 6 g/kg and there is a limited warm air advective pattern component inhibiting orographic lift at this point. The forecast goes with WPC values for QPF for now and falls inline goes with NBM values for the current time, but it should be noted that there is likely a locally higher chance of precipitation and higher amounts along the south and southwest facing slopes of the mountains.

A warming trend will likely develop between Thursday and Friday, then a pair of storms looks to move into the region over next weekend and into the third week of February. The second storm system, likely moving over the region between 14th and 15th could end up being the heavier storm system. It does possess some colder air aloft and 850 mb temperatures means drop to near zero, hinting at the possibilities of more instability. There is remains high confidence in much cooler temperatures during this period.

AVIATION

06/1916Z.

At 1836Z at KLAX, the marine layer was 2400 feet deep with an inversion to 2700 feet and a maximum temperature of 17 C.

High confidence in VFR TAFs for KPMD and KWJF.

Moderate confidence in remaining TAFs, due to uncertainty with regards to ceiling hieghts and timing. There is a 30% chance of no cigs forming overnight at KVNY, KBUR, KPRB, and KOXR, and a 20% chance for other sites where cigs are forecast.

There is a less than 10% chance for an isolated shower and lightning strike near any forecast site, with higher chance of thunderstorms over the mountains through today.

KLAX...There is a 20% chance for no cigs tonight, but if cigs do form, 007-012 feet will likely be the minimum height. No significant east wind expected.

KBUR...There is a 30% chance of no cigs forming overnight, but if cigs do form, 005-010 feet will likely be the minimum height.

MARINE

06/917 AM.

A long period west swell will continue to build into the region today. Seas are expected to reach 10-12 feet across the inner waters along the Central Coast and the outer waters from Point Piedras south to San Nicolas Island. Large seas will begin to decrease Saturday, but northwest winds will increase at the same time. Small Craft Advisory (SCA) winds in the 20-30 knots range will be common across the Outer Waters and along the Central Coast into at least early next week. There is a 40-60% chance for low end Gale Force winds (35-40 knots) during this timeframe, highest chances Sunday.

West to northwest winds will make their way into the waters south of Point Conception Saturday and Sunday afternoon, although likely staying below SCA levels, except for localized gusts to 25 knots. Offshore flow will bring 15-25 knot winds to nearshore areas from Ventura to Santa Monica late Saturday through Monday afternoon, with strongest winds likely along the Malibu Coast late Saturday through Sunday early afternoon.

Choppy waves will be the result of the increase in winds and ocean conditions will remain hazardous into at least Monday.

Patchy dense fog will be tucked underneath the cover of high clouds through late this morning, and there is a moderate chance for dense fog to continue through at least Saturday morning.

BEACHES

06/128 AM.

A long period west swell will continue to build across the coastal waters today, resulting in high surf focused across west facing beaches through Saturday night. Elevated surf will likely continue into next week.

Refer to the SRFLOX and CFWLOX products for more details on the High Surf Advisories along the coast.

LOX WATCHES/WARNINGS/ADVISORIES

CA...High Surf Advisory in effect until 9 PM PST Saturday for zones 340-346-349-350-354-362-366. (See LAXCFWLOX). PZ...Small Craft Advisory in effect until 3 AM PST Monday for zones 645-670-673-676. (See LAXMWWLOX).