textproduct: Los Angeles

SYNOPSIS

04/1218 AM.

Rain and high elevation snow will affect the area today and tonight as a storm moves slowly over the region. The shower activity will diminish Monday. Drier weather is expected Tuesday through late in the week, with cold nights for many areas Wednesday night through Friday.

LONG TERM (THU-SUN)

04/219 PM.

For the extended, both the 12Z GFS and ECMWF, as well as their respective ensembles, are in good synoptic agreement into next weekend. At upper levels, ridge builds offshore of California Through Friday then move over the state Saturday and Sunday. At the same time, offshore surface flow will begin to strengthen noticeably on Friday and continue through the weekend.

Forecast-wise, the above pattern will bring a welcome period of dry weather to Southwestern California. With the ridge building over the area and the increasing offshore surface flow, skies should remain mostly clear into the weekend. As for the offshore flow, both the GFS and ECWMF have impressive LAX-DAG gradients, bottoming out in the -5 to -7 mb range. The amount of upper level support is still in question, but there will be the chance for some advisory-level Santa Ana winds Friday through Sunday. As for temperatures, will expect a warming trend with coastal/valley areas a couple degrees above normal by Sunday. Overnight lows will likely be on the chilly side in wind-sheltered areas.

AVIATION

05/0637Z.

At 0522Z at KLAX, there was no marine layer or inversion. There was a deep moist layer.

Moderate confidence in TAFs. There is a 20 percent chc of a brief shower at all sites through 14Z. There is a 20 percent chc LIFR conds in ground fog at all sites through 15Z. Flight cats may flip back and forth between Low MVFR high MVFR and low VFR through 17Z.

KLAX...Moderate confidence in TAF. There is a 20 percent chc of a brief shower through 14Z. There is a 20 percent chc of 1SM BR BKN004 conds 11Z-15Z. Cigs may alternate between BKN015, BKN025 and BKN035 through 17Z. Good confidence that any east wind component will remain under 8kt.

KBUR...Moderate confidence in TAF. There is a 20 percent chc of a brief shower through 14Z. There is a 20 percent chc of 1SM BR BKN003 conds 11Z-15Z. Cigs may alternate between BKN015, BKN025 and BKN035 through 17Z.

MARINE

04/752 PM.

Another frontal system is currently moving across the southern coastal waters which will bring periods of rain, low visibility, gusty southerly winds, and a slight risk of thunderstorms and waterspouts. Mariners should consider staying in safe harbor through tonight.

Winds across the waters have subsided below SCA levels, but localized GALE Force wind gusts to 35 kts may occur under heavier cells. As of 7 PM, the frontal band was oriented northeast to southwest over the Channel Islands and was moving south. Most of the storm cells are off the L.A. County Coast, or have moved onshore over L.A. County.

Diminishing winds are expected to continue tonight, but seas are expected to remain at SCA levels across the Outer waters and along the Central Coast through early Monday morning. Moderate chance (30-40% chance) of another round of Small Craft Advisory (SCA) level southerly winds in similar areas Monday afternoon through Tuesday. After a brief lull in winds, NW winds are likely to reach 20-30 knots Wednesday afternoon through late Thursday, focused across the Outer Waters especially south of Point Conception (with a low chance of GALE force winds).

LOX WATCHES/WARNINGS/ADVISORIES

CA...Beach Hazards Statement in effect until 10 AM PST Monday for zones 87-349-350-362-366. (See LAXCFWLOX). High Surf Advisory in effect until 10 AM PST Monday for zones 340-346-354. (See LAXCFWLOX). PZ...Small Craft Advisory in effect until 3 AM PST Monday for zones 645-670-673-676. (See LAXMWWLOX).