textproduct: Los Angeles

SYNOPSIS

15/249 AM.

A moderate to strong Santa Ana Wind will bring widespread strong winds and critical fire weather conditions to much of Southwest California through Saturday. Additionally, very warm temperatures bring a high risk of heat illness to all coastal areas. A significant cool down with a chance of widespread rain is expected next week.

LONG TERM (SUN-WED)

15/231 AM.

Upper level support collapses on Sunday. Offshore flow will remain by it will be down to 1 to 2 mb. The much weaker offshore flow will bring about 3 to 5 degrees of cooling (4 to 8 degrees across the Central Coast). Even with the cooling max temps will end up 4 to 8 degrees above normal.

More cooling is in store on Monday as an upper low moves down the coast. Hgts will fall from 580 dam Sunday afternoon to 576 dam Monday afternoon. Actual onshore flow will develop and will increase through the day. Some morning marine layer clouds may even develop over the Central Coast. Max temps will fall 4 to 8 degrees. This will bring max temps down to near normals.

Forecast confidence drops off quickly starting Tuesday. The cold upper low is forecast to continue down the coast and into and over Srn CA during the time period. There is still much mdl and ensemble disagreement on the timing and track of this system. A more inland track would limit the chc/amt of rain while a more westward over ocean track would bring increased chcs of rain and more of it. Timing is very uncertain. Do think some sort of rain will fall during the Tue to Thu time period but due to all of the uncertainty no more than a 30 percent chc during any 12 hour period. Early and certainly subject to change rainfall totals call for around a quarter to half inch for the entire period. Good confidence in much cooler conditions with highs mostly in the upper 60s and lower 70s.

AVIATION

15/0949Z.

At 0832Z at KLAX, there was no marine layer nor inversion.

High confidence in CAVU TAFs, moderate confidence in winds. Timing and strength of gusty NE winds may be off by 2-3 hours and 10kt respectively.

KLAX...High confidence in CAVU TAF. Any east wind component will be AOB 7 kts 12Z-16Z.

KBUR...High confidence in CAVU TAF. Moderate confidence in winds, and N to NE winds may begin as early as 14Z.

MARINE

15/248 AM.

Gusty northeast to easterly winds will affect the coastal waters over the next few days. Moderate to strong Santa Ana winds will affect the waters south of Point Conception today through Saturday morning, and the near shore waters will see gusty easterly winds Friday, possibly reaching Small Craft Advisory (SCA) levels.

These hazardous Santa Ana NE-E winds will be focused from Ventura to Santa Monica and out past Anacapa Island starting today, and conditions could also become hazardous across the San Pedro Channel Friday morning with a 25% chc of 25 kt gusts at Avalon Harbor. The worst conditions are expected Friday morning, and Gale Watches have been issued to target these waters. Refer to MWWLOX for more details. Small Craft Advisory (SCA) may be needed for the nearshore waters along the Central Coast Friday morning due to gusty offshore winds.

There is a solid signal for a trough early to mid next week which could bring hazardous boating conditions along with rain chances to our coastal waters. Will monitor this system.

Long period swells from the west and the south are affecting the coastal waters, and can create a confused sea state. This can make boating more challenging and dangerous, especially for small vessels.

FIRE WEATHER

14/909 AM.

Offshore flow will steadily increase each day through Thursday or Friday, then weaken over the weekend. During the Thursday and Friday peak, northeast winds of 20 to 40 mph with gusts to 40 to 60 mph will be common over the wind prone areas of Los Angeles and Ventura Counties, with localized gusts of 60 to 70 mph in the mountains. Winds will be unusually widespread on Friday, when much of Santa Barbara and San Luis Obispo will experience a few hours windy conditions, especially the interior mountains where winds of 15 to 25 mph and gusts of 30 to 40 mph are expected. Meanwhile, the air will rapidly warm and dry. High temperatures between 85 and 95 will be common by Friday, warmest near the coast where the risk for heat illness is high. Minimum humidities will generally lower into the 5 to 15 percent range by Friday, with poor overnight recoveries starting Thursday.

All of this will add up to a high risk for large fires and rapid fire growth over most of the area, especially over Los Angeles and Ventura Counties as well as interior San Luis Obispo and Santa Barbara Counties where Red Flag Warnings and Fire Weather Watches are in place. While some areas received rain earlier this week, the dry day today will largely remove any benefiting effects on the fuels.

LOX WATCHES/WARNINGS/ADVISORIES

CA...Wind Advisory in effect from 6 AM this morning to 8 PM PDT Friday for zones 88-354-355-358-362-370>374-376-377. (See LAXNPWLOX). Heat Advisory in effect from 10 AM this morning to 8 PM PDT Saturday for zones 340-341-346-347-349-350-354-355-362-366>368. (See LAXNPWLOX). Beach Hazards Statement in effect until 2 PM PDT this afternoon for zones 354-362-366. (See LAXCFWLOX). High Wind Warning in effect from 6 AM this morning to 8 PM PDT Friday for zones 369-375-378>380. (See LAXNPWLOX). Red Flag Warning in effect from 6 AM this morning to 8 PM PDT Saturday for zones 288-354-355-358-362-369>382-548. (See LAXRFWLOX). Red Flag Warning in effect from 3 AM to 6 PM PDT Friday for zones 345-353. (See LAXRFWLOX). PZ...Small Craft Advisory in effect from 9 AM this morning to 3 AM PDT Friday for zones 650-655. (See LAXMWWLOX). Gale Watch in effect from late tonight through Friday afternoon for zones 650-655. (See LAXMWWLOX). Small Craft Advisory in effect until 3 AM PDT early this morning for zones 673-676. (See LAXMWWLOX). Small Craft Advisory in effect from 2 AM to 5 PM PDT Friday for zone 676. (See LAXMWWLOX).