15/1247 PM.
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 is expected Sunday with a chance of widespread rain by Tuesday or Wednesday.
(tdy-Sun), 15/154 PM.
Santa Ana winds arrived on schedule and with more aggressive speeds than expected. Some areas in the San Gabriel Mountains have already reported 70+ mph wind gusts today and models are still indicating additional upper level support Friday morning as well as offshore gradients from the east peaking between 8 and 9mb. So just making some minor tweaks for Friday based on today's conditions. Temperatures have been warmed a few degrees, especially at the coast where temps will be the warmest, even more so than the valleys. And based on today's wind speeds there's at least a 30-40% chance of wind gusts in the LA County mountains reaching 90mph and similar chances for valleys and Ventura county coastal areas to see wind gusts as high as 60 mph. Since even 1mb of offset in the gradients can result in 5 or more degrees offset in the temperatures, confidence in the exact highs is on the lower side but should be in the ball park.
Also, overnight lows will, in general, be quite warm tonight across the coast and valleys. Some areas that stay windy all night may not drop below 75 and wouldn't be surprised if some areas stay above 80 all night.
On Saturday, upper level support and surface gradients weaken but still expecting a windy day, albeit probably 15-30 mph weaker than Friday. And with the offshore flow and cold advection weakening as well temperatures at the coast should cool at least a few degrees while valleys and other interior areas either remain the same or warm slightly.
For Sunday, all areas except the mountains and deserts will cool at least 3-6 degrees. Interior areas will warm as cold advection continues to weaken.
(Mon-Thu), 15/230 PM.
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.
There is increasing confidence in rain chances next week, though timing is still quite uncertain as are the amounts. Virtually all the solutions from the ENS and GEFS ensembles indicate at least some light rain, most likely starting Wednesday, but could start as early as Tuesday afternoon or as late as Wednesday evening. Rain amounts are even more scattered but mostly around a half inch area-wide. It's a tricky pattern with the upper low dropping south along the California coast and a lot of uncertainnesshow far offshore and where it will turn inland. Might take another few days to have more confidence in amounts and timing. There are more than a few solutions that bring an inch or more so this needs to be followed closely, especially with the possibility of brush fires during the current strong Santa Ana winds.
15/1442z.
At 1500Z at KLAX, there was a surface-based inversion. The top of the inversion was 1700 feet with a temperature of 24 degrees Celsius.
For 18Z TAF package, high confidence in CAVU conditions for all sites through the period. Timing and strength of northeast winds may be off by 2-3 hours and 10 knots respectively.
KLAX, High confidence in 18Z TAF with CAVU conditions expected through the period. Any easterly wind component is expected to be below 7 knots after 11Z.
KBUR, High confidence in CAVU conditions through the TAF period. Moderate confidence in winds as timing may be off by 2-3 hours and strength could be +/- 10 knots.
15/1215 PM.
For the Outer Waters, moderate to high confidence in current forecast. Today through Sunday, high confidence in winds and seas remaining below Small Craft Advisory (SCA) levels across PZZ670/673. For PZZ676, there is a 60-80% chance of SCA level winds late tonight and Friday. On Monday and Tuesday, there is a 50-60% chance of SCA level winds across all of the Outer Waters with seas hovering around SCA levels.
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. On Friday, there is a 50% chance of SCA level northeast winds. For Saturday and Sunday, high confidence in winds and seas remaining below SCA levels. On Monday and Tuesday, there is a 50% chance of SCA level winds, mainly in the afternoon and evening hours with seas hovering near SCA levels.
For the Inner Waters south of Point Conception, moderate to high confidence in current forecast. Through tonight, high confidence in SCA level northeast winds from Ventura south to Santa Monica with winds/seas remaining below SCA levels elsewhere. On Friday, there is a 60-70% chance of GALE force winds from Ventura to Santa Monica with a 40-60% chance of SCA level winds elsewhere (especially across the San Pedro Channel). For Friday night and Saturday, there is a 50% chance of SCA level northeast winds from Point Mugu to Santa Monica with high confidence in winds and seas remaining below SCA levels elsewhere. For Sunday through Tuesday, high confidence in winds and seas remaining below SCA levels for most areas except for the western half of the Santa Barbara Channel where there is a 50-60% chance of SCA level winds.
Ca, Wind Advisory in effect until 8 PM PDT Friday for zones 88-354-355-358-362-370>374-376-377. (See LAXNPWLOX). Heat Advisory in effect until 8 PM PDT Saturday for zones 340-341-346-347-349-350-354-355-362-366>368. (See LAXNPWLOX). High Wind Warning in effect until 8 PM PDT Friday for zones 369-375-378>380. (See LAXNPWLOX). Red Flag Warning in effect until 8 PM PDT Saturday for zones 288-354>358-362-369>382-548. (See LAXRFWLOX). Red Flag Warning in effect from 3 AM to 6 PM PDT Friday for zones 342-345-353. (See LAXRFWLOX). PZ, Small Craft Advisory in effect until 3 AM PDT Friday for zones 650-655. (See LAXMWWLOX). Gale Warning in effect from 3 AM to 5 PM PDT Friday for zones 650-655. (See LAXMWWLOX). Small Craft Advisory in effect from 2 AM to 5 PM PDT Friday for zone 676. (See LAXMWWLOX).
