04/227 AM.
A moderate Santa Ana wind event will bring gusty northeast winds to portions of southern California today. Cold conditions will bring freezing conditions to some areas each morning today and Friday. A significant warming trend will begin this weekend and peak next Tuesday and Wednesday.
(tdy-Sat), 04/853 AM.
***UPDATE***
The Santa Ana Winds have been performing better this morning compared to yesterday as expected. Advisory level wind gusts have been observed across typically windy areas this morning, with the Santa Susanas and Western San Gabriels winning this event. A couple gusts even reached 60 mph in these areas. Winds will strengthen and expand especially across coastal and valley areas this morning, then winds are on track to decrease by this afternoon. A few advisory level gusts may linger in the mountain areas a little later. Then slightly more northerly and much weaker winds will likely impact the Western San Gabriel, Santa Susana, and Santa Monica mountains late tonight into Friday morning. Gusts will generally be in the 30 to 40 mph range, with local gusts to 45 mph. 20 to 30 mph winds will likely surface across Malibu to western Santa Monica at times tonight into Friday morning.
Widespread lows in the mid 20s to mid 30s were observed across interior areas this morning, and another chilly night is on tap. Most coasts and valleys south of Point Conception will cool slightly due to the decrease in offshore winds tonight, while interior areas will warm a couple degrees. The only exception to the coasts would be Malibu, where downsloping northerly winds overnight will likely keep overnight lows a bit more elevated.
***From Previous Discussion***
A low end Santa Ana wind event is just starting. Currently the offshore gradients are between 3 and 4 mb offshore and will peak between 4 and 6 mb later this morning. There is a little upper level support along with a little cool air advection to help the winds along. Wind gusts between 35 and 45 mph will develop in the Santa Ana wind corridor (10 miles or so around a line from the Santa Clarita vly to the western Santa Monicas). There will be isolated gusts to 55 mph along the windiest mountain ridges.
Away from the winds, the cool and dry airmass along with clear skies will allow for rapid cooling and freeze warnings are in effect for the far interior including the Antelope Vly. A Frost advisory is in place for the Cuyama Vly and the Antelope Vly foothills.
The offshore flow will warm most areas 1 to 3 degrees. The Central Coast will be the exception where 4 to 5 degrees of warming will occur. The Antelope Vly will cool some as cool air advects in from the high desert. Most max temps will come in near normal today.
It will be cold again in the wind sheltered locations tonight and a freeze watch is in effect for the same areas under a warning this morning.
Not too much to talk about for the Friday and Saturday forecasts. An upper high will nose in from the west and hgts will push up to 582 dam. The offshore flow will continue, but will be weaker than today, and this will keep the low clouds away. There will be some gusty canyon winds in the morning, but with no upper support and weaker gradients they will not reach advisory levels. The weakening offshore flow will bring two days of cooling to most of the csts and lower vlys while the rest of the area warms under sunny skies and rising hgts. By Saturday the mtns and interior will will end up 5 to 10 degrees above normal. The nearshore area, however, will be a degree or two under normal.
(Sun-Wed), 04/303 AM.
Good agreement with all medium range mdls and ensembles. Ridging is forecast to persist over the area. Hgts will increase to at least 586 dam by mid week.
Offshore flow will persist through the period and should eliminate or at least greatly minimize the low cloud coverage. The Long Beach area and western SBA county stand the greatest chc of seeing some morning low clouds. The offshore flow will not be strong enough to generate any advisory level winds.
That leaves the temperatures, which will be the main talking point for the xtnd forecast. It looks like there will be three days of warming everywhere with just a little nearshore cooling Wednesday as the offshore flow weakens some. Went above guidance for the Tu and Wed temps as usually the blended algorithms are slow to catch on to events that are well out of the norm.
Right now it looks like there will be 2 to 4 degrees of warming each day except Tuesday and for the coastal cooling Wednesday. Tuesday should see 3 to 6 degrees of warming. Max temps Tue and Wed will end up 10 to 15 locally 20 degrees over normal. Vly temps will be in the 80s and there is an outside shot of isolated 90 or 91 degree readings.
04/1121z.
Around 0855Z, there was no marine layer depth at KLAX, but there was surface-based inversion up to around 400 feet with temperature near 18 degrees Celsius.
High confidence in the current forecast, except moderate confidence in the current forecast for KPRB. Periods of moderate to strong low-level wind shear are possible through 20Z.
KLAX, VFR conditions are expected through the period. There is a 30 percent chance of east winds between 7 and 10 knots through 19Z.
KBUR, VFR conditions are expected through the period. There is a moderate chance of moderate low-level wind shear and turbulence through 16Z.
04/854 AM.
Moderate confidence in the current forecast. Slightly higher confidence in the forecast for seas versus winds.
At east-facing harbors, including Avalon Harbor on Catalina Island and Smugglers Cove on Santa Cruz Island, there is a 40-50 percent chance of east winds affecting these harbors today.
For the waters southwest through northwest of the Channel Islands beyond 10 NM offshore of the Central Coast and outside the southern California bight, winds and seas should remain below Small Craft Advisory (SCA) levels through Friday morning, then there is a high-to-likely (40 to 60 percent) chance of SCA level winds between Friday afternoon through Sunday. There is a moderate chance of SCA level winds lingering into Monday afternoon and evening.
Inside the southern California bight and for the nearshore waters along the Central Coast out to 10 NM offshore, there is a high- to-likely (40 to 60 percent) chance of gusty northeast to east winds this morning, highest between Rincon Point to Santa Monica and into the San Pedro Channel. Winds and seas should drop below SCA levels this afternoon, but there is a moderate-to-high (30 to 50 percent) chance of SCA level winds redeveloping again tonight through Friday morning. Winds and seas will likely remain below SCA levels through the weekend.
Ca, Beach Hazards Statement in effect through Saturday morning for zones 87-349-350-362-366. (See LAXCFWLOX). Wind Advisory remains in effect until 3 PM PST this afternoon for zones 88-354-355-358-362-369>371-374>376-378>380. (See LAXNPWLOX). Freeze Watch in effect from late tonight through Friday morning for zones 343-344-383. (See LAXNPWLOX). High Surf Advisory in effect until noon PST today for zone 354. (See LAXCFWLOX). PZ, Small Craft Advisory in effect until 2 PM PST this afternoon for zones 650-655-676. (See LAXMWWLOX).
