15/105 PM.
Dry and warmer weather is expected for the remainder of this week. Gusty northerly winds will develop over mountains and Antelope Valley Thursday, shifting to northeast and becoming focused over Los Angeles and Ventura Counties on Friday. There is a chance of rain next Monday or Tuesday.
(tdy-Sat), 15/135 PM.
A cold upper low continues to plot a path through the Great Basin and into Colorado through Friday that will bring periods of gusty north to northeast winds to portions of southwest California. The initial onset of gusty winds will be overnight tonight into Thursday morning across the Grapevine region, the western portion of the Antelope Valley, and into Santa Clarita and possibly the Porter Ranch area. A wind advisory has been issued for that through Thursday morning. The northerly winds will create some downslope warming across the coast and valleys tomorrow leading to 2-4 degrees of warming there. However, thick high clouds will move in overnight tonight that will make skies mostly cloudy at least through mid afternoon.
Upper level winds will shift more northeast Thursday night into Friday creating our next Santa Ana wind event, peaking mid morning Friday through mid afternoon. Expecting at least advisory level winds across the usual Santa Ana wind favored areas of LA/Ventura Counties and possibly low end high wind warning winds in the mountains. Models show 850mb winds around 60-65kt so there is 20-30% chance that high wind warnings could be needed at isolated lower elevation areas, especially in the Simi Valley/Thousand Oaks area of Ventura County as well as the western Santa Monica mountains.
Additional downslope warming off the mountains will push temperatures up into the upper 70s to mid 80s across coast and valleys.
Gradients and upper support drop off quickly later Friday into Saturday, so much less wind expected. However, temperatures will continue to warm up away from the immediate coast with some upper 80s likely in the warmest valleys and intermediate areas in the mid 80s.
(Sun-Wed), 15/155 PM.
There remains a lot of uncertainty about next week but regardless the impacts locally will be minimal. Cooling is likely Sunday as gradients turn onshore flow ahead of a cold upper low moving down the coast from the Pac NW. However, still expecting highs in the 80s in the valleys and mid 70s to around 80 in Downtown LA and other inland coastal areas.
The remainder of the forecast through next week really depends on the track and speed of the cold and cut off upper low sliding down the West Coast. Temperatures will continue to cool, though the amount of daily cooling could be as much as 4-6 degrees or as little as 1-3. Will likely see increasing low clouds and fog for coast and possibly valleys at some point. Rain is a possibility as well, though amounts would be very light and could start as early as Monday night or as late as Wednesday. No rain is a possible outcome as well.
15/2253z.
At 2120Z at KLAX, the marine layer was 1000 feet deep. The top of the inversion was 2700 feet with a temperature of 15 C.
High confidence in CAVU conds for all sites through this evening.
Chances that CIG/VSBY restrictions develop after midnight: KLAX (40%), KLGB (40%), KSMO (30%), and KSMX (30%)
KLAX, Moderate confidence in TAF. CAVU conds expected thru this evening. There is a 40% chance of Low-MVFR CIGs (010-015) develop between 16/08Z and 16/16Z. No significant east wind component expected.
KBUR, High confidence in VFR TAF. No wind issues expected.
15/1157 AM.
For the Outer Waters, moderate to high confidence in current forecast. Today through Friday, high confidence in a combination of Small Craft Advisory (SCA) level winds and seas. On Thursday afternoon and Thursday night, there is a 50-60% chance of GALE force winds and a GALE WATCH has been issued. For Saturday through Monday, there is a 20-30% chance of SCA level winds.
For the Inner Waters north of Point Sal, moderate to high confidence in current forecast. Today through Thursday, high confidence in SCA level winds during the afternoon and evening hours with a 20% chance of GALE force wind gusts Thursday evening. For Friday through Monday, high confidence in winds and seas remaining below SCA levels.
For the Inner Waters south of Point Conception, moderate to high confidence in current forecast. Through tonight, there is a 30-40% chance of SCA level winds across the western half of the Santa Barbara Channel then a 50-60% chance of SCA level winds in this same area Thursday afternoon/evening. Otherwise, winds and seas will remain below SCA levels through Thursday night. On Friday, there is a 50-70% chance of SCA level northeast winds from Ventura south to Santa Monica and potentially across the San Pedro Channel. For Saturday thru Monday, high confidence in winds and seas remaining below SCA criteria for all southern Inner Waters.
Ca, Wind Advisory in effect from 2 AM to 9 AM PDT Thursday for zones 378-381. (See LAXNPWLOX). PZ, Small Craft Advisory in effect from 2 AM to 9 AM PDT Thursday for zones 670-673-676. (See LAXMWWLOX).
