15/203 PM.
Well above normal temperatures will continue through Friday, with locally gusty north to northeast winds peaking Tuesday Night and Wednesday. Dry conditions will continue into next week, but the potential for a winter storm continues to grow in the December 23 to 26 Christmas holiday window.
(tdy-Thu), 15/221 PM.
North to northeast winds will be the most significant weather factor for the next few days. The storm systems currently affecting the Pacific Northwest will move inland tonight and Tuesday, injecting cold air into northern California. This will increase the surface pressure up north while winds aloft strengthen. There will bring breezy conditions to some areas on Tuesday, but all the ingredients align for a Wednesday into Thursday peak, when gusts of 30 to 50 mph are expected for the wind prone areas of all four counties. This includes most interior mountains as well as the the Santa Lucia and Santa Ynez Ranges, and the Santa Susana and the Santa Monica mountains. A few Wind Adivsores are likely. These winds will also push down through many valleys and some coastal areas, including the LA Basin and Malibu strip. Thankfully with the recent rains, the risk for large fires is really small, but we could see some isolated tree damage and power outages as a result.
A shallow marine layer will continue to bring dense fog with low visibilities anywhere the low clouds form. With offshore flow increasing tonight through Wednesday, expecting the low cloud and fog coverage to decrease significantly. At this point, southereastern Los Angeles County is the only place with a high enough chance to mention thanks to weak eddies that form each morning.
High pressure aloft will increase through Tuesday then remain steady through Friday. Combining with the offshore flow, we are looking at high temperatures between 75 and 85 fairly common, which is 10 to 20 degrees above normal. This includes most coastal areas. Not expecting any Heat Advisories or Warnings. Overnight temperatures will remain cool to mild, except some lows staying in the 60s to even lower 70s in some coastal ranges and hills.
(Fri-Mon), 15/226 PM.
All ensemble projections favor a sharp return to onshore flow on Friday, which will persist through the weekend. The ridge of high pressure aloft will break down at the same time. This should all add up to temperatures lowering by 10 degrees or so, but it will still be warmer than normal with highs in the upper 60s to mid 70s.
Further out, pretty much all the ensemble projections bring widespread rain sometime in the December 23-26 window, which will certainly bring impacts to the busy Christmas holiday. About 20% of the projections show a strong storm with high rain totals of 4 or more inches. Being this far out however, there is a wide range of outcomes but if nothing else, be prepared for at least some rain around Christmas.
15/1847z.
At 18Z at KLAX, the marine layer was 800 feet deep. The top of the inversion was at 3200 feet with a temperature of 20 degrees Celsius.
High confidence in VFR conds for KBUR, KVNY, KCMA, KOXR, KPMD and KWJF. For other coastal sites including KLAX as well as KPRB, low to moderate confidence with a 30 to 60 percent chance of LIFR/VLIFR cigs/vsbys tonight between 08-18Z, highest for KLGB and KSMX.
KLAX, Low to moderate confidence. There is a 40-50% chance of IFR/LIFR conditions 08Z-17Z. No significant easterly wind component is expected.
KBUR, High confidence in TAF.
15/148 PM.
For the Outer Waters, moderate to high confidence in current forecast. Today through Tuesday, high confidence in Small Craft Advisory (SCA) level winds for all of the Outer Waters. For Wednesday through Friday, high confidence in SCA level winds continuing across PZZ673/676, but only a 30-50% chance of SCA level winds across PZZ670. Seas will approach SCA level at 10 feet in the Wednesday through Friday time frame.
For the Inner Waters north of Point Sal, moderate to high confidence in current forecast. Today through Tuesday morning, high confidence in winds and seas remaining below SCA levels. For Monday afternoon through Wednesday, there is a 30-40% chance of SCA level winds in the afternoon and evening hours. For Thursday and Friday, 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. For a majority of the southern Inner Waters, high confidence in winds and seas remaining below SCA levels. The only exception will be the western half of the Santa Barbara Channel where there is a 30-50% chance of SCA level winds in the Wednesday through Friday time frame, mainly in the late afternoon and evening hours.
Ca, NONE. PZ, Small Craft Advisory in effect until 3 AM PST Wednesday for zones 670-673-676. (See LAXMWWLOX).
