16/155 PM.
Dense fog will impact the Los Angeles area again through at least Wednesday. Well above normal temperatures will continue through Friday, with locally gusty north to northeast winds peaking tonight through Wednesday Night. Dry conditions will continue at least through Saturday, but there is growing potential for a winter storm next week around Christmas.
(tdy-Fri), 16/225 PM.
An eddy in the Socal bight has prevailed over a strong ridge of high pressure and weak offshore flow to bring persistent low clouds near and especially off the Los Angeles County coast this afternoon. Low clouds and fog will likely push back into the LA County coastal areas this evening with dense fog potentially impacting the evening commute, especially interstates nearest the coast like the 405. A Dense Fog Advisory has been issued for this area, starting at 6 pm. Other coastal areas and lower valleys may see dense fog as well, especially after midnight. Fog will likely be slow to burn off Wednesday morning, potentially impacting the morning commute and flights. Most areas should be clear by 10-11 am.
Advisory level Sundowner winds will keep at least southwest Santa Barbara County cloud and fog free this evening into tonight, but may serve to reboot the eddy overnight. Tightening northerly gradients with moderate upper support from a system passing to our north will likely support more widespread advisory level (30-50 mph) winds for interior mountain and desert areas late tonight and especially into Wednesday. Advisory level winds will likely filter into the valleys and lower mountains near the LA/Ventura County border Wednesday afternoon and evening with a 30 percent chance of reaching the LA Basin, especially nearest the coast, Wednesday evening. A Wind Advisory is in effect for all of the aforementioned areas, except the LA Basin, due to lower confidence in the winds making it to the coast.
The offshore flow and strong ridge aloft will combine to support widespread highs in the 70s and 80s through Thursday with the warmest coastal valleys such as near Woodland hills possibly flirting with 90. Those sensitive to the heat may want to take extra precautions, especially if outside for a prolonged period of time.
(Sat-Tue), 16/225 PM.
The next of a series of storms is expected to impact the West Coast this weekend. Most the impacts from the storm will remain well to our north. However, periods of light rain are possible, mainly San Luis Obispo, possibly teetering into northern Santa Barbara County, at times Saturday through Monday. Further south, the associated breakdown of the ridge will support cooling to coastal valleys in particular.
We continue to track the potential for a wet period during the holidays with an 80 percent chance of a moderate to strong strong sometime in the December 23rd-26th time frame with active weather possibly continuing beyond this period.
16/2333z.
At 2240Z, the marine layer was around 600 feet deep at KLAX. The inversion was topped at 3600 feet with a temperature of 22 degrees C.
High confidence in VFR conds for KPRB, KSBP, KSMX, KBUR, KVNY, KPMD, and KWJF. Moderate confidence in winds for all sites except high for KPRB. Timing of wind shifts may be off +/- 3 hours, and max wind gusts may be 15 kts higher at times. For KSBP, 30% chance for NE winds 10-15 kts to surface from 16Z through the end of the period.
Low confidence in TAFs for KLAX, KSBA, KOXR, KCMA, KSMO, and KLGB. For tonight, moderate to high confidence in VLIFR to LIFR conds for KLAX, KLGB and KSMO as early as 02Z and continuing into at least 16Z. Moderate confidence for KOXR and KCMA. Low confidence for KSBA, 40% chance for VLIFR to LIFR conds as early as 06Z. Flight cat changes may be off +/- 3 hours. Arrival of north winds for KLAX, KLGB, KSBA, and KSMO may be off +/- 3 hours, and gusts may be 10 kts higher than forecast, with highest uncertainty in wind speeds at KSMO.
KLAX, Low confidence in TAF. There is a 40% chance for vsbys less than 1/4SM any point when cigs return, especially 02Z through 16Z. Flight cat changes may be off +/- 2 hours. Any east wind component should remain less than 7 knots, however north winds will arrive sometime between 17/18Z-18/00Z. There is a 30% chance for gusts above 20 kts through 05Z.
KBUR, Moderate confidence in TAF. VFR conditions are expected through the period. North wind arrival may be off +/- 3 hours. There is a 30% chance for gusts to 30 knots after 17/20Z.
16/1209 PM.
High confidence in the current forecast through Thursday, then moderate to high confidence thereafter.
For the waters southwest through northwest of the Channel Islands and the nearshore waters along the Central Coast, there is a 60-90 percent chance of Small Craft Advisory (SCA) level winds through Friday, highest during the afternoon and evening hours. There is a 30-40 percent chance of widespread GALES each afternoon and evening through Wednesday night, but local GALE force gusts are possible each afternoon and evening from Point Conception south to San Nicolas Island. Winds will likely diminish some for Thursday and Friday with chances of SCA level winds decreasing to a 40-70 percent chance, highest Point Conception south to San Nicolas Island, but seas will approach SCA levels for late week.
Inside the southern California bight, winds and seas will remain below SCA levels through Wednesday, but there is a moderate (30-40 percent) chance of SCA level winds across the western portions. Winds will increase on Wednesday and continue into Wednesday night while becoming northerly and impacting near coastal nears from Malibu to Palos Verdes with a 40-60 percent chance of SCA conditions. Winds and seas should drop below SCA levels for Friday and Saturday.
Patchy dense fog will continue at times through at least Wednesday morning, likely becoming more widespread tonight.
Ca, Wind Advisory in effect from noon to 10 PM PST Wednesday for zones 88-356-362-369>375-383. (See LAXNPWLOX). Wind Advisory in effect until 4 AM PST Thursday for zones 349-351. (See LAXNPWLOX). Wind Advisory in effect from 2 AM Wednesday to 4 AM PST Thursday for zones 352-353-376>381. (See LAXNPWLOX). Dense Fog Advisory in effect until 10 AM PST Wednesday for zones 366-368. (See LAXNPWLOX). PZ, Small Craft Advisory in effect until 9 PM PST this evening for zone 645. (See LAXMWWLOX). Small Craft Advisory in effect from 6 PM Wednesday to 2 AM PST Thursday for zone 655. (See LAXMWWLOX). Small Craft Advisory in effect until 3 AM PST Thursday for zones 670-673-676. (See LAXMWWLOX).
