Warm weather will continue through the weekend with night and morning low clouds and fog along the coast and far western valleys. A trough of low pressure to the north will bring cooler weather across the region by next week, as well as greater coverage of marine layer low clouds.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
Marine layer low clouds continue to spread into inland Orange County and the far western valleys in San Diego County. Visibility at the coast is much better than yesterday, though locally dense fog is being reported in the valleys. Low clouds and fog will gradually clear to the coast during the mid to late morning as offshore flow develops. This event will be very weak, with gusts even in the wind-prone areas topping out at around 25 mph. Offshore flow and upper level ridging over the region today will bring another warm day to start the month, with high temperatures around 8-12 degrees above normal away from the coast. The marine layer will remain shallow tonight into Sunday morning, with low clouds and locally dense fog developing once again.
A weak cut-off low off the coast of So Cal will move over the area as it becomes an open wave on Sunday, bringing minor cooling and some scattered high clouds late in the afternoon, perhaps in time for some nice color during the one hour earlier sunset.
Mostly zonal flow will be in place across Southern California for the remainder of the week with a pair of short waves moving inland to the north Wednesday and Friday. Ensembles have trended towards a lower-amplitude solution for the mid-week wave, bringing our already low precipitation chances down to zero for the Wed/Thu time frame. Best we can possibly do is some marine layer drizzle Thu morning, but even that is looking less likely. This pattern will produce a gradual cooling trend and a deeper marine layer through Wed/Thu, along with an increase in westerly winds across the mountains and deserts, strongest Wednesday afternoon into Thursday as onshore gradients peak. Surface gradients turn offshore to the north on Friday, but with a lack of upper level support expect this to be another low- end Santa Ana event that will bring more heat than wind.
010930z, Coasts/Western Valleys, Low clouds with bases 600-1000 feet MSL have filled into coastal areas and western valleys up to 15 miles inland. Bases have slowly lowered over the past few hours and may continue to do so through 12Z with patchy dense FG possible for elevated coastal terrain and western valleys. Minor vis reductions (4-6SM) possible down to sea level 11-15Z. Clouds move back towards the coast by 17z-18z and may linger at beaches and just offshore through the afternoon. Low clouds with similar bases and associated vis reductions return to coastal areas early Saturday evening (00- 03Z Sun), eventually reaching 10-15 miles inland.
Inland Valleys/Mountains/Deserts, VFR conditions prevail through the period.
No hazardous marine concerns through Wednesday.
Long period (19-21 sec) swell from the southwest (200 degrees) today, prevailing into Sunday, bringing elevated surf of 3 to 5 feet with locally higher sets on southwest facing beaches. Surf will gradually fall Sunday into Monday.
Ca, None. PZ, None.
