There could be some patchy dense fog near the coast this morning and again for tonight. Santa Ana winds will return along and below the coastal slopes of the mountains on Saturday and diminish on Sunday with the stronger gusts to around 35 mph. High temperatures as much as 10 to 15 degrees above average for the valleys will continue through Sunday followed be a gradual cooling trend for the early and middle part of next week.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
Tonight through tomorrow night,
Very little has changed in terms of the forecast in the short term, with mild Santa Ana conditions persisting through tomorrow night, and gradually coming down throughout the day tomorrow before a slight uptick in these conditions over the weekend. There will be a few passing high clouds. Temperatures will still be quite warm and around 5 to 10 degrees above average, with temperatures within the inland valleys and the IE getting up into the upper 70s to low 80s for most areas. Gusty winds, especially across the higher terrain and within the mountain passes this afternoon, will begin to decouple and diminish going into the later evening hours. There could be a slight return to onshore flow right around the coastal locations which may allow for some of the dense fog immediately off the coast to advance east and penetrate into some of the coastal areas by later this afternoon and through the early evening until there is a return to weak offshore flow overnight. Some of the wind- sheltered inland areas may get close enough to the freezing mark for there to be areas some patchy frost being possible for the higher valleys.
Friday through Tuesday,
Mild to moderate Santa Ana conditions will have a slight uptick on Saturday and then continue gradually come down throughout the rest of the weekend as the pressure gradient weakens with the ridge beginning to expand northwestward. As this occurs, the ridge axis will become more elongated and negatively tilted, which will act as a blocking pattern and keep the dry conditions persisting through the beginning of next week, with only a gradual cooldown as some troughing to the east over central CONUS does help to influence the region with cooler air advection from the north, although with the ridge still in control, along with weak downsloping winds, temperatures will remain above average. Winds will eventually become more persistent in being onshore going into the early part of next week, which may help the return of some fog/low clouds moving in over portions of the coast and inland areas of San Diego and Orange counties, especially by Monday night into Tuesday morning. The development of the marine layer will continue to become more prevalent going into mid part of next week and start to lift in lieu to the approaching trough upstream. A longwave trough will begin to break down the ridge, with models becoming a lot more displaced. Due to there being so much inconsistencies with the deterministic models itself at this time, it is difficult to say with an certainty if there will be precipitation impacting the region, however, ensembles are displaying that there will be at least an increased chance. Ensembles are also showing next Friday as being the coldest day out of the week, with temperatures dipping just below the below the seasonal average for this time of year.
161615z. Coasts, Patchy and intermittent FG reducing VIS to 1SM will continue to impact the waters through 18z, but shouldn't reach any coastal sites. Similar fog conditions with low clouds based around 200ft MSL to redevelop after 02Z Sat, but with less coverage and duration. 15-25% chance of a brief CIG at KSAN with VIS below 1SM sometime this evening into Saturday morning. Otherwise, limited to no impacts expected to coastal sites.
.Elsewhere, Northeast winds 25-30 kt below Cajon Pass and locally into the northern Inland Empire through this evening. Otherwise, VFR conditions for everywhere but the immediate coastline.
Patchy dense fog is currently reducing visibility to less than 1 nautical mile. Additional patchy dense fog is probable tonight into Saturday. Otherwise, no hazardous marine conditions are expected through Tuesday.
Ca, None. PZ, None.
