Periods of gusty Santa Ana winds will continue this afternoon with weaker winds for Friday into early next week. Inland areas will continue to warm today. There will be slight cooling for today into Friday with not much change for the weekend. Cooling is expected to spread inland next week as high pressure aloft weakens and onshore flow spreads inland. Some return of night and morning coastal low clouds and fog could occur as soon as late Thursday night.
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, with mild Santa Ana conditions persisting through tomorrow night, and gradually coming down. There will be a few passing high clouds. Today will be the warmest day of the week, with temperatures within the inland valleys and the IE getting up into the mid 80s for some 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. Weak offshore winds and clear skies overnight will lead to some sufficient radiational cooling, so some of the wind-sheltered inland areas may get close to the freezing mark again tonight, with some patchy frost being possible for those areas. A few low clouds might develop during the early morning hours along the coastal areas, although it is looking better for the marine layer to return later this upcoming weekend.
Friday through Tuesday,
Mild to moderate Santa Ana conditions will continue to diminish by Friday and gradually into the weekend as the pressure gradient weakens with the ridge expanding 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. Offshore winds will predominantly keep any development of the marine layer mostly confined over the coastal waters, although there could be a return of some fog/low clouds moving in over portions of the coast and inland areas of San Diego and Orange counties beginning later in the weekend. The development of the marine layer will continue to become more prevalent going into early next week. There is also some indication with some of the deterministic models which shows possible subtropical influence from a weakening decaying wave moving up from the southern Pacific Ocean along 120W, which may bring about a slight chance of a shower/thunderstorm over the mountains of San Diego County during the afternoon on Tuesday of next week, although this is still quite far out and therefore is subject to change. Looking beyond the forecast, ensembles are still hinting a return in the chance of precipitation towards the end of next week as there begins a change in the longwave pattern with a break down in the ridge over the E Pac waters.
141630z, Clear skies and VFR conditions through Thursday morning. Areas of east to northeast winds 20-30 kts mainly in foothills and near mountain passes with corridors of 10-20 kts stretching into into adjacent inland valleys for 18z until 03-06z this evening. Mod up/downdrafts and local LLWS in lee of mountains.
No hazardous marine conditions are expected through Sunday.
Ca, None. PZ, None.
