A warm afternoon is expected Sunday across San Diego County, probably a few degrees warmer than Saturday, the National Weather Service said.
High clouds Sunday will slowly thin through Monday as patchy low clouds and fog return to coastal areas Monday night through Wednesday, forecasters said.
Several areas below passes and in wind-prone areas had near-critical fire weather conditions Sunday morning, the NWS said. The lowest daytime humidity of around 10% Sunday, along with some wind gusts of 35 mph below the passes, will continue elevated fire weather conditions in those areas.
Coastal high temperatures Sunday were expected to be 75-80 degrees with overnight lows of 46-56. Inland valley highs will be 87-92 with overnight lows of 43-53.
Mountain highs will be 76-83 with overnight lows of 40-50. Desert highs will be around 91 with overnight lows of 49-59.
It will be hot again on Thursday, before a noticeable change next weekend when a deep, upper-level trough brings colder, windy weather and a chance for showers along and west of the mountains, the NWS said.
On Wednesday through next weekend, a ridge of high pressure will move toward the region, bringing light offshore flow and increasing temperatures well above average for November, forecasters said.
"Afternoon highs will look more like the dog days of summer than the cooler days of autumn with the low to mid-90s for many valleys west of the mountains by Thursday,'' the NWS said.
By the weekend, low pressure will build over the county.
"Say goodbye to that summertime weather and hello winter," forecasters said.
Temperatures will drop to the 60s from the beaches, valleys and to the high desert with high afternoon temperatures only in the 40s and 50s for the mountains by next weekend.
The county may see some areas of light precipitation beginning late Friday night through Saturday night, forecasters said.