Tuesday evening forecast September 21st

Very warm temperatures, dry conditions and isolated winds will remain through at least Wednesday, prompting elevated fire weather. Temperatures along the hottest valleys are likely to reach the 90s to low 100s, coastal areas will reach the 60s to 70s. Due to a weak system, temperatures will start to decline on Thursday and continue dropping trough the weekend. The weak low pressure system could bring a slight chance of thunderstorms on Friday and Saturday across mountains and deserts.

Offshore flow brought very warm temperatures on the final day of summer, with most areas well above average. Relative humidity also dropped 9 to 15% across the interior valleys this morning, due to offshore trends. Plus most areas warmed earlier in the day before the marine layer lingered along the coast. Marine layer clouds will push further inland after dark, but offshore trends expected to be favored Wednesday morning.

Late Wednesday into Thursday onshore flow will strengthen, with low level clouds likely to expand further inland. A weak trough will then slide down into northern California on Thursday. This will allow the marine layer to build and persists through the weekend.

At this time there is still uncertainty on the path of storm we may see on Friday and Saturday. Models are favoring a slight chance of thunderstorms across eastern mountains. The First Alert Weather Center is keeping a watchful eye for any changes to the forecast.