Excessive Heat — East Bay Hills and the Diablo Range, California

2021-07-11 · East Bay Hills and the Diablo Range, California

Event narrative

Mesonet (PG&E) station at San Jose Mines Rd had a high temperature of 104 degrees and remained in the 80s and 90s late into the night.

Wider weather episode

Strong high pressure building over the region in early to mid July brought warm to hot temperatures across the interior. Daytime highs rose into the 100s with locations across the East Bay up to 110 degrees between July 9th and 11th. Overnight lows remained warm, particularly across higher elevations where temperatures were still in the 70s and 80s in the early mornings. Additionally, prolonged dry conditions resulted in near record dry fuels for July. This along with breezy afternoon winds prompted the Diablo Fire in Contra Costa County.

Source: NOAA Storm Events Database, event_id 966975. Narrative written by the NWS forecast office that issued the report.