The counties you named as part of the "above average outlier" account for nearly half the population of the state, so I'm not sure that's really,
for California, an "outlier" region.
The visualization also excludes the middle (that is, there is no color band centered on the middle, everything is forced into "below" or "above" average); if you view it as "most of the state outside the central/north coast is around the national average, and the central/north coast and a small part of the interior is notably below that" its not really all that surprising of a result.
