Which Bay Area is you talkin’ ‘bout? The Monterey Bay Area or the San Francisco Bay Area? They’re both in northern California; although Monterey is more on the central coast.
All the counties contiguous to the San Francisco Bay are "The Bay Area" (unless you are from Los Angeles in which case everything past Bakersfield is "Northern California.") Northern California consists of the Counties NORTH of the BAY AREA and the CENTRAL VALLEY.
Panetta and his former Congressional District have always been part of Bay Area regional politics because it has usually included Santa Clara County. Nothing about Panetta or his district however has ever come close to any Northern California County.