If I leave the Bay Area, will I be able to get a job back here?

It’s not impossible, but let’s consider the factors:

1. Preference of employers. Bay Area employers always prefer local candidates. They don’t want to move you if they can find someone here already with the same skills, which is often the case. Even if you are willing to move yourself, employers don’t want to deal with the logistics and the potential risks of a non-local candidate unless you have the right pedigree/experience or unless you are a known quantity.
2. Relevant experience. If you moved out of town to work for a well-known company in a similar space, then local employers may well consider you. The better the name of the company and the more relevant the technology or service (especially if they can’t find that in local candidates), the more seriously they will consider you.
3. Area of practice. If your area of practice is in so much demand or in a space with few lawyers in the Bay Area, then your odds of being welcomed back increase. People with electrical engineering degrees or with FDA or trade expertise have a leg up out here, for example.
4. Level of experience. Your level of experience has to match the market — if you are too junior or too senior, that makes getting a job harder. That said, senior candidates with great management experience at top companies can be in demand. For law firms, senior jobs are very hard to return to unless you have a decent-sized book, a particular expertise that’s hard to fill out here, or a strong backer.