And the market falls super flat when the economy is in a recession. 

A recession will almost certainly occur in the next 5 years or less.

Granted, the Bay Area is not recession proof and will have its fair share of dips and blips - but the forces driving it are far from standard, requiring an evolving perspective and altogether informed investor type.Lots of people believe the San Francisco Bay Area and the term "speculation" are one and the same - this only goes to show the depth of understanding those people have for the market and its driving forces.

Also, given the anticipation of possible recession, you may want to consider a HE Loan instead of a HELOC (unless you're really close to doing that next deal).

My personal guess is it's going to remain strong even through recessions due to continuous job and population growth, especially from high priced mkts like NY, California, Chicago where business and individuals are moving to Nashville by the truck load. 

I’m just weirdly hesitant because I’ve already got this one in hand and the SoCal RE market just seems to be recession/market proof.  

But, listening to finance professionals talking about the signs of a coming recession.

1. 2014, My first home was in in Merced, CA at the end of the recession.  

Does it make sense to refi if a potential recession is down the road? 

This was during the recession so I know it happened to a lot of good people.