Looking at radar a slug of heavier rain is about to move into areas east of San Diego. I would expect to start seeing FFW's go up shortly once the precip rates increase.
Also, even though an actual CA landfall is looking less likely now (more like Northern Baja), that really has very little material impact on the actual flooding threat.
000
WTPZ34 KNHC 181450
TCPEP4
BULLETIN
Hurricane Hilary Advisory Number 9
NWS National Hurricane Center Miami FL EP092023
900 AM MDT Fri Aug 18 2023
...HILARY REMAINS A POWERFUL CATEGORY 4 HURRICANE...
...HURRICANE WARNING ISSUED FOR PORTIONS OF BAJA CALIFORNIA AND
TROPICAL STORM WATCH ISSUED FOR EXTREME SOUTHERN CALIFORNIA..
Now that's something you don't see every day
12z NAM/NAM Hi-Res and HRRR all show a SW-NE band of of 4-5"+ in Western/Central Mass. in particular. Hopefully the higher end numbers on e.g. HRRR are overdone, though with high PWATS and any kind of training totals could add up fast.