Originally Posted by
Ivan X
...I believe the pilots knew turbulence was ahead, because the FA's were told to prepare cabin for landing while still at 30,000 feet and 45 minutes before arrival...
They didn't necessarily know there was turbulence ahead; the "prepare-cabin-at-30000ft" is a relatively new United phenomena/SOP (and implemented to protect the flight attendants):
United Airlines Implements New Rule To Protect Flight Attendants