Anytime you fly into convective activity the onset of turbulence is rapid. In almost all cases however you have considerable notice well before that. Onboard weather radar sees storms out to at least 160 miles. Weather updates are issued. Radar overlays from ground radar stations are available on WiFi equipped aircraft. ATC broadcast warnings and offers suggested routings many times. The company dispatcher should have supplied updates. The area in question was forecast to have storms and should have been discussed in the crew briefing before the flight so the flight attendants could restructure the service schedule.