PIERCE, Neb. (AP) _ Heavy rain has prompted a flood warning for the North Fork of the Elkhorn River in Pierce County. The National Weather Service said Wednesday that it expects the river to rise above flood stage Thursday evening and reach 3 feet (1 meter) above flood stage by Friday afternoon before returning below flood stage by late Saturday morning. At its crest the water would rise up against the levee protecting Pierce. The service says sandbagging and other flood protection operations have begun.