The weekend forecast may hold some good news for the Chiefs. Scattered rain showers are predicted for Sunday. If one of those showers settled over Arrowhead Stadium, it might help slow down the Rams’ powerful offense. St. Louis has played just six of its last 25 games outdoors, and only three of those on grass. If you believe that a grass field hurts a speedy team, then that might be a factor. Wind and rain would almost certainly affect the Rams passing attack. The Chiefs have not allowed a 300-yard passer in their last six games, a streak that will be put to the test against Kurt Warner, who has passed for 300 in every game this season.