The wind is more of a predictive factor than the rain as far as sports books setting the over/under. As long as it's not heavy rain. Both teams are used to it and both can run the ball effectively when they want to. Allen's handled the rainy games pretty will in his career to my memory. The Philly game last year and the home blowout game against the Texans are the two that come to mind. Since the over/under is at 47 I'll go
Bills 30
Seahawks 17