of pure muscle, no way in hell...
in 12 weeks i would say 20 would be a stretch...
water would be somewhat of a strength advantage to hold onto for competition, and you could weigh in 50lbs up from now if you consider that... it will benefit your leverages somewhat... it will aid your pressing more than anything and could possibly leave you gasping on events like truck pull or farmers walk... i think a leaner 20lb gain would be optimal... and very possible with hard work...