Source : Webster's Revised Unabridged Dictionary (1913)

Forceful \Force"ful\, a.
   Full of or processing force; exerting force; mighty. --
   {Force"ful*ly}, adv.

         Against the steed he threw His forceful spear.
                                                  --Dryden.

Source : WordNet®

forcefully
     adv : with full force; "we are seeing this film too late to feel
           its original impact forcefully"