  We consider the real emission QCD correction to heavy Higgs boson production
via weak boson fusion in high energy $pp$ collisions. The ${\cal O}(\alpha_s)$
corrections are determined for the complete electroweak $q q \rightarrow q q
W^+ W^-$ process. The presence of a third parton in the final state affects the
formation of rapidity gaps only slightly. In particular, soft emission into the
gap region is severely suppressed. Also, we investigate how the additional hard
emission affects forward-jet-tagging and central-jet-vetoing efficiencies in
the search for $H \rightarrow W^+ W^- \rightarrow \ell^+ \nu \ell^- \bar{\nu}$
decays.
