The Collaborative International Dictionary of English v.0.48:
Southeastward \South`east"ward\, Southeastwardly \South`east"ward*ly\, adv. Toward the southeast. [1913 Webster]WordNet (r) 3.0 (2006):
southeastwardly adv 1: in a southeastward direction; "the river flows southeastward to the gulf" [syn: southeastward, southeastwardly]