Source : Webster's Revised Unabridged Dictionary (1913)

Northeasterly \North`east"er*ly\, a.
   Pertaining to the northeast; toward the northeast, or coming
   from the northeast.

Northeasterly \North`east"er*ly\, adv.
   Toward the northeast.

Source : WordNet®

northeasterly
     adj 1: coming from the northeast; "northeasterly winds" [syn: {northeast}]
     2: situated in or oriented toward the northeast; "the
        northeasterly part of the island" [syn: {northeastern}, {northeast}]