The Collaborative International Dictionary of English v.0.48:

Advisory \Ad*vi"so*ry\, a.
   Having power to advise; containing advice; as, an advisory
   council; their opinion is merely advisory.
   [1913 Webster]

         The General Association has a general advisory
         superintendence over all the ministers and churches.
                                                  --Trumbull.
   [1913 Webster]

WordNet (r) 3.0 (2006):

advisory
    adj 1: giving advice; "an advisory memorandum", "his function
           was purely consultative" [syn: advisory,
           consultative, consultatory, consultive]
    n 1: an announcement that usually advises or warns the public of
         some threat; "a frost advisory"

Moby Thesaurus II by Grady Ward, 1.0:

38 Moby Thesaurus words for "advisory":
   admonition, admonitory, bulletin, cautionary, communicative,
   consultative, consultatory, council, deliberative, didactic,
   directive, educational, educative, enlightening, exhortative,
   exhortatory, expostulative, expostulatory, hortative, hortatory,
   informational, informative, informing, instructive, monitorial,
   monitory, moralistic, notice, preachy, prediction, recommendatory,
   remonstrant, remonstrative, remonstratory, sententious, synodal,
   synodic, warning