The Collaborative International Dictionary of English v.0.48:

Surprising \Sur*pris"ing\, a.
   Exciting surprise; extraordinary; of a nature to excite
   wonder and astonishment; as, surprising bravery; a surprising
   escape from danger. -- Sur*pris"ing*ly, adv. --
   Sur*pris"ing*ness, n.
   [1913 Webster]

   Syn: Wonderful; extraordinary; unexpected; astonishing;
        striking.
        [1913 Webster] Surquedous

WordNet (r) 3.0 (2006):

surprisingly
    adv 1: in a surprising manner; "he was surprisingly friendly"
    2: in an amazing manner; to everyone's surprise; "amazingly, he
       finished medical school in three years" [syn: amazingly,
       surprisingly, astonishingly]

Moby Thesaurus II by Grady Ward, 1.0:

81 Moby Thesaurus words for "surprisingly":
   abruptly, abundantly, acutely, amazingly, amply, astonishingly,
   astoundingly, awesomely, bang, confoundingly, conspicuously,
   copiously, dash, eminently, emphatically, exceptionally,
   exquisitely, extraordinarily, exuberantly, famously, for a wonder,
   generously, glaringly, hastily, impetuously, impressively,
   impulsively, incredibly, intensely, like a flash,
   like a thunderbolt, magically, magnanimously, magnificently,
   markedly, marvelously, nobly, notably, of a sudden,
   on short notice, particularly, peculiarly, plop, plump, plunk,
   pointedly, pop, precipitantly, precipitately, precipitously,
   preeminently, profusely, prominently, pronouncedly, remarkably,
   richly, sharp, shockingly, signally, singularly, slap, smack,
   splendidly, staggeringly, startlingly, strange to say, strikingly,
   stunningly, sudden, suddenly, superlatively, surpassingly,
   unawares, uncommonly, unexpectedly, unusually, without notice,
   without warning, wonderfully, wondrous, worthily