WordNet (r) 3.0 (2006):

updraft
    n 1: a strong upward air current

Moby Thesaurus II by Grady Ward, 1.0:

77 Moby Thesaurus words for "updraft":
   air current, anabasis, ascension, ascent, clamber, climb, climbing,
   crosscurrent, current, current of air, downdraft, draft, elevation,
   escalade, fall wind, flow of air, following wind, fountain, gush,
   gyring up, head wind, increase, indraft, inflow, inhalation,
   inrush, inspiration, jet, jetstream, jump, katabatic wind, leap,
   levitation, monsoon, mount, mounting, movement of air, rise,
   rising, rocketing up, saltation, shooting up, soaring, spout,
   spring, spurt, stream, stream of air, surge, tail wind, takeoff,
   taking off, undercurrent, upclimb, upcoming, upgang, upgo, upgoing,
   upgrade, upgrowth, uphill, upleap, uplift, upping, uprisal, uprise,
   uprising, uprush, upshoot, upslope, upsurge, upsurgence, upsweep,
   upswing, vault, wind, zooming