The Collaborative International Dictionary of English v.0.48:

Squally \Squall"y\ (-[y^]), a.
   1. Abounding with squalls; disturbed often with sudden and
      violent gusts of wind; gusty; as, squally weather.
      [1913 Webster]

   2. (Agric.) Interrupted by unproductive spots; -- said of a
      field of turnips or grain. [Prov. Eng.] --Halliwell.
      [1913 Webster]

   3. (Weaving) Not equally good throughout; not uniform;
      uneven; faulty; -- said of cloth.
      [1913 Webster]

WordNet (r) 3.0 (2006):

squally
    adj 1: characterized by short periods of noisy commotion; "a
           home life that has been extraordinarily squally" [syn:
           squally, squalling]
    2: characterized by brief periods of violent wind or rain; "a
       grey squally morning"

Moby Thesaurus II by Grady Ward, 1.0:

41 Moby Thesaurus words for "squally":
   aeolian, airish, airy, blasty, blowy, blustering, blusterous,
   blustery, boreal, breezy, brisk, castellatus, cirrose, cirrous,
   cloud-flecked, clouded, cloudy, cumuliform, cumulous, dark, dirty,
   drafty, favonian, flawy, fresh, gloomy, gusty, heavy, lenticularis,
   mammatus, nebulous, nimbose, nubilous, overcast, overclouded,
   puffy, stormy, stratiform, stratous, thunderheaded, windy