WordNet (r) 3.0 (2006):

burst forth
    v 1: jump out from a hiding place and surprise (someone); "The
         attackers leapt out from the bushes" [syn: leap out,
         rush out, sally out, burst forth]
    2: be unleashed; emerge with violence or noise; "His anger
       exploded" [syn: explode, burst forth, break loose]
    3: come into or as if into flower; "These manifestations
       effloresced in the past" [syn: effloresce, burst forth]

Moby Thesaurus II by Grady Ward, 1.0:

81 Moby Thesaurus words for "burst forth":
   arise, bail out, be born, become, belch, blow open, blow out,
   bob up, break cover, break forth, break out, bud, burgeon,
   burst out, come, come forth, come out, come to be, crop up,
   debouch, discharge, disembogue, disgorge, effuse, eject, emanate,
   emerge, eruct, erupt, explode, extrude, flare up, flash, flourish,
   gemmate, germinate, get to be, gleam, grow, grow rank, have origin,
   hurl forth, irrupt, issue, issue forth, jump out, leaf, leaf out,
   leave, luxuriate, originate, overgrow, overrun, pop up, protrude,
   pullulate, put forth, put forth leaves, put out buds, riot, rise,
   root, sally, sally forth, shoot, shoot up, spew, spout, spring up,
   sprout, sprout up, start up, strike root, surface, take birth,
   take rise, take root, upspear, upsprout, vegetate, vomit