( ( The winds ) ( ( are ( ( forced ( ( up and ) over ) ) ( the mountains ) ) ) . ) )
(ROOT (S (NP (DT The) (NNS winds)) (VP (VBP are) (VP (VBN forced) (PRT (RP up) (CC and) (RP over)) (NP (DT the) (NNS mountains)))) (. .)))
The winds are forced up and over the mountains.
(ROOT (S (NP (NN Chinook) (NNS winds)) (VP (VBP occur) (SBAR (WHADVP (WRB when)) (S (NP (NN air)) (VP (VBZ is) (VP (VBN forced) (PP (IN over) (NP (DT a) (NN mountain) (NN range)))))))) (. .)))