( Air ( ( rises ( to ( ( the east ) ( of ( ( troughs , ) ( which ( ( leads ( to ( ( the formation ) ( of ( ( clouds and ) precipitation ) ) ) ) ) ( while ( ( ( sinking air ) ( to ( the west ) ) ) ( inhibits ( ( clouds and ) precipitation ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Air)) (VP (VBZ rises) (PP (TO to) (NP (NP (DT the) (JJ east)) (PP (IN of) (NP (NP (NNS troughs)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBZ leads) (PP (TO to) (NP (NP (DT the) (NN formation)) (PP (IN of) (NP (NNS clouds) (CC and) (NN precipitation))))) (SBAR (IN while) (S (NP (NP (VBG sinking) (NN air)) (PP (TO to) (NP (DT the) (NN west)))) (VP (VBZ inhibits) (NP (NNS clouds) (CC and) (NN precipitation))))))))))))) (. .)))
Air rises to the east of troughs, which leads to the formation of clouds and precipitation while sinking air to the west inhibits clouds and precipitation.
(ROOT (NP (NP (NP (VBG Rising)) (CC and) (NP (VBG sinking) (NN air) (NNS influences))) (VP (VBN precipitation) (PP (IN in) (NP (DT a) (NN region)))) (. .)))