( ( ( ( Characteristics ( of ( Air Masses ) ) ) : ) ( ( 1 -RRB- ) ( ( The diagram ) ( below ( depicts ( ( ( two types ) ( of ( air masses ) ) ) ( that ( commonly ( influence ( weather ( in ( the ( United States ) ) ) ) ) ) ) ) ) ) ) ) ) . )
(ROOT (NP (NP (NP (NNS Characteristics)) (PP (IN of) (NP (NNP Air) (NNPS Masses)))) (: :) (NP (LST (LS 1) (-RRB- -RRB-)) (NP (DT The) (NN diagram)) (PP (IN below) (S (VP (VBG depicts) (NP (NP (CD two) (NNS types)) (PP (IN of) (NP (NN air) (NNS masses))) (SBAR (WHNP (WDT that)) (S (ADVP (RB commonly)) (VP (VBP influence) (NP (NP (NN weather)) (PP (IN in) (NP (DT the) (NNP United) (NNPS States)))))))))))) (. .)))
Characteristics of Air Masses: 1) The diagram below depicts two types of air masses that commonly influence weather in the United States.
(ROOT (S (NP (NP (DT The) (JJS best) (NN explanation)) (PP (IN for) (SBAR (WHADVP (WRB how)) (S (NP (NN air) (NNS masses)) (VP (VBP move) (PP (IN across) (NP (DT the) (VBN united) (NNS states)))))))) (VP (VBZ is) (SBAR (IN that) (S (NP (DT the) (VBG prevailing) (NNS westerlies)) (VP (VP (VBP move) (NP (NN air) (NNS masses)) (PP (IN from) (NP (NN west))) (PP (TO to) (ADJP (JJ east))) (PP (IN across) (NP (DT the) (VBN united) (NNS states)))) (CC but) (VP (MD may) (VP (VB be) (VP (VBN deflected) (PP (IN by) (NP (DT the) (NN jet) (NN stream)))))))))) (. .)))