( Generally ( , ( storms ( ( move ( with ( ( the direction ) ( of ( the ( upper-level ( jet stream ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (ADVP (RB Generally)) (, ,) (NP (NNS storms)) (VP (VBP move) (PP (IN with) (NP (NP (DT the) (NN direction)) (PP (IN of) (NP (DT the) (JJ upper-level) (NN jet) (NN stream)))))) (. .)))
Generally, storms move with the direction of the upper-level jet stream.
(ROOT (S (NP (NNP Jet) (NNP streams)) (VP (VBP are) (ADVP (RB fast)) (VP (VBG moving) (NP (NP (NNS rivers)) (PP (IN of) (NP (NN air))) (SBAR (WHNP (WDT that)) (S (VP (VBP are) (VP (VBG going) (PP (IN in) (NP (NP (JJ opposite) (NNS directions)) (VP (VBN called))))))))))) (. .)))
Jet streams are fast moving rivers of air that are going in opposite directions called.