( ( ( Showers and ) thunderstorms ) ( ( caused ( some ( streams ( to ( exceed ( their banks ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Showers) (CC and) (NNS thunderstorms)) (VP (VBD caused) (SBAR (S (NP (DT some)) (VP (VBZ streams) (S (VP (TO to) (VP (VB exceed) (NP (PRP$ their) (NNS banks))))))))) (. .)))
Showers and thunderstorms caused some streams to exceed their banks.
(ROOT (S (NP (DT A) (NN stream) (NN flooding)) (VP (VBZ is) (ADVP (RBS most) (RB likely)) (VP (VBN caused) (PP (IN by) (NP (DT a) (NN thunderstorm))))) (. .)))