It might not stop them completely but it would slow them the first night.
( ( ( ( It ( ( might not ) ( ( stop them ) completely ) ) ) but ) ( it ( would ( ( slow them ) ( the ( first night ) ) ) ) ) ) . )
(ROOT (S (S (NP (PRP It)) (VP (MD might) (RB not) (VP (VB stop) (NP (PRP them)) (ADVP (RB completely))))) (CC but) (S (NP (PRP it)) (VP (MD would) (VP (VB slow) (NP (PRP them)) (NP (DT the) (JJ first) (NN night))))) (. .)))
They won't arrive to their destination in time.
( They ( ( ( wo n't ) ( arrive ( to ( ( their destination ) ( in time ) ) ) ) ) . ) )
(ROOT (S (NP (PRP They)) (VP (MD wo) (RB n't) (VP (VB arrive) (PP (TO to) (NP (NP (PRP$ their) (NN destination)) (PP (IN in) (NP (NN time))))))) (. .)))