(S (S (BASENP (DT A) (JJ tropical) (NN storm) (NN warning)) (VP (VP (VBZ is) (PP (IN in) (BASENP (NN effect)))) (PP (PP (IN from) (NP (BASENP (NN south)) (PP (IN of) (BASENP (NNP Tulum))))) (PP (TO to) (BASENP (NNP Chetumal) (NNP Mexico)))))) (PERIOD .))