Tropical Storm Milton formed in the Gulf of Mexico Saturday and was forecast to strengthen into a hurricane as it headed toward Florida's west coast, the National Hurricane Center said. Forecasters warned Sunday of increasing risks for parts of the coast that could be hit with "life-threatening impacts" of the powerful storm. Milton was forecast to undergo a period of rapid intensification, the hurricane center said. It is predicted to become a hurricane Sunday night and either reach or approach major hurricane strength before arriving in coastal Florida.