Here comes another one. The Gulf coast is preparing for a storm system that could dump up to 20 inches of rain this weekend. Louisiana has already declared a state of emergency. Storm warnings are in effect for Mississippi and Texas — though Texas, in the midst of a historic drought, is unlikely to get much rain. The National Hurricane Center says the storm has an 80-percent chance of strengthening to a tropical cyclone. "High wind, a lot of rain and it's going slow," said New Orleans Mayor Mitch Landrieu. "That's not a good prescription for New Orleans."