It’s an area of low atmospheric pressure, thunderstorms and wind sloshing out of the Caribbean Sea into the Gulf of Mexico. But by the time it dissipates, weather forecasters may have called it by five different names. First it was Invest 97L, then it was Potential Tropical Cyclone Four. Late Friday it became Tropical Depression Four. On Saturday it became Tropical Storm Debby and it could intensify into Hurricane Debby on Sunday or Monday. Why? Various names are used to classify the intensity of storms in the Atlantic Ocean and the eastern and central Pacific Ocean.