The next morning , after passing over the state , Tropical Storm Katrina moved into the Gulf of Mexico , strengthened back to hurricane strength , and from the influence of the warm waters from the Loop Current , began undergoing rapid deepening . The next morning , after passing over the state , Tropical Storm Katrina moved into the Gulf of Mexico , reintensified back to hurricane strength , and due to the warm waters of the Loop Current , began undergoing rapid deepening .