Located to the south of a mid to upper-level ridge over the southern United States , the system moved to the west-northwest into an area ideal for further strengthening ; an upper-level anticyclone formed over the central Gulf of Mexico , and sea surface temperatures along its track were warm . Located to the south of a mid to upper-level ridge over the southern United States , the system tracked to the west-northwest through an environment conducive for further strengthening ; an upper-level anticyclone developed over the central Gulf of Mexico , and sea surface temperatures along its track were warm .