In the overnight hours after formation, the storm was disorganized with a shabby and abstracted center of circulation. 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. The cloud pattern became better organized, keeping a large area of convection with curved rainbands and well-established outflow. Based on reports from Hurricane Hunters, the National Hurricane Center upgraded the depression to Tropical Storm Erin at 1530 UTC on August 13 about 250 miles (400 km) east of Brownsville, Texas. As it continued northwestward, Erin remained disorganized and was not able to strengthen above minimal tropical storm status. At 1200 UTC on August 16 the cyclone made landfall near Lamar, Texas as it weakened to tropical depression status. Three hours later, the National Hurricane Center stopped giving out advisories on Erin as warning responsibility was switched to the Hydrometeorological Prediction Center.