By six hours after development, the depression had of a somewhat exposed low-level center with deep convection taking up most of the northeastern semicircle. Located over sea surface temperatures of about 80º F (27º C), one forecaster said the depression had "a small window of opportunity... for it to reach tropical storm strength before transitioning to an extratropical cyclone." The system organized further, and based on satellite pictures and QuikSCAT data, the National Hurricane Center upgraded the depression to Tropical Storm Chantal at 1215 UTC on July 31 while located about 330 miles (530 km) south of Halifax, Nova Scotia. By three hours later the system formed a well-defined curved banding features, and Chantal reached maximum systained winds of 50 mph (80 km/h) at 40.2º N. The storm speed up northeastward into an area of cold waters and cooler air, and early on August 1 the National Hurricane Center gave out its last advisory on Chantal as it began extratropical transition.