On July 1, the Naval Research Laboratory (NRL) began to track a developing disturbance in the north Bay of Bengal. Following the formation of a low pressure area and circulation centre, the India Meteorological Department (IMD) initiated advisories, declaring it a depression, as it was located about 150 km (90 mi) southeast of Kolkata, West Bengal, in India, along the Bangladeshi coast. The system was noted in the Significant Tropical Weather Advisory issued by the Joint Typhoon Warning Center (JTWC) that same day. The JTWC commented that the consolidated circulation centre was already overland, in southwest Bangladesh. The next day, on July 5, as the depression tracked northwestward into Gangetic West Bengal, the IMD upgraded it to a deep depression. It reached close to Bankura early on July 6, moving westward. Phoolberia in West Bengal received 450 mm of rainfall in 48 hours between 5 and 6 July 2007.