An area of disturbed weather developed near the Andaman Islands on November 9. It gradually became better organised as it passed to the south of the islands, and the system was designated Depression BOB 09 by the India Meteorological Department early on November 11. The Joint Typhoon Warning Center upgraded it to Tropical Cyclone 06B at the same time. Later that day, it intensified into a deep depression as it moved slowly north-westward. The IMD upgraded the system to Cyclonic Storm Sidr early on November 12. The system then began to intensify quickly as it moved slowly northwestward, and the IMD upgraded it to a severe cyclonic storm later that day and a very severe cyclonic storm early the next day.