Edited sentence: A Tropical Cyclone Formation Alert was issued later that day by the Joint Typhoon Warning Center as the cyclone was moving towards the northwest under the influence of a subtropical ridge of pressure.Early on May 3, 1990 reported that a Tropical disturbance formed about 800km (500mi) to the east of Sri-lanka.The Depression was then upgraded to a cyclonic storm early the next day before becoming a Tropical Storm later that day.The disturbance was then designated as Depression BOB 01, early the next day by the India Meteorological Department