At 00:00 UTC on May 16, a depression formed in the southeast Bay of Bengal and was identified as BOB 01. Six hours later, the Indian Meteorological Department upgraded the system to a deep depression. The system began bringing torrential rainfall to Sri Lanka and Southern India. Around 15:00 UTC, the system further developed into Cyclonic Storm Amphan. That morning, landslide and flooding warnings were hoisted for parts of eastern Sri Lanka and the Indian state of Kerala were given expectations of torrential rainfall in the coming days. By 09:00 UTC of May 17, Amphan had intensified into a very severe cyclonic storm. Within 12 hours, the storm had developed an eye and started to rapidly intensify, becoming an extremely severe cyclonic storm. According to the JTWC, it explosively intensified from a Category 1-equivalent cyclone to a Category 4-equivalent cyclone in just 6 hours. The following morning around 10:30 UTC, the IMD upgraded Amphan to a super cyclonic storm with 3-minute sustained winds of 240 km/h and a minimum pressure of 920 hPa. This marked the second year in a row featuring a super cyclonic storm, the previous year seeing Kyarr in the Arabian Sea. On May 20, at approximately 17:30 IST, the cyclone made landfall near Bakkhali, West Bengal after weakening subsequently. It rapidly weakened once inland, and dissipated on the next day. It left behind a trail of catastrophic damage, and was later confirmed to be the costliest storm ever in the basin.
Depression ARB 01
A depression formed overland near Salalah, Oman on May 29. The Public Authority for Civil Aviation in Oman advised residents to exercise caution and not to venture to low-lying areas or sea. The Supreme Committee asked people to remain at home in non-emergency circumstances. The hospital in Sadah was evacuated as the depression intensified. Over of rain fell in Dhofar Governorate on May 29; some areas received the equivalent of two years of rainfall. The highest precipitation total was measured in Mirbat, where of rain fell. Two days of heavy rainfall, accumulating to, caused floods in Salalah. Operations at the port of Salalah were interrupted by the tropical depression. Residents in central Salalah experienced disruptions to power and water services. Military police were dispatched to clear roads and airlift people marooned by the floods. Engineering teams from the Ministry of Defence were deployed to restore utilities and render air where necessary. Two people were found dead in a wadi due to flash floods, while another person died and three were injured when a building collapsed. More than 50 people were rescued from floods.
During May 31, an area of low pressure developed over the south-eastern Arabian Sea and remained as a well marked low pressure area over the same region until the evening. It strengthened into a depression over the east-central and south-east Arabian Sea in the early morning of June 1 when it was centered about 340 km south-west of Goa, 630 km south-southwest of Mumbai and 850 km south-southwest of Gujarat. On June 2, around noon, the prevailing deep depression intensified into a cyclonic storm thereby receiving the name Nisarga. Nisarga intensified into a severe cyclonic storm before making landfall near the coastal town of Alibag in Maharashtra at 12:30 on June 3. At the time, the system was at peak intensity with 3-minute sustained winds of 110 km/h and a central pressure of 984 hPa. The cyclone subsequently weakened into a deep depression by June 4.
Storm names
Within this basin, a tropical cyclone is assigned a name when it is judged to have reached cyclonic storm intensity with winds of 65 km/h. The names were selected by members of the ESCAP/WMO panel on Tropical Cyclones between 2000 and May 2004, before the Regional Specialized Meteorological Center in New Delhi started to assign names in September 2004. There is no retirement of tropical cyclone names in this basin as the list of names is only scheduled to be used once before a new list of names is drawn up. Should a named tropical cyclone move into the basin from the Western Pacific, then it will retain its original name. The next eight names from the list of North Indian Ocean storm names are listed below. Amphan is the last name from the original naming list published in 2004, while Nisarga is the first name from the new naming list published in 2020.
Season effects
This is a table of all storms in the 2020 North Indian Ocean cyclone season. It mentions all of the season's storms and their names, duration, peak intensities, damage, and death totals. Damage and death totals include the damage and deaths caused when that storm was a precursor wave or extratropical low, and all of the damage figures are in 2020 USD.
