2022 North Indian Ocean cyclone season

The 2022 North Indian Ocean cyclone season was an above-average season in terms of depressions and average in terms of deep depressions, but slightly below average in terms of cyclonic storms. It was also the least deadly North Indian Ocean cyclone season since 1988, according to official data. The season's strongest tropical cyclone was Cyclone Asani, with maximum wind speeds of 100 km/h (65 mph) and a minimum barometric pressure of 982 hPa (29.00 inHg). The North Indian Ocean cyclone season has no official bounds, but cyclones tend to form between April and December, with the peak from May to November. These dates conventionally delimit the period of each year when most tropical cyclones form in the northern Indian Ocean.

The scope of this article is limited to the Indian Ocean in the Northern Hemisphere, east of the Horn of Africa and west of the Malay Peninsula. There are two main seas in the North Indian Ocean — the Arabian Sea to the west of the Indian subcontinent, abbreviated ARB by the India Meteorological Department (IMD); and the Bay of Bengal to the east, abbreviated BOB by the IMD. The systems that form over land are abbreviated as LAND. The official Regional Specialized Meteorological Centre in this basin is the India Meteorological Department (IMD), while the Joint Typhoon Warning Center (JTWC) releases unofficial advisories. On average, three to four cyclonic storms form in this basin every season.

Season summary

The season began with BOB 01 which formed on 3 March over the Bay of Bengal. It peaked as a deep depression, before weakening as a well-marked low-pressure area on 6 March. The system became the eighth system to form in March since reliable records began in 1891. On 20 March, another deep depression classified as BOB 02 formed in the Andaman Sea. BOB 02 made landfall in Myanmar before dissipating. After more than 1 month of inactivity, a low-pressure system formed off the coast of Andaman and Nicobar Islands on 6 May. On the next day, JTWC classified it as Tropical Cyclone 02B, followed by IMD which recognized it as Depression BOB 03. The depression intensified into a cyclonic storm, named Asani, making it the first named storm in the season. Soon, Asani was upgraded to Category 1 cyclone by JTWC, and IMD upgraded to a severe cyclonic storm. Afterward, Asani began to weaken rapidly due to high wind shear. and made landfall in Andhra Pradesh as a deep depression. Later in May, BOB 04 quickly consolidated into a depression as it landed on the south Burmese coast.

Activity ceased for approximately 2 months before Depression ARB 01 was designated and struggled against strong wind shear and dry air intrusions. In August, four systems were designated by the IMD. Land Depression 01 was short-lived and degenerated to a remnant low over Chhattisgarh. Depression ARB 02 formed a couple of days later and even though the IMD kept the system as a depression, the JTWC upgraded ARB 02 to Tropical Cyclone 03A. Having a tropical storm-force cyclone form in the Arabian Sea in August is rare, and the last system to become one was Cyclone Aurora in 1983. Depression BOB 05 followed and the brown ocean effect aided the system to maintain depression status for a few more days. After BOB 05, Deep Depression BOB 06 was designated by the IMD after the JTWC unofficially upgraded it to Tropical Cyclone 04B due to attaining tropical storm-force winds. BOB 06 later made landfall in Digha, West Bengal and caused 32 deaths. In September, the IMD briefly designated Land Depression 02.

In late October, the IMD monitored an area of low pressure, which was designated as BOB 07 and later became Cyclonic Storm Sitrang, officially the second named storm of the season. The cyclonic storm abruptly headed north-northeast and early on October 24, it made landfall in Patuakhali, Bangladesh. Sitrang is the first tropical cyclone to hit Bangladesh since Cyclone Mora in 2017, and caused 35 fatalities. After Sitrang, Depression BOB 08 formed and struggled to consolidate a well-defined center before causing minor impacts to parts of southern India. In December, Deep Depression BOB 09 formed. IMD later upgraded it to Cyclonic Storm Mandous. Despite moderate easterly mid-level wind shear, Mandous intensified to a Severe Cyclonic Storm as it neared Sri Lanka. It made landfall near Chennai, India, as a Deep Depression and caused 9 deaths. The remnants of Mandous transferred across southern India and into the Arabian Sea. The system quickly developed and was designated as Depression ARB 03 by IMD. The storm unexpectedly rapidly developed and the JTWC designated it as Tropical Cyclone 07A, peaking with winds of 60 mph (95 km/h). After ARB 03, Depression BOB 10 formed and meandered in the Bay of Bengal before dissipating.

Systems Deep Depression BOB 01

Towards the end of February, a cyclonic circulation formed over the Strait of Malacca and the adjoining Andaman Sea, which later intensified into a low pressure area on midday (17:30 IST) of 28 February, as the disturbance formed a low-level circulation, according to a INSAT-3D satellite imagery. Early the next day, at 09:00 UTC (14:30 IST), the disturbance further intensified into a well-marked low pressure area, as it developed a defined cyclonic vortex, and three-and-a-half-hour later, the United States-based Joint Typhoon Warning Center (JTWC) started monitoring the same disturbance as Invest 90B. Alt URL On 3 March of midnight (05:30 IST), the well-marked low organized to a depression and the India Meteorological Department (IMD) identified the system as BOB 01, making it the first system of the season. This intensification was possible because of a favourable Madden–Julian oscillation (MJO) phase, along with a feeble easterlies outflow. Additionally, sea surface temperatures (SST) of were warm enough for tropical cyclogenesis to take place, along with moderate to high vertical wind shear. During the next day, the JTWC issued a Tropical Cyclone Formation Alert (TCFA) on the system. Alt URL The depression subsequently intensified into a deep depression, and by 21:00 UTC (02:30 IST), the JTWC started initiating advisories for Tropical Cyclone 01B. Alt URL After maintaining its intensity for a day, the JTWC issued its last warning for the system, at 15:00 UTC (20:30 IST) as the increasing dry air had weakened its convective mass. Alt URL The IMD subsequently weakened back to a depression due to the same reason. On 6 March, the IMD issued its last advisory for the system and downgraded it to a well-marked low pressure area, as its convective mass got further disorganized by the wind shear.

Deep Depression BOB 02

In mid-March, a low-pressure area formed in the southwest Bay of Bengal, offshore of Sri Lanka, which later intensified into a well marked low pressure area, and the JTWC started monitoring the disturbance as Invest 91B. Alt URL It meandered east-southeast for three days, and on 20 March, the IMD reported that a depression formed over the Bay of Bengal, giving it the designation BOB 02. On that day, the JTWC issued a TCFA for the system. The system gradually intensified, into a deep depression by 00:00 UTC (05:30 IST) the next day, as the convection had further organized favorable conditions such as moderate to high sea-surface temperatures. On 22 March, the JTWC cancelled the TCFA due to the land interaction in Myanmar until the landfall. BOB 02 rapidly weakened overland, degenerating into a depression and by 03:00 UTC (08:30 IST) the next day the system weakened into a well-marked low pressure area and IMD issued last advisory.

Severe Cyclonic Storm Asani

During the first week of May, a strong pulse of Madden-Julian Oscillation (MJO) and Equatorial Rossby wave (ERW) prevailed in this basin. These two conditions led to a cyclonic circulation forming over the southern Andaman Sea on 4 May. At the same time, a Westerly wind burst occurred on the same day which resulted in formation of twin cyclones over the either side of the Indian Ocean. The southern hemisphere counterpart being Tropical Cyclone Karim and the northern hemisphere counterpart being this cyclonic circulation. The JTWC followed suit and designated it as Invest 92B on the next day. Alt URL On 6 May, under the influence of the same disturbance, a low pressure system formed off the coast of Andaman and Nicobar Islands. Subsequently, the JTWC issued its TCFA, as it had rapidly consolidated its convective structure for the past few hours, along with development of a well-defined low-level center. Alt URL By the morning of 7 May, the system became more well-marked over the same region. At 09:00 UTC (14:30 IST), the JTWC initiated advisories on the system and classified it as Tropical Cyclone 02B, while IMD followed the suit and upgraded it to Depression BOB 03. Alt URL Three hours later, the system was further upgraded to a deep depression status by the IMD, after forming a defined central dense overcast cloud pattern. By 05:30 IST (00:00 UTC) of the next day, the system organized into Cyclonic Storm Asani, becoming the first cyclone of the season. Nine hours later, the JTWC upgraded it to a Category 1 status. Alt URL At 12:00 UTC (17:30 IST), the IMD further upgraded it to a severe cyclonic storm, as microwave imagery showed a well-organized system. On 10 May, the cyclone began to encounter high wind shear due to which the JTWC downgraded it as a tropical storm while the IMD continue to maintain it as a severe cyclonic storm. Alt URL it began to make a sudden westward jog and mild decrease in wind shear made the JTWC to upgrade it again into a Category 1-equivalent tropical cyclone. Alt URL Nine hours later, Asani was further downgraded into a tropical storm, it began to weaken rapidly due to higher wind shear as well as dry air intrusion. Alt URL On 11 May, 12:00 UTC, Asani further weakened to a Deep Depression as it made landfall in the Indian State of Andhra Pradesh. The next day, the IMD issued its last advisory as the system degenerated into a low pressure area.

Depression BOB 04

A fresh cyclonic circulation developed on early 19 May, over the Gulf of Martaban, due to the enhancement of the annual South-West monsoon over the basin. By the evening, under the influence of that circulation, a low pressure system spawned over the same region. At 18:00 UTC (23:30 IST), the JTWC also acknowledged that same circulation at the night of the same day. Alt URL By 00:30 UTC (06:00 IST) the JTWC published its TCFA for the system after it had rapidly consolidated its convective structure for the past few hours, and also formed a well-defined low-level center. Alt URL But eight hours later, the JTWC, cancelled it because its close proximity over land. Alt URL However, according to IMD, it rapidly consolidated into a well-marked low pressure area in the morning of the same day, and further into a depression at 11:30 IST (03:00 UTC), as it moved northeastwards, towards the south Burmese coast. Between 08:00 UTC (13:30 IST) and 09:00 UTC (14:30 IST), the system made landfall over the southern Burmese coast, from Mawlamyine. The system maintained its depression status as it travelled inland. By 00:00 UTC (05:30 IST) the next day, the system finally weakened into a well-marked low pressure area over the Burma-Thailand.

The system helped the monsoon to further advance into parts of southern Arabian Sea, southern parts of Maldives and parts of southern and east-central Bay of Bengal.

Depression ARB 01