2023 North Indian Ocean cyclone season

Depression (IMD)
Duration	30 January – 2 February
Peak intensity	45 km/h (30 mph) (3-min); 1004 hPa (mbar)

On 25 January, a cyclonic circulation formed over the equatorial Indian Ocean and the adjoining Bay of Bengal.[4] Under an influence of cyclonic circulation, a low-pressure area formed on 27 January.[5] Substantially, it concentrated into a well-marked low-pressure area on 29 January.[6] During the next day, the well-marked low organized to depression.[7] The JTWC later issued a Tropical Cyclone Formation Alert (TCFA) for the system.[8] However, increasing land interaction with Sri Lanka prompted the JTWC to downgrade the system's chance for development to medium and subsequently canceling its TCFA.[9] The disturbance finally weakened into a well-marked low pressure over Gulf of Mannar on 2 February.[10]

Extremely severe cyclonic storm (IMD)
Category 5 tropical cyclone (SSHWS)
Duration	9 May – 15 May
Peak intensity	215 km/h (130 mph) (3-min); 938 hPa (mbar)

A circulation formed on 6 May over the Bay of Bengal as a result of the amplitude of the Madden–Julian oscillation (MJO), according to the IMD.[11] The JTWC also began monitoring the system on 7 May, marking its flaring convection to the west of the circulation.[12] On 9 May, the system was upgraded to a depression.[13] The JTWC later issued a TCFA on the system as it was situated in very warm sea surface temperatures.[14] The storm subsequently intensified into a deep depression at 03:00 UTC of 9 May,[15] before upgrading further to a cyclonic storm on 11 May, attaining the name Mocha.[16] The JTWC followed suit in upgrading the system to tropical cyclone status the same day.[17] Mocha quickly intensified to a severe cyclonic storm at 12:00 UTC after reaching winds of 105 km/h (65 mph).[18] After forming an eye,[19] Mocha became a very severe cyclonic storm on 12 May.[20] Mocha rapidly intensified to an extremely severe cyclonic storm at 18:00 UTC,[21] before undergoing an eyewall replacement cycle.[22] After having completing the cycle on 13 May, Mocha rapidly intensified and reached a peak intensity as a Category 5-equivalent tropical cyclone the next day,[23] shortly before the storm entered unfavorable conditions.[24] Mocha weakened before making landfall near Sittwe of Myanmar.[25] Mocha began to rapidly weaken after landfall from Myanmar's terrain, with wind shear also degrading the storm.[26] The system downgraded to a depression on 15 May,[27] shortly before becoming marked as a low-pressure area.[28]

The death toll from Cyclone Mocha varies significantly. ASEAN reported a total of 145 deaths,[29] whereas the National Unity Government of Myanmar (NUG) stated that Mocha killed at least 463 people, including three indirect deaths in Bangladesh. The cyclone also injured 719 people and left 101 others missing.[30] It caused about US$1.5 billion of damage in Myanmar.[31]

Extremely severe cyclonic storm (IMD)
Category 3 tropical cyclone (SSHWS)
Duration	6 June – 19 June
Peak intensity	165 km/h (105 mph) (3-min); 958 hPa (mbar)

A cyclonic circulation formed over the Arabian Sea on 5 June.[32] On the same day, a low-pressure area formed as a result of cyclonic circulation.[33] The following day, it significantly intensified into a depression.[34] The JTWC issued a TCFA on the system.[35] The IMD upgraded the depression to a deep depression, and subsequently to a Cyclonic Storm Biparjoy.[36][37] The JTWC subsequently classified it as Tropical Cyclone 02A. [38] By 00:00 UTC on 7 June, the IMD upgraded the system to a severe cyclonic storm with winds of 100 km/h (65 mph).[39] Biparjoy cloud tops warmed and the convective burst collapsed, resulting in an upper-level outflow from the storm and pushing it back towards its system core.[40] Biparjoy was upgraded to a very severe cyclonic storm at 06:00 UTC, at which point the system became a Category 2-equivalent tropical cyclone.[41][42] The cyclone was sheared due to moderate easterly vertical wind shear, with the deep convection displaced from the LLCC.[43] Biparjoy unexpectedly rapidly intensified and became a Category 3-equivalent cyclone on 11 June.[44][45] Biparjoy reached its peak intensity as an extremely severe cyclonic storm, with maximum 3-minute sustained winds of 165 km/h (105 mph).[46] The shear decreased and convective organization and areal extent increased.[47] Biparjoy gradually weaken with convective banding over the northern semicircle.[48] Biparjoy made landfall on 16 June near Naliya, India, with sustained winds of 95 km/h (60 mph).[49][50] Shortly after the landfall, the JTWC discontinued warnings on the system.[49] The cyclone was later marked as a well-marked low-pressure area by the IMD on 19 June, prompting the discontinuation of advisories on the system.[51]

In Pakistan, 81,000 individuals were evacuated from the southeastern coast, and authorities have established 75 relief camps at schools to provide assistance.[52] At least 23 people were injured as well as 4,600 villages were affected by power outages in India.[53] A total of 12 people were confirmed to have been killed by the storm.[54][55][56]

Deep depression (IMD)
Tropical storm (SSHWS)
Duration	31 July – 3 August
Peak intensity	55 km/h (35 mph) (3-min); 988 hPa (mbar)

On 29 July the IMD noted a cyclonic circulation forming over North Odisha and nearby Gangetic West Bengal. On the same day, it noted the formation of low pressure area over same region and on next day it moved over the Northeastern part of Bay of Bengal.[57] By the same time at 06:00 UTC on 31 July, the JTWC designated it as Invest 95B and gave low chance of developing. Despite its low level circulation exposed, it continued to intensify and at 12:00 UTC of the same day, the IMD upgraded it to a well marked low.[57] On 21:00 UTC, the JTWC upgraded it to a tropical storm designated as 04B and peaked as a 40 kt storm. On 00:00 UTC of 1 August, the IMD upgraded it to a Depression designated as BOB 03. It continued to intensify till Deep Depression intensity off the coast of Bangladesh and made landfall at Khepupara in Bangladesh at 12:00 UTC.[57] The JTWC stopped issuing advisories by 06:00 UTC stating that it made landfall. It continued to move into Eastern India while maintaining intensity. It weakened into Depression over Jharkhand on 2 August 18:00 UTC. Continued to move west-northwest, it became a well-marked low pressure area over north Chhattisgarh and nearby region by 12:00 UTC on 3 August.[57]

Depression (IMD)
Duration	30 September – 1 October
Peak intensity	45 km/h (30 mph) (3-min); 1002 hPa (mbar)

IMD marked a low pressure area off the Konkan coast and rapidly upgraded into a depression designated as ARB 02 on 30 September.[58] ARB 02 made landfall with the same speed and caused heavy rainfall that day. It moved overland and later gradually weakened into a well marked low pressure area by the IMD on 1 October.

Extremely severe cyclonic storm (IMD)
Category 3 tropical cyclone (SSHWS)
Duration	20 October – 24 October
Peak intensity	175 km/h (110 mph) (3-min); 959 hPa (mbar)

On 16 October 2023, the India Meteorological Department (IMD) began monitoring the potential for a formation of a cyclonic circulation in the Arabian Sea.[59] In Arabian Sea, the relatively higher sea surface temperature, pointing to positive Indian Ocean Dipole, created the favourable condition for the formation of cyclogenesis.[60] A cyclonic circulation formed over the Arabian Sea on 16 October.[59] A low-pressure area formed as a result of the cyclonic circulation on morning of 18 October. It intensified into Depression on 21 October. At the same day, the system intensified into Cyclonic Storm, received the name Tej.

Very severe cyclonic storm (IMD)
Category 2 tropical cyclone (SSHWS)
Duration	21 October – 25 October
Peak intensity	120 km/h (75 mph) (3-min); 985 hPa (mbar)

On October 21, Tropical Depression 06B formed in the Bay of Bengal. It was upgraded to a Cyclonic Storm on October 23, receiving the named Hamoon. On October 24, Hamoon rapidly intensified into a high end Category 1 equivalent storm. At 10 pm October 24, Hamoon started to impact the coastal areas of Chittagong and Cox's Bazar.

A tropical cyclone off the coast of Bangladesh in June 9

• Under the influence of another cyclonic circulation, a low-pressure area formed over the northeast Bay of Bengal on 9 June,[61] which later concentrated into a well-marked low-pressure area on the same day.[62] The JTWC reported that the system had become a Tropical Cyclone 03B after its low-level circulation center became fully exposed within disorganized convection on the western semicircle of the storm.[3][63] The system weakened back into a low-pressure area over Bangladesh and IMD issued the last advisory.[64] The JTWC also discontinued warnings on the system around 03:00 UTC on 10 June.[65]