The satellite image shows cyclone ‘Ditwah’ moving north-northwest after passing Sri Lanka, heading toward India. (Image: @WeatherMonitors/X)

Cyclone ‘Ditwah’, formed from a deep depression near the Sri Lanka coast, has begun moving towards the north Tamil Nadu, Puducherry and south Andhra coasts.

According to Chennai’s Regional Meteorological Centre (RMC) Director B Amudha, strong winds, heavy rain and dangerous sea conditions are expected over the next few days.

The RMC has issued a red alert in some Cauvery delta districts and an orange alert in five districts — Chennai, Tiruvallur, Kancheepuram, Ranipet and Chengalpattu for November 29 and 30. Thanjavur, Tiruvarur, Nagapattinam and Mayiladuthurai are the delta districts that have been issued a red alert.

A red alert indicates an extremely heavy rain of over 20 cm in 24 hours, while an orange alert means very heavy rain of 11 cm to 20 cm.

Amudha said ‘Ditwah’ is currently classified as a cyclonic storm and is not expected to become a severe cyclone at this time. She said gale winds near the storm centre could reach 60 to 80 kmph, with gusts up to 90 kmph, while outer bands may see winds of 35 to 45 kmph, gusting to 55 kmph. Similar winds are expected over parts of the Arabian Sea near Kerala, Lakshadweep, and Maldives.

WHAT IS THE MEANING OF THE NAME ‘DITWAH’?

Amudha said the name, ‘Ditwah’, referring to the lagoon, was suggested by Yemen. It is likely named after Detwah Lagoon, a large, saline lagoon on the northwest coast of the island of Socotra in Yemen.

The systematic naming of tropical cyclones is a crucial component of disaster management and warning systems worldwide. This international practice, formalised by bodies such as the World Meteorological Organization (WMO) and the UN ESCAP Panel on Tropical Cyclones, helps in the quick identification of storms in warning messages, enhances media reporting, and significantly increases community preparedness.

For the North Indian Ocean, the Regional Specialised Meteorological Centre (RSMC) in New Delhi is responsible for naming a system once its maximum wind speed attains a threshold of 62 kmph. A name is chosen sequentially from a pre-approved consolidated list contributed by the 13 member countries of the WMO/ESCAP Panel, including India, Pakistan, Sri Lanka, and Yemen.

These names must adhere to strict criteria, being neutral to politics, religion, culture, and gender; they must be short (maximum eight letters), easy to pronounce, and cannot be reused.

WHAT IS THE CYCLONE’S LATEST POSITION AND PATH?

The India Meteorological Department (IMD) said the deep depression over the Southwest Bay of Bengal intensified into the cyclonic storm ‘Ditwah’.

As of 11.30 am on Thursday, the system had moved north-northwestwards at a speed of 15 kmph during the preceding six hours. The cyclone’s current position places it close east of Pottuvil in Sri Lanka, approximately 90 km south-southeast of Batticaloa in Sri Lanka, and 700 km south-southeast of Chennai.

The IMD has forecast that the system will reach the southwest Bay of Bengal off the coasts of North Tamil Nadu, Puducherry, and adjoining south Andhra Pradesh early on November 30 (around 3 am). While an exact place of landfall is yet to be determined, the system is expected to intensify further as it approaches the coastline.

WHAT IS ITS EXPECTED IMPACT?

The intensifying cyclonic storm poses a significant threat to south India, prompting warnings for heavy rainfall, strong winds, and hazardous sea conditions.

Andhra Pradesh and Rayalaseema: Coastal districts of Andhra Pradesh are likely to see heavy rain and strong winds. Heavy to very heavy rain is expected in districts such as Chittoor, Nellore, Prakasam, YSR Kadapa, Annamayya, and Sri Sathya Sai for two days starting November 29. On November 30, both South Coastal Andhra Pradesh and Rayalaseema are forecast to receive heavy to very heavy rain at a few places and extremely heavy rain at isolated places.

Tamil Nadu and Puducherry: An orange alert has been issued for Chennai and other coastal districts of Tamil Nadu for November 29 and 30. Heavy to very heavy rain and isolated extremely heavy rain are likely over numerous districts, including Tiruvarur, Nagapattinam, Mayiladuthurai, Cuddalore, Villuppuram, and Chennai, particularly on November 29. Coastal areas of Tamil Nadu, Puducherry, and Karaikal are expected to experience strong surface winds with speeds of 35 to 45 kmph.

In response to the deteriorating conditions, district administrations in Andhra Pradesh are establishing control rooms and issuing alerts. Fishermen have been strongly advised not to venture into the southwest and adjoining west-central Bay of Bengal, the Gulf of Mannar, and the Comorin area until December 1.