Doppler radar machine to be established in Puttalam in early December

By Rathindra Kuruwita

Sri Lanka receives nearly 30 percent of its annual rainfall during October and November, according to Director General of Meteorology, Athula Kumara Karunanayake, in an interview with The Island.

This period, known as the inter-monsoon season, is characterised by mostly clear mornings, with rainfall typically beginning in the evenings or at night. “Usually, rains start in central Sri Lanka and spread to coastal areas as the night progresses,” he said.

Karunanayake said a La Niña climate pattern—associated with cooler ocean surface temperatures in the central and eastern equatorial Pacific—is expected to become more active in November, bringing intensified rainfall. “Although La Niña was less active than expected in October, we anticipate it will strengthen this month, with heavy rains likely to exceed 100 millimetres,” he said. The northern, north-western, eastern, and Uva provinces are expected to be most affected, while the western province will likely see less rain.

This period also brings increased risk from depressions and cyclones forming in the Bay of Bengal, contributing to morning mist across Sri Lanka due to dust brought by winds from the Indian mainland. These conditions are expected to clear soon, giving way to more frequent rainfall. “Rains typically last between 45 to 90 minutes but are intense, often accompanied by strong winds, thunder, and lightning,” he added.

He urged caution during storms, advising people to unplug electronic devices and avoid open spaces. Special warnings were issued to farmers working near metal equipment and to fishermen at sea. “When there is thunder and lightning, unplug all electrical and electronic devices. Avoid open areas. This is also a period when farmers are actively engaged in agriculture and often work near metallic objects, which can make them vulnerable to lightning strikes. Therefore, we strongly urge farmers to remain sheltered during the rain. We have also advised fishermen at sea to avoid standing up on their boats during storms,” he said.

Karunanayake said that rain during the morning, instead of the evening, is often a result of turbulence in the Bay of Bengal. He also linked the increase in extreme weather events to climate change, highlighting the urgent need for Sri Lanka to invest in advanced technology for faster disaster prediction. “Providing landslide warnings 90 to 120 minutes ahead could drastically reduce loss of life and property,” he said.

Sri Lanka has long aimed to implement the Doppler radar technology, which significantly improves weather forecasting accuracy. Japan has agreed to provide one Doppler radar machine as a grant, with installation scheduled to begin in Puttalam in early December. However, the radar is expected to become operational only by July 2027 due to extensive setup requirements. Japan is investing nearly three billion yen in this project.

Karunanayake has also initiated discussions to secure a second Doppler radar to achieve nationwide coverage. He recently submitted a request to the Japan International Cooperation Agency (JICA) office in Colombo, which will forward it to their Tokyo headquarters. If successful, this could lead to a government-to-government agreement providing Sri Lanka with an additional radar.

Doppler radar technology offers comprehensive meteorological capabilities, enabling detection of various types of precipitation, thunderstorm rotation, airborne debris, and wind dynamics. Once operational, it will allow Sri Lankan authorities to predict rainfall volumes up to two hours in advance, enhancing early warning capabilities for the National Building Research Organisation (NBRO). “The radar in Puttalam will cover half the country, but a second one in Pottuvil is essential for full island-wide coverage,” Karunanayake said.