The rare phenomenon of twin cyclones — Luban and Titli — occurring at the same time, over the Arabian Sea and the Bay of Bengal respectively, is happening after nearly 40 years.
The north Indian Ocean has witnessed similar weather phenomena on 23 occasions since 1891, according to a study. While it is generally feared that twin cyclones adversely influence rainfall during the northeast monsoon, the State has recorded good rainfall during most of the years when two weather disturbances developed simultaneously, notes a study by weather blogging site Chennaiyil Oru Mazhaikalam , based on the India Meteorological Department’s data. The study compiled cyclone data between 1891 and 2017. The combination of cyclone and depression in Arabian Sea and Bay of Bengal as seen now, was recorded in November 2015. However, it was in November 1977 that two cyclones had formed similar to the present trend, the study said.
In 1977, the State had recorded 71 cm of rainfall during northeast monsoon against its average of 44 cm. K. Srikanth of Chennaiyil Oru Mazhaikalam said the north Indian Ocean has been active with several such instances during the 1960s and 1970s. But, such tropical weather disturbances had reduced after 1977. “We need to study the reasons for the subdued phase in the ocean and the factors influencing it. This may impact the rainfall pattern,” he said.
Another interesting factor is that about 50% of such twin cyclones occurred when El Nino, a global weather phenomenon, was active and these cyclones took similar tracks in many instances, he added.
Weather forecast
Tamil Nadu is expected to remain largely dry except for light rains in one or two places till Friday. Chennai too may have only light rains.
According to IMD, the severe cyclonic storm ‘Titli’ is likely to intensify into a very severe cyclonic storm and cross Odisha and north Andhra Pradesh coasts between Gopalpur and Kalingapatnam by Thursday morning.
‘Luban,’ the very severe cyclonic storm over the westcentral Arabian sea is likely to move towards Yemen and South Oman Coasts by Sunday. Officials of the Meteorological department have warned fishermen not to venture into deep sea areas of westcentral Arabian sea till Sunday and Bay of Bengal till Thursday.
The onset of Northeast monsoon may occur only after the life cycle of these systems are completed.
