Yesterday’s (Friday) depression intensified into a deep depression and lay centred at midnight last night over the South-West Bay of Bengal at 310 km North-East of Trincomalee (Sri Lanka) as it got closer to the Tamil Nadu coast in India at 300 km East-South-East of Nagapattinam; 320 km East-South-East of Puducherry and about 390 km South-East of Chennai.
India Meteorological Department (IMD) said in an update this (Saturday) morning that the sytem, which is only a gust away from being a cyclone, will likely shift track towards West-South-West and move towards the North Tamil Nadu coast through tomorrow (Sunday).
Five March cyclones, says Skymet
Meanwhile, private forecaster Skymet Weather gave a different perspective saying cyclonic storms can theoretically form during the latter half of March though the probability is very less. There have been only five cyclones during March between 1900 and 2021 and none of them managed to make a landfall.
GP Sharma, President, Meteorology and Climate Change, Skymet Weather, told BusinessLine that he suspects a sixth storm, the first of this year and the earliest ever of March, may have materialised over the South-West Bay as inferred from evolving features of Friday’s deep depression and guidance from global forecast models.
‘Favourable conditions’
“It is still in the open waters and enjoys favourable conditions including elevated sea-surface temperatures (SSTs) though slightly lower towards the Tamil Nadu coast. The wind shear values also continue to be moderate. Extended stay for the next 24 to 36 hours may be sufficient for the system engine to rev up as it feeds on moisture and helps the parent system make grade, if it has not already,” he said.
Sharma also hinted at the odds of the likely storm sparing the Tamil Nadu coast from a direct impact although the northern parts of the coast could receive heavy rain or thundershowers during the next couple of days. He saw the system weakening from entrainment of continental dry air and weakening over the seawaters itself. But how this would actually pan out would bear constant watching and validation.
None over Arabian Sea basin
Skymet Weather earlier said all March cyclones have so far formed in the Bay or the adjoining Indian Ocean and none in the Arabian Sea. The warm waters in the Bay make conditions conducive for cyclogenesis. On the other hand, the Arabian Sea typically features colder sea temperatures during this time of the year.
Out of the five cyclones that Skymet recalls, the closest and strongest was in 1925 around mid-March, which struck somewhere between Sri Lanka and Tamil Nadu.
The most recent was in the year 2000, which also has been the only cyclone of the 21st century so far. It had appeared over the South Bay as a feeble system around March 27 but went on to become a cyclone in the subsequent three days, attaining speed of up to 85 km/hr but recurving away from the Tamil Nadu coast. It however lost steam before hitting any coastline as approaching landmass led to increased wind shear.
Rough sea conditions
Meanwhile, the IMD said high winds from the deep depression will make sea conditions ‘very rough’ (wave heights of 13-20 ft) over the South-West and adjoining West-Central Bay of Bengal, Gulf of Mannar, the Comorin area, along and off Tamil Nadu, Puducherry and South Andhra Pradesh coasts until Monday.
Fishermen are advised not to venture into the South-West and adjoining West-Central Bay; adjoining Equatorial Indian Ocean, the Gulf of Mannar, the Comorin area, along and off the Tamil Nadu, Puducherry and South Andhra Pradesh coasts till Monday.