With October on the horizon, something appears ‘heating’ up in the neighbourhood Bay of Bengal of Odisha, Andhra and Andaman region. As the State had taken a hit by cyclones in two successive years of 2013 and 2014, this could be a hat-trick year provided the current disconcerting conditions in the Bay of Bengal get accentuated further by the last week of October.
According to local Met Director Sarat Sahu, right from the deadliest 1999 Super Cyclone to more recent Hudhud, sea surface temperature then had been over 27 degree Celsius. Also the depth of the warm ocean had extended much deep at least up to 50 mt. Besides, along with the presence of a disturbance with sufficient vorticity (rotation) and convergence, the wind gradient velocity was also much lower at around 2 - 8m/second.
Sample the 2015 reality check. The actual measurements in the first week of October and the predictions for the second week up to October 10, 2015 show a high degree of ‘heating’ up of Bay of Bengal, which somewhat raises the eyebrows of weather-watchers.
Significant enough is the sea surface temperature now is as high as around 31 degree C near Odisha - Andhra coast to around 30 degree C in Andaman seas. It needs to be remembered that the south-west monsoon hasn’t withdrawn from Odisha till date. But a lame-duck monsoon in its last-leg resulting in further heating up of Bay of Bengal and post-withdrawal the clear-sky coupled with hotter sun radiation would further heat up the sea much more, observed cyclone experts here. Moreover, the depth at 20 degree C (D20) isotherms observed near Andaman seas is as deep as 125 mt and it is around 50mt at Odisha - Andhra coast. Above all, the significant wind velocity by the mid-October was predicted to fall to around 2 - 8 m/s near Odisha - Andhra coast and Andaman seas respectively. But the lone factor missing this time till date is non-existence of any near-surface disturbance as observed during the 1999 Super Cyclone.
However, the latest weather forecast by the Indian Meteorological Department sounds no music to ears as it reveals the persistence of an upper-air cyclonic circulation in the east central Bay of Bengal - the womb of lethal cyclones. And weathermen describe the persisting system as an ambience conducive for formation of low pressure near Andaman seas at future date provided the above conditions remain the same. What further added to the worry is the prevalence of moist air and the resulting humidity in atmosphere now. According to Met experts, dry air inflow would only dissuade the formation of low pressure that evolves into cyclones in late October. Also, another watch out indicator is presence of thunder storm activities as late as October first week in Odisha.
A peek at the history shows Odisha being hit by cyclones in three consecutive years of 1971, 1972 and 1973.
However, experts at IMD here are keeping a watch at the developments happening in Bay of Bengal at present and they say the situation could become much clearer after the withdrawal of south west monsoon.