Low Pressure Area Over Bay Of Bengal, Prolonged Weather Activity Over Northeast India

The low-pressure area over the Bay of Bengal (BoB) became well-marked and is lying over West Central and adjoining Southwest BoB. The cyclonic circulation is extending up to mid-tropospheric levels. The well-marked low pressure will move northward and shift to West-Central BoB in the next 12 hours. Later, the system will steer more of northward and weaken, as well, over the sea itself, after about 24 hours. The remnant of the low pressure will remain over the central and northern parts of the BoB for subsequent 48-72 hours. Positioning of this weakened system will enhance the rainfall activity over Northeast India.

There is an east-west-oriented trough likely along the Indo-Gangetic plains across Uttar Pradesh, Bihar, and North Bengal. The remnant of low pressure will fuel moist southerly winds over Bangladesh and Northeast India. A semi-permanent cyclonic circulation is likely, in the lower levels, persisting for one week over eastern parts of Bangladesh and adjoining Assam & Meghalaya region. Under the combined influence of these systems, pre-monsoon activity will trigger over the entire northeastern region and spill over to West Bengal, across Bangladesh.

An uptick in the weather activity is likely to commence over northeastern states from 10th April onwards. The state of West Bengal will also get trapped in the pre-monsoon thunderstorm activity, starting 11th April. Active pre-monsoon conditions will prevail for nearly one week, until 17th April. Fairly widespread rain and thunderstorms, moderate to intense in nature, are likely over large areas of West Bengal and Northeast India. Gangetic West Bengal will have the risk of severe thunderstorms at a few stations. These places will include the capital city Kolkata, Midnapur, Howrah, Hooghly, Contai, Diamond Harbor, Digha, Kharagpur, Jhargram, Kalaikunda, Panagarh, Bardhaman and Bankura. The weather activity may as well extend to North Bengal and hilly areas of Sub-Himalayan West Bengal, as well. Some of these stations will have to watch out for severe thunderstorms, locally called ‘Kal-Baishakhi,’ invariably accompanied with severe lightning and gale-speed winds, during this period.