Kolkata, Aug 8 (PTI) The Met department forecast heavy rainfall over the Gangetic West Bengal till Thursday owing to low pressure over northwest Bay of Bengal, which is likely to intensify into a depression.While the coastal districts are likely to receive heavy rains, the interior places in southern West Bengal are likely to get thunderstorms with lightning and gusty wind, the Met said.A well-marked low pressure in northwest Bay of Bengal, which is likely to concentrate into a depression by Tuesday, is likely to bring in its wake heavy rain, with the intensity being higher in the coastal districts of the state till Thursday, the Met said.The weather officer said heavy rainfall is likely in South 24 Parganas, North 24 Parganas, Purba Medinipur and Paschim Medinipur, during the period.Gangetic West Bengal has suffered 46 per cent rainfall deficiency during this monsoon since June 1, according to Met department data. PTI AMR SBN SOM SOM