The India Meteorological Department on Wednesday said that isolated, extremely heavy rainfall is very likely over West Bengal, Sikkim, Assam, and Meghalaya during the next two days. It also predicted exceptionally heavy rainfall over Sub-Himalayan West Bengal and Sikkim on Thursday. India Weather Forecast: IMD Predicts Extremely Heavy Rainfall Over West Bengal, Sikkim, Assam, Meghalaya in Next Two Days.