New Delhi, Aug 25 : Widespread rainfall activity with isolated heavy to very heavy falls are very likely to continue over northeast India, sub-Himalayan West Bengal and Sikkim till August 27 and reduce thereafter with isolated heavy rainfall over the region, the IMD said. Isolated extremely heavy falls also likely over Assam and Meghalaya on Wednesday, India Meteorological Department (IMD) said in a release here. Fairly widespread to widespread rainfall activity with isolated heavy falls are very likely to continue over Bihar, east Uttar Pradesh, and Uttarakhand till August 27. Scattered to fairly widespread rainfall activity with isolated heavy falls over Tamil Nadu during next 5 days and over Kerala and Mahe on August 26 and 28. Thunderstorms, accompanied with lightning, are likely over east India during next three days, the IMD said, while subdued rainfall activity is likely to continue over northwest and central India and west coast during next 5 days. /IANS