Heatwave conditions are likely to persist in large parts of Bengal for the next three days, the regional Met office in Calcutta said.

While the mercury is likely to hover around the 40 degree Celsius mark, relative humidity in the atmosphere is expected to decrease, enhancing dry heat conditions in Calcutta and in other parts of the state, it was learnt.

As an indirect impact of the severe cyclonic storm Mocha, which is brewing over the Bay of Bengal and which the Met office has predicted to skip the Indian coast while moving towards the Bangladesh-Myanmar border, the Met office has forecasted thundershowers in some coastal south Bengal districts like North and South 24 Parganas as well as East Midnapore on Saturday and Sunday.

While almost all south Bengal districts would remain under the grips of a heat wave till Friday, north Bengal districts like Malda, Uttar and Dakshin Dinajpur would also experience similar weather conditions. The decrease in humidity caused by its movement towards the sea under influence of the cyclonic formation is being replaced by the moving hot air from the north west causing the heat wave to persist, Met officials explained.

Suri in Birbhum recorded the highest maximum temperature in the state on Wednesday at 43.4 degrees followed closely by Bankura at 43.3. The maximum temperature of Darjeeling was recorded to be 24.2 degree Celsius.