Patna: This summer could be cooler than last year, according to the Met department.

The India Meteorological Department (IMD), in its seasonal outlook forecast, has predicted that the eastern, east-central and southern parts of the country are likely to experience slightly below-normal maximum temperatures from April to June - the summer season. A Met scientist said the unusual weather conditions are because of global warming.

"Seasonal monthly mean temperature would be below normal," said Anand Shankar, a scientist in the Patna Met office. "The moisture incursion and sub-humid wave blowing from the Bay of Bengal would prevail during the period. That will allow the easterly winds to hit the eastern region more leading to development of thunderstorms at the end of this month.

"The weather forecast expects 30-35 degrees Celsius temperature in Bihar till Thursday and there is a possibility of slight increase in the mercury column in the successive weeks. Thunderstorms are also likely in the last week of April because of moisture incursion created by low pressure on land," added Shankar.

Normal heat wave conditions are likely to prevail in the core heat wave zone during summer in Bihar, Punjab, Himachal, Uttarakhand, Delhi, Haryana, Rajasthan, Uttar Pradesh, Gujarat, Madhya Pradesh, Chhattisgarh, Jharkhand, Bengal, Odisha and Telangana. "There are less chances of heat wave conditions during April in Bihar. It can be experienced in May and June when the temperatures will rise," said Shankar.

An IMD report has also warned about thunderstorm, accompanied with squall, in isolated parts of Bihar, Jharkhand, the Gangetic Bengal and north coastal Andhra Pradesh. "The prevailing conditions are forming because of moisture incursion from the Bay of Bengal. It is also combined with a hit of easterly winds in the eastern region and low land pressure," said Shankar. "We are witnessing changes in the weather conditions compared to previous years because of global warming and anthropogenic factors."