If Met office forecasts are any indication, several states of eastern India, including West Bengal, Bihar, Jharkhand and Odisha, will be in the grip of heatwave conditions for the next week or so.

A special bulletin issued by of India Meteorological Department (IMD) on Monday afternoon suggests that in addition to the east India states, parts of northwest India too are likely to report extremely high temperatures in the remaining days of April. In the absence of rain or thunderstorms, heatwave conditions might extend well into early May, said a senior IMD official based in New Delhi.

College girls take ice-creams to beat the heat at Sakchi in in Jamshedpur on Monday Bhola Prasad

A special bulletin issued by IMD's Regional Meteorological Centre at Alipore in Calcutta sounded a heat wave warning in southern Bengal between April 25 and 28. The bulletin said heat wave conditions are likely to prevail over the districts of South Bengal except South 24 Parganas and East Midnapore between Monday and Tuesday.

Heatwave conditions are also likely to prevail over Bankura, Purulia east and West Burdwan, West Midnapore , Jhargram and Birbhum district of south Bengal on April 27 and 28 (Wednesday and Thursday).

Pavement dwellers carry drinking water on the city street on a hot summer day in Kolkata PTI picture

According to the bulletin, similar conditions are also likely to prevail over Malda and South Dinajpur districts of North Bengal.

" A dry north-westerly wind is dominating over most parts of Bengal. Heatwave conditions prevailed over several parts of Bengal, including Calcutta, West Burdwan, West Midnapore, Birbhum, Malda and North 24-Parganas during the past 24 hours, " said G. K. Das, head of the Met centre in Alipore, Calcutta.

He said in the absence of rain and dry weather conditions, the heatwave might get extended into early May, the peak summer month.

A commuter uses an umbrella to shield herself from the sun, on a hot summer day in Lucknow PTI picture

Jharkhand is also facing its worst summer in recent years with relentless heatwave conditions across various pockets, especially north- western parts of the state covering the Palamau region, for the past two fortnights.

Monday's bulletin issued by IMD's Ranchi centre suggested that heatwave conditions would prevail in three districts of Kolhan - East Singhbhum, West Singhbhum, Seraikela- Kharsawan _ Koderma, Giridih, Garhwa, Palamau, Chatra and capital Ranchi for at least four days till Thursday.

Met data suggests that most places across Jharkhand were in the grip of extreme heat recording 42 degree Celsius and above for the last two days.The maximum temperature in most places was three to four notches above normal.

Bihar is also reeling under heatwave conditions with maximum temperatures crossing the oppressive 40°C mark at several places.

Weathermen at Patna Met office said heatwave conditions prevailed over six districts, including Patna, Buxar, Sheikhpura, West Champaran, Samastipur, and Banka, on Sunday while 14 other districts were likely to come under similar conditions in the next 72- hours. Buxar was the hottest place in the state on Sunday with the highest maximum temperature of 42.8°C.

As per a forecast issued by Patna Meteorological Centre, heatwave conditions are likely at isolated places over Buxar, Bhojpur, Kaimur, Rohtas, Jehanabad, Arwal, Aurangabad, Gaya, Patna, Nalanda, Sheikhpura, Nawada, Jamui and Banka till Wednesday.

Due to a dominating northwesterly dry air and high solar insolation, the day temperature is likely to rise further by two to three degree Celsius over several districts of interior Odisha during the next few days, said an IMD bulletin on Monday.

According to the bulletin, heatwave conditions are likely to prevail at isolated places over the districts of Angul, Khurda, Cuttack, Nayagarh, Boudh , Sonepur, Sambalpur and Bolangir till Thursday.

A pedestrian quenches his thirst on a hot summer day, at Cannaught Place in New Delhi PTI picture

“Our models are showing that Odisha, Jharkhand, east Uttar Pradesh, Chhattisgarh, Bihar will be badly impacted by the heat wave,” explained a senior scientist of the national weather forecasting centre at IMD - New Delhi. He added that a feeble western disturbance was approaching around April 28 but that it won't offer any relief.

Hence, maximum temperatures could go upto 46-47 °C over some parts of northwest India, the Palamau region of Jharkhand and some parts of south Madhya Pradesh.

In Met parlance, a heat wave is declared in areas where normal maximum temperatures are in excess of 40°C when the actual maximum temperature is between 4°C -5°C higher. A heatwave can also be declared when the actual maximum temperature remains above 45°C or more for a day irrespective of normal maximum temperatures.