NEW DELHI: The searing heatwave sweeping large parts of east India has spread to southern parts of the country on Tuesday, sending the maximum temperature to two to seven degrees Celsius above normal in parts of Tamil Nadu, Andhra Pradesh, Odisha and Gangetic West Bengal, the India Meteorological Department (IMD) said.
In Tamil Nadu, Salem recorded 42.3 degrees Celsius while it was 42 degrees Celsius in Erode on Tuesday.
In a statement, the IMD said heatwave to severe heatwave conditions are expected in east India and south peninsular India during the next five days. Heatwave to severe heatwave conditions are expected in parts of Tamil Nadu, Karnataka, Telangana, Odisha, Bihar, West Bengal, Sikkim, Uttar Pradesh and Jharkhand during this period.
This would be made worse by high humidity in Tamil Nadu, Puducherry, coastal Andhra Pradesh, Karnataka, Goa, Kerala, Assam, Meghalaya, Tripura and Bihar, it added.
Increasing nighttime heat is even more common in cities because of the urban heat island effect, in which metro areas are significantly hotter than their surroundings.
The threshold for a heatwave is met when the maximum temperature of a weather station reaches at least 40 degrees Celsius in the plains, 37 degrees in the coastal areas and 30 degrees in the hilly regions, and the departure from normal is at least 4.5 notches. A severe heatwave is declared if the departure from normal temperature exceeds 6.4 notches.
The Met Office has said four to eight heatwave days are expected in different parts of the country in April against a normal of one to three days. Ten to 20 days of heatwave days are expected against a normal of four to eight in the entire April-June period.
The areas and regions predicted to witness a higher number of heatwave days are Madhya Pradesh, Gujarat, Odisha, Andhra Pradesh, Madhya Maharashtra, Vidarbha, Marathwada, Bihar and Jharkhand. Some places may record more than 20 heatwave days.