The India Meteorological Department on Friday declared red alert in four districts of Kerala ahead of the onset of southwest monsoon in the state within 24 hours. The districts that have been asked to remain vigilant are Thrissur, Ernakulam, Malappuram, and Kozhikode.

All four districts will experience “isolated heavy to very heavy rainfall” in the coming days. While Thrissur has been put on red alert on June 10, heavy rainfall is likely to lash the other three districts the following day.

“A low-pressure area is very likely to form over southeast and adjoining East-central Arabian Sea off Kerala-Karnataka coast around June 9,” The Indian Express quoted the weather department as saying. “It is likely to move north-northwestwards and intensify gradually. Conditions are likely to become favourable for advance of southwest monsoon into some parts of Northeastern states during next 48 hours.”

On Thursday evening, the Kerala State Disaster Management Authority had issued an orange alert in Kollam, Alappuzha, Ernakulam and Thiruvanathapuram district for June 10. The agency had said there was a possibility of heavy to very heavy rainfall, between 115 mm to 204.5 mm, in these places.

Meanwhile, the weather department said heat wave conditions would prevail in parts of the country, including Delhi, Uttar Pradesh, Haryana, Rajasthan, and Madhya Pradesh till the arrival of the monsoon.