The southwest monsoon hit the coast of Kerala on June 8. (File photo)

Red alert issued in Kerala from today has been extended till Monday amid the possibility of extremely heavy rainfall, the Indian Meteorological Department said. The southwest monsoon is set to intensify in the coming days, with the weather department predicting "very heavy rain".

Red alert, a warning to take preventive measures, has been issued in Idduki district till June 20, in Pathanamthitta and Kottayam on June 19 and Ernakulam on June 20. District Collectors have been alerted to not leave their districts.

Sea conditions are forecast to be 'rough to very rough' with wind speed reaching 40-50 kmph. "Fishermen are advised not to venture into these areas," the Met department said in a statement. These conditions are likely to prevail till June 22. The districts are likely to receive extremely heavy rainfall upwards of 20 cm, a Met Department official was quoted as saying by news agency PTI.

The southwest monsoon hit the coast of Kerala on June 8 -- a week later than expected - marking the beginning of the four-month rainfall season in the country.

Last year, Kerala had a severe monsoon season, with the worst floods of almost a century that devastated the state and left over 400 people dead.