Thiruvananthapuram: Kerala is likely to receive rain at isolated places across the state till Monday, October 20, according to the India Meteorological Department (IMD). The agency has issued a yellow alert for multiple districts, warning of heavy rainfall ranging from 7 cm to 11 cm in 24 hours.

Thunderstorms with lightning and gusty winds reaching speeds of 30–40 kmph are also expected at one or two places until October 18. Fishermen have been advised not to venture into the sea during this period.

Meanwhile, the IMD said the southwest monsoon has been weak over Kerala, with rain reported at isolated locations on Tuesday. Conditions are favourable for its withdrawal from the remaining parts of the country within the next two days, coinciding with the likely onset of the northeast monsoon over the southeast peninsular region.

An upper air cyclonic circulation currently lies over the southwest Bay of Bengal and adjoining equatorial Indian Ocean, which may move west-northwestwards towards the Comorin area. Under its influence, a low-pressure area is likely to form over the southeast Arabian Sea and adjoining Lakshadweep region around October 19.

District-wise yellow alert

• October 15: Thiruvananthapuram, Kollam, Pathanamthitta, Kottayam, Ernakulam, Idukki
• October 16: Thiruvananthapuram, Kollam, Pathanamthitta, Alappuzha, Kottayam, Ernakulam, Idukki, Thrissur
• October 17: Thiruvananthapuram, Kollam, Pathanamthitta, Alappuzha, Kottayam, Ernakulam, Idukki, Thrissur
• October 18: Pathanamthitta, Idukki, Thrissur, Palakkad, Malappuram, Wayanad

Swell surge warning
A swell surge alert has been issued for the coasts of Thiruvananthapuram and Kollam. Swell waves between 1.0–1.1 metres high with a period of 18–19.5 seconds are expected till 11.30 pm on October 15.

Fishermen and coastal residents have been advised to exercise utmost caution, as there is a possibility of wave surges. Boating and recreational activities should be undertaken with due care, the IMD warned.