KOCHI/THIRUVANANTHAPURAM: The southwest monsoon is likely to set over Kerala before June, experts said while warning that the state's coastal areas and Lakshadweep are likely to experience strong winds, touching speeds of 45-55kmph over the next 24 hours.Coastal flooding is likely in low-lying areas of the state till Friday midnight due to the combined effect of the spring tides with high-swell waves, rough seas and gusty winds, the weather department said."There is a possibility of wave surge or flooding along the low-lying areas of Kerala coast between 12.30 pm on May 11 and 11.30 pm on May 12," State Emergency Operations Centre's head scientist Sekhar Kuriakose said."Normally, the onset of southwest monsoon over South Andaman Sea is by May 20. Now it is likely to be on May 15, which is early by five days as conditions are favourable. So based on that, there is a probability of early onset of monsoon in Kerala before June," S Sudevan, director of India Meteorological Department (IMD), said.Senior atmospheric scientist and former director of IMD Dr P V Joseph said he was expecting the state to receive the first monsoon shower around May 25."As of now, we can expect a normal monsoon. El Nino is expected to impact the second half of the monsoon sometime in August," he said.Weather expert C K Rajan, too, was expecting the monsoon by May 25. "We can expect a near normal monsoon, he added.Privately-owned Skymet Weather Services, meanwhile, attributed the summer showers to the trough extending from north interior Karnataka till interior Tamil Nadu . The trough has been attracting humid northwesterly winds from the Arabian Sea , leading to rain and thundershowers over most parts of Kerala till Saturday morning.Heavy rainfall was reported from Quilandy (Kozhikode) 10cm, Kannur and Aryankavu (Kollam district) 9cm each and Varkala (Thiruvananthapuram) 8 cm. While there was no large change in maximum temperature over Kerala during the past 24 hours. Palakkad recorded the highest maximum temperature of 38 degrees centigrade.During March 1 to May 10, Kerala recorded normal rains with a percentage departure of six percent, with 178.3 mm actual rainfall as against the expected normal rainfall of 189.9 mm.