THIRUVANANTHAPURAM: The India Meteorological Department (IMD) has forecast that the rains will intensify in the state at least till Saturday. It has issued orange alerts indicating heavy to very heavy rainfall in Idukki, Thrissur, Malappuram and Kasaragod districts on Wednesday. Other districts, except Thiruvananthapuram and Kollam, might experience isolated heavy rainfall on the day. Though the situation is likely to improve by Thursday, the weather experts have warned of strong westerlies causing the rainfall. The northern districts and central districts of Ernakulam and Idukki experienced heavy rainfall on Tuesday.