The sudden change in the weather is being attributed to an upper air cyclonic circulation over Southeast Bay of Bengal and adjoining Southwest Bay of Bengal, which is extending up to 5.8 km above mean sea level
More than 170 flood warnings remained in place early Monday, mostly across northern England and along the southern coast.
The orange alert is the second-highest level of alert second only to Red alert which, if issued, would entail closing of schools and restriction on movements in airbases.
The India Meteorological Department (IMD) has forecast heavy to very heavy rainfall at isolated places in Uttarakhand including the Kumaun region, which has been put on orange alert.
Thrissur, Palakkad, Wayanad, Kannur and Kasaragod were issued 'Orange Alerts' for today. In addition, all schools and colleges in Malappuram and Wayanad districts will remain closed.