Roanu will delay southwest monsoon: Experts

Visakhapatnam: Although cyclone Roanu brought the much-needed respite to the people of Andhra Pradesh, experts in the field of meteorology said the occurence would delay the onset of the southwest monsoon right from Kerala this year.
Prof KVSR Prasad, head of the department of meteorology and oceanography, Andhra University, said cyclone Roanu completely used up the energy that is required for the onset of monsoon as well as the moisture content right from its origin over the sea near Sri Lanka."We can't say by how many days the onset would be delayed, but this we can ascertain that the monsoon will definitely be delayed across the country right from Kerala," he added. Because the cyclone pulled away all the moisture content, parts of the state including Vizag began receiving warm winds on Saturday, Prasad said.
Meanwhile, Prof CV Naidu of the same department who has specialised in monsoon dynamics said the monsoon if Roanu crossed or made landfall along the Andhra coast without moving towards Bangladesh, the monsoon will not be delayed.
Explaining his reasoning, Prof Naidu said, "Monsoon requires strong south-westerly winds in the lower level and easterly winds in the upper level. If cyclone Roanu made landfall along the Andhra coast, the south-westerly winds could have been well established by this time. It didn't happen because of the existence of weak south-westerly and easterly winds over the Andhra coast. As a result, Roanu changed it path near Machilipatnam coast and moved in the upward direction."
"The re-curving of the cyclone from Andhra coast is a clear indication of the existence of weak easterly winds in the upper level and south-westerly in the lower level. The upper level winds should be established minimum 12 kilometres away from the mean sea level," Naidu told TOI.
Meanwhile, officials of the India Meteorological Department (IMD) said cyclones and depressions not only make an impact on the onset of monsoon, but also the withdrawal of the rainy season. However, according to them, the southwest monsoon is scheduled to make onset in both Andhra Pradesh and Telangana between June 8 and 12 and withdraw on October 15.