THIRUVANANTHAPURAM: Disappointing all those waited for its grant entry, the south west monsoon missed its June 1 date with the state. Weak westerlies are delaying the advancement of monsoon, the northern limit of which passes through Maldives and Comorin areas. Now, the India Meteorological Department (IMD) is expecting the onset on June 4 in the state.
The IMD had predicted the onset on June 1, with a model error of +4 or -4 days. While conditions for the onset of monsoon are becoming favourable, rainfall reported in the state on Thursday was insufficient.
Only if 60 per cent of 14 stations in the state record a rainfall of 2.5 mm or more for two consecutive days, the IMD can declare the onset on the second day. According to P S Biju, scientist at IMD, the presence of northerly winds was weakening the westerly winds bringing moisture to the state. Criteria such as depth of westerlies, value of outgoing long wave radiation are becoming favourable for the onset of monsoon. However, insufficient rainfall in the state is a sign of delay in the onset.
For the past seven years, onset date was in accordance with the forecast date issued by the IMD. If the monsoon gets delayed after June 4, the IMD will fail to maintain its 7-year record. Since 2006, the onset of monsoon in the state was before June.
Kerala is considered as the gateway of monsoon. Monsoon has advanced to Andamans on May 24, four days after the predicted date.