The official weather forecasting agency, India Meteorological Department (IMD) has predicted that the South-West Monsoon may arrive at the Kerala coast on May 29, which is three days earlier than the scheduled date. The forecast is subjected to a model error of +/- 4 days
With the strengthening of monsoon winds and widespread rainfall activity, the South-West Monsoon advanced into southeast Bay of Bengal and Andaman & Nicobar Islands on May 12, almost eight days in advance. The monsoon system usually advances by its two wings ? the eastern wing which advances over Bay of Bengal and the western wing which advances over the Arabian Sea.
Quoting the forecasts of global agencies, Center for Ocean Land Atmosphere Studies (COLA), International Research Institute for Climate Studies and Policy (IRI) and the European Centre for Medium Range Weather Forecast, FE on May 13 had said that the South-West Monsoon may arrive at the Kerala coast about five to seven days earlier.
The IMD while making its present forecast has taken into consideration six predictors ? minimum temperature over north-west India, pre-monsoon rainfall peak over southern peninsula, outgoing long wave radiation over south China Sea, lower tropospheric zonal wind over southeast Indian Ocean, upper tropospheric zonal wind over the east equatorial Indian Ocean and outgoing long wave radiation over south-west Pacific region.
The IMD, in its initial forecast made on April 16, this year had said that average cumulative rainfall over the country in the four-month monsoon season would be 99% of the long period average of 89 cm. This forecast is subjected to a model error of +/-5 %.
