This document released by India Meteorological Department (IMD) every year sheds light on the operational forecast for the south-west monsoon. Through an in-house research the operational forecast are issued in two stages:

1. Long range forecast for all India rainfall issued in April.
2. Forecast update issued in June.

With a brief description of the two statistical models used by IMD for preparing quantitative and probabilistic forecast of the south-west monsoon the document then lists five predictors for April forecast used by IMD’s Ensemble Statistical Forecasting system. The five parameters are also used to prepare probability forecast for five pre-defined rainfall categories.

In the next level the document discusses about Ministry of Earth Science’s recently initiated Monsoon Mission programme that aims to improve monsoon forecast over the country from short range to long range. For this purpose the Indian Institute of Tropical Meteorology (IITM), Pune is made responsible for implementing the dynamical model framework for long range forecasts and also to coordinate research work to improve long range forecasts that uses dynamical models.

Further the document also draws attention towards the emerging partnership between IITM with various national and international institutions to improve the skill of the Coupled Forecasting Systems model for more accurate long range forecasts of monsoon rainfall. IMD is also taking into account the experimental forecasts prepared by several national institutions.

The last section of the document lists the long range forecast for the 2012 south-west monsoon.

Click below to download the document.