Monsoon seasonal rainfall to be above normal: IMD

"The monsoon seasonal rainfall during the forthcoming monsoon is likely to be 106% of the Long Period Average (LPA) with a model error of ± 5%," read an official statement.

The LPA of the seasonal rainfall over the country as a whole for the period 1951-2000 is 89 cm.  The India Meteorological Department (IMD) released the long range forecast for the 2016 southwest monsoon season rainfall this evening.

The Indian Institute of Tropical Meteorology (IITM), Pune, Ministry of Earth Sciences, has been coordinating and working along with different climate research centers from India and abroad on the development of a coupled model for the forecasting of Indian summer monsoon rainfall under the Monsoon Mission project.

The latest high resolution research version of the Coupled Forecasting System (CFS) originally developed by the National Centers for Environmental Prediction (NCEP), USA has been used to generate experimental forecast for the 2016 southwest Monsoon season rainfall using the February initial conditions.

This experimental forecast based on the Monsoon Mission coupled dynamical model suggests that the monsoon rainfall during the 2016 monsoon season (June to September) averaged over the country as a whole is likely to be 111% ± 5% of long period model average (LPMA).

The India Meteorological Department (IMD) issues various monthly and seasonal operational forecasts for rainfall during the southwest monsoon season.  Operational forecasts for the southwest monsoon season (June – September) rainfall are issued in two stages. The first stage forecast is issued in April and the second stage forecast is issued in June.

"The El Nino conditions over equatorial Pacific Ocean that established in April, 2015 reached to strong condition in July and peaked in December, 2015. Thereafter, the El Nino conditions started weakening even though Sea Surface Temperatures over the Pacific Ocean are still above normal.  The atmospheric conditions over the Pacific also reflect patterns consistent with the El Niño conditions.  Analysis of previous data suggests that monsoon season rainfall over the country as a whole was deficient or below normal (<96% of LPA) during 65% of the El Nino years," the statement said.

"However, during 71% of the years followed by El Nino years, monsoon was normal and above (≥96 % of LPA). The latest forecast from the Monsoon Mission Coupled Climate Model indicates that El Nino conditions to weaken to moderate to weak levels during the first half of the monsoon season and ENSO neutral conditions likely to get established thereafter," read an official statement.

At present, neutral Indian Ocean Dipole (IOD) conditions are prevailing over the Indian Ocean. The latest forecast from the Monsoon Mission Coupled Climate Model indicates positive IOD conditions are likely to establish during the middle of the monsoon season and weaken to neutral conditions thereafter.