Monsoon 98% normal: First forecast

The official weather forecasting agency, the India Meteorological Department (IMD), has estimated that average rainfall over the country in ...

The official weather forecasting agency, the India Meteorological Department (IMD), has estimated that average rainfall over the country in the 4-month monsoon season will be 98 per cent of the normal index of 88 cm. The forecast is subject to a model error of +/-5%.

Using a probabilistic model for forecast, it has also said that there is 75% probability for the monsoon to be “near normal or above normal.”

Saying so, the IMD has said it will revise this forecast by the end of June, taking into consideration two other vital factors like

El Nino (warming of the Pacific waters) and the South Indian Ocean zonal wind. Thus, the current forecast pertains to June, the first month of the monsoon season.

Story continues below this ad

Releasing the IMD’s forecast here today, Union Minister for Science and Technology Kapil Sibal said: ‘‘El Nino is an important factor influencing the Indian monsoon. Deficient rainfall in monsoon 2004 was due to suppressed rainfall activity in July, which was due to unexpected emergence of El Nino. IMD this time will watch the developments in the Pacific Ocean before making the final forecast for the remaining three months by the end of June.”

The Indian Express, on April 19, quoting forecasts of different global models said that there would be good rains in June and the fate of the monsoon in the remaining three months depended upon the development of the El Nino phenomena.

The IMD’s current forecast for June is based on the eight-parameter statistical model. ‘‘Out of the 10 predictors in the model, only two, namely Eurasian snow cover in December and wind pattern in January and February were unfound unfavourable,” said acting director-general of IMD B Lal.

Lal said that in the end of June the IMD will also come out with a forecast of rainfall in July and forecasts of rainfall in four broad homogenous regions of the country.

Story continues below this ad

The IMD said it had consulted US-based National Center for Environmental Prediction (NCEP), Indian Institute of Tropical Meteorology (IITM), Pune, Indian Institute of Science, (IISc) Bangalore, and the Space Application Centre, (SAC) Ahmedabad. IITM has predicted 100% normal monsoon, while IISc has predicted 96% normal monsoon and SAC has predicted 95% normal monsoon.