India Meteorological Department on Thursday announced that the coming monsoon is ``mostly likely’’ to be normal, with a rainfall of 99 per cent of the long period average [LPA], with a model error of plus or minus five per cent.
The forecast also noted that there was a 47 per cent probability of the rainfall to be between 96 percent and 104 per cent, 24 per cent probability for it to be between 90-96 per cent, 17 per cent probability for between 104 to 110 per cent, eight per cent probability for being below 90 per cent and four per cent probability for above 110 per cent of the LPA.
In other words, rainfall was likely to be between 94 per cent and 104 per cent of the LPA, with a greater possibility for it to be near the lower end of the band than the upper end.
A press release issued at the briefing noted that recent forecasts from international and national agencies indicated that there was a probability for emergence of a weak El Nino conditions during the later part of the season and the development of a weak negative Indian Ocean Dipole event during the second half of the year.
If these came true, they could have an adverse impact on the rainfall at the tail end of the season.
The forecasts come close on the heels of a conference of national and international weather experts organised by IMD under the aegis of the World Meteorological Organisation at Pune on April 19 and 20.
A statement issued at the end of the meet, which looked at the likely monsoon scenario for the south Asia region had also predicted that the rainfall during the season was most likely to be within the normal range, but that there was a ``slight tendency’’ for it to be below normal.
The statement also noted that in terms of spatial distribution of rainfall, there was likelihood for below normal rainfall over some areas of north-western and southern parts of South Asia, while being close to the long-period average over the remaining parts.
Secretary, Ministry of Earth Sciences, Shailesh Nayak, declined to comment on the forecast made by the experts at the meet with regards to the possibility of below normal rainfall in south and northwest parts of the region, which corresponds to Tamil Nadu and other parts of southern peninsular region and Rajasthan and other parts of northwest India, apart from Sri Lanka and some parts of Pakistan.
``It was a climate forecast for the South Asian region as a whole. The forecast we are making now is for India’’.
He also noted that the forecast made now was for the nation as a whole and that forecast for different regions of the country would be made later in June along with an update for the all-India rainfall forecast and month-wise forecasts for July and August.
``With the data available at the moment, only a long term forecast for the country in its entirety and a season as a whole can be made now. One would have to wait till June middle to make region-wise forecasts’’.
The IMD press release noted that the forecast was being made following a detailed analysis of the various global parameters that are considered to have an influence on Indian monsoon including sea surface temperatures over the Pacific Ocean and snow cover over Eurasia.
It has also taken into account forecasts made by international institutions including the WMO’s Lead Centre for Long Range Forecast- Multi-Model Ensemble, the United State’s National Centres for Environmental Prediction, UK’s Meteorological office, European Centre for Medium Range Weather Forecasts, Japan Meteorological Agency, and Asian-Pacific Economic Cooperation Climate Centre at Korea as also national institutions such as Space Applications Centre, Ahmedabad, Indian Institute of Tropical Meteorology, Pune and CSIR’s Centre for Mathematical Modelling and Computer Simulation, Bangalore.
The heading has been corrected for a typo error