Quantitatively, the monsoon rainfall for the country is likely to be 93% of the long period average with a model error of +/-4% and coefficient of variation of 10%. The LPA rainfall over the country for the period 1941-1990 is estimated at 89 cm. As the IMD has cautioned about a model error of +/-4%, the quantitative rainfall may slip down to 89% of the LPA - a situation which may invite grave consequences.

Earlier on April 17, this year, the IMD making an initial forecast for the South-West Monsoon had said that countrywide average cumulative rainfall in the season would be 96% with a model error of +/-5%.

The scaling down of the expectation to 93% of the LPA is significant when the monsoon system has suffered a setback and its advance over Orissa, Maharashtra and north Andhra Pradesh has been delayed by about two weeks and by about 10 days over Bihar, Chhattisgarh, Jharkhand, south Madhya Pradesh and south Gujarat. As a result in the first month of the season till June 22, the average cumulative rainfall over the country is less by 52%, that over northwest India is less by 41%, that over central India is less by 75%, that over southern peninsula is less by 23% and that over northeast India is less by 53%.

According to area categorisation, northwest India consists of Jammu and Kashmir, Himachal Pradesh, Punjab, Rajasthan, Haryana, Chandigarh, Delhi, Uttaranchal and Uttar Pradesh. Northeast India consists of Arunachal Pradesh, Meghalaya, Assam, Nagaland, Manipur, Mizoram, Tripura, Sikkim, West Bengal, Bihar and Jharkhand. Central India consists of Gujarat, Madhya Pradesh, Chhattisgarh, Maharashtra, Goa and Orissa. Southern peninsula consists of Andhra Pradesh, Karnataka, Tamil Nadu, Kerala, Lakshadweep and Andaman and Nicobar Islands.

The rainfall over northwest India, which is the granary of country, is likely to be 81% of its LPA (61.2 cm) with a model error of 8% - this means the rainfall here may slip down to 73%. The coefficient of variation in this region is 19%. However, IMD's forecast of rainfall over central India raises some hope. It has said that the rainfall over this region would be 99% of its LPA (99.4 cm) with a model error of +/-8% and coefficient of variation of 14%.

The rainfall over northeast India is likely to be 92% of its LPA (142.9 cm) with a model error of +/-8% and coefficient of variation of 8%. The rainfall over southern peninsula would be 93% of its LPA (72.5 cm) with a model error of 8% and coefficient of variation of 15%.

The IMD has predicted that the countrywide rainfall in July, this year would be 93% of its LPA (29.3cm) subject to a model error of +/-9% and coefficient of variation of 13%. In August it would be 101% of its LPA (26.2 cm) with a model error of +/-9% and coefficient of variation of 14%.

The IMD while making its forecast has taken inputs from several global agencies. The latest observations and forecasts from both dynamical and statistical models suggest high probability (about 60%) for El Nino conditions to appear during the monsoon season. El Nino phenomena is the warming of the Pacific waters above the normal range which causes drought in many parts of the globe. The probability for neutral conditions prevailing over Pacific is about 40% and that for La Nina conditions (cooling of Pacific waters below normal) is negligible. La Nina causes excess rains.

Finally, the analysis of the forecast data shows some parts of the country may experience acute water stress condition or drought. The situation look critical for northwest India, particularly Punjab and Haryana - the granary of the country.

The secretary in the Union ministry for earth sciences, Dr Sailesh Nayak said that IMD and Indian Institute of Tropical Meteorology have planned experiments on cloud seeding and find out which type of clouds can cause rainfall in the process. This project would come out with concrete results within two years. But two years would be a long wait. It is time that government come out with appropriate contingency plans to deal with the current situation.