Monsoon shows early signs of withdrawal in Rajasthan

NEW DELHI: Some signs of monsoon withdrawal have started to appear in parts of Rajasthan but meteorologists at the weather office believe it may take some more days before all conditions to declare the start of the end of this year’s rainy season to develop.

"Some parameters of monsoon withdrawal are yet to take place for us to say that the withdrawal has happened from Rajasthan," said KJ Ramesh, director general of the India Meteorological Department ( IMD). "We are closely monitoring the situation and will be issuing a release as soon as it happens," he said.

BP Yadav, head of National Weather Forecasting Centre of IMD, said, "Over the next five days we don’t see the withdrawal taking place. We are watching if there is any development in the weather."


Official criteria for declaring monsoon withdrawal include: cessation of rainfall activity over a particular area for continuous five days; establishment of anticyclone in the lower troposphere and below; and, considerable reduction in moisture content.

While dry weather conditions are prevailing in western part of the desert state, meteorologists are waiting for the wind pattern to change to north westerly and moisture levels to reduce further, Yadav said.

Weathermen said wind pattern in the area is still south westerly. "The establishment of anticyclone over central Pakistan and adjoining Rajasthan has not come. Once, it’s there it will change the wind pattern." said a meteorologist who requested not to be named.

Anticyclone is a weather system where air slowly circulates in a clockwise (northern hemisphere) or anticlockwise (southern hemisphere) direction. Anticyclones are associated with calm weather.

The normal date for withdrawal of the monsoon from west Rajasthan is September 1. India receives 70% of its annual rains during the four-month monsoon season, which lasts till the end of September. In 2015, the retreat of monsoon started on September 4.

Rainfall from June 1to September 5 was 3% below average. The IMD is retaining its forecast that rainfall will be 6% above the long-period average, following two successive years of deficit monsoons.

For the four days to September 10, the weather office has forecasted heavy rain at a few places in east and northeast India, including West Bengal, Sikkim and Bihar. For the subsequent two days, it expects rains in few places over west Himalayan region and central India.

It also forecast rains at most places over northeast, east and few places in south and west coast.

Over the past several years, the monsoon has lingered on in northern India until the last week of September. By mid-October, the monsoon withdraws completely from the northern half of the peninsula.

The retreat of the southwest monsoon coincides with the onset of the northeast monsoon (October-December) covering southern India. The southwest monsoon reached Kerala coast on June 8 this year and covered the country by July 13.

India receives an average 890 mm of rainfall from June-September period, which is pivotal for the country’s rural economy. Monsoon rain is vital for India as 55% of the arable land depends entirely on rain for irrigation. While agriculture accounts for about 15% of the economy, the monsoon has a wider impact because it affects millions of people in villages and weak rainfall can lead to a spurt in food prices.