Monsoon remains shaky as ‘trough’ vanishes

03 Aug 2009

While there was some revival of the monsoon in the last week of July, rain continues be scanty in several states. The monsoon was subdued over Uttar Pradesh, Uttarakhand, Haryana, Punjab, Jammu and Kashmir, Rajasthan, Madhya Pradesh, Gujarat, central Maharashtra, Marathwada, Vidarbha, Chhattisgarh, coastal Andhra Pradesh and north interior Karnataka during the 24 hours ending Sunday morning.

The woes are compounded by the fact that the anticipated low-pressure area in the Bay of Bengal has once again failed to materialise. The India Meteorological Department and the European Centre for Medium-Range Weather Forecasts had maintained their outlook for the trough, which would have brought rain to much of central and northern India, until only two days ago.

In its update on Sunday, the IMD traced out an upper air cyclonic circulation over northwest Bay of Bengal and neighbourhood. This would have had to descend to lower levels to set up the 'low,' but that was not to be.

Satellite picture analysis suggested that the 'pull' of feverish convection and storm-building in the west Pacific may just have proved too strong for the flows to pause and set up a circulation in the Bay.

The impact was such that even westerlies heading into the north of India were made to do the bidding of the buzz in the far-east and join a large stream of eastward moisture-laden flows emptying themselves into the west Pacific.

The cumulative rainfall for the period 1 June to 29 July 29 was only 353.2 mm as compared with the long-period average of 437.4 mm; but in terms of the distribution of precipitation, its performance was far worse.