The Hindu Business Line : `Break monsoon' scaled down; `weak monsoon' in

THE National Centre for Medium Range Weather Forecasting (NCMRWF) has scaled down its `break monsoon' alert to a `weak monsoon' phase that has taken effect from Sunday.

This has been necessitated by the emergence of weather conditions over central and peninsular India prejudicial to the establishment of a classic break monsoon. These are in turn attributed to upper air cyclonic circulations over the southwest Bay of Bengal and Uttar Pradesh.

According to Dr Akhilesh Gupta, Director, NCMRWF, the monsoon trough is still aligned along the plains of the northwest, and is seen tagging the prevailing weak monsoon circulation. During break monsoon, the trough is drawn to the Himalayan foothills.

The presence of the trough is bringing subdued rainfall in the northwest and along the plains, even as the Northeastern States and Assam continue to witness heavy rains resulting form the interaction of the western disturbance and the monsoon circulation. However, the circulation is seen weakening further during the next 24 hours.

Good for monsoon: Viewed from the view of overall monsoon performance, the prevailing weather configuration is seen boosting sentiments since rains will have extended to a much larger area beyond only those which would have benefited from a `break monsoon' - southeast peninsular India and the northwest region.

Giving an update, Dr Gupta said that overall performance of monsoon has been +1 per cent as on July 13. Six meteorological sub-divisions have been consistently returning deficient/scanty figures over the past six weeks.

These are Assam and Meghalaya, Nagaland/Manipur/Tripura, Jharkhand, East Uttar Pradesh, Marathwada and Bihar. Going forward, however, two among these - Marathwada (-42 per cent) and Nagaland/Manipur/Tripura (-52 per cent) - do not offer much scope of any dramatic improvement, while all the rest four are seen improving their position further.

Problem of plenty: On the other extreme, there are another six sub-divisions in the north and the northwest which have been consistently showing excess rainfall. These are Haryana/Delhi/Chandigarh (+85 per cent), Eastern Uttar Pradesh (+90 per cent), Gujarat (+136 per cent), Saurasthra/Kutch (+67 per cent), Punjab (+69 per cent) and Himachal Pradesh (+50 per cent).

Further rain in these areas can create a problem of plenty, Dr Gupta said. Especially since western disturbances are occurring more frequently these days in a pattern discernible from last winter onwards.

On Sunday afternoon, the upper air cyclonic circulation that originated over southwest Bay of Bengal off the Tamil Nadu coast lay over north interior Karnataka and neighbourhood. The system is likely to move in westward direction and cause scattered to fairly widespread rains in the south peninsula viz. Kerala, Tamil Nadu, Andhra Pradesh and Karnataka, during the next 2-3 days.

The other upper air cyclonic circulation was positioned over west Uttar Pradesh and neighbourhood. A western disturbance in the form of an upper air cyclonic circulation lay over Punjab and the adjoining area.

Under the influence of these systems, northwest India may receive scattered to fairly widespread rains during next two days. The rain activity is expected to reduce thereafter.

The axis of monsoon trough passed through Ganganagar, Aligarh, Allahabad, Daltonganj, and Sagar Islands and up to east central Bay of Bengal.

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