Vinson Kurian

Thiruvananthapuram , July 13

THE country is heading for a possible `break monsoon,' which is expected to set in by Sunday (July 17).

Disclosing this to Business Line, Dr Akhilesh Gupta, Director, National Centre for Medium Range Weather Forecasting (NCMRWF), said that pieces of the `break monsoon' jigsaw puzzle have been falling into place one after the other.

A major imponderable was the rainfall pattern in peninsular India, which had refused to do the forecaster's biding until now. Other major synoptic features indicating break monsoon are strengthening westerlies over the plains and an anti-cyclonic anomaly (a ridge of high pressure, marked by subsidence of air) over central India. Both these are now getting firmly established.

Rain for Tamil Nadu, Northeast: The `break monsoon' condition will translate into enhanced rainfall activity over the Northeastern States, regions close to the foothills of the Himalayas and parts of southeast peninsular India, including Tamil Nadu. In its forecast, the NCMRWF said precipitation is likely to enhance over Tamil Nadu, Rayalaseema and south coastal Andhra Pradesh over the next 3-4 days.

Oh the other hand, rainfall activity will get subdued over central India, the plains of north India and remaining parts of peninsular India.

"Break monsoon is a blessing in disguise considering the known pattern of distribution of region-bound rainfall. While the flood-hit parts in the northern plains and the northwest could enjoy the `break,' some regions where the monsoon has been deficient/scanty till now can hope to get some well-deserved drenchers," Dr Gupta said.

For instance, Tamil Nadu (-45 per cent), Rayalaseema and south coastal Andhra Pradesh stand to benefit from the spell during the ensuing `break' phase. Some preparatory clouding is already seen over parts of Tamil Nadu.

Monsoon turns surplus: This `levelling' feature associated with this phase will ultimately help improve the monsoon performance in the long run. Already, the seasonal performance up till Wednesday indicates that rainfall is above normal by one per cent. The figure was - 2 per cent on July 6.

Though not having a one-to-one relationship with the `break monsoon,' the evolving cyclone in the western Pacific is another factor aiding the break monsoon . The system has already taken shape as a depression and was hovering over northeast Philippines on Wednesday. It is seen moving further northwest into the South China Sea by Sunday, when `break monsoon' will have been established over India.

Going further forward, the system is expected to intensify into a cyclone and make landfall along the southeast China coast by Wednesday next (July 20). Though this its expected to weaken subsequently overland, monsoon over India is not expected to revive at least till the following Friday (July 22). The revival will be associated with the formation of a low-pressure area over head Bay of Bengal. It was too premature to even hazard a guess when this would happen, Dr Gupta said.

Interaction on: In its forecast for the next five days, the NCMRWF said the ongoing interaction of monsoon system with the prevailing western disturbance is likely to continue for another 24 hours. Scattered to fairly widespread rainfall may continue to occur over many parts of the northwest, viz. Uttar Pradesh, Uttaranchal, Himachal Pradesh, Punjab and Haryana.

The monsoon system in the form of an upper air cyclonic circulation over west Uttar Pradesh and adjoining area persisted. The dominating westerlies are seen dragging the system, with it the monsoon trough, to the Himalayan foothills where it will dissipate over the next 48 hours.

Scattered to fairly widespread rainfall is likely to continue over many parts of northwest India viz., Uttar Pradesh, Uttaranchal, Himachal Pradesh, Punjab and Haryana during the next 24 hours.

Scattered to fairly widespread rainfall is expected over east Uttar Pradesh, Bihar, Jharkhand and fairly wide spread to wide spread rainfall with isolated heavy rains over West Bengal, Orissa and the Northeastern States during the next four days.

Rainfall activity over the northeast and West Bengal is likely to enhance.

Scattered to fairly widespread rainfall is expected over Chhattisgarh, east Madhya Pradesh and Vidarbha and scattered over west Madhya Pradesh during the next 24 hours, but will reduce in intensity thereafter.

In the south, fairly widespread rainfall is likely over coastal Karnataka and Kerala, and isolated to scattered over rest of the areas in the region during next two days.

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