India Meteorological Department (IMD) has declared that the monsoon has currently entered into a weak phase over Central, Peninsular and North-West India and will stay as such for over the next seven days, while rainfall is forecast to simultaneously increase over North-East India during the same period.

A weak phase is normal during this stage after the monsoon has covered most parts early by at least a week to 10 days. This phase also witnesses a spurt in rain over the North-East and the East Coast.

Rainfall surplus at 37%

Reviewing the progress of the monsoon, the IMD said that the seasonal rains have covered most parts of the country except parts of Rajasthan, Delhi, Haryana and Punjab. But the hiatus comes after it rained a surplus of 37 per cent over the East, Central and adjoining North-West India and ahead of normal. But some of this surplus may drain out by June 30 till when the 'silent period' may extend.

Actual rainfall till Monday has been 13.78 cm against its normal of 10.05 cm. The IMD said that there is currently no buzz in the Arabian Sea that could potentially revive the rains over the ensuing week.

As for North India, numerical models continue to suggest that intruding dry westerlies from across the border will prevail during this period. They are responsible for blocking, in the first place, the monsoon easterlies over Delhi-Chandigarh-West Uttar Pradesh for over the last few days.

Cross-equatorial flows

The cross-equatorial flows over the Arabian Sea responsible for bringing moisture from the Southern Hemisphere too have weakened to about half of their desirable intensity as they approach the West Coast. Such weak monsoonal winds are likely to prevail during the next seven days, the IMD said.

Consensus numerical forecasts show low probability of formation of helpful low-pressure systems over the core monsoon areas as well as over the North Bay of Bengal till at least June 30. This rules out revival of easterly monsoon winds from the Bay along the monsoon trough to the plains of North India.

More rains for East

But wind convergence and localised easterly and south-easterly winds will bring fairly widespread rainfall over Odisha, West Bengal, Sikkim, Jharkhand, Chhattisgarh and Bihar during the next five days.

Isolated heavy rainfall is forecast over the plains of West Bengal and Odisha during this period; over North Chhattisgarh and Jharkhand on Wednesday; and over the hills of West Bengal and Sikkim until Friday.

Under the influence of strengthening of moist south-westerly winds from the Bay, fairly widespread to widespread rainfall is likely over North-East India punctuated by isolated heavy to very heavy rain.

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