The Hindu Business Line : Rainfall figures slip back into negative territory

The actual rainfall till date was 792.0 mm against a seasonal normal of 804.9 mm. Seven met sub-divisions had `excess' rainfall, while 19 ended up in the `normal' category and 10 in the `deficient'.

RAIN VACUUM

The weekly deficit was left behind by a monsoon readying to withdraw from the northwest.

This represents weak monsoon conditions, during when the monsoon trough retreats from the plains to the foothills of the Himalayas.

Active monsoon conditions always feature a full-blown trough dipping into the Bay of Bengal, housing one or more resident `low's rolling in from the Bay.

While retreating to the foothills, the trough takes away the rain belt also with it and causes precipitation to be confined to the northeast and South India.

WEEKLY DEFICITS

At least 11 met sub-divisions on both sides of the plains totted up rainfall deficiencies of well above 50 per cent during the week ending September 13. Some of these were (with percentage deficit figures in brackets): West Uttar Pradesh (92); Haryana (88); Punjab (87); East Madhya Pradesh and Coastal Andhra Pradesh (82); Uttaranchal (81); and Chhattisgarh (80).

The ensuing 26 per cent deficit is what has driven the seasonal rainfall figures also into negative territory. The final figure would have been worse had it not been for some significantly surplus weekly rain recorded elsewhere in Lakshadweep (+301); Kerala (+161); and South Interior Karnataka (+105).

The most significant feature about this monsoon would be that the normally west Northeast is likely to end up notably in the deficit, with drought-like situations existing in some places. The other extreme saw the desert met-subdivision of West Rajasthan recording a rainfall `excess' rainfall and East Rajasthan `normal.'

`LOW' MATERIALISES

The cyclonic circulation over west central Bay concentrated into a low off the Andhra Pradesh coast on Friday. The National Centre for Medium Range Weather Forecasting (NCMRWF) said this is expected to become `well marked' and move slowly to the west-northwest.

Fairly widespread to widespread rainfall with isolated heavy to very heavy falls is likely over south peninsula, Konkan and Goa during the next three days. The ongoing rainfall activity over the Northeast is likely to reduce during the next 3-4 days.

The ongoing rainfall activity over parts of Northwest India also is likely to scale down within the next 24 hours, as the causative western disturbance moves away to the east. Another western disturbance is likely to approach Jammu and Kashmir and the adjoining areas by around Monday.

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