The Hindu Business Line : `Low' turns into depression; landfall likely today

THURSDAY'S low-pressure area over north-west Bay of Bengal concentrated into a depression and lay centred close to Balasore off the Orissa coast on Friday afternoon.

The bolstered monsoon flow will help the system churn in fast to create a landfall over Orissa early Saturday morning, said Dr Akhilesh Gupta, Director, National Centre for Medium Range Weather Forecasting (NCMRWF).

Speaking to Business Line, Dr Gupta said the west-northwest trajectory of the system would result in a heavy torrent over Orissa, Chhattisgarh, east and west Madhya Pradesh and Vidarbha over the next three to four days.

Even parts of Jharkhand and south Bihar can look forward to some wet session, though not as intense as in their neighbourhood to the immediate south.

Equitable share: Significantly, locational features and dynamics will combine to deliver just what the weatherman ordered - equitable distribution of rain as the session wears on.

Some districts in east Uttar Pradesh and south Bihar have recorded deficient/scanty rainfall during the season till now. These areas can hope to benefit from the ensuing spell. Widespread to fairly widespread rains will help the farmer's cause in no small measure, Dr Gupta said.

In anticipation of the approaching landfall, the prevailing low-pressure system over the mainland has moved out from its overnight perch over northwest Madhya Pradesh further northwest, across the international border into Pakistan where it has coalesced with the seasonal low.

The associated upper air cyclonic circulation lies over north Gujarat and adjoining southwest Rajasthan. Even this is expected to weaken within the next 24 hours. Just as well, since no two systems (low/depression) can hope to co-exist and dictate terms over the mainland.

Mid-tropospheric cyclonic circulation likely: But the exit of the system could well leave the field open for the formation of a mid-tropospheric cyclonic circulation (MTC) over Gujarat and the northeast Arabian Sea.

The MTC and the depression/low over the Bay are `brothers-in-arms' and feed into each other, getting intensely active to produce a hectic spell all over central India and the immediate northwest.

The Gujarat floods earlier in the season have been directly attributed to an MTC that managed not just to endure but also extend the tenure of the prevailing low/depression.

Once it drops anchor, an MTC stays for much longer than a low/depression and guarantees sustained rainfall in areas falling within its direct footprint. There is also the offshore trough running from Konkan to north Kerala to reckon with; this is likely to persist for the next five days.

In its forecast for the next five days, NCMRWF said the hilly regions of northwest India would get scattered to fairly widespread rains during next two to three days.

Isolated to scattered rainfall is likely over the plains. With the west-northwestward movement of depression, the rainfall activity over the region is expected to increase after three days.

Widespread rain: In the east and the northeast, Orissa, Jharkhand and Gangetic West Bengal are likely to receive fairly widespread rainfall with isolated heavy rains during the next two to three days. Scattered to fairly widespread rainfall activity is likely over east Uttar Pradesh, Bihar, sub-Himalayan West Bengal and the Northeastern States during the next three to four days.

In central India, the west-northwestward movement of depression will lead to widespread rainfall with isolated heavy to very heavy showers over Chhattisgarh, east and west Madhya Pradesh and fairly widespread to widespread rainfall over Vidarbha during the next three to four days.

Towards the south, scattered to fairly widespread rainfall activity is likely to continue over Karnataka, coastal Andhra Pradesh and Kerala. Isolated to scattered rains are expected over the rest of the areas in the region.

In the west, widespread rainfall with isolated heavy to very heavy showers are expected over Konkan and Goa, Gujarat and South East Rajasthan during the next three to four days.

Scattered to fairly widespread rainfall is likely over Madhya Maharashtra and Marathwada and the remaining parts of Rajasthan during the period.

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