The Hindu Business Line : Emerging rain spell may last a fortnight

Thiruvananthapuram, Aug 3 The reviving monsoon promises at least a fortnight of action-packed spell, notwithstanding the odd storm brewing over the northeast Arabian Sea taking a likely westerly path, as Super Cyclone Gonu did in the early onset phase in June.

A building high-pressure area in the “behaving” west Pacific will ensure that storms in that basin would move only west to northwest to keep the Bay of Bengal in good vibes, just in case.

Occasional migrant circulations from west-northwest-moving Pacific systems have been known to hop into the Bay and set up low-pressure systems.

Pacific storms heading east-to-northeast are harmful (as in Typhoon Man-Yi that forced the “break monsoon” during mid-July).

ROGUE STORM

To do a recap, Gonu had taken away the entire monsoon flows towards Oman, but emerging flows in its wake had packed some punch as revealed in an explosive burst of rain along the west coast and spread over the peninsula.

In this case, however, the rogue storm is projected as taking shape around August 13 over the south Gujarat coast.

It would later slide into the sea and move gradually away from the coast towards Sindh, Pakistan.

But the preparatory middle-level cyclonic circulation would be active from next Monday (August 6) itself, and would have presided over some of the heaviest rainfall all along the west coast till such time as it leaves coast.

In this manner, the south Gujarat-Mumbai-Konkan belt is bracing for another round of battering, already advertised in the sporadic heavy showers along the west coast where an offshore trough persists.

SURPLUS IN TACT

Meanwhile, all-India area-weighted rainfall figures for the season have made smart gains from a week of vigorous monsoon phase in the east of the country, and showed a surplus of three per cent age points as on August 1.

This reverses the trend of steep loss from the surplus amounting to seven percentage points each in the two preceding weeks marking the “break monsoon” phase.

The surplus had been cut to four per cent as on July 25 from a seasonal peak of 20 per cent.

But a hectic week ending August 1 witnessed some of the heaviest rainfall in the east and northeast, helping wipe out the large rainfall deficiencies in that part of the country.

This also helped ensure that the rainfall surplus figure did not go below the three per cent mark.

Himachal Pradesh (-38 per cent), east Madhya Pradesh (-34 per cent), west Uttar Pradesh and Haryana-Chandigarh and Delhi (-23 per cent each) and Marathwada (-20) are now the problem areas, with the first three being consistently in the deficient list for quite sometime now.

CRUCIAL ROLES

August 1 aggregates showed that 31 Met sub-divisions have had excess/normal rainfall, with those in the deficient category being reduced to merely five.

The reviving monsoon could make a qualitative change to this tally, with easterlies from the Bay of Bengal and the occasional westerly trough playing crucial roles to ensure even spread of rainfall.

On Friday, the India Meteorology Department said that the anticipated ‘low’ in the northwest Bay of Bengal was likely to form by Saturday. It will subsequently become more marked.

From August 8, the rainfall belt will later to shift to Madhya Pradesh, Maharashtra, Goa, Gujarat and south Rajasthan.

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