Weather Vane. Dry July seen setting the trend

 The normally rainy month of July has ended with a 16 per cent overall deficit in rainfall, with the southern peninsula carrying the largest deficit of 49 per cent. As if this was not enough, the first week of August (the second rainiest month) hasn’t been great either with a deficit of 26 per cent.

It is again the South Peninsula which has reported the biggest shortfall of 51 per cent. What does this portend for the rest of the monsoon season?

The India Meteorological Department has struck a sombre note in its long-range forecast for the second half of the monsoon, where it expects rainfall at 84 per cent of the long-period average. It has also retained its original forecast of 88 per cent for the whole season (June to September).  

Global models do not suggest anything drastically different. The El Nino is strengthening with the latest super cyclone Soudelor in the northwest Pacific merely serving to accentuate it, by hastening the spread of warm water across the basin.

A positive phase Indian Ocean Dipole (that mimics El Nino-La Nina in our backyard) may be emerging, but its capacity to neutralise the impact of El Nino seems to be limited this time around. The rains are projected to be confined to East and North-east India, according to the Japanese and South Korean forecasters.   The last week of July saw a rare cyclone ‘Komen’ spin up over north-east Bay of Bengal, cross the Bangladesh coast but only to head back into mainland India, bringing heavy rainfall over North-east, East and adjoining Central India. This helped limit the rain deficit (June 1 to August 5) to six per cent but the South Peninsula managed to cut its shortfall by barely a percent to 21 per cent.     

During the last two weeks, normal or above normal rainfall has occurred in West Rajasthan, West Madhya Pradesh, Vidarbha, Gangetic West Bengal, Jharkhand and Tamil Nadu.  

Normal or above normal rainfall also occurred in one of the two weeks in Jammu and Kashmir, East Rajasthan, East Madhya Pradesh, Konkan-Goa, Madhya Maharashtra, Gujarat,  Odisha, Nagaland, Manipur, Mizoram and Tripura.  

Below-normal rainfall occurred over Himachal Pradesh, Punjab, Kerala, Coastal Karnataka, South Interior Karnataka, Coastal Andhra Pradesh, Sub-Himalayan West Bengal, Sikkim and Marathawada.

The India Met Department has said in its outlook for the next 10 days that rainfall is likely to increase over East and Central India with widespread showers over the western Himalayas.

But South Peninsula may continue to remain largely dry.

An extended-range weather forecast by India Met Department, Indian Institute of Tropical Meteorology, and Indian Council of Agricultural Research for the next two weeks suggests the following:

August 7 to 13: Deficient rainfall likely for most parts of Central India and North-west India. Normal rainfall is likely over Northeast India with pockets of above normal rains.

August 14 to 20: Subdued rainfall for North-west India. There are indications of improvement over central India.

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