Monsoon 2015 downgraded to 90%

August 28, 2015 7:35 PM | Skymet Weather Team

The peak of Monsoon season comes to an end with the beginning of September. June had ended with above normal rains to the tune of 16%. But, July consumed all the surplus rainfall left over by June and registered 17% less rains than the long period average (LPA). Thereafter, August followed suit and is likely to end with a rainfall deficiency of over 20% for the month.

With two major months of the Monsoon season recording significant rainfall deficiencies, a big recovery in September looks unlikely. Consequently, the revised Monsoon forecast of Skymet stands at 90% of the long period average (LPA). This also means that September will not see copious amounts of rainfall and will possibly end up with a +/- 5% of the monthly average rainfall of 173 mm.

Relieving Factors of Monsoon 2015

In spite of such large deficiencies, around 65% of the regions in the country have received normal to excess rainfall till date.

Good Monsoon rains in Rajasthan, Gujarat and Madhya Pradesh boosted Kharif crops including pulses, oilseeds and coarse cereals. Chhattisgarh and Odisha also observed decent rains. Rainfall was timely and adequate in West Bengal, Bihar, Vidarbha, Andhra Pradesh and Tamil Nadu. The worst affected pockets so far have been Marathwada, Madhya Maharashtra, Rayalaseema and North Interior Karnataka. It must be noted that the best of the Monsoon seasons also leave behind some rain deficit pockets.

Well distributed rainfall till middle of August increased the overall Kharif acreages to 890.82 lakh hectare as compared to 863.61 lakh hectare at this time last year. Thus, the total sown area witnessed a modest gain of 3.24%.

Till date rice has been sown in 300.55 lakh hectare, pulses in 97.44 lakh hectare, coarse cereals in 163.75 lakh hectare, oilseeds in 163.78 lakh hectare and cotton in 108.67 lakh hectare.

Factors affecting Monsoon 2015

We should not forget that Monsoon as such is a complex phenomenon in terms of its arrival, withdrawal and variability. The in-built complexities of Southwest Monsoon are further influenced by external oceanic atmospheric phenomena. The most prominent factors affecting Monsoon 2015 are a strong El Nino, the Indian Ocean Dipole (IOD) and an erratic Madden-Julian Oscillation (MJO).

Strong El Nino

This season we have experienced an extreme kind of El Nino. It started evolving last year and crossed the threshold value in the spring/fall of 2014. The most-talked about phenomenon this Monsoon, is invariably linked with poor rains in the Indian Subcontinent.

El Nino remained very strong throughout the season and impacted rainfall over South and Central parts of the country. Weather models across the Globe have consensus about this El Nino being the strongest in the recent decades. Increased numbers of typhoons in the recent past also aided in the spread of warm waters across the Pacific, accentuating the El Nino affects.

All the four Nino indices in the East and Central Pacific displayed warm status of the Ocean. The index value of the Nino 3.4 region remained around 2 throughout the month of August.

Here’s a look at the Nino indices in the last four weeks:

Erratic MJO path

We expected MJO to play a neutral role in August and turn favorable in September, increasing Monsoon rains.

After making its appearance over the Indian Ocean in June, it never revisited the region. Rather MJO remained for a record-high duration in July and August over the East Pacific and Africa. The Intra Seasonal Oscillation (MJO) observed an extended cycle exceeding 45 days, over unfavorable location (for Indian Monsoon) of the Pacific Ocean.

This also resulted in increased typhoon activity, adversely affecting the flow of Monsoon current in the Bay of Bengal.

During a normal Monsoon season (bereft of El Nino) its amplitude or powers are invariably less over the cooler waters of the Eastern Pacific Ocean and more over warmer waters of the Indian Ocean. In case of an El Nino year, the Eastern Pacific warms up and MJO gains amplitude there as well.

IOD

This Monsoon, IOD retained the positive sign for a fairly long period, but it never got a chance to be in consonance with the MJO. A combination of positive IOD and MJO in favorable regions of the Indian Ocean, could enhance the Monsoon activity in July and August. On the contrary, its positive effects got neutralized by a strong El Nino.

Just by itself, IOD does not have the potential to significantly alter the rainfall pattern, especially in an El Nino year. IOD normally finds it difficult to neutralize the negative effects of a strong El Nino. IOD along with MJO gains the strength to subdue the effects of El Nino on Indian Monsoon.

The Arabian Sea also remained dormant for a long period and did not observe any northward propagation of commonly observed Monsoon rainfall pattern. The combination of all these factors impacted Monsoon rainfall this year.

Rain in West Coast and Northeast India

The two most heavy rainfall pockets of the country, Northeast India and the West Coast, have witnessed large rain deficiencies. Few pockets in these regions even exceed 7000 mm of rainfall during the four-month long Monsoon season. Rainfall deficiency figures in these pockets reflect in the overall Monsoon performance, but these deficiencies can easily be absorbed as the normal rains are quite high in these areas.

Nevertheless, agriculture has fared well. Most of the water reservoirs portray a better storage picture than last year. Even other sectors have not been hampered or gravely affected. Surplus rains in June boosted the consumer sentiments, leading to a rise in the sales of leading automobile manufacturers in India.

The consumer inflation fell sharply from a troubling 5.4% in June to 3.78% in July. Not only this, even food inflation declined from 5.48% in June to 2.15% in July. Taking into consideration the early concerns about an inadequate Monsoon and its impact on food production and prices, this comes as an extremely welcome development for consumers and the government as it has not affected the economy adversely.

Image credit- Aljazeera

 

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