Weak Monsoon For Days To Come?

MAY 7, 2016

Monsoon activity is going to be weak on the Arabian Sea side in the near future. The rains will get stuck in Goa and northern Karnataka for another 10 days even though it is expected to rain heavily in these areas in the next few days owing to a cyclonic circulation. So when will it reach Mumbai? Hard to say now but NOAA's model says on June 18.

The model further says it will reach Gujarat around June 21. It expects the monsoon to have spread to eastern Madhya Pradesh, Bihar, Maharashtra, Gujarat by June 22. But one takes that with a pinch of salt as the model has been making wild predictions in the past week.

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Interesting sidelight: There is a 30-40% possibility of a tropical cyclone developing in the Arabian Sea till June 15. There is a similar chance in the Bay of Bengal from June 6-10

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The silver lining in the gloomy scenario is that the Bay of Bengal stream is going to rejuvenate soon. With the cyclonic circulation over Andhra Pradesh intensifying into a low and hitting Chittagong area of Bangladesh on June 11-12 and then drenching the northeastern states of India.

This low pressure area/depression is going to pull in the monsoon into eastern India.

Some forecast models suggest the Arabian Sea stream will snap out of its Rip Van Winkle sleep around June 18 and monsoon will lash Mumbai and Gujarat thereafter.

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Good news is that the Madden Julian Oscillation, MJO, enters the Indian Ocean on June 12 and is expected to stay for next few weeks. As a result the monsoon will really intensify. A booster dose, so to speak.

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Image credit: Rediff

Meanwhile the Indian Institute of Tropical Meteorology  (IITM), Pune, India,  have given the following rain forecast maps based on multi-model ensemble (MME) till June 25, 2016. The first set shows the expected rainfall in mm/day. The second set shows the forecast anomaly, that is whether below average or above average.

Not a very happy picture. Though rains will spread throughout India (except western Rajasthan, Haryana and Punjab) by June 25, they will be meagre except in Bihar, Jharkhand, West Bengal, Indian west coast and north east states.

The rainfall anomaly forecast map shows below average rains in most of the areas till June 20 (except the ubiquitous north eastern states). Good rains also in coastal Maharashtra and Gujarat from June 11-15 (A low pressure area?). Things get better during June 21-25 period with western Madhya Pradesh, Maharashtra, West Bengal showing above average rains. The White color denotes normal average precipitation.