The Application Laboratory of Japanese national forecaster Jamstec has become the second major agency to forecast normal- to above-normal North-East monsoon for most parts of the country this year.

Earlier, the Busan, South Korea-based APEC Climate Centre, had come out with a similar forecast for July to November. Interestingly, both say December might be comparatively drier.

This should come as a relief to Tamil Nadu, which depends on the North-East monsoon season (October to December) for most of its requirements, especially after major failures over the last few years.

Monsoon revives

The Japanese forecast cames on a day when the ongoing South-West monsoon seemed to have revived over the southern peninsula, with rain-bearing clouds emerging along the west coast as well as on the east coast.

Satellite pictures on Wednesday showed the clouds approaching the Kerala coast, while they had already struck the east coast, stretching out from Chennai in Tamil Nadu to Nellore in Andhra Pradesh.

Banks of clouds filled most parts of the south-central and south-west Arabian Sea (not too far off from Maldives and Lakshadweep Islands), trailing those approaching the Kerala coast.

The build-up is equally impressive over south-east and adjoining east-central Bay of Bengal (around the Andaman & Nicobar Islands) and north-east Bay (off the Myanmar coast and South of Kolkata).

These are attributed to weak offshore trough, the repository of monsoon moisture, persisting along the Goa to Kerala along the west coast, and a cyclonic circulation hanging over the east-central Bay.

India Met Department (IMD) has already forecast heavy to very rain from the reviving monsoon for most parts of South India into the weekend before spreading out further to other parts of the peninsula.

Japanese outlook

Meanwhile, the Japanese forecaster observed that a positive Indian Ocean Dipole (IOD) phase, which had quickly emerged in May, persists, and will stay as such into the autumn, before dying out in the winter.

The IOD phenomena (positive and negative phases) mimic the El Nino-La Nina in the Indian Ocean, and is based on temperature differential between the Indian Ocean’s western and eastern basins.

The positive IOD phase represents warming of the West Indian Ocean relative to the East (beneficial for the concurrent Indian monsoon) and vice versa. “We may observe co-occurrence of a positive IOD and an El Nino Modoki-like state (weakly warm Equatorial Pacific),” the agency said, which can combine to bring normal to above normal rainfall for India.

It forecast a wetter-than-normal conditions also for the west coast of Canada, Mexico, East Africa, southern parts of West Africa, most part of South-East Asia, and south Philippines. In contrast, parts of the US, South America, southern parts of Africa, West Europe, East China, and most part of Indonesia and Australia will experience a drier-than-normal conditions.

“In particular, we notice that Indonesia and Australia may experience extremely drier than normal condition,” the Japanese forecaster added.