The 15th session of the South Asian Climate Outlook Forum (SASCOF-15) that met in Thiruvananthapuram from  September 23 to 25, has extended a normal outlook for North-East monsoon for India this year.

Above normal rainfall is likely during the October to November season for most parts of Sri Lanka, Maldives and the eastern parts of Myanmar.

But the SASCOF saw prospects of below-normal rainfall over the southern parts of Myanmar and over some areas along the foothills of the Himalayas (mostly Central Nepal).

Excess SW Monsoon

The normal to above-normal rainfall outlook is grounded on a persisting positive phase of the Indian Ocean Dipole (IOD) and the near-neutral conditions (neither El Niño or La Nina) in the Equatorial Pacific.

The positive IOD, marked by elevated sea-surface temperatures over the West Indian Ocean compared to the East, is driving an excess South-West monsoon in India, especially over the central parts.

On the other hand, an El Niño, represented by the warming of the East Equatorial Pacific relative to the West, has traditionally presided over a deficit South-West monsoon in India, though with honourable exceptions. 

But near-neutral conditions in the Pacific, combined well with a positive IOD phase during the ongoing South-West monsoon, which is forecast to continue during the October-December season as well.

The consensus climate outlook from SASCOF also suggested that most parts of South Asia would witness normal to slightly-normal temperatures during this period.

Several experts from eight South Asian countries, including Afghanistan, Bangladesh, Bhutan, India, Maldives, Myanmar, Nepal and Sri Lanka, and international experts attended the SASCOF session.

Concurs with others

The SASCOF forecast aligns with the seasonal outlook already made available by the Application Laboratory of Jamstec, the Japanese national forecaster, and the APEC Climate Centre based in Busan, South Korea.

The UK Met Office and the European Centre for Medium-Range Weather Forecasts mostly agree with the outlook, although the former sees above-normal rainfall for southern parts of Kerala and Tamil Nadu.

Meanwhile, the ongoing South-West monsoon promises to spill into October as a cyclonic circulation drives rain into Maharashtra, Goa, Karnataka, Kerala, Andhra Pradesh and Telangana.

A trough thrown down by this circulation into Jharkhand across Telangana, South Chhattisgarh and Interior Odisha is bringing in some badly needed showers over some parched regions in East India as well. The moisture incursion into the trough from the Bay of Bengal will cause fairly widespread to widespread rainfall with isolated heavy to very heavy falls over Bihar, East Uttar Pradesh and Bengal during next four days.

Elsewhere, helpful cyclonic circulations hung over North Konkan and Madhya Maharashtra as well as over Kutch and adjoining South-West Rajasthan, an India Met Department (IMD) update said this (Thursday) morning.

Heavy rainfall outlook

Heavy rainfall was observed yesterday (Wednesday) in isolated places over West Madhya Pradesh and Chhattisgarh as a result of the prevailing atmospheric features mentioned above.

Thunderstorms broke out at isolated places over Punjab, West Uttar Pradesh, Madhya Pradesh, Gujarat, Konkan, Goa, Rayalaseema, Marathawada, Bihar, Madhya Maharashtra and Vidarbha during this phase.

The forecast valid for the rest of the day today said that heavy to very-heavy rainfall is likely over Bihar, while heavy rains are forecast over Himachal Pradesh, Uttarakhand, East Uttar Pradesh, Madhya Pradesh, Chhattisgarh, Jharkhand, plains of Bengal, Odisha, Gujarat, Madhya Maharashtra, Konkan, Goa, and Lakshadweep and Lakshadweep.

Squally weather may prevail over the South Gujarat coast. Fishermen are advised not to venture into these areas. 

Outlook from October 1 to 3 said fairly widespread to widespread rainfall with isolated heavy falls is likely over parts of Central and East India as well as South Peninsular India. Scattered to fairly widespread rainfall is forecast over the rest of the country except over some parts of North-West India and the Islands where isolated rainfall is likely.