North-West India only red spot on likely ‘normal’ monsoon map

Rajasthan, Punjab, Haryana, Delhi, Uttar Pradesh, Coastal and Interior Tamil Nadu, and Goa have been identified as areas which are likely to witness less than normal rain during the 2017 monsoon.

This is the assessment from South Asian Climate Outlook Forum (Sascof-10) that met in Thimphu, Bhutan, from April 24 to 26.

It sought to mostly endorse the ‘normal monsoon’ outlook issued in by India Meteorological Department (IMD) in its forst long-range forecast issued earlier.

The only difference is that Sascof has given out an indicative picture about the spatial distribution of rainfall. The IMD had pushed the same to June when its second-stage monsoon forecasts are due.

According to Sascof, most of West, Central and Peninsular India are expected to receive normal rain while excess showers are indicated for drought-hit Kerala, Karnataka, and the western flanks (ghats) and southern parts of of Tamil Nadu.

Coastal Andhra Pradesh, Odisha and adjoining Bengal too may benefit from surplus rain while it will be ‘normal’ to ‘excess’ over the North-Eastern States.

Along with North-West India, contiguous North, Central and South-East Pakistan too may take a hit during the June to September season. But across the international border, Gujarat, entire Madhya Pradesh, Maharashtra and Telengana are projected to be in the ‘normal’ category.

Jammu & Kashmir, Himachal Pradesh and most of Uttarakahand also are expected to witness normal rain. A similar outlook is valid for most of East India extending from eastern Uttar Pradesh to Jharkhand, Bihar and Chhattisgarh.

Sascof based its forecast on strong model consensus that prevailing ‘neutral’ conditions in the equatorial Pacific would develop into ‘weak El Nino’ conditions during the second half of this year.

But it also recognised uncertainty in the timing and intensity of a developing El Nino that has, on occasions, had a general negative impact on the monsoon rainfall.

The impact of El Nino on the monsoon is also found to be significantly weakened from a differential warming of the Indian Ocean - when its West heats up relative to the East in a phenomenon called positive phase of Indian Ocean Dipole (IOD).

This is more or less similar to the El Nino-La Nina phenomena in the equatorial Pacific, but has more telling impact due to proximity to mainland India. A negative phase of the Indian Ocean Dipole (East Indian Ocean warming up relative to the West) could harm the prospects of a concurrent monsoon.