The statement went on to note that seasonal rainfall over the southern peninsula, which includes five meteorological subdivisions (coastal Andhra, Rayalaseema, Tamil Nadu and Puducherry, south interior Karnataka and Kerala), had also received below-average rainfall in the same months.
In Andhra Pradesh, Visakhapatnam, Guntur and Prakasam districts received 54%, 63% and 68% less rainfall.
The southwest monsoon, the country’s principal monsoon season, also ended on a ‘below normal’ note, triggering droughts in several states.
“It is likely that several states are heading into severe drought, and the water crisis is expected to worsen in the coming months as the summer sets in.
The ‘other’ monsoon South Asia has two monsoons: the southwest or summer monsoon from June to September, and the northeast or winter monsoon between October and December.
According to a 2012 study, India receives about 11% of its annual rainfall – with many districts in the south receiving 30-60% – during the northeast monsoon season.
A 2017 report prepared by the Regional Meteorological Centre, Chennai, reads: … for the extreme southeastern state of Tamil Nadu and the Union Territory of Puducherry…, the normal southwest monsoon seasonal rainfall realised is only about 35% (317.2 mm) of its annual rainfall (914.4 mm) as this subdivision comes under the rain-shadow region during the southwest monsoon.
On September 29 last year, the IMD issued an operational forecast for the 2018 northeast monsoon, saying that the rainfall over the south “is most likely to be normal (89%-110% of long period average), with a tendency to be [on] the positive side of the normal.” It added that the rainfall over Tamil Nadu is most likely to be above normal, i.e. over 112% of the long-term average.
And “apart from the global weather phenomenon of the El Niño Southern Oscillation, the northeast monsoon is also affected by factors like the Indian Ocean dipole and the Madden-Julian Oscillation,” he said.
Oscillations are climate patterns that involve a back-and-forth variation of some climate variable.