Only Kannur, Kottayam and Thiruvananthapuram districts received normal rainfall as the southwest monsoon begins to wind up its four-month cycle.
The average seasonal rainfall recorded in Kerala is 26 per cent deficient. Wayanad district showed a shortfall of 39 per cent and Alappuzha and Palakkad, 35 and 32 per cent respectively.
The southwest monsoon which has been playing truant right from its commencement in June has never demonstrated resurgence, except for a build-up in some locations.
El-Nino effect
“The rainfall recorded is as expected according to our forecast in April and updated in June. The deficiency has been attributed to the El-Nino effect,” K. Santhosh, Director, Meteorological Centre, Thiruvananthapuram (Indian Meteorological Department), told The Hindu on Thursday.
Rainfall is said to be normal when the recording is between 94 and 104 per cent, below normal (between 90-96 per cent), deficient (less than 90 per cent), above normal (104-110), and excess (above 110).
For calculation purpose, seasonal rainfall is worked out, such as from June 1 to September 30, and October 1 to December 31.
Fag end
. “Signs of withdrawal are seen from Rajasthan, Madhya Pradesh, and Uttar Pradesh. However, the wind and pressure patterns are still lively in Kerala. The withdrawal is complete when it reaches the line from coastal Andhra Pradesh to coastal Karnataka,” he said.
Northeast monsoon
Dr. Santhosh said that the start of northeast monsoon would be declared only after October 10. This is done based on several parameters such as strengthening of the easterly winds and formation of low-pressure areas off the coast of Andhra Pradesh. Besides, the depth of easterlies should be up to 2.1 km from the ground level, he added.
The deficit in southwest monsoon is usually made up during other seasonal rainfall, including the northeast monsoon.
“However there is no one-to-one relation. In 2012, considered to be a bad year, both the monsoons failed. The southwest monsoon was 24 per cent deficient while northeast, 35 per cent deficient,” Dr. Santhosh said.
