The southwest monsoon, scheduled to draw to a close in Kerala on September 30, proved good for the State this year after an erratic beginning. The cumulative rainfall in Kerala stands at 1,727.7 mm as of September 18, against the long period average of 1,918 mm, showing a departure of 10%. After a couple of extreme rainfall events in August and at the beginning of September, the season has been normal so far in the State.
A departure of plus/minus 19% rainfall is considered ‘normal’ rainfall, according to the India Meteorological Department (IMD). The monsoon season (June-September) had started on an erratic note with rains staying away from the State in June and July, both months recording a deficient rainfall.
Withdrawal in three days
A weather bulletin issued by the IMD on Sunday said due to an anti-cyclonic flow over northwest India, dry weather is likely to prevail over West Rajasthan, Punjab, Haryana, Chandigarh, and Delhi in the next five days and conditions are becoming favourable for the withdrawal of southwest monsoon from parts of northwest India during the next three days.
“Cessation of rainfall activity over northwest India for continuous five days, reduction in moisture, and anti-cyclonic activity up to 1.5 km are the main criteria to be met to announce the beginning of the withdrawal of monsoon. The present synoptic conditions do not forecast the formation of any major weather systems over the Bay of Bengal during the fag end of September, delaying the withdrawal,” said a senior scientist from the IMD.
Usually, the complete withdrawal of the southwest monsoon heralds the advent of north-easterly winds bringing in the northeast monsoon to parts of peninsular Andhra Pradesh and Tamil Nadu and then to Kerala. The State used to get an average rainfall of 491 mm during the northeast monsoon. However, last year, Kerala recorded the highest rainfall of 1,026.3 mm, an excess of 109%.
