After the ‘driest’ August in recent times, the southwest monsoon has become active in the State, triggered by the cyclonic circulations over the Bay of Bengal. Ranni in Pathanamthitta received the highest rainfall of 13 cm followed by Peerumedu in Idukki with 11 cm in the 24 hours ending 8.30 a.m. on Saturday. According to a bulletin issued by the India Meteorological Department (IMD) on Saturday, most parts of the State are likely to receive rain or thundershowers, with some districts receiving intense rainfall, till September 8.
A cyclonic circulation is likely to form over the North Bay of Bengal around Sunday. Under its influence, a low pressure area is likely to form during the subsequent 48 hours. Further, a cyclonic circulation persists over Comorin area and another over the north interior Tamil Nadu. Under the combined influence of the weather systems and a trough from Interior Karnataka to the Comorin area, the State is likely to receive isolated heavy showers, especially in south and central Kerala for the next five days.
Yellow, orange alerts
A yellow alert has been issued for four districts — Thiruvananthapuram, Kollam, Pathanamthitta and Alappuzha — on Sunday, warning of isolated heavy rains. An orange alert has also been issued for Alappuzha (Monday and Tuesday) and Idukki (Wednesday), indicating intense rainfall. The State that witnessed an 87% drop in rainfall in August and a 60% drop in June rainfall needs some heavy showers in September to avert a water crisis.
Countering El Nino
According to Skymet Weather, the sea surface temperature anomaly in the tropical Pacific indicates that El Nino conditions are intensifying from moderate to strong, diminishing the prospects of the monsoon over the country. However, the Indian Ocean Dipole (IOD), which can offset the negative impact of El Nino, has risen substantially during the last four weeks and has remained above the threshold mark of +0.4°C for the second consecutive week. Nevertheless, El Nino is considered more powerful and more inclined to corrupt the monsoon pattern. The borderline IOD index needs to amplify rapidly to strike a balance with the growing El Nino stature, according to Skymet.
