The South West Monsoon touched Kerala on June 8, as against the normal date of June 1, as per the Indian Meteorological Department (IMD).
The IMD was expecting the SW Monsoon to hit the state on June 4, but the severe cyclonic storm Biparjoy delayed its onset.
There is a rainfall deficit in many parts of the state especially in South Kerala. In selected areas of North Kerala, there is abundant rain but in some parts in North and Central Kerala, there is a shortfall.
The IMD predictions about the onset of the monsoon since 2005 have been proven correct but it got delayed by four days due to the Biparjoy cyclone in the Arabian Sea.
The IMD officially declares the monsoon onset when around 60% of the weather stations in the state record 2.5 mm of water or more for two consecutive days after May 10.
The IMD had confirmed that monsoon has touched the state after measuring the rainfall in the weather stations in the state.
However in South Kerala, especially the capital city of Thiruvananthapuram, Kollam and Pathanamthitta districts, rain has been playing hide and seek with many areas not getting proper rainfall.
Even as some areas of North and Central Kerala are receiving abundant rain, the weather officials told IANS that the state was facing a rain deficit. While there will be no rain for a couple of days in the next three to four days there is more than above average rainfall in central and North Kerala.
A yellow alert has been issued in Kozhikode, Kannur, Wayanad, Malapuram, Thrissur, Ernakulam and Idukki districts of Kerala for several days.
The rain shortfall in some parts of the state is attributed to the formation of a cyclonic circulation at an altitude of 1.5 km above Madhya Pradesh which has influenced the monsoon.
Weather officials said that this cyclonic circulation has diverted the winds away from the Kerala coast leading to the rain deficit.
Scientists in the Radar research institutes are of the opinion that once this cyclonic circulation above Madhya Pradesh diminishes, the monsoon will regain strength and intensity.
The South West monsoon has been deficient in Kerala 14 times between 1901 to 2021 while 1918 witnessed the most deficient monsoon.
Even as several agencies have forecast 2023 as an El Nino year, that can destabilize the monsoon, the data available with the Indian Meteorological Department shows that of the 15 El Nino years the country has witnessed between 1951 and 2022, only five have affected Kerala.
As per the IMD data, Kerala received poor rainfall in 1965, 1972, 1987, 2002 and 2015. However during the six El Nino years of 1953, 1957, 1963, 1969 and 1991 the state received an abundance of rainfall or rather above normal rainfall.
According to experts, Kerala need not worry going by the historical data of the El Nino effect in the state. Generally the El Nino event happens between August and September but by then the state would have received 60 percent of its rainfall.
The scientists also said that if there was a positive Indian Ocean Dipole (warmer sea surface temperatures in the western Indian Ocean relative to the east), the state will negate the El Nino effect and is expected to get good rains in the four months of the South West monsoon.
A departure of 19% plus or minus of the monsoon is considered normal.
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