Kerala is likely to be on its toes this southwest monsoon season as the India Meteorological Department (IMD) has warned of an above-normal monsoon season for the State.
Though the monsoon is likely to be normal in the rest of the country, the southern peninsula is likely to receive above-normal rainfall under the influence of positive Indian Ocean Dipole (IOD) conditions, according to the latest forecast by the IMD.
The positive IOD is likely to play a pivotal role in the enhanced precipitation in the State. This is likely to occur by middle July. (An IOD is defined by warmer sea temperature over western Indian Ocean than eastern Indian Ocean leading to higher evaporation due to the increased sea surface temperature leading to enhanced rainfall along the western coast)
The latest global model forecasts indicate high probabilities of positive IOD conditions over the Indian Ocean. The forecasts also warn of above-normal rainfall in June as well for Kerala and the southern peninsula in general, says K. Santhosh, Director, IMD, Thiruvananthapuram.
A strong positive IOD had played a major role in the 2018 and 2019 floods in Kerala. In 2018, June and July recorded above-normal rainfall, which was followed by large excess rainfall in August. In 2019, it was deficient monsoon in June and July, which was followed by large excess precipitation in August. The impact was relatively low in 2019 compared to 2018 due to reduced precipitation in June and July.
This year, the forecast indicates above-normal rainfall in June as well, which is likely to be followed by positive IOD conditions leading to increased rainfall in the coming months.
“The KSDMA is monitoring the developments. It is almost certain that June and July are likely to witness intense monsoon spells across the State. Regarding August, we are observing whether the development of El Niño conditions over the Pacific, which leads to reduced rainfall, will overshadow the impact of the positive IOD,” says Sekhar L. Kuriakose, member secretary, Kerala State Disaster Management Authority (KSDMA).
The Chief Minister has convened a meeting of all department heads on May 30 to review monsoon preparedness, says Mr. Kuriakose