Staff Reporter
Panaji
As Cyclone ‘Biparjoy’ is rapidly intensifying into a severe cyclonic storm, the India Meteorological Department (IMD) on Wednesday predicted that all conditions are favourable for the onset of monsoon over Kerala by Friday.
Meteorologists are, however, predicting a “mild” monsoon onset over Kerala and “weak” progress beyond southern peninsula under the influence of the cyclonic storm.
The IMD’s latest forecast indicates several meteorological features associated with the onset of monsoon over Kerala. These features include the persistence of westerly winds over the south Arabian Sea, an increase in the depth of westerly winds to middle tropospheric levels and an increase in cloudiness over areas covering the southeast Arabian Sea, Lakshadweep and Kerala coasts.
Based on these observations, the IMD has stated that conditions are becoming favourable for the monsoon to arrive in Kerala within the next 48 hours.
While the southwest monsoon typically takes around four days to progress from Kerala to Goa, historical data suggests that there have been delays ranging from one to 14 days for the monsoon to reach Goa. In some exceptional cases, the monsoon had arrived earlier than the expected date.
Meanwhile, ‘Biparjoy’ is intensifying into a very severe cyclonic storm. It is currently centred approximately 860 kilometres west-southwest of Goa, 970 km southwest of Mumbai, 1,050 km south-southwest of Porbandar and 1,350 kilometres south of Karachi.
The storm is expected to further intensify in the next 12 hours and move nearly northwards over the next 24 hours, followed by a north-northwestward trajectory over the subsequent three days.
According to a Press Trust of India report from New Delhi, meteorologists are predicting a “mild” monsoon onset over Kerala and “weak” progress beyond the southern peninsula under the cyclone’s influence.
The IMD has not yet predicted any major impact of the cyclone on countries adjoining the Arabian Sea including India, Oman, Iran and Pakistan.
Forecasting agencies said the storm has been undergoing “rapid intensification”, escalating from just a cyclonic circulation to a severe cyclonic storm in just 48 hours, defying earlier predictions.
Atmospheric conditions and cloud mass indicate that the system is likely to sustain the strength of a very severe cyclone till June 12.
Scientists say cyclonic storms in the Bay of Bengal and the Arabian Sea have been intensifying rapidly and retaining their intensity for a longer duration due to climate change.
According to a study ‘Changing status of tropical cyclones over the north Indian Ocean’, the frequency, duration and intensity of cyclones in the Arabian Sea have increased by about 20% in the post-monsoon period and 40% in the pre-monsoon period. There has been a 52% increase in the number of cyclones in the Arabian Sea, while very severe cyclones have increased by 150 %.
“The increase in cyclone activity in the Arabian Sea is tightly linked to the rising ocean temperatures and increased availability of moisture under global warming. The Arabian Sea used to be cool, but now it is a warm pool,” said Roxy Mathew Koll, climate scientist at the Indian Institute of Tropical Meteorology.
“The oceans have become warmer already on account of climate change. In fact, a recent study shows that the Arabian Sea has warmed up by almost 1.2 degree Celsius since March, thus conditions are very much favourable for the rapid intensification of the system (Cyclone Biparjoy) so it has potential to sustain the strength for a longer period,” said Raghu Murtugudde, Professor, Department of Atmospheric and Oceanic Science, University of Maryland and IIT Bombay.