The Indian Meteorological Department (IMD) announced recently that the onset of monsoon over Kerala is expected to be around June 4, indicating a slight delay compared to the usual date. Typically, the southwest monsoon arrives over Kerala on June 1, with a standard deviation of approximately seven days.
To predict the monsoon onset, the IMD employs six factors: i) Minimum Temperatures over Northwest India, ii) Pre-monsoon rainfall peak over the south Peninsula, iii) Outgoing Longwave Radiation (OLR) over the South China Sea, iv) Lower tropospheric zonal wind over the Southeast Indian Ocean, v) Mean sea-level pressure over the Subtropical NW Pacific Ocean, and vi) Upper tropospheric zonal wind over the North East Indian Ocean.
Last year, the monsoon onset over Kerala happened on May 29, two days after the IMD's projected date. The IMD noted that the operational forecasts for the date of monsoon onset over Kerala have been accurate in the past 18 years (2005-2022), with the exception of 2015.
In the meantime, the Meteorological Department reported that duststorms and dust-raising winds are expected in isolated areas of Haryana, Delhi, West Uttar Pradesh, and Rajasthan over the next three days, and in Madhya Pradesh and the Vidarbha region over the next two days.
Kuldeep Srivastava, IMD, Delhi, stated that heatwave conditions in the first half of May were less severe due to Western disturbances affecting parts of northwest India. He further mentioned that as the next western disturbance is approaching northwest India, they are not expecting heatwave conditions there for the next 7 days.
However, he stated that temperatures will be higher, reaching up to 40°C. The IMD's forecast also indicates light to moderate widespread rainfall activity in northeast India over the next five days.
The statement also added that heavy rainfall is highly likely at isolated places over Arunachal Pradesh on May 16, 19, and 20, and over Assam & Meghalaya and Manipur, Mizoram & Tripura from May 16 to 20.
