E-Paper
Monsoon arrives in Kerala after 7-day delay; progress to be slow in 1st week
The monsoon, which is the lifeblood of India’s economy and delivers nearly 70% of the country’s rain, normally arrives in Kerala around June 1
The monsoon arrived in Kerala on Thursday, seven days after it normally does, the India Meteorological Department (IMD) said even as climate scientists and meteorologists have warned that it is expected to be a weak onset due to the severe Cyclone Biparjoy. The progress of the weather system that brings rain across the country and is directly linked to a healthy rural economy is likely to be slow in its first week.
The monsoon normally arrives in Kerala around June 1 before advancing northwards and covering the entire country by July 15. It is the lifeblood of India’s economy as it delivers nearly 70% of the country’s rain. As much as 51% of India’s farmed area accounting for 40% of production is rain-fed and 47% of the population is dependent on agriculture for livelihood.
“During [the past] 24 hours, clouding has increased over Southeast Arabian sea with Outgoing Longwave Radiation (OLR) being <200 w/m2. The depth of westerlies over [the] Southeast Arabian Sea extends up to mid-tropospheric levels. The strength of Westerlies in the lower levels has increased by about 19 knots. Thus, there has been widespread rainfall over Kerala during [the] past 24 hours. Considering...the... conditions, Southwest Monsoon has set in over Kerala...,” the IMD said in a statement.
The IMD added conditions were favourable for further advance of the monsoon into more parts of the central Arabian Sea, Tamil Nadu, Karnataka, and southwest, central, northeast Bay of Bengal, northeastern states, and remaining parts of Kerala during the next 48 hours.
IMD declares the arrival of monsoon in Kerala based on features that include 60% of 14 weather stations in Kerala and Mangaluru (Karnataka) reporting rainfall of 2.5 mm or more for two consecutive days after May 10.
as well as the extent of cloudiness.
Private forecaster Skymet Weather vice president (climate and meteorology) Mahesh Palawat said the arrival criteria are gradually being met but they cannot expect widespread rains, especially in the interior parts of the south peninsula for the next four to five days. “There will be moderate rainfall over coastal Kerala and coastal Karnataka.”
He said active monsoon conditions may pick up only after June 14-15. “As expected, this has been a weak onset with slow progression expected.”
Former earth sciences ministry secretary M Rajeevan said there may not be widespread rains everywhere. “We expect some rains along the west coast over the next three to four days. Once this cyclone moves away from the Bay of Bengal, the current also will get strengthened. By June 20, the Bay of Bengal also will be active... I am worried about the monsoon in the interior parts of the country. There could be a delay in onset here. Farmers should be very careful for not going for early sowing etc.”
Climate experts and meteorologists cited the formation of Cyclone Biparjoy over the southeast Arabian Sea and pointed out that it pulled all the convection along its track leading to the weakening of monsoon flow. The monsoon flow was expected to resume properly once the cyclone dissipated.
“Biparjoy is not good for our monsoon because it is pulling all the moisture along with it away from the Indian coast. Its formation is not near the Indian coast and hence monsoon progress will remain very poor until around June 12. It may strengthen the cross-equatorial flow after the cyclone dissipates, but that is a long way away,” an IMD official said on June 6 when the cyclone formed.
The cyclone pulled away most of the moisture. It rapidly intensified over the southeast Arabian Sea on Tuesday and Wednesday from a deep depression (55.65 km per hour) to a very severe cyclone (121 km per hour) in just 24 hours. That marked an increase in windspeed of 65 km per hour in 24 hours, which is termed rapid intensification, climate scientists said.
Vineet Kumar Singh, a researcher at South Korea’s Jeju National University who is tracking Biparjoy, said the cyclone will not make landfall at least until June 14 or 15. “It is moving very slowly. It can be one of the longest-lived cyclones to develop in the pre-monsoon season. From June 12 onwards, Biparjoy is expected to move slightly northwest but after June 13, its path is uncertain. The cyclone will continue to divert moisture for the next five days. One thing for certain as of now, no strong monsoon current at least until June 18.”
Palawat said there was some rainfall in parts of Kerala due to the cyclone that pushed some moisture towards the west coast since it is a very large system. He added that westerly winds were expected to pick up over the next two to three days. Clouding was likely to increase as the cyclone moved northwards and picked up moisture from around it.
Palawat asked farmers to consider commencing the sowing after a week or 10 days in view of weak onset. “Once rains pick up sowing can begin so that crop is not affected. June rains may be below normal due to delay in rains,” Palawat said.
Rains were expected to pick up over northeast India in view of a low-pressure area developing over the Bay of Bengal, which will help pull monsoon winds to the region.
Indian Institute of Tropical Meteorology climate scientist Roxy Mathew Koll said since Cyclone Biparjoy was away from the coast, it was taking up a large share of the moisture. Koll added the monsoon rains may not be widespread at least for the current week. “It is not a classical monsoon onset. The rains we are seeing over Kerala is the monsoon picking up the leftover moisture from the cyclone.”
Last year, IMD declared the monsoon arrival even though all criteria were not met. On May 16, it said the monsoon was likely to arrive in Kerala on June 4 with a model error of +/-4 days.
HT on June 1 reported the monsoon progress was likely to be dampened after its expected arrival in Kerala around June 4 with a model error of +/-4 days due to the chances of the development of a low-pressure area over the Arabian Sea around two days later. Experts
IMD has forecast a “normal” monsoon at 96% with an error margin +/-5%) of the long-period average (LPA) of 87 cm calculated from 1971 to 2020. Skymet Weather has said “below normal” rainfall was expected at 94% of LPA with an error margin of +/-5%.
There is a nearly 100% probability of El Nino conditions during monsoon. It is expected to continue until next year, IMD said last month. El Nino is characterised by an unusual warming of waters in the eastern equatorial Pacific Ocean, which has a high correlation with warmer summers, drought, and weaker monsoon rains in India.
The 2023 El Nino is expected to develop following a triple dip La Nina event (2020-22). La Nina is the opposite of El Nino and is characterised by cooler currents in the equatorial eastern Pacific.
