E-Paper
‘Normal’ monsoon likely during Aug-Sept, says IMD
According to IMD data, in July, the country recorded the highest rain after 2005, with a 17% excess but east and northeast India recorded the lowest July rains in 122 years at 45% deficiency.
New Delhi: Monsoon rain during the second half of monsoon (August to September) is likely to be “normal” (94 to 106%) of the long period average, India Meteorological Department has forecast on Monday.
Normal to above normal rain is likely over south India except parts of west coast; westcentral and northwest India. Below normal rainfall is likely over many parts of west coast; some parts of eastcentral, east and northeast India during the next two months, IMD said. The LPA for August and September based on the average rainfall data for 1971 to 2020 period is 422.8 mm.
Though monsoon is expected to be normal over the country for the next two months, IMD has cautioned that parts of east and northeast India which are reeling under high rainfall deficiency may not get adequate rain in the second half of monsoon also. “There is some scope for the high rain deficiency to be recovered in Jharkhand, Gangetic West Bengal and East Uttar Pradesh. But some deficiency may remain for Bihar, some northeastern states and other parts of the Indo-Gangetic Plains. Above normal or excess rains are not expected for the region,” said M Mohapatra, director general, IMD.
Monthly rainfall in August is also likely to be normal (94 to 106 % of Long Period Average) with normal to above normal rainfall likely over most parts of southeast India, northwest India and adjoining westcentral India and below normal rainfall likely over the west coast and many parts of eastcentral, east and northeast India.
During August above normal maximum temperatures are likely over many parts of the eastcentral, east and northeast India and some parts of northwest and south interior peninsular India while normal to below normal maximum temperatures are likely over remaining parts of the country. Above normal minimum temperatures are likely over some parts of east central, east, northeast and hilly areas of northwest India and normal to below normal minimum temperatures are likely over many parts of northwest, westcentral and south India, IMD has forecast.
Currently, La Niña conditions are prevailing over the equatorial Pacific region which is likely to continue upto end of the year. IMD’s Monsoon mission coupled forecasting system (MMCFS) indicates that the negative IOD conditions are likely to develop during the rest of monsoon season. But due to supportive factor of La Nina, Mohapatra said they are not expecting a very significant effect of negative IOD conditions.
La Nina refers to the large-scale cooling of surface temperatures in the central and eastern equatorial Pacific Ocean, coupled with changes in the tropical atmospheric circulation (winds), pressure and rainfall. It occurs every two to seven years. In India, La Nina is associated with strong monsoon and above average rains and colder winters. IOD is the difference between the temperature of the ocean in two parts -- in the Arabian Sea on the west and the Bay of Bengal in the east. A neutral IOD doesn’t affect the monsoon but a negative one is bad for it.
East and Northeast India recorded lowest July rain in 122 years
In July, the country recorded the highest rain after 2005 with 17% excess rain. Highest July rain was recorded in 1988 with 34.3% excess rain followed by 25.1% excess rain in 1994 and 18.9% excess rain in 2005. But east and northeast India recorded the lowest July rain in 122 years according to data presented by IMD. In July 2022 there was 45% rain deficiency for the region followed by 41.3% deficiency in 1903.
HT reported on Monday that highly uneven rainfall so far in the southwest monsoon is impacting the cultivation of paddy and other crops, particularly in the Gangetic plains of Uttar Pradesh, Bihar, Jharkhand and West Bengal, although they were 8% more than normal across the country since June. In July, there was 16.9% excess rain over the country with 10.8% excess over northwest India; 42.7% excess over central India; 60.4% excess over peninsular India and 44.7% deficiency over east and northeast India as on July 31. Rainfall was lower by 8% of average in June. Central India which received very good rains this July recorded as much it had recorded in 1993 last which is 42.7% excess rain.
Mohapatra explained that in June against a normal of 11 low pressure systems days, there were no low-pressure system days which is a major reason for the rain deficiency recorded in June. Despite no formation of LPS, strong cross-equatorial monsoon winds and persistent lower-level strong southwesterly winds and moisture convergence over the northeastern region led to very heavy rain and flooding over Assam, Meghalaya and other northeastern regions in June.
However, in July against a normal of 14 LPS days, there were 21 LPS days. The first LPS formed over north Odisha and adjoining south Jharkhand between July 4 and 8. The second LPS over south coastal Odisha persisted for 11 days between July 9 and July 20. Two more LPS had also formed which helped bring above normal rains to central and south peninsular India. Further, the monsoon trough, an elongated low-pressure area and a zone of high convergence lay south of the normal position for most days of July except July 20 and 21; July 29 to 31 when it was in its normal position or north of normal position. The south of normal position of the trough brought concentrated rains to central and south India but no rain over the paddy belt of Indo-Gangetic Plains.
In June, highest extremely heavy rain events (over 20 cm in 24 hours) were reported in the past 5 years with 80 such events compared to only 35 last year. In July, highest very heavy rainfall events (11.5 to 20 cm) were reported in the past 5 years with 812 such events compared to only 638 last year.
‘Forecast for paddy growing IGP region was not reasonable’
IMD had forecast on July 1 that ‘normal’ to ‘above normal’ rainfall is likely over some parts of north India, central India and most parts of south peninsula in July. ‘Normal’ to ‘below normal’ rainfall is likely over most parts of east and northeast India and areas adjacent to the east central India and some parts of west south Peninsular India during July. Monthly rainfall for July over the country is likely to be ‘normal’ (94 to 106 % of long period average) IMD had said. “Our forecast for central and south India was accurate but for the IGP region particularly Uttar Pradesh it was not accurate. The IGP region has been worst affected by rainfall deficiency this month,” Mohapatra explained.
Monsoon rainfall during the four monsoon months (June to September) is likely to be “normal” at 103% of Long Period Average with a model error of +/-4%, IMD had said while presenting its second stage long range forecast for monsoon on May 31. If IMD’s forecast is realised, this will be the fourth consecutive year that monsoon rain will be in the “normal” or “above normal” category. Last year monsoon rainfall was 99% of LPA (normal); in 2020, monsoon was 109% of LPA (above normal); in 2019 monsoon was 110% of LPA (above normal). The last time India saw four consecutive years of normal or above normal monsoons was 14 years ago, between 2005 and 2008, according to IMD officials. The period between 1988 and 1999 also saw only normal or above normal monsoon years according to IMD officials. The LPA is the average rainfall calculated for the 1971 to 2020 period which is 87 cm.
The Monsoon season, which begins on June 1, is crucial for summer crops and brings about 70% of India’s annual rainfall. It is crucial to the country’s agriculture, which is one of the mainstays of its economy. Monsoon spurs farm produce and improves rural spending.
Monsoon rains are a lifeline for about 60% of the country’s net cultivated area, which has no irrigation. The monsoon impacts inflation, jobs, and industrial demand. Good farm output keeps a lid on food inflation. Ample harvests raise rural incomes and helps inject demand into the economy.
