E-Paper
Monsoon advances across country 14 days early: IMD
Monsoon is normally expected to cover all parts of the country, except a small part of Rajasthan, by July 5.
Monsoon has entered almost all parts of the country, except some areas of Uttar Pradesh, parts of Punjab, Rajasthan and Gujarat, within a span of 10 days and its progress is at least a fortnight in advance, according to scientists at the Indian Meteorological Department (IMD).
Monsoon is normally expected to cover all parts of the country, except a small part of Rajasthan, by July 5. It advanced to most parts of Madhya Pradesh, entire Chhattisgarh, Odisha, West Bengal, Jharkhand and Bihar, most parts of east Uttar Pradesh and some parts of west Uttar Pradesh, entire Uttarakhand, Himachal Pradesh, Jammu and Kashmir, Ladakh, Gilgit-Baltistan, Muzaffarabad and some parts of north Haryana, Chandigarh and north Punjab on Sunday.
It was in 2013 when the monsoon had last covered the entire country on June 13, as per dates analysed by O P Sreejith, head, climate monitoring and prediction group, IMD Pune.
The northern limit of monsoon (NLM) is passing through Diu, Surat, Nandurbar, Bhopal, Nowgong, Hamirpur, Barabanki, Bareilly, Saharanpur, Ambala and Amritsar. The conditions are favourable for further advance of southwest monsoon into most parts of Madhya Pradesh, remaining parts of east Uttar Pradesh, Delhi and some more parts of west Uttar Pradesh, Haryana and Punjab in the next 48 hours, the weather body has said.
There has been 25% excess rain over the country since June 1. Of the 36 subdivisions, 12 recorded ‘large excess’ rain (60% above normal), 10 recorded ‘excess’ (20% to 59%) and nine recorded ‘normal’ (-19% to 19%).
“In the last two to three days, pre-monsoon rain started occurring in parts of Punjab, Haryana and Delhi. Parts of Uttarakhand and Himachal Pradesh reported heavy rain. Some parts of Uttar Pradesh also reported 10 to 12 cm rain. There is no western disturbance affecting the northwestern region now. This is only because of strong monsoon winds blowing over the region. The easterly winds have picked up, so the IMD has declared monsoon onset over many parts of northwest India,” R K Jenamani, senior scientist, National Weather Forecasting Centre, said.
“Monsoon has been very active this year right from its onset. The westerly and south-westerly winds are very strong over the Arabian Sea and now a low-pressure area over the Bay of Bengal is pulling the monsoon flow. Both branches on the Arabian Sea and Bay of Bengal side are supporting the advancement of monsoon over the country, except in dry regions of Rajasthan and Gujarat,” Jenamani explained.
The new monsoon dates were issued by the weather body last year based on the onset data from 1961 to 2019, and withdrawal data from 1971 to 2019. Until 2019, the onset and withdrawal dates were determined based on records between 1901 and 1940. As per the old monsoon progress dates, the monsoon would cover the entire country only by July 15.
Monsoon’s progress over the entire country has advanced in recent years, according to IMD scientists.
“We had issued new monsoon onset and withdrawal dates last year because we noticed that monsoon dates had advanced in some regions and delayed in some regions in recent years due to many factors, including climate change. The thresholds have changed now. For example, the new onset dates are delayed by three to seven days in many parts of central, west and east India because we noticed this delay while the complete coverage of the monsoon in the country has been advanced,” M Rajeevan, secretary, ministry of earth sciences, said.
Rajeevan added: “This year is exceptional because the monsoon has covered parts of central India very early. Monsoon has covered the entire country by June end in the past but this year, its trajectory is exceptional. Monsoon dates have definitely changed in recent decades, it’s a very dynamic system. Its movement is strongly influenced by low pressure systems forming over the Bay of Bengal. I remember a very long time ago the first monsoon low would form over Bay of Bengal around June 15, but now it’s forming early as you can see.”
“Last year too the monsoon had covered the entire country by around June 26, so it’s not rare. The movement of monsoon depends on how early a low-pressure system forms. Its active progress will sustain till the low-pressure system sustains and then the monsoon progress may weaken temporarily. In recent years, monsoon onset dates have advanced because of a change in its pattern,” D S Pai, scientist and head of climate research services at IMD Pune, said.
A low pressure area is lying over northwest Bay of Bengal and adjoining coastal areas of West Bengal and north Odisha. The low pressure area is likely to move west-northwestwards across Odisha, Jharkhand and north Chhattisgarh in the next two to three days. A trough (area of low pressure) is running from central Pakistan to the centre of low-pressure area over northwest Bay of Bengal and another trough (area of low pressure) is running from the cyclonic circulation associated with low pressure area to east central Arabian Sea. An offshore trough (area of low pressure) at mean sea level is also running from north Maharashtra coast to Lakshadweep area.
Under the influence of above systems, widespread rainfall with isolated thunderstorm and lightning is likely over most parts of northwest, central, east, northeast and south Peninsular India and over parts of west India.
Heavy to very heavy rainfall is very likely over parts of northwest India during the next three days, over parts of east, central and west India during the next three to four days, over parts of northeast India during the next five days and over parts of south Peninsular India during the next four to five days. Extremely heavy rain (over 20 cm) is also very likely over Konkan and Goa on June 14 and 15 and over coastal Karnataka and central Maharashtra on June 15.
