Monsoon arrives a fortnight early across states, says IMD
Heavy to very heavy rainfall is very likely over parts of northwest India during next 3 days
Monsoon has advanced into almost all parts of the country except some parts of Uttar Pradesh, parts of Punjab, Rajasthan and Gujarat within a span of only 10 days. Its progress is at least a fortnight in advance according to IMD scientists.
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; and 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.
Monsoon covered the entire country on June 16, 2013, according to monsoon dates analysed by OP 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. Conditions are favourable for advance of southwest monsoon into most parts Madhya Pradesh; remaining parts of east Uttar Pradesh; Delhi; some more parts of west Uttar Pradesh, Haryana and Punjab during next 48 hours, India Meteorological Department. There was 25% excess rains over the country since June 1. Out of 36 subdivisions, 12 recorded ‘large excess’ rain (60% above normal); 10 recorded ‘excess’ (20 to 59%) and 9 recorded ‘normal’ (-19% to 19%).
“In the last 2-3 days pre-monsoon rain started occurring in parts of Punjab, Haryana, Delhi. Parts of Uttarakhand and Himachal
Pradesh reported heavy rain. Some parts of Uttar Pradesh also reported 10 to 12 cm rain. The easterly winds have picked up so IMD has declared monsoon onset over many parts of northwest India,” said RK Jenamani, senior scientist, national weather forecasting centre.
Monsoon has been very active this year right from onset. The westerly and south-westerly winds are very strong over Arabian Sea and now a low-pressure area over 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 dry regions of Rajasthan and Gujarat,” explained Jenamani.
New monsoon dates were issued by IMD last year based on 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 global climate change.
“For example, the new onset dates are delayed by 3 to 7 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 is advanced. 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 BOB.
“I remember a very long time ago the first monsoon low would form over BOB around June 15, but now it’s forming early as you can see,” said M Rajeevan, secretary, ministry of earth sciences.
“Last year also monsoon had covered the entire country by around June 26 so it’s not rare. The movement of monsoon depends on how early a lowpressure system forms. Its active progress will sustain till the lowpressure system sustains and then monsoon progress may weaken temporarily,” said DS Pai, scientist and head of climate research services at IMD Pune.
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 during next 2-3 days. A trough (area of low pressure) is running from central Pakistan to the centre of lowpressure area over Northwest Bay of Bengal in lower and another trough (area of low pressure) is running from the cyclonic circulation associated with low pressure area to eastcentral 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 next 3 days; over parts of east, central and west India during next 3-4 days; over parts of northeast India during next 5 days and over parts of south Peninsular India during next 4-5 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 Madhya Maharashtra on June 15.