More heat before rains revive by weekend: IMD
After a “break” of about 13 days, the monsoon is likely to revive by the end of this week, the India Meteorological Department (IMD) said on Sunday, days after a deviation in the predicted weather pattern led to delayed and scanty rainfall in most parts of the country.
After having announced previously that the monsoon would arrive in the national capital about two weeks ahead of schedule, IMD, in its forecast last week, said the monsoon was unlikely to advance in the remaining parts of north-west India, including Delhi, till at least July 7. If the monsoon arrives on July 7, that will make the 2021 onset in the national capital as delayed as in 2012 and the most delayed since 2006, according to the weather office’s records.
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On Sunday, IMD said there was just 1% excess rain in the country. Between July 1 and July 4 there is a 40% deficiency in rain, with 65.1% deficiency over northwest India. Though Delhi witnessed a two-day spell of rain, temperatures in the Capital are expected to go up once again as western disturbances have moved away and the monsoon arrival is unlikely before July 7-8, said IMD scientist RK Jenamani.
After the “break”, the southwest monsoon is again set to enter an active phase, M Rajeevan, secretary of ministry of earth sciences said, noting that forecast models show signs of increasing rain activity from July 8. He said that models indicate the formation of a weather system in the Bay of Bengal.
“Monsoon Update: @moesgoi models show signs of revival- increasing rains in South, west coast & East Central India from 8 Jul… Models also make an early indication of formation of a weather system over BoB by12th & subsequent active monsoon phase,” Rajeevan tweeted.
This time, the “break” phase of the monsoon is likely to last for 12-13 days. “We have a record of 21 days of break monsoon in the past. So, such fluctuations happen. Monsoon will start reviving by the end of the week, as per our models,” said M Mohapatra, director general, IMD. The current “break” phase of the monsoon has already lasted seven days.
The subdued monsoon also coincides with the critical period of sowing and paddy transplantation. IMD cautioned on Thursday that subdued monsoon conditions in early July are likely to impact agricultural activities such as sowing and transplantation of crops, irrigation scheduling, and also affect power requirements.
“June last week to July first week is the most critical period for farming. For south India, most of the sowing happens around June 15. Those sowing late will not be able to do so, and those who have sown crops, those crops may not germinate when there is such a large gap in rain. The yield may be significantly affected and farmers will have to depend on contingency crops,” said GV Ramanjaneyulu, executive director, Centre for Sustainable Agriculture, Hyderabad.
After a good spell of rains in the first two and half weeks of June, the southwest monsoon has not advanced further since June 19. Delhi, Haryana, parts of west Uttar Pradesh, Punjab, west Rajasthan are yet to see the arrival of the monsoon.
In its forecast for July, IMD said the country as a whole will witness good rainfall this month.
The northern limit of the southwest monsoon (NLM) continues to pass through Barmer, Bhilwara, Dholpur, Aligarh, Meerut, Ambala and Amritsar for the past 15 days.
“Prevailing meteorological conditions, large-scale atmospheric features and the forecast wind pattern by dynamical models suggest that no favourable conditions are likely to develop for further advance of southwest monsoon into remaining parts of Rajasthan, west Uttar Pradesh, Haryana, Chandigarh, Delhi and Punjab during next 4-5 days. Hence, subdued rainfall activity is very likely to continue to prevail over northwest, central and western parts of peninsular India during the next 4-5 days,” IMD said in its bulletin on Sunday.
IMD scientists said the weakening of the monsoon flow this time was mainly because of the unfavourable location of Madden Julian Oscillation (MJO) and the absence of low-pressure systems forming over the Bay of Bengal. “MJO was over eastern Africa; it has started propagating towards the India Ocean. This movement will make conditions conducive for monsoon revival. A low-pressure area is also likely to form over Bay of Bengal around July 11. Together, they will help monsoon advance,” said OP Sreejith, climate monitoring and prediction group, IMD.
MJO is a band of rain clouds that moves eastwards over the tropics and is responsible for most weather variations in the region – including the south-west and north-east monsoons.
Sreejith said that the current “break” phase cannot be compared to break monsoons in the past. “The term break monsoon can be used only when the monsoon has covered the entire country. Right now, the trough cannot be called a monsoon trough either. When the monsoon has covered the country, breaks happen during some years. Models are showing chances of very good rain over the west coast after a week.”
The country will receive “normal” rain in July, between 94 and 106% of long period, IMD said last week. During July, when most of the monsoon rain usually happens, “below normal” (<94%) to “normal” (94 to 106%) rain is likely over most areas of north-west India, parts of south peninsular, central, east and north-east India, IMD said in its forecast. “Normal” to “above normal” (>105%) rainfall is likely over parts of central India and adjacent areas of peninsular India and Gangetic plains in July.
“After July 8, rains are likely to pick up over the west coast covering all of Maharashtra, Gujarat, Rajasthan, etc., and models are showing good rains so the deficiency may be covered gradually,” IMD said.