‘Break’ monsoon likely to disrupt sowing of crops, says IMD
The country will receive “normal” rain in July, between 94% and 106% of long period average, but monsoon will revive only during the second week, India Meteorological Department said in its forecast for the month on Thursday.
It also cautioned that subdued monsoon conditions during the next seven days are likely to impact agricultural activities like sowing and transplantation of crops, irrigation scheduling, etc, and also affect power requirements.
Crops sown early will require protective irrigation to stop soil moisture from evaporating. But the sowing of other major crops like rice in northwest and central India may not be affected.
During July, when most of monsoon rain happens normally, "below normal" (<94%) to "normal" (94% to 106%) rain is likely over most areas of northwest India, parts of south peninsular, central, east and northeast 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.
The latest global model forecasts indicate that the prevailing neutral El Nino-Southern Oscillation (ENSO) conditions are likely to continue over the equatorial Pacific Ocean and that there is an enhanced possibility of development of negative Indian Ocean Dipole (IOD) conditions over the Indian Ocean during the July to September period.
“While neutral ENSO conditions don’t affect the monsoon, negative IOD conditions are not favourable to Indian monsoon. This is because the sea surface temperatures are higher in the eastern equatorial Indian ocean while cooler sea temperatures are found near the Somalia coast, so it doesn’t support the monsoon progress. There is, however, still a high probability of normal monsoon over the country during July,” said M Mohapatra, director general, IMD.
As sea surface temperature (SST) conditions over the Pacific and the Indian oceans are known to have strong influence on Indian monsoon, IMD is carefully monitoring them, IMD said in its statement.
ENSO is a periodic fluctuation in sea surface temperature and the air pressure of the overlying atmosphere across the equatorial Pacific Ocean according to the National Oceanic and Atmospheric Administration.
ENSO has a major influence on weather and climate patterns such as heavy rain, flood, and drought. Like ENSO, the change in temperature gradients across the Indian Ocean results in changes in the preferred regions of rising and descending moisture and air which is called the IOD according to Australian Bureau of Meteorology.
Mohapatra said monsoon covered most parts of the country except parts of northwest India, including Haryana, Delhi, Punjab, parts of Uttar Pradesh and Rajasthan by June 19 but monsoon flow started weakening from June 26 onwards. This was mainly because of strengthening of mid-latitude westerly winds which weakened the flow of easterly monsoon winds; unfavourable Madden Julian Oscillation location; and absence of formation of any low-pressure system over North Bay of Bengal which could bring rain.
Spatially, monsoon coverage reduced significantly in the past two days and the monsoon is unlikely to revive in the next seven to 10 days, Mohapatra said. “There is a chance that a low-pressure area will form over the Bay of Bengal around July 11 or 12. There is no chance of monsoon picking up very much before that,” added Mohapatra.
“Break monsoon phases occur during monsoon. There have been some break monsoon phases which have lasted for 10 days. This is not a record of a situation but cannot be called normal either,” Mohapatra said during the briefing.
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 will be significantly affected and farmers will have to depend on contingency crops. They may choose short duration crops like millets, green gram etc but those are also difficult to source. In northwest India there is no rain till now so only those supported by irrigation will go ahead. This is a significant setback,” said G V Ramanjaneyulu, executive director, Centre for Sustainable Agriculture, Hyderabad.
Humidity likely to increase over NW India
Heat wave conditions are very likely over Punjab, Haryana, Chandigarh, Delhi and some parts of Uttar Pradesh, north Rajasthan, and northwest Madhya Pradesh during the next couple of days. But it is likely to decrease in intensity and coverage due to south-westerly winds from the Arabian Sea.
Scientists are expecting south-westerly winds from Arabian Sea to affect the northwest region, including Delhi, for a week which will help abate heat wave conditions, but humidity will increase and may lead to very uncomfortable conditions as the impact of heat will be accentuated with high humidity.
Flooding likely in NE
Under the influence of strong, moist south-westerly winds from Bay of Bengal blowing to the northeastern states and parts adjoining east India, widespread and very heavy to occasionally extremely heavy (over 20 cm) rain is very likely over Bihar, sub-Himalayan West Bengal, Sikkim and northeastern states during the next five days. Continuous rain is very likely to increase the inflow to rivers and reservoirs originating in the Himalayas, leading to flood like situation in some catchments, IMD has warned.