The India Meteorological Department (IMD) on Monday said monsoon rain is likely to be “normal” in August and September, between 95 per cent and 105 per cent of the long-period average (LPA).
According to the IMD, during August and September, “below normal” to “normal” rainfall is likely over many areas of the northwest, east and northeast India while “normal” to “above normal” rainfall is most likely over peninsular India and adjacent central India.
The monsoon halted its progress across central India in the third week of June, resulting in a three-week delay in the rain during the key sowing season.
The IMD said after witnessing uncharacteristically heavy rain and an irregular weather pattern in July, Delhi is likely to receive normal rainfall in August. Normally, the national Capital receives 210.6 mm and 247.7 mm rainfall in July and August, respectively.
In another forecast for August, IMD Director General Mrutunjay Mohapatra said monsoon is also likely to be normal in the month. West Madhya Pradesh and adjoining Rajasthan, some parts of interior Maharashtra, Jammu & Kashmir, Ladakh, some parts of Punjab and Himachal Pradesh are likely to receive below-normal rainfall in August, Mohapatra said.
Karnataka, Tamil Nadu, Telangana, Rayalaseema region of Andhra Pradesh, Konkan and Goa, central Maharashtra, south Gujarat, northeastern States, Bihar are likely to receive above-normal rainfall during the month, he added.
July recorded a 7 per cent deficiency in rain, with 26 per cent deficiency over east and northeast India; 27 per cent excess over south peninsula; 7 per cent deficiency over northwest India and 7 per cent deficiency over central India. June ended with 10 per cent excess rain but a monsoon break of around 12 days from June 19 to July 11 led to a long dry spell in many parts of the country.
Every year, the IMD issues forecast for the second half of the southwest monsoon, for August and September. The spatial distribution suggests that below normal to normal rainfall is likely over many parts of the north, east and northeast parts of the country. Normal to above-normal rainfall is most likely to be experienced over most parts of peninsular India and adjacent central India, the IMD said.
The IMD has also started issuing a month-wise forecast for the four-month rainfall season from this year. For August, it said, “Rainfall averaged over the country as a whole is most likely to be normal (94 to 106 percent of LPA).” The LPA of the August rainfall over the country as a whole for the period 1961-2010 is 258.1 mm.
Mohapatra added that currently the Sea Surface Temperatures (SSTs) and the atmospheric conditions over the equatorial Pacific Ocean indicate neutral ENSO (El Nino) conditions. The SSTs are one of the major factors that influence the Indian monsoon. The SSTs over central and east equatorial the Pacific Ocean are showing a cooling tendency.
The latest forecasts suggest that ENSO neutral conditions are likely to continue during the remaining part of the monsoon season and increased the possibility of re-emergence of the La Nina conditions in the end of the monsoon season or thereafter. La Nina is associated with the cooling of the Pacific Ocean waters, while El Nino is linked to its heating. Mohapatra said it has been observed that if October, November and December have La Nina conditions, then it helps in cyclogenesis (development or strengthening of cyclonic circulation in atmosphere) over the Bay of Bengal.
Rainfall between 96 per cent and104 per cent of LPA is considered “normal”; between 90 per cent and 96 per cent is considered “below normal” and between 104 per cent and 110 per cent is considered “above normal” by IMD.