Monsoon rains in August and September are likely to be more than anticipated with chances of a particularly active September. Rains during June and July have so far been scrupulously textbook with India getting 44.7cm (until July 30) as opposed to the historical normal of 44.3. This has contributed to farmers sowing more than what they did same time last year.
In a forecast update on Friday, the India Meteorological Department (IMD) said that rainfall in the “second half of the monsoon” is likely to be 104% — another of their models puts it at 106% — of the Long Period Average (LPA), a 50 year average of what’s usual for that period. Rains within a 4% window of what’s forecast are considered to be ‘normal’ by the IMD.
However, rainfall in August is likely to be only 97% of its LPA, the IMD said, sticking to a forecast estimate from June. August, like July, is a key month for the monsoon as it contributes about 30% of the overall monsoon rainfall. (July tops with 33%). September is the month when the monsoon is on the wane, and contributes only about 16%.
Active September
Were the IMD’s forecast to hold, this would imply that September rains could be significantly more than what’s normal and go up to as much as 20%.
“July rainfall was below what we had expected [the IMD forecast 103% LPA] and subdued rainfall over Central India is likely to continue until August 5,” said Mrityunjay Mohapatra, Director-General, IMD.
“Extended range models show a pickup thereafter and September rains too are likely to be on the higher side,” he added.
Another IMD scientist said that by the second half of the season, La Nina like conditions, or a cooling of the Central Equatorial Pacific, is likely to commence. “In August, though the forecast is for 97%, the inbuilt error of the forecast model is +-9%. And given the conditions emerging, there are chances of more rain than expected. September too is likely to see good rains,” D.S. Pai, head, Climate Research and Services, IMD Pune told The Hindu .
There’s expected to be a strengthening of the monsoon in the first half of August especially in South and Central India, he added.
Data from 685 districts show that nearly 38% registered normal rains, 33% deficient or no rains and 29% excess rains. North, Northwest India and States along the Konkan coast are those that have recorded less rain than normal, according to the IMD data sets.
In June, the IMD had forecast 3% excess rains for July, again with an error margin of 9%, but actual rains have been less than anticipated but within normal margins. In June, the IMD forecast overall monsoon rainfall to be 102% of the LPA but in its latest update has only specified that rainfall will be ‘normal.’
