The India Meteorological Department (IMD) expects rainfall during the current South-West monsoon to be ‘below normal', marking a downgrade from its earlier ‘normal' forecast issued on April 19.
The country as a whole will receive only 95 per cent of its long period average (LPA) rainfall of 887.5 millimeter (mm) over the four-month monsoon season from June to September. That makes it a ‘below normal' monsoon, which corresponds to rainfall ranging between 90 to 96 per cent of LPA.
The latest forecast update from the IMD (subject to a plus or minus four per cent model error) is less optimistic compared with its first-stage long range prediction that had pegged overall monsoon rainfall at 98 per cent of LPA. Technically, it translated into a ‘normal' monsoon, defined in terms of aggregate rainfall between 96 to 104 per cent of LPA.
The IMD's forecast downgrade is reflected in its probability projections for various scenarios. There is a 19 per cent chance now of the monsoon even turning out to be ‘deficient' – meaning rainfall below 90 per cent of LPA. That possibility was only six per cent in the April 19 forecast. The likelihood of a normal-to-excess monsoon rainfall has, likewise, been reduced from 64 per cent to 44 per cent (see Table).
The IMD has also released monsoon forecast for the country's four broad geographical regions, and also separately for July and August. While rainfall during the entire season is likely to be 97 per cent of the LPA of 615 mm for North-West India, these are placed at 95 per cent each for East and North-East (LPA of 1,438.3 mm) and Central India (975.5 mm), and 94 per cent for the Southern Peninsula (715.5 mm).
The IMD, moreover, sees rainfall in July for the country as a whole to be only 93 per cent of the LPA, while being 94 per cent in August.
This is significant because the current month so far has recorded cumulative rainfall of over 111 per cent (relative to the LPA for this period), with these at 118 per cent for the Southern Peninsula, 126 per cent for Central India, 134 per cent for North-West India and 89 per cent for East & North-East India.
What this suggests is a weakening of monsoon activity after a great start to the season. “The first half of July could witness a weak phase, though such breaks are normal. Also, we foresee a revival from the second half,” said the IMD Director-General, Dr Ajit Tyagi.
July normally receives 289.2 mm or nearly a third of the season's total rainfall, making it also the month when the bulk of sowing for the kharif season happens. A dry July — and also August — may not be the best news for farmers.