Monsoon recovers from slow start – rainfall running 20% higher than “normal”

The SW Monsoon has, after a late, slow start, spread across all of India and is just crossing the NW frontier into Pakistan. This normally only happens around the 15th of July. Just 5 weeks ago the IMD’s updated long range forecast (Forecast 2) warned that the monsoon would be later than predicted and that total rainfall could be deficient.

  1. Rainfall over the country as a whole for the 2015 southwest monsoon season (June to September) is likely to be deficient (<90% of LPA).
  2. Quantitatively, monsoon season rainfall for the country as a whole is likely to be 88% of the long period average with a model error of ±4%.
  3. Region wise, the season rainfall is likely to be 85% of LPA over North-West India, 90% of LPA over Central India, 92% of LPA over South Peninsula and 90% of LPA over North-East India all with a model error of ± 8 %.
  4. The monthly rainfall over the country as whole is likely to be 92% of its LPA during July and 90% of LPA during August both with a model error of ± 9 %.

Moreover the risk of this being a La Nina year could further depress rainfall, we were warned by IMD. The fear of drought led to government updating emergency plans and for state governments to prepare emergency budgets. A private forecaster, Skymet,  however suggested that Indian farmers need not worry too much.

Economic Times Skymet is a young weather forecasting agency that has, with gradually amplifying audacity, been challenging the monopoly of the India Meteorological Department (IMD), the hoary state-led colonial-era institution, on matters related to climate and weather in India. ….. The IMD has usually been the final word on droughts but this time Skymet has asserted that the IMD is grievously mistaken. The IMD expects India to get ‘below normal’ rains during the coming monsoon months between June and September whereas Skymet says farmers and citizens needn’t be worried: India is going to have ‘normal’ rains.

(The IMD scientists – based on my small experience with them – are very sober and very rigorous, doing good science. But the organisation’s presentation skills are conspicuous by their absence and their public relations skills are sadly lacking. The IMD website is particularly poor. They have little clue as to how to present their forecasts for the media or the general public.)

In the event, the monsoon has surged over the last 10 days and the all-India-spread has been reached almost 2 weeks earlier than “normal”. Last year this was achieved on 17th July.

Monsoon spread till 28 June 2015 - Skymet graphic from IMD data

Monsoon spread till 28 June 2015 – Skymet graphic from IMD data

It is still early days and the monsoon is only one month into its 4 month season, but currently the rainfall (weighted average) is running some 23% above “normal”. So far it would seem that Skymet’s optimism may be closer to the mark than IMD’s dour pessimism. A weak La Nina year is still possible but 2015 will not go down as a peak La Nina year.

Rainfall during June 2015

Rainfall during June 2015

In the wettest East/North East region, rainfall is close to normal. In all other regions rainfall has been “in excess”. So far the cumulative rainfall would be classified as being “plentiful”.

 

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