Monsoon Predictions of 2019 – Near Normal Versus Below Normal?

IMD issued a Long Range Forecast on Monday 15th April 2019.

This time India Meteorological Department has used the word “NEAR NORMAL”. It is difficult to understand whether it means ‘NORMAL’ or ‘BELOW NORMAL’.

Let us study the data given by the IMD and try to understand.

As per the model used by IMD chances of getting normal rainfall (96 – 104 %) is 39 percent. Chances of getting below normal rainfall (90 – 96 %) is 32 percent. Rest of the probabilities may not be discussed as the values are too low compare to 32 and 39. (Shown in the table below).

 

CATEGORY	RAINFALL RAIN (% OF LPA)	FORECAST PROBABILITY (%)
Deficient	< 90	17
Below Normal	90 – 96	32
Near Normal	96 – 104	38
Above Normal	104 – 110	10
Excess	>110	2

Click here for more understanding of LRF & LPA

SkyMet Prediction:

Skymet too changed LRF forecast issued in March 2019 and predicted 93% of rainfall on 03^rd April during the season which is below normal.

All the agencies are of view that there would be weak El Nino and neutral IOD condition in the season.

 

Previous Predictions of IMD:

IMD predicted 97 % and later reduced to 95 % but the actual rainfall received by the country was 91 % during the monsoon of 2018. North East monsoon also was poor in 2018. After facing drought in 2014 and 2015 India received good rainfall in 2016 which was 97 % during the season.

 

Following data to judge the prediction of IMD & SkyMet:

Year	IMD predicted in %	SkyMet Predicted in %	Actual r/f in %	El Nino/La Nina	IOD
2008	100	–	98	Mod La Nina	Neutral
2009	96	–	77	Mod El Nino	Neutral
2010	98	–	102	Mod La Nina	Negative
2011	95	–	101	Weak La Nina	Neutral
2012	99	–	93	Neutral	Positive
2013	98	–	106	Neutral	Neutral
2014	96	94	88	Neutral	Neutral
2015	93	102	86	Very strong El Nino	Strong negative
2016	106	105	97	Weak La Nina	Weak positive
2017	96	95	95	Decreasing	Neutral
2018	97	100	91	Neutral	Neutral

 

Click here for more understanding of LRF & LPA