As promised earlier, I will talk today to you all about the fourth factor that affects the Indian Monsoon.
Before that the three factors that we looked at were
1. ENSO
2. Mascarene High
3. IOD – Indian Ocean Dipole
Unlike the other three factors, this fourth factor isn’t a new thing to most of us but it is something that is common in Summer. That is ‘Heat’.
Heating up of India Peninsula is the fourth factor which affects the Monsoon. For Indian Peninsula to heat up, the temperatures in May should be higher than that of April. This helps in creating of low pressure that pulls the winds into Indian Peninsula.
Just Look at the Average Temperatures of April and May along with Rainfall Percentages for each of the years in the attached picture.
Looking at the statistics for 16 years for the average temperatures in Hyderabad City, you can observe whenever the May temperature was higher than April we had a Normal monsoon. Refer to the years 2003, 2005, 2006, 2007, 2008, 2010 2011 2013. All these years had Normal, above normal or near normal monsoon ranging from 98% to 108%.
The cooler May is associated with El Nino which results in unseasonal rainfall in all the Monsoon deficit years except 2009 & 2015 where El Nino Dominated.
Summer peaks in the month of May and a hot summer is very much required for good monsoon. 2017 April was a very hot month with 40.7 average but the first two days of may started off on a cooler note at 39 and 38.
So let’s hope for a hot may without much rain so that we can have a rainy monsoon from June to September. My next update on the fifth factor affecting the monsoon and the predictions for 2017 monsoon will come in the last week of May.
