“We are expecting next two-three days increased rainfall activity but only for defining the onset, we need certain criteria to be covered, so that is what just we are waiting. But otherwise, monsoon is very close to the southern tip,” says DS Pai, IMD.
There is a delay and now looks like the delay is going to be extended by another three to four days. IMD is forecasting that monsoon should hit Kerala soon and the soon could be this week.
Actually, last almost one week monsoon is organising over Arabian Sea and if you observe last two to three days, clouding has been developing. The winds are getting strengthened. As of now, winds have strengthened to the level that we want, but the depth is only up to 2.1 kilometres. So, we are expecting that next two to three days, conditions will become more favourable. Depth of monsoon westerlies will increase and already since yesterday there has been good rainfall activity, fairly widespread activity over Kerala and we are expecting that next two-three days the winds to become more stronger, depth of westerlies to become more and rainfall activity to increase and conditions to become favourable for onset of monsoon.Help us understand that could you possibly give us a date of the onset of the monsoon considering there is a little bit of a delay, but it is pretty much on track like you are saying?
Yes, as I said, almost monsoon is in our doorstep. You can see that currently, it has covered many parts of southeast Arabian Sea, south Sri Lanka and west Bay of Bengal also. Only a surge at any time can lead it to reach over Kerala. Though as I said, we are expecting next two-three days increased rainfall activity but only for defining the onset, we need certain criteria to be covered, so that is what just we are waiting. But otherwise, monsoon is very close to the southern tip.
So far, it seems that it is a normal prediction for the monsoon. Could you tell us a little bit more because from we understand it is a 96% with a 5% plus-minus room for error.
Yes, so actually this year because of associated with the expected El Nino which is almost certain because all the models are indicating a probability of around more than 95 percentage, so generally El Nino related associated with that monsoon is to be below normal, it happens.
But along with that, we also have got favourable condition, expected favourable condition over Indian Ocean which is what we call a positive Indian Ocean Dipole which can to some extent compensate the negative impact of the El Nino that is why though rainfall will be less than 100 percentage but it will be within the normal range that 96 percentage which we have.
You highlighted about this southwestern Arabian Sea whirlwind formation. Help us understand what could be the implications? Could parts of Gujarat and Maharashtra also have an early onset of monsoon?
See, as of now, there is some cyclonic circulation over southeast Arabian Sea which we are expecting next 24 to 48 hours to become a low-pressure area. But different models are indicating different way. So, if the low pressure moves along the coast, much faster progress of monsoon can be observed along the west coast but some other models are also indicating this low pressure system to move more away from the coast.
So, then, after reaching Kerala, there can be two-three days of stagnation. So, we have to wait and watch because this is a transitional period because monsoon is just there and many models are indicating different, there is a lot of uncertainty in the model forecast from different models, so just maybe it become more clarified after one or two days.
So, we are just waiting for that but as of now, we say that monsoon will be there in the southern tip within the next two or three days, further progress will depend on how the system moves which has got lot of uncertainty.
Historically, how many times monsoon has been delayed, it has got extended from last week of May to first week of June and when that has happened in the past what has been the rainfall distribution pattern for rest of the year?
See, there has been many years when monsoon got delayed, even to 8th or 9th June. For example, in year 1997, there was one of the strongest El Nino ever seen in the last century. In spite of that, monsoon rainfall was 102% of the long period average. So, in short to say that there is no relationship between monsoon arriving over Kerala and total quantum of rainfall that you receive in a season because even after reaching Kerala it can move very faster.
Even last 30 or 40 years, we have seen that compared to earlier year, monsoon is now covering entire country one week earlier than previous normals. So, things are not like that, that delay can cause the quantum reduced rainfall. There is no relationship at all.