Consolidating North East Monsoon showers in 2017
Posted on: 23/Dec/2017 4:50:29 PM
Technically, the easterlies are told to prevail in January and official announcements claim the northeast monsoon to withdraw in later days of January. However, statistically, northeast monsoon would end by 31st of December. It has been one more year! There was good monsoon, and there is going to be not much water problem in 2018 in Chennai. By end of 2017 and starting week of 2018, there are possibilities of easterly waves. These showers are not confirmed though. Below is a brief on the likeliness of unseasonal rain showers in January or February.
After onset of monsoon by end of October, there were 4 systems for the northeast monsoon.
Low pressure during 1st week of November (31st October to 8th November)
There were north coastal starting from Tiruvallur to Tiruvarur districts that spread as rains. Most of the rains Chennai received were during this period starting from first week of November. The showers were prevalent for 9 long days and were too long in the basin. If this rain was not there in the city, it would have ended up in severe drought. There were MJO support. In a single day, there was about 300 mm rainfall.
Depression in the mid of November (11th to 15th November)
Out of this depression, there were rain showers only to Nagai, Tiruvarur, Chennai and Tiruvallur. These were parallel to the TN coast and moved on to Odisha.
Ockhi cyclone (28th November to 2nd December)
Rain showers received during Ockhi cyclone filled Kanyakumari and Tirunelveli dams within just a day or two. There were rain showers in Theni, Virudhunagar districts as well. If this cyclone was not there, all over southern Tamil Nadu would have experienced drought condition. There was MJO support. And Papanasam Dam saw 451mm in a single day when Ockhi cyclone neared TN coast. It was a hell of downpour! In fact, it was for the very first time that Kanyakumari witnessed such cyclonic winds unlike any time in its history!
Deep depression during first week of December (5th to 9th December)
There was not even a single rain shower during this period. It had migrated to Odisha coast.
Districts with worst and most showers in 2017
Districts that performed the worst were Pudukottai with - 49 percent rainfall, Ramanathapuram with - 46 percent, Coimbatore with - 43 percent, Trichy with - 41 percent, Erode with - 36 percent and Sivaganga with - 36 percent.
The districts that performed the best includes those with core northeast monsoon and lying along the coast and southern Tamil Nadu. This includes 48 percent in Tirunelveli, 27 percent in Nagapattinam, 25 percent in Kanyakumari, 23 percent in Chennai, 20 percent in Tiruvannamalai and 20 percent in Karaikkal.
Courtesy: Tamil Nadu Weatherman
