‘Monsoon Low’ good omen for Odisha; wet Puri forecast on Rath Yatra Day

Last year a Monsoon Depression was formed in July end. 2018 Monsoon was erratic and devastating for Odisha. The 'Monsoon Low' in 2019 rekindles hope of good monsoon 2019 sans destruction.

Bhubaneswar: With Odisha having recorded a nearly 34 per cent deficient rainfall vis-a-vis the normal for the month of June till date, the State is all set to witness a virtually wet week during June last week and further extending up to July first week.

Importantly, when the pilgrim town of Puri will be witnessing the annual Rath Yatra on July 4, weather analysis shows that the city is likely to witness a morning spell of rains, which seems to be an important alert for the government officials overseeing the Rath Yatra here. A good rain spell is sufficient to flood the Badadanda (Grand Road).

Meanwhile, weather experts see the formation of ‘Monsoon low’ in the Bay of Bengal a good sign for the SW Monsoon 2019. Significantly, it is the monsoon depressions that help in making the SW Monsoon active over the landmass of the country.

Weather analysis showed that during the Monsoon season of June – September, in the normal course, nearly two depressions per month used to be formed in the Bay of Bengal (BoB) that helped in making the monsoon flow quite vigorous.

But for the last few years, the number of monsoon depressions in BoB had greatly reduced.  Monsoon 2018 had seen mere three monsoon depressions. Last year, the first monsoon depression was formed by the end of July only.

Though this year the month of June is not going to see any monsoon depression, only a ‘Monsoon Low’ will form by June 21-22 and the ‘Low’ is likely to move to the landmass of south Odisha and north Andhra coast by June 24 – 25. The ‘Low’ will bring fairly widespread rain over the coastal and southern regions of Odisha, including Puri.

In weather parlance, the system is termed as ‘Monsoon Low’, not Monsoon Depression, as the wind speed associated with the system is around 12 knots. A low pressure area will only be termed as Monsoon Depression when the wind speed will be over 17-30 knots.

Experts blame lower tropospheric relative humidity level in BoB for  fewer Monsoon Depressions. Simply put, the lower region of atmosphere over the earth surface has less moisture content (humidity). And this reduced moisture over BOB is linked to warming of northern Indian Ocean that sucks the moisture from the BoB atmosphere.

This analysis showed a clear link between global warming and reduced monsoon rains over India.

Met watchers at IMD here believe that post Fani, the tropospheric humidity level over BoB has increased, which is why when the Monsoon jet has been little weak this year, the high humidity at the lower troposphere has resulted into a ‘Low’ to boost Monsoon flow.

And given that the weak El Nino conditions to persist till the end of monsoon,  also most importantly the Indian Ocean Dipole (IOD) remaining neutral till monsoon end, Met observers here believe more such monsoon depressions in July and prior to mid-August  would bring good rain to Odisha. High rate of Monsoon Depressions during June-Sept may act as a barrier for formation of devastating cyclones in BoB during October.