Conditions are favourable for some good spells of rain in September. “The climatology and model predictions indicate that the monsoon trough for September extends from Rajasthan to Bay of Bengal.
Once the monsoon trough starts shifting towards the south, during the retreat phase, any system to cross the coast between Odisha and AP will bring good rains. We can expect three to four good spells of rain in September,” O.S.R.U. Bhanu Kumar, an Emeritus Professor in the Department of Meteorology and Oceanography, told The Hindu on Thursday.
Contrary to popular perception, the monsoon rainfall has been better than last year in the three meteorological sub-divisions of AP – Coastal AP, Rayalaseema and Telangana – so far this year.
This indicates that the rainfall is normal in AP by and large. The rainfall in coastal AP is 10 to 12 per cent more than normal. In Rayalaseema it is 1 to 2 per cent in excess of the normal but it is deficit in Telangana by around 2 per cent till a couple of days ago.
“The Indian Ocean Dipole mode is also very favourable this year. The impact of El Nino can be ruled out this year. Even if El Nino develops now, it wouldn’t have much impact on the rainfall.
When the sea surface temperature raises 4 degree Celsius above the normal during November, December, January, and February it could have an adverse impact on the rainfall during the following year,” Prof. Bhanu Kumar said. The crucial months for monsoon rains in Telangana are July and August and for coastal AP and Rayalaseema, September is crucial. “The only problem this year is that there is not much inflow into Srisailam. Had Polavaram project been completed, the situation would have been much better,” he said.
Upper air circulation : An upper air circulation lies over west central Bay of Bengal and adjoining north coastal AP. A trough runs from Orissa to south Tamil Nadu across coastal AP. Under its influence, rain or thunder showers are likely at many places over coastal AP during the next 24 hours. Heavy rainfall is also likely at one or two places over coastal AP during the same period, according to a spokesman of the Cyclone Warning Centre here.
