Dams in Maharashtra only 58% full, monsoon set to withdraw from Sept 1

PUNE: The southwest monsoon may start withdrawing even before it gave the country its share of rain. With dams half full in Maharashtra and the country staring at an overall rainfall deficiency of -12%, the Indian Institute of Tropical Meteorology (IITM) has sounded the monsoon withdrawal alarm from early September.
A recent extended range forecast by IITM has put the monsoon withdrawal date from northwest India as September 1, indicating that the overall deficiency in rainfall is only bound to increase then.The monsoon usually withdraws from central India and parts of Maharashtra from October 1, the process could be faster this year, scientists said.
Technically, the monsoon withdrawal is on schedule, only this time it is ending when large parts of the country have remained parched through the season. Poor rain has hit kharif crops in Maharashtra and driven farmers to suicide in Marathwada, which has recorded the highest rain deficit in the country at – 50%. Other parts of the country that are badly hit are central Maharashtra, northern Karnataka, eastern and western Uttar Pradesh and Punjab. The total storage in the 91 main reservoirs across the country has plummeted to 58% of the total live storage capacity, a recent Central Water Commission (CWC) report stated.
Officials said water scarcity in these parts is imminent now, the concern compounded by the fact that there is no rain likely even before the withdrawal begins. An IITM scientist said there is no monsoon system over the Bay of Bengal till mid-September. In fact, the extended range forecast, which was based on the initial conditions on August 24, further showed that rainfall in September may be as bad as that in August. "Rainfall anomaly will be mainly negative over the entire country except northeast and parts of southern peninsula for the next 10 to 15 days," the forecast said.
"Generally, a monsoon system forms over the Bay of Bengal by mid-September, and moves towards central India and the western parts of the country, thereby slowing the process of monsoon withdrawal to some extent. The recent forecast however shows an absence of any such monsoon system over Bay of Bengal by mid-September, in which case, the withdrawal may even be fast this year," the scientist said, adding, "This situation is typical of an El Nino year, when monsoon withdrawal begins early and is faster than usual."
However, more concrete information on this will be revealed in subsequent extended range forecasts, officials said.
The forecast did not even see any significant monsoon intra-seasonal oscillations (MISO) activity for the next 10 to15 days. MISO is a large-scale system associated with monsoon. India is said to get significant rainfall under the influence of MISO, even during El Nino years.
The India Meteorological Department (IMD) has, however, not declared monsoon's withdrawal dates as of now. Officials at the met office said they would wait for some time to declare the time-frame of monsoon withdrawal this year. "Monsoon has become weak. However, there could be a western disturbance during the first week of September. We would therefore wait for a western disturbance and only then declare something," the official said.
A western disturbance is usually associated with rains and a monsoon withdrawal cannot be declared during the event of rain. One of the parameters of monsoon withdrawal is cessation of rainfall activity over the area for continuous five days.
G P Sharma, vice president, meteorology, at Skymet Weather Services said that the private forecaster is currently observing the situation and has not declared the withdrawal date as of now. "Withdrawal of monsoon is a long process, beginning from west Rajasthan. It takes 15 days for monsoon to withdraw completely from west Rajasthan. Also, every year there is some variability in monsoon's withdrawal dates. Like, last couple of years, monsoon withdrawal was delayed," he said.