PUNE: That rain has a habit of being fickle is a no-brainer but when the monsoon pitches tent in one place and refuses to budge, it’s a cause of concern. Climate scientists are seeing a unique pattern this August with fewer monsoon breaks over parts of the core rainfall zone such as
Madhya Maharashtra
and Vidarbha, leading to sub-optimal showers in several parts of northern and northeastern India this wet season.
Scientist Rajendra
Jenamani
of
IMD
’s National Weather Forecasting Centre said: “The biggest monsoon gain in August has been seen in central and south peninsular India, including parts of Maharashtra, where monsoon has been active almost continuously since July. The monsoon trough has hardly moved to the north of its normal position since July, causing deficient rainfall over parts of north and
northeast
India.”
The monsoon core zone also consists of regions like east and west MP, east Rajasthan, Gujarat, Konkan-Goa and Marathwada. “The prevailing pattern has caused rainfall to be sub-optimal in several parts of north India as well as the Northeast,” an IMD official said Wednesday.
In the fortnight thus far this August, Punjab has recorded a rain deficiency of over 50%, whereas Haryana, Chandigarh and Delhi got 29% less rainfall. West and east UP’s deficits were 39% and 46% during the August 1-17 period. A similar situation is being observed in Bihar and parts of the Northeast. Though scientists are scrambling to understand this unusual phenomenon, IMD officials said there was a need for rainfall to pick up over parts of north India at the earliest, especially since monsoon’s withdrawal was expected to start from September.
Jenamani said a fresh low-pressure area was likely to form over north Bay of Bengal around August 19, which will reactivate the monsoon and cause heavy rainfall in central India.
According to DS Pai, director of the Kerala government’s
Institute of Climate Change Studies
, the monsoon trough was south of its normal position during most of July. “This has resulted in large rainfall deficiencies in areas along the plains of Himalayas.”
This July, central as well as peninsular India received record rainfall, while UP, Jharkhand, Bengal and Bihar recorded deficient precipitation, Jenamani said. “In comparison, Odisha has seen major improvement. Parts of Northeast and north India will get good rain only when the monsoon trough moves to the north of its normal position.”
He said various systems, be it depressions or low pressures, are forming consecutively and preventing the monsoon trough from moving north. “July 2022 had a total of 21 low-pressure system days and four low-pressure systems against a normal of three low-pressure systems and 14 low-pressure days,” he said. The same trend continued in August, he said.
