Monsoon: Models painting picture bad to worse. 10-day delay in advancement IITM Meteorology says

(TimesofIndia) The monsoon is likely to be delayed by 10 days, according to scientists at the Indian Institute of Tropical Meteorology (IITM) here. The IITM's third experimental real-time forecast says that a feeble monsoon will reach central India after June 20 as against the usual June 15. Last year, the monsoon had covered the entire country by June 15.

The scientists had earlier forecast that the southwest monsoon would set over Kerala on June 3.

"The low pressure system currently over the Bay of Bengal will move northwards and dissipate after May 30. It was this low pressure system that caused the present heavy rainfall in Orissa, Bihar and West Bengal. These heavy pre-monsoon showers will continue for another two days in these parts. Once the low pressure system over the Bay of Bengal dissipates, pre-monsoon showers in these parts will diminish," an IITM scientist said.

The scientist, however, said that the pre-monsoon showers in Pune on Tuesday had nothing to do with the low pressure system over the Bay of Bengal.

With the advent of supercomputers, the IITM is developing, upgrading and modernizing the long sought-after ERPS (Extended Range Prediction System) with the help of state-of-the-art operational climate models under the National Monsoon Mission. As a result of this, it has come up with an experimental real-time forecast of the active-break spells of the monsoon for up to 20 days in advance.

Consistent with the IITM forecast given on the basis of the conditions on May 16, the recent forecast indicates that the monsoon will reach the Kerala coast by June 3. Rainfall will be confined to the west coast, north-east India and Gangetic West Bengal till June 15.

The forecast says that the surface pressure gradient pattern will be weak till June 12. This pattern, however, seems to become well-defined thereafter. The upper level Westerlies might move northwards slowly after June 12 and reach the northernmost part of India by June 20, the forecast says. 

"Thus, the strengthening and progression of the monsoon seems to be slackened till June 15, with the monsoon reaching central India after June 20 as a feeble current. The large-scale forecast also suggests that the monsoon will be over southern tip for the next 25 days," the IITM scientist said.