New Delhi, Jun 9 (IANS): The slow progress of Southwest Monsoon has meant that the all India cumulative rainfall during this year's monsoon first week -- between June 1 to 8 -- is minus 42 per cent (large deficit), the Extended Range Forecast issued by the IMD said on Thursday.

Among the regions, the rainfall over northwest India is below LPA by minus 94 per cent, minus 88 per cent for central India, minus 26 per cent for south peninsula and little better, yet deficit of minus 7 per cent below the LPA for east and northeast India, the India Meteorological Department (IMD) data showed.

During the week between June 2 and 8, for the country as a whole, the weekly cumulative all India rainfall departure from its long period average (LPA) was minus 42 per cent with weekly cumulative over northwest India being minus 96 per cent of its LPA. For central India, it was minus 90 per cent of its LPA while for south peninsula, it is minus 30 of its LPA. For east and northeast, it is minus 2 per cent of LPA.

Starting this year, the IMD has introduced the new rainfall normal - called as the LPA, the Long Period Average - based on rainfall data from 1971-2020 for the southwest monsoon season replacing the current rainfall normal that was based on data from 1961-2010.

From Thursday onwards, the IMD is expecting regular advancement of SW monsoon as the Extended Range Forecast said that conditions are favourable for advancement of SW monsoon over some more parts of east India and some parts of central India by June 15. It also said that the southwest monsoon is likely to advance over some more parts of east and central India and some parts of Uttar Pradesh by June 22.