GUWAHATI, April 16 - The India Meteorology Department (IMD) today said that there is maximum probability for normal southwest monsoon rainfall over the country this year.The IMD in a press release stated that quantitatively the seasonal monsoon rainfall is likely to be 97 per cent of the long period average (LPA) with a model error of plus/minus five per cent. The LPA for rainfall during the period between 1951 and 2000 is 89 cm.
It said the long range forecast for the 2018 southwest monsoon seasonal rainfall, for the period between June and September, suggests maximum probability for normal monsoon rainfall (96 per cent to 104 per cent of the LPA) and low probability for deficient rainfall during the season.
It said the moderate La Nina conditions developed in the equatorial Pacific during last year started weakening in the early part of this year and currently have turned to weak La Nina conditions. The latest forecasts from the Monsoon Mission Coupled Forecasting System (MMCFS) and other global models indicate conditions over the Pacific to turn to neutral El Nino – Southern Oscillation (ENSO) climate pattern conditions before the beginning of the monsoon season.
La Nina is the positive phase of the ENSO and is associated with cooler-than-average sea surface temperatures in the central and eastern tropical Pacific Ocean.
The IMD further said that at present, neutral Indian Ocean Dipole (IOD) conditions are prevailing over the Indian Ocean. The latest forecasts from the MMCFS and global models indicate weak negative IOD conditions may develop during the middle of the monsoon season. The IOD influences the strength of monsoons over the Indian subcontinent.