Northeast monsoon 2023 has been predicted to be normal by the National Weather Service. Seasonal rainfall is forecast to be normal, 88%-112% of long period average (LPA) for the three month long season from October to December. The season, though, has not made a promising start, as all sub divisions of South Peninsula other than Kerala, have performed poorly in October.
Based on data from 1970 to 2020, the LPA of northeast monsoon rainfall for South Peninsular India is 334.13mm. The five sub divisions, put together receive about 30% of the annual rainfall during this season. Northeast monsoon is the life line for Tamil Nadu and Puducherry and this meteorological sub division receives about 48% of the annual rainfall during October to December. Individual sub division normal rainfall for the season stands at : Tamil Nadu – 449.6mm, Kerala – 491.6mm, Coastal Andhra Pradesh – 338.1mm, Rayalaseema – 223.3mm, South Interior Karnataka – 204.1mm.
The onset of northeast monsoon can happen anytime between Oct 11 and Oct 27. However, in the recent past, more onset has been observed during 2nd half of October, occasionally spilling over to November. The most delayed onset was on Nov 11 in the year 1915. Northeast monsoon rainfall is largely influenced by global climate parameters such as ENSO, IOD and MJO. While positive IOD favours good monsoon, El Nino does not adversely impact to spoil the seasonal rains.
