Monsoon to reach Kerala by May 27

Bhubaneswar: The India Meteorological Department (IMD) has announced that this year, the southwest monsoon is likely to set in over Kerala on May 27. Southwest monsoon normally sets in over Kerala on June 1, with a standard deviation of about seven days.

IMD has been issuing operational forecasts for the date of monsoon onset over Kerala from 2005 onwards.  An indigenously developed state-of-the-art statistical model with a model error of ± 4 days is used for the purpose, according to an IMD statement. Last year, IMD had forecast the arrival on June 4 with a margin of 4 days.

The advance of the southwest monsoon over the Indian mainland is marked by monsoon onset over Kerala and is an important indicator characterizing the transition from the hot and dry season to the rainy season. As the monsoon progresses northward, relief from scorching summer temperatures is experienced over the areas.

India Meteorological Department (IMD) has been issuing operational forecasts for the date of monsoon onset over Kerala from 2005 onwards. An indigenously developed state-of-the-art statistical model with a model error of ± 4 days is used for the purpose.

The 6 Predictors used in the models are:

i) Minimum Temperatures over North-west India,

ii) Pre-monsoon rainfall peak over south Peninsula,

iii) Mean sea level pressure over Subtropical NW Pacific Ocean,

iv) Outgoing Long wave Radiation (OLR) over south China Sea,

v) Lower tropospheric zonal wind over Northeast Indian Ocean,

vi) Upper tropospheric zonal wind over Indonesia Region.

IMD’s operational forecasts of the date of monsoon onset over Kerala during the past 20 years (2005-2024) were proved to be correct except in 2015.