Study on Northeast monsoon forecasts normal or near normal rain in most T.N. districts during November

TN to receive close to normal rainfall in Nov; some districts may experience less in Dec (75).

A district level seasonal forecast brought out by former meteorologists indicates that most districts may receive close to normal rainfall in November. However, some districts may experience relatively less rainfall in December.

The Northeast monsoon long-range forecast of rainfall was done based on South Indian Ocean Convergence Zone (SIOCZ) model as part of a research study by a team of former meteorologists of India Meteorological Department -- Onkari Prasad. O.P.Singh and K.Prasad.

According to the study, the State is likely to end with a close to normal rainfall. Tamil Nadu receives an average seasonal rainfall of nearly 44 cm during NE monsoon. Most of the districts, which have received a deficit rainfall so far since the start of the monsoon, may get compensated with a normal or close to their average share of rain in November. Dharmapuri has been predicted to experience 36% excess rainfall during November.

However, there may be a drop in rainfall during December and districts like Virudhunagar, Salem, Villupuram, Madurai and Krishnagiri may have a shortfall of rainfall by over 20%. The study said that most districts, including Chennai, would end with near normal rainfall by the end of the season as they would be compensated with rains during November. The study recalled that like in 2023, the combination of climate phenomenon, El Nino and positive Indian Ocean Dipole, had previously occurred during 2006 and 2015 as well when Tamil Nadu received 15% and 52% excess rainfall respectively.

Noting that SIOCZ model forecasts were still in research mode, the study said there may be pitfalls in such three month-forecasts for the season. Weather experts added that NE monsoon cannot be controlled by a few weather factors. Earlier, in its monsoon forecast using Australian Rainman International software, Tamil Nadu Agricultural University had said most districts would experience normal NE monsoon rain. Seven districts, including Chennai, Chengalpattuand Tiruppur would receive close to normal rainfall.