Monitoring the Situation
Between June and Sept, Tamil Nadu recorded 26cm, around 20% below normal. Chennai recorded 38cm, 15% below normal; Tiruvallur 32cm, 32% below normal; Chengalpet 18cm, 54% below normal; and Kancheepuram 29cm, 38% below normal. A possible factor is the negative phase of the Pacific decadal oscillation (PDO), a long-term pattern of changes in Pacific Ocean temperatures. The Indian Ocean dipole (IOD), which reflects differences in sea surface temperatures between the western and eastern Indian Ocean, is currently neutral. A positive IOD generally favours the northeast monsoon. Tamil Nadu also recorded above-normal temperatures as weak southwest monsoon rainfall over Kerala led to reduced cloud cover. You Can Also Check: Gold Rate in Chennai | Silver Rate in Chennai | Bank Holidays in Chennai | Public Holidays in Chennai | Chennai AQI | Weather in Chennai | Petrol Price in Chennai | Diesel Price in Chennai | CNG Price in Chennai | LPG Price in Chennai
Chennai gets about 87cm during the northeast monsoon, accounting for nearly 60% of its annual rainfall, while Tamil Nadu receives around 45cm, or 48% of its annual rainfall, during the season. “Conditions may become favourable for the onset of the northeast monsoon between Oct 15 and 21. This year, El Nino, the periodic warming of the central and eastern tropical Pacific Ocean, is likely to peak in Nov and may continue till March 2027. “Since 2001, El Nino years have brought normal northeast monsoon rainfall over Tamil Nadu, whereas in the preceding two decades, El Nino years were associated with above-normal rainfall.
In Oct, central and northern Tamil Nadu are expected to get normal to above-normal rainfall,” said Mrutyunjay Mohapatra, director general of meteorology, IMD. This shows that the relationship has changed,” said Mohapatra. Chennai: Many parts of central and northern Tamil Nadu , which house several of Chennai’s drinking-water reservoirs, may receive below-normal rainfall during the Oct-Dec northeast monsoon, which is likely to set in by the third week of Oct. Chennai may get normal rainfall, while southern and western districts could get above-normal rainfall. Overall, India Meteorological Department has forecast a normal northeast monsoon over south peninsular India. In Oct, some parts of Tamil Nadu, including Chennai, may get above-normal rainfall, while several areas could see below-normal rain. Both maximum and minimum temperatures are likely to remain above normal across Tamil Nadu in Oct. The monsoon is likely to be normal over south peninsular India during Oct-Dec and normal to above-normal over many parts of Tamil Nadu and Kerala. El Nino has been associated with above-normal northeast monsoon rainfall over Tamil Nadu.