கார்த்திகை மாதம் போனால் கடும் மழை இல்லையே wrote Vairamuthu for the film Duet 15 years back. While we have seen Northeast Monsoon extend at times well into January more often than not heavy rain episodes start to fade away from mid December, in particular for North TN unless there are supporting synoptic conditions.But at times Nature does surprise us with some unexpected rains too. Yesterday saw many parts of Chennai receive sharp spell of showers that lasted for about 10 – 15 minutes.
Overall though looking at how the conditions currently prevailing over Indian Ocean it appears so a seasonal shift towards Southern Hemisphere is well & truly on. Influence of Equatorial Rossby wave is seen over Indian Ocean but the disturbance south of Equator seems to be taking more energy indicating the shift in ITCZ conditions into Southern Hemisphere. Additionally MJO influence is seen to improve over Maritime Continent which will bring the suppressed phase over Indian Ocean soon. If NEM 2019 decides to surprise us the prevalence of MJO over Maritime continent could push a pulse into Bay but as things stand probability looks weak.
The influence of Easterlies is seen favoring from south of Delta latitude. This is likely to bring some moderate rains over a few places in Delta districts & South TN today. North TN including Chennai will remain relatively dry though one or two places could get light drizzle during the morning hours.