Many parts of Tamil Nadu received rains last evening / night under the influence of the Well Marked Low which intensified into a Depression yesterday noon thereby becoming the first depression in nearly a 100 years over Arabian Sea during the month of March.
This disturbance currently lying about 300 kms to the Southwest of Trivandrum according to IMD is now expected to intensify into a Deep Depression over the next 24 hours or so. The next 12 – 24 hours will possibly see the system maintain intensity post which it will slowly start to diminish in influence under slightly less favorable conditions.
Nevertheless the depression has given fairly widespread rains in South Tamil Nadu and scattered rains to most parts of Tamil Nadu except the Northern parts of the state. Theni district that was in the news for the last couple days due to the tragic incident of trekkers getting caught amidst Forest fires in the upper reaches of Kurungani Hills also saw some moderate rains lash many parts of the district bringing some relief from the forest fires that have been raging in the area for the last few days.
The Highlight last night has to be Tirunelveli district which saw widespread rains with some heavy spells lashing the district after midnight. The TN Public Works Department ARG at Kadayam to the West of Tirunelveli recorded 113 mm of which 106 fell in 3 hours between 1:00 and 4:00 AM. Tirunelveli town also has recorded good rains with the IMD AWS there recording 42 mm till 4:30 AM in the morning.
With the Depression now expected to move further North along the coast of Kerala the rainfall pattern will slightly change. With the angle of wind changing the rains in South TN will slow down after the current spell with possibly the next couple of hours seeing rains before they shift towards Kerala. Places like Chennai in the North TN region fall under the more drier Outflow from the High Pressure Zone parked over Bay. This prevents us enjoying any meaningful rain spells from the current disturbance
Parts of North Kerala along with few places in the Nilgiris Ghat could see isolated heavy spells of rains as moisture is likely to get trapped by some of the taller peaks of Western Ghats creating localized favorable conditions for a heavy thunderstorm or two during the later part of the day.
Early part of the day is likely to see the current spell of moderate rains over South TN to persist for a few hours before bringing a pseudo break to South TN from heave spells of rains.