Winter season is breathing last over Northern Plains and parallelly South Peninsula is racing to catch up the Pre Monsoon season. States of Tamil Nadu, Kerala, Rayalaseema and South Interior Karnataka are the early pickers of seasonal thunderstorms. Mercury levels are scaling high, exceeding 35°C at many places.
These include Dharmapuri, Coimbatore, Madurai, Salem, Paramathy, Alapuzha, Punalur and Cannur. Nandyal in Rayalaseema recorded highest maximum of 37.2°C yesterday, closely followed by Tirupathi at 37.1°C.
Meteorological conditions are shaping up favorably for commencement of pre monsoon thunderstorms, to begin with, over South Peninsula. Heat remains an important ingredient to trigger convective storms over this region. Proximity of ocean on either side of the coastline provides enough moisture to raise the heat and water content of the thunderstorm cells. Interiors are always more vulnerable than the coastal stations.
An oscillating trough in the lower layers of the atmosphere has started appearing over the region and is expected to shift over central Peninsula in the next 48hr. Streaming northeasterly winds from Bay of Bengal with sufficient force are raising the vertical column of instability. Weather activity will be light and isolated during next 72hrs. Spread and intensity will pick up on 26th& 27thFeb and largely cover Tamil Nadu, Pondicherry, Kerala, Mahe and South Interior Karnataka.
Interiors of Tamil Nadu , oriented north-south from Salem, Karur, Coimbatore, Sulur and Tirupur to Thanjavur, Trichy and Madurai will be more vulnerable. Being heat triggered, weather activity will be witnessed during later half of the day on 26th and 27thFeb. It is expected to recede on 28th and vacate on 01stMar the entire region.