Erstwhile cyclone ‘Mandous’ has weakened to a rudimentary cyclonic circulation over North Interior Tamil Nadu and adjoining South Interior Karnataka on Monday morning but brought overnight moderate to heavy rain over parts of three contiguous States in the South. Parts of Chennai woke up to a wet morning after being lashed by moderate to heavy rain.
This provided a testimony to the rain-generating capacity of low-pressure areas or cyclonic circulations even after the parent storm may have undergone rapid weakening after landfall. Unlike the ‘here-and-now’ impact of a cyclone, its remnant leaves a lasting impression on land in terms of sustained moderate to heavy rain over a much larger area than the former commands.
Cold, wet, slippery Bengaluru
Bengaluru to the West-North-West, too, was subjected a steady drizzle ever since the depression from a weakened cyclone crossed in from adjoining Rayalaseema and North Interior Tamil Nadu. Temperatures had dipped noticeably throughout the windy and slushy weekend. It continues to be cold though the rain has stopped briefly on Monday morning after a cold and wet night.
Meanwhile, India Meteorological Department (IMD) said the remnant circulation will likely emerge into South-East and adjoining East-Central Arabian Sea off the North Kerala-Karnataka coast. The sea waters are warmer here, and will allow the circulation to build fresh traction. The IMD said it will set up a fresh low-pressure area by Tuesday, while moving away from the coast.
Fresh burst of winds
The easterly winds generated by the ‘low’ and an added south-westerly component from the Arabian Sea will pump up enough moisture to trigger light to moderate rainfall at most places over Tamil Nadu on Monday with heavy rainfall at isolated places. Kerala and Mahe will join the party both on Monday and Tuesday, before the rainfall activity relents over the region.
Squally weather (wind speeds reaching 35-45 kmph gusting to 55 kmph) has been forecast over the South-East and adjoining East-Central Arabian Sea and along and off the Kerala-Karnataka coast on Monday and Tuesday. Fishermen are advised not to venture into the affected areas of the Arabian Sea and along and off Kerala-Karnataka coast on both these days.
Successor circulation brewing
The IMD has maintained the watch for a fresh cyclonic circulation to emerge into the South Andaman Sea by Tuesday, an area where cyclone Mandous traces its roots. Fairly widespread rainfall with isolated heavy falls is forecast over the gateway of Andaman and Nicobar Islands on Wednesday and Thursday. The system will move straight to the West along a track to the immediate South of Sri Lanka.
This will likely bring the next phase of rains over the South Peninsula since the circulation would bring strong easterly flows from the South China Sea into the Bay of Bengal and towards the Tamil Nadu coast. IMD’s numerical models hints at a follow-up circulation mimicking this track from December 22.