Cyclone ‘Mandous’ over South-West Bay of Bengal kept the weathermen on tenterhooks as the storm beat earlier forecasts and showed signs of intensification towards Thursday evening. India Meteorological Department (IMD) promptly revised and upgraded the outlook for the storm to the next level as a severe cyclone, to be officially declared later in the night.

The cyclone had showed weariness and slowed in the morning but burst forth doubling speed to 12 kmph as it lay about 280 km East-North-East of Trincomalee and 380 km East of Jaffna (both Sri Lanka); 420 km East-South-East of Karaikal and about 520 km South-East of Chennai. The severe cyclone is expected to maintain its intensity till Friday morning, the IMD said.

Landfall near Mahabalipuram

It is forecast to weaken gradually back into a cyclone over the seas and the IMD has not changed the expected landfall area on the North Tamil Nadu and Puducherry to adjoining South Andhra Pradesh coasts between Puducherry and Sriharikota around Mahabalipuram with a maximum sustained wind speeds of 65-75 kmph gusting to 85 kmph around Friday midnight. 

Light to moderate rainfall has been predicted on Friday at most places with heavy to very heavy rainfall at a few places and extremely heavy rainfall at isolated places over north coastal Tamil Nadu, Puducherry; isolated heavy to very heavy over adjoining south coastal Andhra Pradesh, north interior Tamil Nadu and Rayalaseema; and heavy at isolated places over south interior Karnataka and Kerala.

Less warm waters

On Saturday, a day after the landfall, the rainfall is likely to reduce to being light to moderate at most places with heavy to very heavy rainfall at isolated places over north Tamil Nadu and Rayalaseema and heavy at isolated places over south coastal Andhra Pradesh, south interior Karnataka and Kerala. 

Cyclones and tropical storms thrive best on waters warmed beyond the threshold of 27.5°c. On Thursday, however, sea-surface temperatures were cooler along the north Tamil Nadu-south Andhra Pradesh coasts, a disincentive for strengthening. But the cyclone apparently took advantage of the lower wind shear values (disruption from opposing winds) to intensify and gather speed.  Earlier, the cyclone formation itself had been delayed several hours than expected until midnight on Thursday.