Cyclone ‘Gaja’ looks to be slowing down a bit on its tracks, prompting India Met Department (IMD) to delay its landfall from tomorrow morning to evening. Global models confirmed that the cyclone enjoys a favorable environment to sustain, with a low to moderate wind shear, a good window effect on top, and suitably warm ocean waters at its base.
The vertical wind shear (change in wind speed and direction with height) values are low, which confirms that the storm structure is intact. Higher values can lop off the storm head and undermine it. ‘Window effect’ on top refers to the pressure valve generating the spiral winds within the storm an escape route even as it builds more at its base, in effect allowing it to ‘breathe’ and sustain itself. Ocean waters warmed to above the threshold limit of 27.5 deg C.
Based on these attributes, the US Joint Typhoon Warning Centre anticipates the system to undergo intensification; it does not see any weakening on the final stretch as it readies for a landfall.
On Wednesday morning, IMD tracked ‘Gaja’ at about 540 km east of Chennai and 640 km north-east of Nagapattinam, with a projected track to the west-south-west. It has extended the watch for its intensification into an intense cyclone during the next 24 hours and suggested it could happen as early as by this evening.
As per the IMD, while moving further west-southwestwards, it could weaken gradually tomorrow and cross the Tamil Nadu coast between Pamban and Cuddalore as a cyclone in the evening. Rains may start at many places over Coastal Tamil Nadu, Puducherry, and the adjoining districts of South Coastal Tamil Nadu from this evening with a ‘yellow’ alert being declared.
Rainfall has also been anticipated at many places over South Coastal Andhra Pradesh from this evening with heavy falls at isolated places. This would be updated to a ‘red color warning’ tomorrow (not amounting to ‘red alert’) for Tamil Nadu and Puducherry with rains likely at most places and heavy to very heavy at a few places.
Extremely heavy falls (20 cm and above) are forecast at local places over Cuddalore, Nagapattinam, Tiruvarur, Thanjavur, Pudukkottai, Tuticorin and Ramanathapuram districts. As for South Coastal Andhra Pradesh, the ‘yellow alert’ will be retained with the forecast of rainfall at most places with heavy falls at isolated places. The same alert is valid for Rayalaseema, while it will be an ‘orange alert’ (next only to ‘red’) for Kerala with rainfall predicted at most places and heavy to very heavy at isolated places.