Tropical cyclone likely post 7th December

The two weather systems, one in extreme west central Bay of Bengal and the other in southeast Bay of Bengal, have merged into a well-marked low pressure area. This system will intensify and turn into a depression in next 24 hours and further deepen in 48 hours. It is gradually moving in the westward direction and coming closer to the Tamil Nadu coast. This system appears to be reorganising and strengthening and will continue to bring rain in South India.

Following are the two reasons for this consistent low pressure area since the last 4 days are:

• The vertical extent of the system is comparatively lower at 10,000 ft. (the intensity of a low pressure area increases with the increase in its height above sea level)
• Weak wind field- the speed of the wind is quite low at present.

As predicted earlier, this new development has brought in good amounts of rain in Tamil Nadu, with Chennai recording 56 mm, Pamban 98 mm and Nagapattinam 54 mm of rain, on the 2^nd of December. Even other parts of peninsula India, Lakshadweep, Andaman and Nicobar Islands have been receiving light showers, under the influence of this system. The intensity of rain is likely to come down and regain strength after 24 hours, reducing the variation of day and night temperatures substantially.

On the other hand, the lull continues in North India in the absence of any significant weather system. Delhi will continue to maintain day temperatures 4 degrees above normal at 28 degrees, while minimum will remain near normal around 9 degrees, at least for the next one week. The Western Disturbances in the higher latitudes are still not strong enough to bring a change in weather conditions of the northern plains.