Given the upcoming cyclonic storm, South India especially Chennai and Puducherry need to be high alert.

Last week depression in the Arabian sea intensified into a borderline tropical storm named Gati. This cyclone will be moving towards Somalia coast to make landfall near Ras Hafun. Another Monsoon depression is likely to come up over the south-west Bay of Bengal. There are chances of this system strengthening to even a maiden cyclonic storm of the season in the Bay of Bengal. If so, that system is likely to be named as ‘Nivar’ and will be crossing Tamil Nadu coast on 25th of November. Extremely heavy rains are expected over Tamil Nadu and Kerala, the possibility of a flood-like situation is likely at many places.

The air pollution in Delhi this year was on the verge of declaring health emergency early in the season. The national capital witnessed the worst week of foul air when the AQI was narrowly transiting between very poor to hazardous. Possibly this could be the worst fortnight of November in the past few years. Then comes the rains on the 15th of November and the post-Diwali day becomes the best ever seen in the recent past. The air quality which had plunged to very severe turned moderate at most places and even satisfactory at a few of them. But the sense of joy was short and AQI worsened again. Sequential passage of western disturbances across the hilly states dropped the minimum temperature in the plains to a record low of single digit at most places over Punjab, Haryana and Delhi. Kapurthala recorded the lowest temperatures of 4.4 degrees on the 22nd of November. The inversion layer has become thick and difficult to scatter the pollutants with the marginal heating as we move into the fourth week of November. There is a substantial relief from stubble burning and their dwindling number suggest to have crossed the peak and are expected to decline further. The new air panel as constituted by the government in place of erstwhile EPCA has started walking the tight rope amidst speculations of fear of failure or hope of success. It is no way going to be easy to catch the bull of pollution by horns and tame it in a short frame of time. Possibly this fight is going to be a long drawn to bring the culprits within the ambit of legislation for strict implementation. During the current season, the commission has quite rightly decided to strictly enforce existing laws, rules, guidelines, directions and SOPs to minimise the air pollution on an emergency base. Any new solutions are going to be time-consuming and need to be deliberated upon for judicious implementation.

The seasonal rainfall deficiency is likely to get recovered substantially during the week over the south peninsula. Localised flooding due to heavy rains is likely over Tamil Nadu, coastal Andhra Pradesh, Rayalaseema and Kerala. Winter is also going to tighten the grip and cold wave conditions are likely over plains of north India.

North India

Rain and snow will continue across the hilly states during the first half of the week. Foothills of Punjab and Haryana are likely to have light rainfall during this period. Plains will witness partly cloudy skies with a thin sheet of clouds. The night temperatures will rise during the first half and drop significantly to single digits at many places between 26tha on 29th of November. Misty mornings with chill in the air and shallow fog in pockets is expected over Punjab, Haryana, north Rajasthan and west UP.

East and Northeast India

This will be the least weather active region and practically no rainfall is expected during the week. Night temperatures will drop by 2-3 degrees over Bihar Jharkhand and West Bengal during the latter half of the week. Similar conditions are expected for the entire the north East India

Central parts

Generally, sunny days and clear nights are likely for the entire region on 23rd and 24th. The state of Odisha will experience a drop in minimum temperature by 2-3 degree Celsius. Raina and thundershowers are expected over Odisha, Chhattisgarh and Vidarbha between 25th to 27th which are likely to be more intense on 26th.

South peninsula

A Monsoon depression is likely to form in the south-west bay of Sri Lanka and Tamil Nadu coast. This will intensify into a cyclonic storm, the firs of the season in Bay of Bengal. State of Tamil Nadu needs to gear up to brace for fierce rainfall activity. Gale speed winds accompanied with extremely heavy and flooding rains are expected over Tamil Nadu and Puducherry commencing 23rd November. 24 and 25th November are going to be penultimate days to experience catastrophic weather conditions over most parts. Heavy rains are also expected over Rayalaseema, Andhra Pradesh south interior Karnataka and Kerala during the period.

Delhi NCR

Delhi recorded the lowest minimum temperature of the season at 6.9 degree Celsius on 22nd November morning. This equaled the earlier lowest record of Nov 2006 - this being the lowest in the last 17 years. Earlier Delhi recorded 6.1 degrees on 29th Nov 2003. No rainfall is expected during the week. Mistry mornings and partly cloudy sky are likely during the first half and mostly sunny days in the latter half. Marginal rise in the night temperatures will occur till 25th of November and drop thereafter to record a single temperature again by the weekend to cause a cold wave condition.

Chennai

This will be a rainy week for the city with the threat of a cyclone crossing Tamil Nadu coast south of the capital city Chennai. Heavy rainfall is expected between 23rd and 26th of November. Moderate rainfall will continue thereafter.

Delhi Pollution

This year Delhi NCR is witnessing its lowest share of air pollution post Deepawali. This miracle has been sanctioned by Gods themselves.

On the 15th of November, the entire North-West India including Punjab, Haryana, Uttar Pradesh, Rajasthan, Delhi and North MP received rain and thundershower that washed away most of the pollutants. Wind speed was also remained moderate, which added to the process of dispersal (of pollutants).

Usually, a spike in pollution poster Deepawali is very common, it reaches as high as ‘Hazardous’ category but this year air pollution in the area reached only till ‘Poor’ category that too for a short while, as moderate winds from the west helped in keeping pollution levels low- in ‘Moderate’ to ‘Poor’ category.

Moderate winds will continue for another 24 hours and pollution will not increase. By November 23rd or 24th, wind direction may change, and the speed of winds will also go down leading to an increase in pollution. May increase to very poor category by November 24. But ‘Hazardous’ category when AQI index crosses 500 is ruled out presently.