While Northeast Monsoon has possibly seen some very active & vigorous phases in South TN and also at times over Delta as well North TN has pretty much seen very subdued monsoon conditions so far. Both Chennai observatories are seeing deficit conditions with Chennai Nungambakkam recording only 40% of the NEM average so far and Meenambakkam slightly better of at 60% of the average rains as of today. Nevertheless things are looking up for North Tamil Nadu with weather models estimating an active phase of Northeast Monsoon for the region including Chennai.
Cyclone Gaja may have wrecked havoc across Central Tamil Nadu but it is possibly the favorable throw of dice as far as North Tamil Nadu is concerned. Moving into Arabian Sea as a strong disturbance it has brought back some order to the Easterlies which will make a lot of difference to the rainfall prospects in the coming days. Initially IMD expected Gaja to reintensify into a cyclone once again in Arabian sea though it appears it may maintain its Deep Depression status and fade away towards Oman coast in the coming few days.
In the meanwhile the current Upper Air Cyclonic Circulation near Andaman is likely to descend down to surface levels as a possible low Pressure Area in the next 24 hours or so. Under the influence of the fairly strong Easterlies it is likely to drift towards the coast of Tamil Nadu / Sri Lanka in the next couple of days. This will possibly bring forth the best phase of Northeast Monsoon 2018 to North Tamil Nadu.
While almost all of Tamil Nadu is likely to see slightly above normal rains during the coming week important mention needs to be made to North Tamil Nadu as it could fall under the convergence of dry and moist winds. The moist winds will be circulated by the developing low pressure while the dry Northerlies tend to normally reach up to South AP latitude at this time of the year. This convergence is likely to trigger intense thunderstorms and bursts of heavy rains which could create temporary water logging.
The coming week will also see some moderate to heavy spells of rains over the Delta region which could hamper relief activities. Though in isolation the spells of rains in Delta may not be too much but considering the aftermath of Cyclone Gaja it could trigger some panic.
The highlight of the coming week is likely to be North TN and there exists fair optimism that both observatories of Chennai could wipe out a majority of the deficit accumulated so far in NEM 2018