In what was a welcome relief for many people in Chennai yesterday saw the return of Sun for a long period of time. While evening saw some parts of the city & suburbs come under short bursts of rains these were isolated mostly. Similar trend of rains continued through the night with isolated short bursts happening at times. Not only Chennai but most parts of North Coastal Tamil Nadu celebrated the return of Sun with rains mostly staying away from the districts of Cuddalore, Villuppuram & adjoining areas of Pondicherry as well.
Satellite image also gives a lot of hope with Peninsular India mostly free of any intense convective clouding compared to the past few days. This could be the trend for the next couple of days until the current Low Pressure Area seen over Andaman Sea moves closer to the East Coast. Satellite image also indicates the influence of the incoming Westerly Trough which has already started to interact with the Cyclonic Circulation over Arabian Sea that is expected to become an LPA in the next few hours.
Wind charts also indicate the weakening of Easterlies as both the circulations start to influence the wind pattern over Peninsular India. This will reflect in the reduction of rainfall over Tamil Nadu. While today we could see some rains over parts of Delta & adjoining areas of Coastal TN along with few parts of South TN & West Interior TN from tomorrow the rains are expected to fade away.
Many could be wondering why we are talking of dry weather when there is an LPA that has formed over the Bay of Bengal. In a crucial difference compared to the earlier two Bay disturbances that were extremely rain bearing for Tamil Nadu & rest of Peninsular India the current LPA has its genesis in a location that is by far the farthest among all. Not only that the starting point is also the Northernmost as well. If one were to compare the starting point of 91B that crossed near Chennai & the current one the difference between the two is nearly 800 kms.
This difference in genesis opens up different dynamics in terms of not only the track but also intensity. With almost the entire Bay ahead of it the disturbance could intensify well in advance compared to the life cycles of the earlier two disturbances. This gives an opportunity for the upcoming disturbance to intensify into a Cyclone with Bay still very warm. This relatively stronger intensity compared to the earlier two disturbances will also give it a higher probability of WNW or NW track compared to the earlier two disturbances.
As things stand given from where the current LPA has started its journey it looks highly unlikely it may bring about an active spell of rains for Tamil Nadu considering another Westerly trough is expected to influence weather over Indian Sub Continent around 4th of December.