Depression in Bay to make slow progress at the cost of Monsoon onset

The Well Marked Low has intensified into a Depression in Bay of Bengal over the last 24 hours.  Over the next 24 hours we could possibly see the Depression in Bay intensify into a Deep Depression and subsequently into a Tropical Cyclone by around Sunday evening / late night.  It has been making very slow progress pretty much being stationary for most parts of the day yesterday before late in the evening starting to move in a NE direction slowly.


Models are fairly consistent on two scenarios for this disturbance.  In the first 48 hours or so it is expected to make a East / Northeast Movement towards the Myanmar coast.  From there on models are consistent on the disturbance to track back in a Westward direction towards Indian coasts.

As we had explained in our post a few days back tropical disturbances like the current depression in bay are the local level triggers for the winds to change directions.  These direction change are the first step towards the setting of the monsoon and subsequently bringing in the rains through a combination of Tropical disturbances and Easterly waves.

The depression in Bay is already moving slowly and in the process of making a recurve back into Indian Shores there could be some stationary positioning which could delay the completion of the life cycle for this tropical disturbance.  With the disturbance currently being in a NE position to us it is futile to expect Easterlies to move in for us until the system complete its life cycle.  The longer it stays in the open waters around North Bay we could see further delay in the onset of Northeast Monsoon over Tamil Nadu.


Yesterday saw parts of interior and South Tamil Nadu receive rains at many places with Theni district recording good rains at Bodi, Andipatti and Periakulam.  Today also rains are expected in many places to the South of Pondicherry with the delta region expected to record moderate to heavy rains in a few places.

Chennai will see a status quo of weather prevailing, moderately warm during the day and pleasant in the night.