The October climate is cooking up. South West Monsoon is in withdrawal mode. The monsoon trough that was laying over the landmass has moved south over the water. This shift of the monsoon trough over waters doesn't augur well.
As per the IMD's global maritime distress and safety bulletin, the Bay of Bengal is going to witness widespread rainfall and thunderstorm. Such high convection suits to formation and intensification of low pressure systems either in the south-central BoB or Andaman seas.
Against the backdrop, IMD has hoisted a low pressure alert. The premier weather agency of India says, " a low pressure centre likely over north Andaman sea on and around Oct 10." Currently, a cyclonic circulation is lying over central BoB.
As per the weather charts, the north Bay of Bengal and east-central bay have clouds. The wind speed is slow and is measured at around 7-15 km/hr. And it is predicted to rise to 28-30km/hr by Oct 14.
But the wind speed over central, south BoB and Andaman seas will be hovering at around 50km/hr. For which, monsoon is, which is moderate at present in the regions of bay mentioned above, going to be stronger by Oct 13-14.
Strong monsoon over BoB is like laying a red carpet to cyclonic activity. And Andaman sea is famous for giving birth to cyclonic activity because it has high mid-troposphere moisture (sea surface temperature is also over 30 dec C), and coupled with high wind speed, the conditions seem favourable for cyclongenesis.
Above all, the Madden Julian Oscillation, a rainfall and wind activity that moves towards the east, has entered into its strong phase from today. The strong phase is predicted to remain in the Indian ocean till Oct 16. The weak phase will start only after October 25.
Therefore, the period of Oct 7-16 is conducive for cyclone genesis in the south, central BoB and Andaman seas.
Given the conducive conditions in the above-mentioned regions of BoB, the LPS that is going to form has the potential to intensify into a cyclone.
Will It Intensify?
As per the model prediction based on the conditions of BoB and monsoon trough at 11:30 hours today, a low pressure system will form in the south Andaman sea on and around Oct 13 at midnight. At the same hour, another cyclonic circulation extending from south to central bay is predicted to persist. Both will merge by Oct 15.
The system is predicted to undergo rapid intensification. By Oct 15 evening, the system will intensify into a depression. The system will intensify into a cyclone in the next 24 hours.
As per the weather charts of NCEP-GFS, the system will grow to the stature of a very severe cyclonic storm by Oct 17, still over the waters of the bay.
With further rapid intensification, the cyclonic system is predicted to reach near Odisha coasts by midnight of October 17. Moving in the northwest direction, the system is predicted to cross the Odisha coast between Puri and Bhadrak (around Jagatsinghpur) in the morning hours on Oct 18.
If the model predicted parameters are to be believed, the intensification parameters show the cyclone developing into an extremely severe cyclonic storm at the time of landfall.
The predicted cyclonic storm will have a life span of nearly 72 hours over the bay, which is very normal.
As per the predicted timeline, rain or stormy wind is unlikely to hit Odisha this Durga Puja. But the weather system will be going to affect the State from Oct 17 onwards.