An evolving low in Bay that is now under the watch of IMD will hold the key for the weather pattern over early part of next week. During summer months more often than not we see a Low in Bay of Bengal as a trigger to shift the winds from Easterlies to Westerlies in time for the onset of Southwest Monsoon over the Indian Sub continent. Within the next 24 – 48 hours or so we are likely to see the Season’s first Low in Bay.
Models were having extremely divergent views on the possible genesis and tracks over the last few days. The last 24 hours or so though has seen some consistency with regard to the possible genesis of the disturbance. Major models like ECMWF & GFS expecting the genesis to be off Sri Lanka Coast in South Bay and adjoining waters of Equatorial Indian Ocean.
While the models are consistent with the possible genesis location there is still some divergence on the track and intensities. Overall though the pattern that is emerging is an initial Northwest Movement and a subsequent Northeast recurve with some intensification. The recurve scenario is likely to happen if this disturbance evolves into a strong cyclone. The key to intensification is the genesis location as any track over the Sri Lankan landmass could mean possibly a marginal intensification probably resulting in a more NW track over South Tamil Nadu & interior Peninsular India.
As things stand it would be prudent to wait and watch rather than jump into any conclusions on possible impact for Tamil Nadu though it is likely we are going to see some rains starting from Sunday over most parts of the state. The likely quantum of rains and actual areas of impact would be clearer by tomorrow with better consistency expected from the models in terms of the track and likely recurve location as well.