Late February / Early March is normally not the time when weather bloggers look for possible disturbance in Bay of Bengal instead the expectation is mostly towards trying to find when the Veppasalanam thunderstorms may start in the interior ares of Peninsular India. But nature does indeed surprise many a times and the current weather charts does provide an opportunity for a welcome distraction during the Off season time in the form of a potential disturbance moving into Bay of Bengal from the South China Sea.
History though says the chances for any organized disturbance during the months of February & March is not very high with just 13 disturbances (Depression & stronger) happening since the year 1891 over Bay of Bengal. Interestingly the tracks also show a certain consistency as well, a NE recurve or a low latitude West to East movement closer to Sri Lankan latitude, is seen in nearly 80% of the instances during these two months indicating the strong influence the Semi Permanent Ridges over the Indian Sub Continent and adjoining regions hold.
The presence of Equatorial Rossby wave over Eastern Indian Ocean & adjoining areas of Maritime Continent is one of the key reasons for weather models showing up this potential disturbance over Equatorial Bay consistently. While playing a favorable role in triggering this potential disturbance ER Wave could also mean the counter circulation south of Equator may retain control over this circulation coming into Bay from East on account of the much more favorable conditions over South Indian Ocean due to the presence of ITCZ in the region.
As one Weather Blogger mentioned offline irrespective of whether the disturbance evolves stronger & comes towards East coast of Peninsular India it is indeed a welcome distraction during the off season time. We will keep a tab on the twists & turns that is ahead of us for the next week or so.