ENSO Influence on Bay of Bengal Cyclogenesis Confined to Low Latitudes

Tropical cyclones (TCs) in the Bay of Bengal (BoB) can lead to substantial damage to society on densely populated coastal areas of the Indian subcontinent. The low-latitudinal cyclones (LLCs, originating between 5°N–10°N) constitute ≈40% of TCs formed in the BoB. We investigate the interannual variability of post-monsoonal (October to December) BoB LLCs and their teleconnection with ENSO and IOD. It is found that the years with the fewer number of BoB LLCs are associated with anomalous equatorial easterlies that are largely connected with the El Niño and positive IOD. Likewise, equatorial westerly phases, often associated with the La Niña and negative IOD years, favor the LLC formation by providing the initial spin-up required for cyclogenesis. This teleconnection between ENSO/IOD and BoB TC frequency is confined in the low-latitudinal region with little influence on cyclogenesis north of 10°N during ENSO and IOD except during negative IOD. These results may help extend the lead time and improve the seasonal prediction of BoB TCs.