On the peculiar storm track of TC Favio during the 2006–2007 Southwest Indian Ocean tropical cyclone season and relationships to ENSO

Summary

The 2006–2007 Southern Indian Ocean tropical cyclone season proved to be devastating for the already flood-ravaged coastline of Mozambique. The landfall of Tropical Cyclone Favio on 22 February 2007 led to several deaths and considerable damage. A unique aspect of Tropical Cyclone Favio was its westward track around the southern tip of Madagascar and then northwestwards through the Mozambique Channel to make landfall in southern Mozambique – most tropical cyclones in this region track southeastwards after approaching Madagascar and recurve back into the South Indian Ocean. In addition to its track, Tropical Cyclone Favio was highly unusual in that it made landfall in Mozambique during an El Niño year, an occurrence that has only happened one other time in the known record. It is shown that the impacts of the 2006–2007 El Niño over the South Indian Ocean (in terms of sea surface temperature and atmospheric circulation) were very different from previous El Niño events, thus helping to create more favourable conditions for landfall than would otherwise be expected. An analysis relating the unusual behaviour of Favio to the large scale climate mode patterns in 2006–2007 is presented. It is concluded that the unique track and anomalous landfall of Tropical Cyclone Favio are related and that seasonally-based statistical models for predicting the risk of landfall in Mozambique should be adjusted to accommodate anomalous circulation patterns that occur on synoptic to intraseasonal scales.