Australia’s BOM sees weak trade winds hastening La Nina’s decline

Australia’s Bureau of Meteorology has warned that the decline of the La Nina phenomenon is likely to be hastened by a shift in trade winds in its latest El Nino wrap up, issued Tuesday.

The weather phenomenon, which is often associated with drier weather across key parts of South America, is declining according to the bureau’s observation of sea surface temperatures in the central Tropical Pacific region.

While sea surface temperature patterns indicate a weak La Nina is still in place, a weakening in western Pacific trade winds has arisen after a separate tropical weather phenomenon brought heavy monsoon activity to Australia. 

"The rapid weakening of the trade winds may hasten the decline of La Nina," the BOM’s ENSO wrap-up states, but warns that the event is likely to be felt into the late southern hemisphere summer, with some models expecting it to linger into autumn.

El Nino and its counterpart La Nina can have a profound impact on agricultural markets, with the current La Nina condition often cited as the cause of drier weather across key parts of Argentina and Brazil.

The dryness across Argentina and southern Brazil have seen downward revisions made to soybean and corn production expectations from those countries.

South Africa has also seen a prolonged period of drought which may also affect the country’s corn production.