Eastern Pacific hurricane season sparks into life

After a very slow start, cyclones are coming thick and fast, in one region.

Tropical Storm Estelle has developed, and looks to be following a similar track to its predecessors [EPA]

There has been a marked lack of cyclone activity in the Pacific in 2016.

In the western part of the Basin, the only cyclone (typhoon) to date was Typhoon Napartak, which hit Taiwan on July 7.

If the season here, which runs throughout the year, is to yield anything approaching an average number of cyclones (around 16), activity will have to increase very sharply.

The lack of activity is directly related to the decline of El Nino, which peaked in late 2015, and the expected development of La Nina later in the year.

Put very simply, El Nino results in a warming of the surface waters of the central and eastern Pacific, and La Nina results in a cooling.

As cyclones generally require a sea surface temperature of at least 26.5C for the formation, any cooling hinders their development.

The Pacific is the world’s largest ocean, and on the eastern side, things are very different. Here the cyclone (hurricane) season has really come to life in recent days.

After a quiet first half of the year, things sparked into life on 2 July with the formation of Tropical Storm Agatha. This was followed in quick succession by hurricanes Blas, Celia and Darby.

All were “fish storms”, heading out into open water. In the past couple of days, Tropical Storm Estelle has developed, and looks to be following a similar track to its predecessors. It, too, is expected to attain hurricane status by Monday.

This burst of activity is thought to be linked to what is known as the Madden-Julian oscillation (MJO). The MJO, discovered only as recently as 1971, is an atmospheric disturbance which travels from Asia to the Americas on a repeating 30 to 60-day cycle.

Its main impact is on increases and decreases in rain across the tropics, but it is also known to have a positive impact on hurricane formation in the northeastern Pacific.

The MJO could persist in the region long enough to spawn another tropical storm, which would be named Frank. If Frank does develop, that would be six storms in July, just one short of the monthly record of seven set in 1985.

Source: Al Jazeera, News Agencies