Jun 7, 2002 3 min read

WASHINGTON (AP) – El Nino conditions continued to develop in the equatorial Pacific in May as ocean surface temperatures increased. In a large portion of the Pacific, including along the coasts of Ecuador and Peru, temperatures were 1.8 degrees Fahrenheit above normal, the federal Climate Prediction Center reported Thursday.

This represents a “significant transition” from local warm areas earlier in the year toward a more extensive basinwide warming typical of El Nino, the center said.

This increase in ocean temperature, combined with observations of abnormally heavy rainfall in parts of South America and the lack of rain over Indonesia, indicates that El Nino is continuing to develop.

The El Nino climate phenomenon can affect weather around the world, but the impact should be less than during the strong El Nino of 1997-98, according to forecasters at the National Oceanic and Atmospheric Administration.

El Nino is characterized by an abnormally warm sea surface in the central equatorial Pacific Ocean.

This results in increased evaporation and rising air currents that can affect the winds overhead that steer the movement of weather. The new warming resulted from a weakening of the east winds that normally blow across that portion of the Pacific.

In late April and during the last half of May the low-level equatorial easterly winds substantially weakened throughout the Pacific, followed by an increase in sea temperature.

Buoy data indicate that the oceanic thermocline – the boundary between warm surface water and cold water below – has deepened east of the International date line since mid-May, consistent with the oceanwide weakening of the winds.

While some month-to-month variability is likely, indications are that the El Nino will continue to develop, the center reported.

Normally, El Nino does not significantly affect the United States during summer, although it does historically tend to suppress Atlantic hurricane activity.

However, NOAA forecasters feel El Nino will probably not be strong enough to affect hurricane activity this year.

El Nino can affect weather worldwide including causing winter storms to be more vigorous along the Pacific coasts of Canada, Alaska and the U.S. Northwest. Winter storms also tend to be more vigorous in the Gulf of Mexico and along the southeast coast of the United States, resulting in wetter-than-normal conditions in that region.

Other effects can include causing abnormally dry conditions over northern Australia, Indonesia and the Philippines, drier-than-normal conditions over southeastern Africa and northern Brazil and reduced Indian monsoon rainfall.

It tends to produce wetter-than-normal conditions along the west coast of tropical South America and from southern Brazil to central Argentina.