Scientists gain better view on how weather forms

By Mark Lawin

SAN FRANCISCO (Reuters) - Climate scientists said on Tuesday they have begun using information from a tropical phenomenon that may give them a one to three-week jump on hurricanes, cyclones, monsoons and other weather patterns.

Traditional weather forecasts normally range from single hours up to five days ahead. But scientists at an American Geophysical Union conference in San Francisco said that they may be able to use data from the tropical weather pattern known as the Madden-Julian Oscillation, or MJO, to improve their understanding of looming weather developments.

Discovered in 1971 by Roland Madden and Paul Julian, the Madden-Julian Oscillation is a large, slowly evolving weather event originating in the tropics that affects weather globally.

MJOs happen about two to six times a year over a 40-to-50 day cycle that includes periods of high and low precipitation.

MJO data has revealed their direct influence upon mid-latitude weather, summer monsoons, hurricane development as well as El Nino and La Nina weather events.

The data help accurately forecast the onset of and breaks in monsoons in Southeast Asia, which have economic consequences.

"We believe this data has important implications in regards to MJO effects on agriculture production," said Duane Waliser of the NASA Jet Propulsion Laboratory and the US CLIVAR, a climate science consortium.

Waliser said MJOs move in an eastward direction across the planet and directly influence weather downstream from them, including hurricane development in the Atlantic Ocean.